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const char *
gnutls_pk_algorithm_get_name (gnutls_pk_algorithm_t algorithm
);
Convert a gnutls_pk_algorithm_t value to a string.
const char *
gnutls_sign_algorithm_get_name (gnutls_sign_algorithm_t sign
);
Convert a gnutls_sign_algorithm_t value to a string.
int gnutls_init (gnutls_session_t *session
,gnutls_connection_end_t con_end
);
This function initializes the current session to null. Every
session must be initialized before use, so internal structures can
be allocated. This function allocates structures which can only
be free'd by calling gnutls_deinit()
. Returns zero on success.
con_end
can be one of GNUTLS_CLIENT
and GNUTLS_SERVER
.
session |
is a pointer to a gnutls_session_t structure. |
|
con_end |
indicate if this session is to be used for server or client. |
void
gnutls_deinit (gnutls_session_t session
);
This function clears all buffers associated with the session
.
This function will also remove session data from the session
database if the session was terminated abnormally.
int gnutls_bye (gnutls_session_t session
,gnutls_close_request_t how
);
Terminates the current TLS/SSL connection. The connection should
have been initiated using gnutls_handshake()
. how
should be one
of GNUTLS_SHUT_RDWR
, GNUTLS_SHUT_WR
.
In case of GNUTLS_SHUT_RDWR
then the TLS connection gets
terminated and further receives and sends will be disallowed. If
the return value is zero you may continue using the connection.
GNUTLS_SHUT_RDWR
actually sends an alert containing a close
request and waits for the peer to reply with the same message.
In case of GNUTLS_SHUT_WR
then the TLS connection gets terminated
and further sends will be disallowed. In order to reuse the
connection you should wait for an EOF from the peer.
GNUTLS_SHUT_WR
sends an alert containing a close request.
Note that not all implementations will properly terminate a TLS connection. Some of them, usually for performance reasons, will terminate only the underlying transport layer, thus causing a transmission error to the peer. This error cannot be distinguished from a malicious party prematurely terminating the session, thus this behavior is not recommended.
This function may also return GNUTLS_E_AGAIN
or
GNUTLS_E_INTERRUPTED
; cf. gnutls_record_get_direction()
.
GNUTLS_E_SUCCESS
on success, or an error code, see
function documentation for entire semantics.
int
gnutls_handshake (gnutls_session_t session
);
This function does the handshake of the TLS/SSL protocol, and initializes the TLS connection.
This function will fail if any problem is encountered, and will return a negative error code. In case of a client, if the client has asked to resume a session, but the server couldn't, then a full handshake will be performed.
The non-fatal errors such as GNUTLS_E_AGAIN
and
GNUTLS_E_INTERRUPTED
interrupt the handshake procedure, which
should be later be resumed. Call this function again, until it
returns 0; cf. gnutls_record_get_direction()
and
gnutls_error_is_fatal()
.
If this function is called by a server after a rehandshake request
then GNUTLS_E_GOT_APPLICATION_DATA
or
GNUTLS_E_WARNING_ALERT_RECEIVED
may be returned. Note that these
are non fatal errors, only in the specific case of a rehandshake.
Their meaning is that the client rejected the rehandshake request or
in the case of GNUTLS_E_GOT_APPLICATION_DATA
it might also mean that
some data were pending.
int
gnutls_rehandshake (gnutls_session_t session
);
This function will renegotiate security parameters with the client. This should only be called in case of a server.
This message informs the peer that we want to renegotiate parameters (perform a handshake).
If this function succeeds (returns 0), you must call the
gnutls_handshake()
function in order to negotiate the new
parameters.
Since TLS is full duplex some application data might have been
sent during peer's processing of this message. In that case
one should call gnutls_record_recv()
until GNUTLS_E_REHANDSHAKE
is returned to clear any pending data. Care must be taken if
rehandshake is mandatory to terminate if it does not start after
some threshold.
If the client does not wish to renegotiate parameters he will
should with an alert message, thus the return code will be
GNUTLS_E_WARNING_ALERT_RECEIVED
and the alert will be
GNUTLS_A_NO_RENEGOTIATION
. A client may also choose to ignore
this message.
gnutls_alert_description_t
gnutls_alert_get (gnutls_session_t session
);
This function will return the last alert number received. This
function should be called if GNUTLS_E_WARNING_ALERT_RECEIVED
or
GNUTLS_E_FATAL_ALERT_RECEIVED
has been returned by a gnutls
function. The peer may send alerts if he thinks some things were
not right. Check gnutls.h for the available alert descriptions.
If no alert has been received the returned value is undefined.
int gnutls_alert_send (gnutls_session_t session
,gnutls_alert_level_t level
,gnutls_alert_description_t desc
);
This function will send an alert to the peer in order to inform him of something important (eg. his Certificate could not be verified). If the alert level is Fatal then the peer is expected to close the connection, otherwise he may ignore the alert and continue.
The error code of the underlying record send function will be
returned, so you may also receive GNUTLS_E_INTERRUPTED
or
GNUTLS_E_AGAIN
as well.
session |
is a gnutls_session_t structure. |
|
level |
is the level of the alert |
|
desc |
is the alert description |
int gnutls_alert_send_appropriate (gnutls_session_t session
,int err
);
Sends an alert to the peer depending on the error code returned by
a gnutls function. This function will call gnutls_error_to_alert()
to determine the appropriate alert to send.
This function may also return GNUTLS_E_AGAIN
, or
GNUTLS_E_INTERRUPTED
.
If the return value is GNUTLS_E_INVALID_REQUEST
, then no alert has
been sent to the peer.
const char *
gnutls_alert_get_name (gnutls_alert_description_t alert
);
This function will return a string that describes the given alert
number, or NULL
. See gnutls_alert_get()
.
gnutls_sec_param_t gnutls_pk_bits_to_sec_param (gnutls_pk_algorithm_t algo
,unsigned int bits
);
This is the inverse of gnutls_sec_param_to_pk_bits()
. Given an algorithm
and the number of bits, it will return the security parameter. This is
a rough indication.
const char *
gnutls_sec_param_get_name (gnutls_sec_param_t param
);
Convert a gnutls_sec_param_t value to a string.
unsigned int gnutls_sec_param_to_pk_bits (gnutls_pk_algorithm_t algo
,gnutls_sec_param_t param
);
When generating private and public key pairs a difficult question is which size of "bits" the modulus will be in RSA and the group size in DSA. The easy answer is 1024, which is also wrong. This function will convert a human understandable security parameter to an appropriate size for the specific algorithm.
gnutls_cipher_algorithm_t
gnutls_cipher_get (gnutls_session_t session
);
Get currently used cipher.
gnutls_kx_algorithm_t
gnutls_kx_get (gnutls_session_t session
);
Get currently used key exchange algorithm.
gnutls_mac_algorithm_t
gnutls_mac_get (gnutls_session_t session
);
Get currently used MAC algorithm.
gnutls_compression_method_t
gnutls_compression_get (gnutls_session_t session
);
Get currently used compression algorithm.
gnutls_certificate_type_t
gnutls_certificate_type_get (gnutls_session_t session
);
The certificate type is by default X.509, unless it is negotiated as a TLS extension.
int gnutls_sign_algorithm_get_requested (gnutls_session_t session
,size_t indx
,gnutls_sign_algorithm_t *algo
);
Returns the signature algorithm specified by index that was
requested by the peer. If the specified index has no data available
this function returns GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE
. If
the negotiated TLS version does not support signature algorithms
then GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE
will be returned even
for the first index. The first index is 0.
This function is useful in the certificate callback functions to assist in selecting the correct certificate.
session |
is a gnutls_session_t structure. |
|
indx |
is an index of the signature algorithm to return |
|
algo |
the returned certificate type will be stored there |
Since: 2.10.0
size_t
gnutls_cipher_get_key_size (gnutls_cipher_algorithm_t algorithm
);
Get key size for cipher.
size_t
gnutls_mac_get_key_size (gnutls_mac_algorithm_t algorithm
);
Get size of MAC key.
const char *
gnutls_cipher_get_name (gnutls_cipher_algorithm_t algorithm
);
Convert a gnutls_cipher_algorithm_t type to a string.
const char *
gnutls_mac_get_name (gnutls_mac_algorithm_t algorithm
);
Convert a gnutls_mac_algorithm_t value to a string.
const char *
gnutls_compression_get_name (gnutls_compression_method_t algorithm
);
Convert a gnutls_compression_method_t value to a string.
const char *
gnutls_kx_get_name (gnutls_kx_algorithm_t algorithm
);
Convert a gnutls_kx_algorithm_t value to a string.
const char *
gnutls_certificate_type_get_name (gnutls_certificate_type_t type
);
Convert a gnutls_certificate_type_t type to a string.
const char *
gnutls_pk_get_name (gnutls_pk_algorithm_t algorithm
);
Convert a gnutls_pk_algorithm_t value to a string.
a pointer to a string that contains the name of the
specified public key algorithm, or NULL
.
Since: 2.6.0
const char *
gnutls_sign_get_name (gnutls_sign_algorithm_t algorithm
);
Convert a gnutls_sign_algorithm_t value to a string.
a pointer to a string that contains the name of the
specified public key signature algorithm, or NULL
.
Since: 2.6.0
gnutls_mac_algorithm_t
gnutls_mac_get_id (const char *name
);
Convert a string to a gnutls_mac_algorithm_t value. The names are compared in a case insensitive way.
a gnutls_mac_algorithm_t id of the specified MAC
algorithm string, or GNUTLS_MAC_UNKNOWN
on failures.
gnutls_compression_method_t
gnutls_compression_get_id (const char *name
);
The names are compared in a case insensitive way.
gnutls_cipher_algorithm_t
gnutls_cipher_get_id (const char *name
);
The names are compared in a case insensitive way.
return a gnutls_cipher_algorithm_t value corresponding to
the specified cipher, or GNUTLS_CIPHER_UNKNOWN
on error.
gnutls_kx_algorithm_t
gnutls_kx_get_id (const char *name
);
Convert a string to a gnutls_kx_algorithm_t value. The names are compared in a case insensitive way.
gnutls_protocol_t
gnutls_protocol_get_id (const char *name
);
The names are compared in a case insensitive way.
gnutls_certificate_type_t
gnutls_certificate_type_get_id (const char *name
);
The names are compared in a case insensitive way.
a gnutls_certificate_type_t for the specified in a
string certificate type, or GNUTLS_CRT_UNKNOWN
on error.
gnutls_pk_algorithm_t
gnutls_pk_get_id (const char *name
);
Convert a string to a gnutls_pk_algorithm_t value. The names are
compared in a case insensitive way. For example,
gnutls_pk_get_id("RSA") will return GNUTLS_PK_RSA
.
a gnutls_pk_algorithm_t id of the specified public key
algorithm string, or GNUTLS_PK_UNKNOWN
on failures.
Since: 2.6.0
gnutls_sign_algorithm_t
gnutls_sign_get_id (const char *name
);
The names are compared in a case insensitive way.
return a gnutls_sign_algorithm_t value corresponding to
the specified cipher, or GNUTLS_SIGN_UNKNOWN
on error.
const gnutls_cipher_algorithm_t *
gnutls_cipher_list (void
);
Get a list of supported cipher algorithms. Note that not necessarily all ciphers are supported as TLS cipher suites. For example, DES is not supported as a cipher suite, but is supported for other purposes (e.g., PKCS#8 or similar).
a zero-terminated list of gnutls_cipher_algorithm_t integers indicating the available ciphers.
const gnutls_mac_algorithm_t *
gnutls_mac_list (void
);
Get a list of hash algorithms for use as MACs. Note that not necessarily all MACs are supported in TLS cipher suites. For example, MD2 is not supported as a cipher suite, but is supported for other purposes (e.g., X.509 signature verification or similar).
Return a zero-terminated list of gnutls_mac_algorithm_t integers indicating the available MACs.
const gnutls_compression_method_t *
gnutls_compression_list (void
);
Get a list of compression methods. Note that to be able to use LZO
compression, you must link to libgnutls-extra and call
gnutls_global_init_extra()
.
a zero-terminated list of gnutls_compression_method_t integers indicating the available compression methods.
const gnutls_protocol_t *
gnutls_protocol_list (void
);
Get a list of supported protocols, e.g. SSL 3.0, TLS 1.0 etc.
const gnutls_certificate_type_t *
gnutls_certificate_type_list (void
);
Get a list of certificate types. Note that to be able to use
OpenPGP certificates, you must link to libgnutls-extra and call
gnutls_global_init_extra()
.
a zero-terminated list of gnutls_certificate_type_t integers indicating the available certificate types.
const gnutls_kx_algorithm_t *
gnutls_kx_list (void
);
Get a list of supported key exchange algorithms.
a zero-terminated list of gnutls_kx_algorithm_t integers indicating the available key exchange algorithms.
const gnutls_pk_algorithm_t *
gnutls_pk_list (void
);
Get a list of supported public key algorithms.
Since: 2.6.0
const gnutls_sign_algorithm_t *
gnutls_sign_list (void
);
Get a list of supported public key signature algorithms.
a zero-terminated list of gnutls_sign_algorithm_t integers indicating the available ciphers.
const char * gnutls_cipher_suite_info (size_t idx
,char *cs_id
,gnutls_kx_algorithm_t *kx
,gnutls_cipher_algorithm_t *cipher
,gnutls_mac_algorithm_t *mac
,gnutls_protocol_t *version
);
Get information about supported cipher suites. Use the function iteratively to get information about all supported cipher suites. Call with idx=0 to get information about first cipher suite, then idx=1 and so on until the function returns NULL.
idx |
index of cipher suite to get information about, starts on 0. |
|
cs_id |
output buffer with room for 2 bytes, indicating cipher suite value |
|
kx |
output variable indicating key exchange algorithm, or |
|
cipher |
output variable indicating cipher, or |
|
mac |
output variable indicating MAC algorithm, or |
|
version |
output variable indicating TLS protocol version, or |
int
gnutls_error_is_fatal (int error
);
If a GnuTLS function returns a negative value you may feed that value to this function to see if the error condition is fatal.
Note that you may want to check the error code manually, since some non-fatal errors to the protocol may be fatal for you program.
This function is only useful if you are dealing with errors from the record layer or the handshake layer.
int gnutls_error_to_alert (int err
,int *level
);
Get an alert depending on the error code returned by a gnutls
function. All alerts sent by this function should be considered
fatal. The only exception is when err
is GNUTLS_E_REHANDSHAKE
,
where a warning alert should be sent to the peer indicating that no
renegotiation will be performed.
If there is no mapping to a valid alert the alert to indicate internal error is returned.
void
gnutls_perror (int error
);
This function is like perror()
. The only difference is that it
accepts an error number returned by a gnutls function.
const char *
gnutls_strerror (int error
);
This function is similar to strerror. The difference is that it
accepts an error number returned by a gnutls function; In case of
an unknown error a descriptive string is sent instead of NULL
.
Error codes are always a negative value.
const char *
gnutls_strerror_name (int error
);
Return the GnuTLS error code define as a string. For example, gnutls_strerror_name (GNUTLS_E_DH_PRIME_UNACCEPTABLE) will return the string "GNUTLS_E_DH_PRIME_UNACCEPTABLE".
Since: 2.6.0
void gnutls_handshake_set_private_extensions (gnutls_session_t session
,int allow
);
This function will enable or disable the use of private cipher
suites (the ones that start with 0xFF). By default or if allow
is 0 then these cipher suites will not be advertized nor used.
Unless this function is called with the option to allow (1), then no compression algorithms, like LZO. That is because these algorithms are not yet defined in any RFC or even internet draft.
Enabling the private ciphersuites when talking to other than gnutls servers and clients may cause interoperability problems.
gnutls_handshake_description_t
gnutls_handshake_get_last_out (gnutls_session_t session
);
This function is only useful to check where the last performed handshake failed. If the previous handshake succeed or was not performed at all then no meaningful value will be returned.
Check gnutls_handshake_description_t
in gnutls.h for the
available handshake descriptions.
gnutls_handshake_description_t
gnutls_handshake_get_last_in (gnutls_session_t session
);
This function is only useful to check where the last performed handshake failed. If the previous handshake succeed or was not performed at all then no meaningful value will be returned.
Check gnutls_handshake_description_t
in gnutls.h for the
available handshake descriptions.
ssize_t gnutls_record_send (gnutls_session_t session
,const void *data
,size_t sizeofdata
);
This function has the similar semantics with send()
. The only
difference is that it accepts a GnuTLS session, and uses different
error codes.
Note that if the send buffer is full, send()
will block this
function. See the send()
documentation for full information. You
can replace the default push function by using
gnutls_transport_set_ptr2()
with a call to send()
with a
MSG_DONTWAIT flag if blocking is a problem.
If the EINTR is returned by the internal push function (the
default is send()
} then GNUTLS_E_INTERRUPTED
will be returned. If
GNUTLS_E_INTERRUPTED
or GNUTLS_E_AGAIN
is returned, you must
call this function again, with the same parameters; alternatively
you could provide a NULL
pointer for data, and 0 for
size. cf. gnutls_record_get_direction()
.
session |
is a gnutls_session_t structure. |
|
data |
contains the data to send |
|
sizeofdata |
is the length of the data |
ssize_t gnutls_record_recv (gnutls_session_t session
,void *data
,size_t sizeofdata
);
This function has the similar semantics with recv()
. The only
difference is that it accepts a GnuTLS session, and uses different
error codes.
In the special case that a server requests a renegotiation, the
client may receive an error code of GNUTLS_E_REHANDSHAKE
. This
message may be simply ignored, replied with an alert
GNUTLS_A_NO_RENEGOTIATION
, or replied with a new handshake,
depending on the client's will.
If EINTR
is returned by the internal push function (the default
is recv()
) then GNUTLS_E_INTERRUPTED
will be returned. If
GNUTLS_E_INTERRUPTED
or GNUTLS_E_AGAIN
is returned, you must
call this function again to get the data. See also
gnutls_record_get_direction()
.
A server may also receive GNUTLS_E_REHANDSHAKE
when a client has
initiated a handshake. In that case the server can only initiate a
handshake or terminate the connection.
session |
is a gnutls_session_t structure. |
|
data |
the buffer that the data will be read into |
|
sizeofdata |
the number of requested bytes |
void
gnutls_session_enable_compatibility_mode
(gnutls_session_t session
);
This function can be used to disable certain (security) features in
TLS in order to maintain maximum compatibility with buggy
clients. It is equivalent to calling:
gnutls_record_disable_padding()
Normally only servers that require maximum compatibility with everything out there, need to call this function.
void
gnutls_record_disable_padding (gnutls_session_t session
);
Used to disabled padding in TLS 1.0 and above. Normally you do not need to use this function, but there are buggy clients that complain if a server pads the encrypted data. This of course will disable protection against statistical attacks on the data.
Normally only servers that require maximum compatibility with everything out there, need to call this function.
int
gnutls_record_get_direction (gnutls_session_t session
);
This function provides information about the internals of the
record protocol and is only useful if a prior gnutls function call
(e.g. gnutls_handshake()
) was interrupted for some reason, that
is, if a function returned GNUTLS_E_INTERRUPTED
or
GNUTLS_E_AGAIN
. In such a case, you might want to call select()
or poll()
before calling the interrupted gnutls function again. To
tell you whether a file descriptor should be selected for either
reading or writing, gnutls_record_get_direction()
returns 0 if the
interrupted function was trying to read data, and 1 if it was
trying to write data.
size_t
gnutls_record_get_max_size (gnutls_session_t session
);
Get the record size. The maximum record size is negotiated by the client after the first handshake message.
ssize_t gnutls_record_set_max_size (gnutls_session_t session
,size_t size
);
This function sets the maximum record packet size in this connection. This property can only be set to clients. The server may choose not to accept the requested size.
Acceptable values are 512(=2^9), 1024(=2^10), 2048(=2^11) and 4096(=2^12). The requested record size does get in effect immediately only while sending data. The receive part will take effect after a successful handshake.
This function uses a TLS extension called 'max record size'. Not all TLS implementations use or even understand this extension.
size_t
gnutls_record_check_pending (gnutls_session_t session
);
This function checks if there are any data to receive in the gnutls buffers.
int gnutls_prf (gnutls_session_t session
,size_t label_size
,const char *label
,int server_random_first
,size_t extra_size
,const char *extra
,size_t outsize
,char *out
);
Apply the TLS Pseudo-Random-Function (PRF) using the master secret on some data, seeded with the client and server random fields.
The label
variable usually contain a string denoting the purpose
for the generated data. The server_random_first
indicate whether
the client random field or the server random field should be first
in the seed. Non-0 indicate that the server random field is first,
0 that the client random field is first.
The extra
variable can be used to add more data to the seed, after
the random variables. It can be used to tie make sure the
generated output is strongly connected to some additional data
(e.g., a string used in user authentication).
The output is placed in *OUT
, which must be pre-allocated.
session |
is a gnutls_session_t structure. |
|
label_size |
length of the |
|
label |
label used in PRF computation, typically a short string. |
|
server_random_first |
non-0 if server random field should be first in seed |
|
extra_size |
length of the |
|
extra |
optional extra data to seed the PRF with. |
|
outsize |
size of pre-allocated output buffer to hold the output. |
|
out |
pre-allocate buffer to hold the generated data. |
int gnutls_prf_raw (gnutls_session_t session
,size_t label_size
,const char *label
,size_t seed_size
,const char *seed
,size_t outsize
,char *out
);
Apply the TLS Pseudo-Random-Function (PRF) using the master secret on some data.
The label
variable usually contain a string denoting the purpose
for the generated data. The seed
usually contain data such as the
client and server random, perhaps together with some additional
data that is added to guarantee uniqueness of the output for a
particular purpose.
Because the output is not guaranteed to be unique for a particular
session unless seed
include the client random and server random
fields (the PRF would output the same data on another connection
resumed from the first one), it is not recommended to use this
function directly. The gnutls_prf()
function seed the PRF with the
client and server random fields directly, and is recommended if you
want to generate pseudo random data unique for each session.
session |
is a gnutls_session_t structure. |
|
label_size |
length of the |
|
label |
label used in PRF computation, typically a short string. |
|
seed_size |
length of the |
|
seed |
optional extra data to seed the PRF with. |
|
outsize |
size of pre-allocated output buffer to hold the output. |
|
out |
pre-allocate buffer to hold the generated data. |
int (*gnutls_ext_recv_func) (gnutls_session_t session
,const unsigned char *data
,size_t len
);
int (*gnutls_ext_send_func) (gnutls_session_t session
,unsigned char *data
,size_t len
);
int gnutls_server_name_set (gnutls_session_t session
,gnutls_server_name_type_t type
,const void *name
,size_t name_length
);
This function is to be used by clients that want to inform (via a TLS extension mechanism) the server of the name they connected to. This should be used by clients that connect to servers that do virtual hosting.
The value of name
depends on the type
type. In case of
GNUTLS_NAME_DNS
, an ASCII zero-terminated domain name string,
without the trailing dot, is expected. IPv4 or IPv6 addresses are
not permitted.
session |
is a gnutls_session_t structure. |
|
type |
specifies the indicator type |
|
name |
is a string that contains the server name. |
|
name_length |
holds the length of name |
int gnutls_server_name_get (gnutls_session_t session
,void *data
,size_t *data_length
,unsigned int *type
,unsigned int indx
);
This function will allow you to get the name indication (if any), a client has sent. The name indication may be any of the enumeration gnutls_server_name_type_t.
If type
is GNUTLS_NAME_DNS, then this function is to be used by
servers that support virtual hosting, and the data will be a null
terminated UTF-8 string.
If data
has not enough size to hold the server name
GNUTLS_E_SHORT_MEMORY_BUFFER is returned, and data_length
will
hold the required size.
index
is used to retrieve more than one server names (if sent by
the client). The first server name has an index of 0, the second 1
and so on. If no name with the given index exists
GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE is returned.
session |
is a gnutls_session_t structure. |
|
data |
will hold the data |
|
data_length |
will hold the data length. Must hold the maximum size of data. |
|
type |
will hold the server name indicator type |
|
indx |
is the index of the server_name |
int
gnutls_safe_renegotiation_status (gnutls_session_t session
);
Can be used to check whether safe renegotiation is being used in the current session.
Since: 2.10.0
int
gnutls_session_ticket_key_generate (gnutls_datum_t *key
);
Generate a random key to encrypt security parameters within SessionTicket.
Since: 2.10.0
int
gnutls_session_ticket_enable_client (gnutls_session_t session
);
Request that the client should attempt session resumption using SessionTicket.
Since: 2.10.0
int gnutls_session_ticket_enable_server (gnutls_session_t session
,const gnutls_datum_t *key
);
Request that the server should attempt session resumption using
SessionTicket. key
must be initialized with
gnutls_session_ticket_key_generate()
.
Since: 2.10.0
int gnutls_priority_init (gnutls_priority_t *priority_cache
,const char *priorities
,const char **err_pos
);
Sets priorities for the ciphers, key exchange methods, macs and compression methods.
The priorities option allows you to specify a colon separated list of the cipher priorities to enable.
Common keywords: Some keywords are defined to provide quick access to common preferences.
"PERFORMANCE" means all the "secure" ciphersuites are enabled, limited to 128 bit ciphers and sorted by terms of speed performance.
"NORMAL" means all "secure" ciphersuites. The 256-bit ciphers are included as a fallback only. The ciphers are sorted by security margin.
"SECURE128" means all "secure" ciphersuites with ciphers up to 128 bits, sorted by security margin.
"SECURE256" means all "secure" ciphersuites including the 256 bit ciphers, sorted by security margin.
"EXPORT" means all ciphersuites are enabled, including the low-security 40 bit ciphers.
"NONE" means nothing is enabled. This disables even protocols and compression methods.
Special keywords: "!" or "-" appended with an algorithm will remove this algorithm.
"+" appended with an algorithm will add this algorithm.
Check the GnuTLS manual section "Priority strings" for detailed information.
Examples:
"NONE:+VERS-TLS-ALL:+MAC-ALL:+RSA:+AES-128-CBC:+SIGN-ALL:+COMP-NULL"
"NORMAL:-ARCFOUR-128" means normal ciphers except for ARCFOUR-128.
"SECURE:-VERS-SSL3.0:+COMP-DEFLATE" means that only secure ciphers are enabled, SSL3.0 is disabled, and libz compression enabled.
"NONE:+VERS-TLS-ALL:+AES-128-CBC:+RSA:+SHA1:+COMP-NULL:+SIGN-RSA-SHA1",
"NORMAL:COMPAT
" is the most compatible mode.
priority_cache |
is a gnutls_prioritity_t structure. |
|
priorities |
is a string describing priorities |
|
err_pos |
In case of an error this will have the position in the string the error occured |
On syntax error GNUTLS_E_INVALID_REQUEST
is returned,
GNUTLS_E_SUCCESS
on success, or an error code.
void
gnutls_priority_deinit (gnutls_priority_t priority_cache
);
Deinitializes the priority cache.
int gnutls_priority_set (gnutls_session_t session
,gnutls_priority_t priority
);
Sets the priorities to use on the ciphers, key exchange methods, macs and compression methods.
int gnutls_priority_set_direct (gnutls_session_t session
,const char *priorities
,const char **err_pos
);
Sets the priorities to use on the ciphers, key exchange methods,
macs and compression methods. This function avoids keeping a
priority cache and is used to directly set string priorities to a
TLS session. For documentation check the gnutls_priority_init()
.
session |
is a gnutls_session_t structure. |
|
priorities |
is a string describing priorities |
|
err_pos |
In case of an error this will have the position in the string the error occured |
On syntax error GNUTLS_E_INVALID_REQUEST
is returned,
GNUTLS_E_SUCCESS
on success, or an error code.
int
gnutls_set_default_priority (gnutls_session_t session
);
Sets some default priority on the ciphers, key exchange methods, macs and compression methods.
This is the same as calling:
gnutls_priority_set_direct (session, "NORMAL", NULL);
This function is kept around for backwards compatibility, but
because of its wide use it is still fully supported. If you wish
to allow users to provide a string that specify which ciphers to
use (which is recommended), you should use
gnutls_priority_set_direct()
or gnutls_priority_set()
instead.
int
gnutls_set_default_export_priority (gnutls_session_t session
);
Sets some default priority on the ciphers, key exchange methods, macs and compression methods. This function also includes weak algorithms.
This is the same as calling:
gnutls_priority_set_direct (session, "EXPORT", NULL);
This function is kept around for backwards compatibility, but
because of its wide use it is still fully supported. If you wish
to allow users to provide a string that specify which ciphers to
use (which is recommended), you should use
gnutls_priority_set_direct()
or gnutls_priority_set()
instead.
const char * gnutls_cipher_suite_get_name (gnutls_kx_algorithm_t kx_algorithm
,gnutls_cipher_algorithm_t cipher_algorithm
,gnutls_mac_algorithm_t mac_algorithm
);
Note that the full cipher suite name must be prepended by TLS or SSL depending of the protocol in use.
gnutls_protocol_t
gnutls_protocol_get_version (gnutls_session_t session
);
Get TLS version, a gnutls_protocol_t value.
const char *
gnutls_protocol_get_name (gnutls_protocol_t version
);
Convert a gnutls_protocol_t value to a string.
int gnutls_session_set_data (gnutls_session_t session
,const void *session_data
,size_t session_data_size
);
Sets all session parameters, in order to resume a previously
established session. The session data given must be the one
returned by gnutls_session_get_data()
. This function should be
called before gnutls_handshake()
.
Keep in mind that session resuming is advisory. The server may choose not to resume the session, thus a full handshake will be performed.
session |
is a gnutls_session_t structure. |
|
session_data |
is a pointer to space to hold the session. |
|
session_data_size |
is the session's size |
int gnutls_session_get_data (gnutls_session_t session
,void *session_data
,size_t *session_data_size
);
Returns all session parameters, in order to support resuming. The
client should call this, and keep the returned session, if he
wants to resume that current version later by calling
gnutls_session_set_data()
This function must be called after a
successful handshake.
Resuming sessions is really useful and speedups connections after a successful one.
session |
is a gnutls_session_t structure. |
|
session_data |
is a pointer to space to hold the session. |
|
session_data_size |
is the session_data's size, or it will be set by the function. |
int gnutls_session_get_data2 (gnutls_session_t session
,gnutls_datum_t *data
);
Returns all session parameters, in order to support resuming. The
client should call this, and keep the returned session, if he wants
to resume that current version later by calling
gnutls_session_set_data()
. This function must be called after a
successful handshake. The returned datum must be freed with
gnutls_free()
.
Resuming sessions is really useful and speedups connections after a successful one.
session |
is a gnutls_session_t structure. |
|
data |
is a pointer to a datum that will hold the session. |
int gnutls_session_get_id (gnutls_session_t session
,void *session_id
,size_t *session_id_size
);
Returns the current session id. This can be used if you want to check if the next session you tried to resume was actually resumed. This is because resumed sessions have the same sessionID with the original session.
Session id is some data set by the server, that identify the current session. In TLS 1.0 and SSL 3.0 session id is always less than 32 bytes.
session |
is a gnutls_session_t structure. |
|
session_id |
is a pointer to space to hold the session id. |
|
session_id_size |
is the session id's size, or it will be set by the function. |
int
gnutls_session_is_resumed (gnutls_session_t session
);
Check whether session is resumed or not.
int (*gnutls_db_store_func) (void *Param1
,gnutls_datum_t key
,gnutls_datum_t data
);
void gnutls_db_set_cache_expiration (gnutls_session_t session
,int seconds
);
Set the expiration time for resumed sessions. The default is 3600 (one hour) at the time writing this.
void
gnutls_db_remove_session (gnutls_session_t session
);
This function will remove the current session data from the
session database. This will prevent future handshakes reusing
these session data. This function should be called if a session
was terminated abnormally, and before gnutls_deinit()
is called.
Normally gnutls_deinit()
will remove abnormally terminated
sessions.
void gnutls_db_set_retrieve_function (gnutls_session_t session
,gnutls_db_retr_func retr_func
);
Sets the function that will be used to retrieve data from the resumed sessions database. This function must return a gnutls_datum_t containing the data on success, or a gnutls_datum_t containing null and 0 on failure.
The datum's data must be allocated using the function
gnutls_malloc()
.
The first argument to retr_func
will be null unless
gnutls_db_set_ptr()
has been called.
void gnutls_db_set_remove_function (gnutls_session_t session
,gnutls_db_remove_func rem_func
);
Sets the function that will be used to remove data from the resumed sessions database. This function must return 0 on success.
The first argument to rem_func
will be null unless
gnutls_db_set_ptr()
has been called.
void gnutls_db_set_store_function (gnutls_session_t session
,gnutls_db_store_func store_func
);
Sets the function that will be used to store data from the resumed sessions database. This function must remove 0 on success.
The first argument to store_func()
will be null unless
gnutls_db_set_ptr()
has been called.
void gnutls_db_set_ptr (gnutls_session_t session
,void *ptr
);
Sets the pointer that will be provided to db store, retrieve and delete functions, as the first argument.
int gnutls_db_check_entry (gnutls_session_t session
,gnutls_datum_t session_entry
);
Check if database entry has expired. This function is to be used when you want to clear unnesessary session which occupy space in your backend.
int
(*gnutls_handshake_post_client_hello_func)
(gnutls_session_t Param1
);
void gnutls_handshake_set_post_client_hello_function (gnutls_session_t session
,gnutls_handshake_post_client_hello_func func
);
This function will set a callback to be called after the client hello has been received (callback valid in server side only). This allows the server to adjust settings based on received extensions.
Those settings could be ciphersuites, requesting certificate, or anything else except for version negotiation (this is done before the hello message is parsed).
This callback must return 0 on success or a gnutls error code to terminate the handshake.
Warning: You should not use this function to terminate the handshake based on client input unless you know what you are doing. Before the handshake is finished there is no way to know if there is a man-in-the-middle attack being performed.
void gnutls_handshake_set_max_packet_length (gnutls_session_t session
,size_t max
);
This function will set the maximum size of all handshake messages.
Handshakes over this size are rejected with
GNUTLS_E_HANDSHAKE_TOO_LARGE
error code. The default value is
128kb which is typically large enough. Set this to 0 if you do not
want to set an upper limit.
The reason for restricting the handshake message sizes are to limit Denial of Service attacks.
const char *
gnutls_check_version (const char *req_version
);
Check GnuTLS Library version.
See GNUTLS_VERSION
for a suitable req_version
string.
void
gnutls_credentials_clear (gnutls_session_t session
);
Clears all the credentials previously set in this session.
int gnutls_credentials_set (gnutls_session_t session
,gnutls_credentials_type_t type
,void *cred
);
Sets the needed credentials for the specified type. Eg username,
password - or public and private keys etc. The cred
parameter is
a structure that depends on the specified type and on the current
session (client or server).
In order to minimize memory usage, and share credentials between
several threads gnutls keeps a pointer to cred, and not the whole
cred structure. Thus you will have to keep the structure allocated
until you call gnutls_deinit()
.
For GNUTLS_CRD_ANON
, cred
should be
gnutls_anon_client_credentials_t in case of a client. In case of
a server it should be gnutls_anon_server_credentials_t.
For GNUTLS_CRD_SRP
, cred
should be gnutls_srp_client_credentials_t
in case of a client, and gnutls_srp_server_credentials_t, in case
of a server.
For GNUTLS_CRD_CERTIFICATE
, cred
should be
gnutls_certificate_credentials_t.
session |
is a gnutls_session_t structure. |
|
type |
is the type of the credentials |
|
cred |
is a pointer to a structure. |
void
gnutls_anon_free_server_credentials (gnutls_anon_server_credentials_t sc
);
This structure is complex enough to manipulate directly thus this helper function is provided in order to free (deallocate) it.
int
gnutls_anon_allocate_server_credentials
(gnutls_anon_server_credentials_t *sc
);
This structure is complex enough to manipulate directly thus this helper function is provided in order to allocate it.
void gnutls_anon_set_server_dh_params (gnutls_anon_server_credentials_t res
,gnutls_dh_params_t dh_params
);
This function will set the Diffie-Hellman parameters for an anonymous server to use. These parameters will be used in Anonymous Diffie-Hellman cipher suites.
void gnutls_anon_set_server_params_function (gnutls_anon_server_credentials_t res
,gnutls_params_function *func
);
This function will set a callback in order for the server to get the Diffie-Hellman parameters for anonymous authentication. The callback should return zero on success.
void
gnutls_anon_free_client_credentials (gnutls_anon_client_credentials_t sc
);
This structure is complex enough to manipulate directly thus this helper function is provided in order to free (deallocate) it.
int
gnutls_anon_allocate_client_credentials
(gnutls_anon_client_credentials_t *sc
);
This structure is complex enough to manipulate directly thus this helper function is provided in order to allocate it.
void
gnutls_certificate_free_credentials (gnutls_certificate_credentials_t sc
);
This structure is complex enough to manipulate directly thus this helper function is provided in order to free (deallocate) it.
This function does not free any temporary parameters associated with this structure (ie RSA and DH parameters are not freed by this function).
int
gnutls_certificate_allocate_credentials
(gnutls_certificate_credentials_t *res
);
This structure is complex enough to manipulate directly thus this helper function is provided in order to allocate it.
void
gnutls_certificate_free_keys (gnutls_certificate_credentials_t sc
);
This function will delete all the keys and the certificates associated with the given credentials. This function must not be called when a TLS negotiation that uses the credentials is in progress.
void
gnutls_certificate_free_cas (gnutls_certificate_credentials_t sc
);
This function will delete all the CAs associated with the given
credentials. Servers that do not use
gnutls_certificate_verify_peers2()
may call this to save some
memory.
void
gnutls_certificate_free_ca_names (gnutls_certificate_credentials_t sc
);
This function will delete all the CA name in the given credentials. Clients may call this to save some memory since in client side the CA names are not used. Servers might want to use this function if a large list of trusted CAs is present and sending the names of it would just consume bandwidth without providing information to client.
CA names are used by servers to advertize the CAs they support to clients.
void
gnutls_certificate_free_crls (gnutls_certificate_credentials_t sc
);
This function will delete all the CRLs associated with the given credentials.
void gnutls_certificate_set_dh_params (gnutls_certificate_credentials_t res
,gnutls_dh_params_t dh_params
);
This function will set the Diffie-Hellman parameters for a certificate server to use. These parameters will be used in Ephemeral Diffie-Hellman cipher suites. Note that only a pointer to the parameters are stored in the certificate handle, so if you deallocate the parameters before the certificate is deallocated, you must change the parameters stored in the certificate first.
void gnutls_certificate_set_rsa_export_params (gnutls_certificate_credentials_t res
,gnutls_rsa_params_t rsa_params
);
This function will set the temporary RSA parameters for a certificate server to use. These parameters will be used in RSA-EXPORT cipher suites.
void gnutls_certificate_set_verify_flags (gnutls_certificate_credentials_t res
,unsigned int flags
);
This function will set the flags to be used at verification of the certificates. Flags must be OR of the gnutls_certificate_verify_flags enumerations.
void gnutls_certificate_set_verify_limits (gnutls_certificate_credentials_t res
,unsigned int max_bits
,unsigned int max_depth
);
This function will set some upper limits for the default
verification function, gnutls_certificate_verify_peers2()
, to avoid
denial of service attacks. You can set them to zero to disable
limits.
int gnutls_certificate_set_x509_trust_file (gnutls_certificate_credentials_t res
,const char *cafile
,gnutls_x509_crt_fmt_t type
);
This function adds the trusted CAs in order to verify client or
server certificates. In case of a client this is not required to
be called if the certificates are not verified using
gnutls_certificate_verify_peers2()
. This function may be called
multiple times.
In case of a server the names of the CAs set here will be sent to
the client if a certificate request is sent. This can be disabled
using gnutls_certificate_send_x509_rdn_sequence()
.
This function can also accept PKCS 11 URLs. In that case it will import all certificates that are marked as trusted.
int gnutls_certificate_set_x509_trust_mem (gnutls_certificate_credentials_t res
,const gnutls_datum_t *ca
,gnutls_x509_crt_fmt_t type
);
This function adds the trusted CAs in order to verify client or
server certificates. In case of a client this is not required to be
called if the certificates are not verified using
gnutls_certificate_verify_peers2()
. This function may be called
multiple times.
In case of a server the CAs set here will be sent to the client if
a certificate request is sent. This can be disabled using
gnutls_certificate_send_x509_rdn_sequence()
.
int gnutls_certificate_set_x509_crl_file (gnutls_certificate_credentials_t res
,const char *crlfile
,gnutls_x509_crt_fmt_t type
);
This function adds the trusted CRLs in order to verify client or server
certificates. In case of a client this is not required
to be called if the certificates are not verified using
gnutls_certificate_verify_peers2()
.
This function may be called multiple times.
int gnutls_certificate_set_x509_crl_mem (gnutls_certificate_credentials_t res
,const gnutls_datum_t *CRL
,gnutls_x509_crt_fmt_t type
);
This function adds the trusted CRLs in order to verify client or
server certificates. In case of a client this is not required to
be called if the certificates are not verified using
gnutls_certificate_verify_peers2()
. This function may be called
multiple times.
int gnutls_certificate_set_x509_key_file (gnutls_certificate_credentials_t res
,const char *certfile
,const char *keyfile
,gnutls_x509_crt_fmt_t type
);
This function sets a certificate/private key pair in the
gnutls_certificate_credentials_t structure. This function may be
called more than once (in case multiple keys/certificates exist for
the server). For clients that wants to send more than its own end
entity certificate (e.g., also an intermediate CA cert) then put
the certificate chain in certfile
.
Currently only PKCS-1 encoded RSA and DSA private keys are accepted by this function.
This function can also accept PKCS 11 URLs. In that case it will import the private key and certificate indicated by the urls.
int gnutls_certificate_set_x509_key_mem (gnutls_certificate_credentials_t res
,const gnutls_datum_t *cert
,const gnutls_datum_t *key
,gnutls_x509_crt_fmt_t type
);
This function sets a certificate/private key pair in the gnutls_certificate_credentials_t structure. This function may be called more than once (in case multiple keys/certificates exist for the server).
Currently are supported: RSA PKCS-1 encoded private keys, DSA private keys.
DSA private keys are encoded the OpenSSL way, which is an ASN.1 DER sequence of 6 INTEGERs - version, p, q, g, pub, priv.
Note that the keyUsage (2.5.29.15) PKIX extension in X.509 certificates is supported. This means that certificates intended for signing cannot be used for ciphersuites that require encryption.
If the certificate and the private key are given in PEM encoding then the strings that hold their values must be null terminated.
The key
may be NULL
if you are using a sign callback, see
gnutls_sign_callback_set()
.
void gnutls_certificate_send_x509_rdn_sequence (gnutls_session_t session
,int status
);
If status is non zero, this function will order gnutls not to send the rdnSequence in the certificate request message. That is the server will not advertize it's trusted CAs to the peer. If status is zero then the default behaviour will take effect, which is to advertize the server's trusted CAs.
This function has no effect in clients, and in authentication methods other than certificate with X.509 certificates.
int gnutls_certificate_set_x509_simple_pkcs12_file (gnutls_certificate_credentials_t res
,const char *pkcs12file
,gnutls_x509_crt_fmt_t type
,const char *password
);
This function sets a certificate/private key pair and/or a CRL in the gnutls_certificate_credentials_t structure. This function may be called more than once (in case multiple keys/certificates exist for the server).
MAC:ed PKCS12 files are supported. Encrypted PKCS12 bags are supported. Encrypted PKCS#8 private keys are supported. However, only password based security, and the same password for all operations, are supported.
The private keys may be RSA PKCS#1 or DSA private keys encoded in the OpenSSL way.
PKCS12 file may contain many keys and/or certificates, and there is no way to identify which key/certificate pair you want. You should make sure the PKCS12 file only contain one key/certificate pair and/or one CRL.
It is believed that the limitations of this function is acceptable for most usage, and that any more flexibility would introduce complexity that would make it harder to use this functionality at all.
int gnutls_certificate_set_x509_simple_pkcs12_mem (gnutls_certificate_credentials_t res
,const gnutls_datum_t *p12blob
,gnutls_x509_crt_fmt_t type
,const char *password
);
This function sets a certificate/private key pair and/or a CRL in the gnutls_certificate_credentials_t structure. This function may be called more than once (in case multiple keys/certificates exist for the server).
MAC:ed PKCS12 files are supported. Encrypted PKCS12 bags are supported. Encrypted PKCS#8 private keys are supported. However, only password based security, and the same password for all operations, are supported.
The private keys may be RSA PKCS#1 or DSA private keys encoded in the OpenSSL way.
PKCS12 file may contain many keys and/or certificates, and there is no way to identify which key/certificate pair you want. You should make sure the PKCS12 file only contain one key/certificate pair and/or one CRL.
It is believed that the limitations of this function is acceptable for most usage, and that any more flexibility would introduce complexity that would make it harder to use this functionality at all.
res |
is a gnutls_certificate_credentials_t structure. |
|
p12blob |
the PKCS12 blob. |
|
type |
is PEM or DER of the |
|
password |
optional password used to decrypt PKCS12 file, bags and keys. |
Since: 2.8.0
int gnutls_certificate_set_x509_key (gnutls_certificate_credentials_t res
,gnutls_x509_crt_t *cert_list
,int cert_list_size
,gnutls_x509_privkey_t key
);
This function sets a certificate/private key pair in the
gnutls_certificate_credentials_t structure. This function may be
called more than once (in case multiple keys/certificates exist for
the server). For clients that wants to send more than its own end
entity certificate (e.g., also an intermediate CA cert) then put
the certificate chain in cert_list
.
res |
is a gnutls_certificate_credentials_t structure. |
|
cert_list |
contains a certificate list (path) for the specified private key |
|
cert_list_size |
holds the size of the certificate list |
|
key |
is a gnutls_x509_privkey_t key |
Since: 2.4.0
int gnutls_certificate_set_x509_trust (gnutls_certificate_credentials_t res
,gnutls_x509_crt_t *ca_list
,int ca_list_size
);
This function adds the trusted CAs in order to verify client
or server certificates. In case of a client this is not required
to be called if the certificates are not verified using
gnutls_certificate_verify_peers2()
.
This function may be called multiple times.
In case of a server the CAs set here will be sent to the client if
a certificate request is sent. This can be disabled using
gnutls_certificate_send_x509_rdn_sequence()
.
res |
is a gnutls_certificate_credentials_t structure. |
|
ca_list |
is a list of trusted CAs |
|
ca_list_size |
holds the size of the CA list |
Since: 2.4.0
int gnutls_certificate_set_x509_crl (gnutls_certificate_credentials_t res
,gnutls_x509_crl_t *crl_list
,int crl_list_size
);
This function adds the trusted CRLs in order to verify client or
server certificates. In case of a client this is not required to
be called if the certificates are not verified using
gnutls_certificate_verify_peers2()
. This function may be called
multiple times.
res |
is a gnutls_certificate_credentials_t structure. |
|
crl_list |
is a list of trusted CRLs. They should have been verified before. |
|
crl_list_size |
holds the size of the crl_list |
Since: 2.4.0
int
gnutls_global_init (void
);
This function initializes the global data to defaults. Every
gnutls application has a global data which holds common parameters
shared by gnutls session structures. You should call
gnutls_global_deinit()
when gnutls usage is no longer needed
Note that this function will also initialize the underlying crypto backend, if it has not been initialized before.
This function increment a global counter, so that
gnutls_global_deinit()
only releases resources when it has been
called as many times as gnutls_global_init()
. This is useful when
GnuTLS is used by more than one library in an application. This
function can be called many times, but will only do something the
first time.
Note! This function is not thread safe. If two threads call this function simultaneously, they can cause a race between checking the global counter and incrementing it, causing both threads to execute the library initialization code. That would lead to a memory leak. To handle this, your application could invoke this function after aquiring a thread mutex. To ignore the potential memory leak is also an option.
void
gnutls_global_deinit (void
);
This function deinitializes the global data, that were initialized
using gnutls_global_init()
.
Note! This function is not thread safe. See the discussion for
gnutls_global_init()
for more information.
void gnutls_global_set_mutex (mutex_init_func init
,mutex_deinit_func deinit
,mutex_lock_func lock
,mutex_unlock_func unlock
);
With this function you are allowed to override the default mutex locks used in some parts of gnutls and dependent libraries. This function should be used if you have complete control of your program and libraries. Do not call this function from a library. Instead only initialize gnutls and the default OS mutex locks will be used.
This function must be called before gnutls_global_init()
.
void gnutls_global_set_mem_functions (gnutls_alloc_function alloc_func
,gnutls_alloc_function secure_alloc_func
,gnutls_is_secure_function is_secure_func
,gnutls_realloc_function realloc_func
,gnutls_free_function free_func
);
This is the function were you set the memory allocation functions
gnutls is going to use. By default the libc's allocation functions
(malloc()
, free()
), are used by gnutls, to allocate both sensitive
and not sensitive data. This function is provided to set the
memory allocation functions to something other than the defaults
This function must be called before gnutls_global_init()
is called.
This function is not thread safe.
alloc_func |
it's the default memory allocation function. Like |
|
secure_alloc_func |
This is the memory allocation function that will be used for sensitive data. |
|
is_secure_func |
a function that returns 0 if the memory given is not secure. May be NULL. |
|
realloc_func |
A realloc function |
|
free_func |
The function that frees allocated data. Must accept a NULL pointer. |
void
gnutls_global_set_log_function (gnutls_log_func log_func
);
This is the function where you set the logging function gnutls is going to use. This function only accepts a character array. Normally you may not use this function since it is only used for debugging purposes.
gnutls_log_func is of the form, void (*gnutls_log_func)( int level, const char*);
void
gnutls_global_set_log_level (int level
);
This is the function that allows you to set the log level. The level is an integer between 0 and 9. Higher values mean more verbosity. The default value is 0. Larger values should only be used with care, since they may reveal sensitive information.
Use a log level over 10 to enable all debugging options.
int
gnutls_dh_params_init (gnutls_dh_params_t *dh_params
);
This function will initialize the DH parameters structure.
void
gnutls_dh_params_deinit (gnutls_dh_params_t dh_params
);
This function will deinitialize the DH parameters structure.
int gnutls_dh_params_import_raw (gnutls_dh_params_t dh_params
,const gnutls_datum_t *prime
,const gnutls_datum_t *generator
);
This function will replace the pair of prime and generator for use in the Diffie-Hellman key exchange. The new parameters should be stored in the appropriate gnutls_datum.
int gnutls_dh_params_import_pkcs3 (gnutls_dh_params_t params
,const gnutls_datum_t *pkcs3_params
,gnutls_x509_crt_fmt_t format
);
This function will extract the DHParams found in a PKCS3 formatted structure. This is the format generated by "openssl dhparam" tool.
If the structure is PEM encoded, it should have a header of "BEGIN DH PARAMETERS".
int gnutls_dh_params_generate2 (gnutls_dh_params_t params
,unsigned int bits
);
This function will generate a new pair of prime and generator for use in
the Diffie-Hellman key exchange. The new parameters will be allocated using
gnutls_malloc()
and will be stored in the appropriate datum.
This function is normally slow.
Do not set the number of bits directly, use gnutls_sec_param_to_pk_bits()
to
get bits for GNUTLS_PK_DSA
.
Also note that the DH parameters are only useful to servers.
Since clients use the parameters sent by the server, it's of
no use to call this in client side.
int gnutls_dh_params_export_pkcs3 (gnutls_dh_params_t params
,gnutls_x509_crt_fmt_t format
,unsigned char *params_data
,size_t *params_data_size
);
This function will export the given dh parameters to a PKCS3 DHParams structure. This is the format generated by "openssl dhparam" tool. If the buffer provided is not long enough to hold the output, then GNUTLS_E_SHORT_MEMORY_BUFFER will be returned.
If the structure is PEM encoded, it will have a header of "BEGIN DH PARAMETERS".
int gnutls_dh_params_export_raw (gnutls_dh_params_t params
,gnutls_datum_t *prime
,gnutls_datum_t *generator
,unsigned int *bits
);
This function will export the pair of prime and generator for use
in the Diffie-Hellman key exchange. The new parameters will be
allocated using gnutls_malloc()
and will be stored in the
appropriate datum.
int gnutls_dh_params_cpy (gnutls_dh_params_t dst
,gnutls_dh_params_t src
);
This function will copy the DH parameters structure from source to destination.
int
gnutls_rsa_params_init (gnutls_rsa_params_t *rsa_params
);
This function will initialize the temporary RSA parameters structure.
void
gnutls_rsa_params_deinit (gnutls_rsa_params_t rsa_params
);
This function will deinitialize the RSA parameters structure.
int gnutls_rsa_params_cpy (gnutls_rsa_params_t dst
,gnutls_rsa_params_t src
);
This function will copy the RSA parameters structure from source to destination.
int gnutls_rsa_params_import_raw (gnutls_rsa_params_t rsa_params
,const gnutls_datum_t *m
,const gnutls_datum_t *e
,const gnutls_datum_t *d
,const gnutls_datum_t *p
,const gnutls_datum_t *q
,const gnutls_datum_t *u
);
This function will replace the parameters in the given structure. The new parameters should be stored in the appropriate gnutls_datum.
int gnutls_rsa_params_generate2 (gnutls_rsa_params_t params
,unsigned int bits
);
This function will generate new temporary RSA parameters for use in RSA-EXPORT ciphersuites. This function is normally slow.
Note that if the parameters are to be used in export cipher suites the bits value should be 512 or less. Also note that the generation of new RSA parameters is only useful to servers. Clients use the parameters sent by the server, thus it's no use calling this in client side.
int gnutls_rsa_params_export_raw (gnutls_rsa_params_t params
,gnutls_datum_t *m
,gnutls_datum_t *e
,gnutls_datum_t *d
,gnutls_datum_t *p
,gnutls_datum_t *q
,gnutls_datum_t *u
,unsigned int *bits
);
This function will export the RSA parameters found in the given
structure. The new parameters will be allocated using
gnutls_malloc()
and will be stored in the appropriate datum.
int gnutls_rsa_params_export_pkcs1 (gnutls_rsa_params_t params
,gnutls_x509_crt_fmt_t format
,unsigned char *params_data
,size_t *params_data_size
);
This function will export the given RSA parameters to a PKCS1 RSAPublicKey structure. If the buffer provided is not long enough to hold the output, then GNUTLS_E_SHORT_MEMORY_BUFFER will be returned.
If the structure is PEM encoded, it will have a header of "BEGIN RSA PRIVATE KEY".
int gnutls_rsa_params_import_pkcs1 (gnutls_rsa_params_t params
,const gnutls_datum_t *pkcs1_params
,gnutls_x509_crt_fmt_t format
);
This function will extract the RSAPublicKey found in a PKCS1 formatted structure.
If the structure is PEM encoded, it should have a header of "BEGIN RSA PRIVATE KEY".
ssize_t (*gnutls_pull_func) (gnutls_transport_ptr_t Param1
,void *Param2
,size_t Param3
);
ssize_t (*gnutls_push_func) (gnutls_transport_ptr_t Param1
,const void *Param2
,size_t Param3
);
ssize_t (*gnutls_vec_push_func) (gnutls_transport_ptr_t Param1
,const giovec_t *iov
,int iovcnt
);
void gnutls_transport_set_ptr (gnutls_session_t session
,gnutls_transport_ptr_t ptr
);
Used to set the first argument of the transport function (like PUSH and PULL). In berkeley style sockets this function will set the connection handle.
void gnutls_transport_set_ptr2 (gnutls_session_t session
,gnutls_transport_ptr_t recv_ptr
,gnutls_transport_ptr_t send_ptr
);
Used to set the first argument of the transport function (like PUSH and PULL). In berkeley style sockets this function will set the connection handle. With this function you can use two different pointers for receiving and sending.
session |
is a gnutls_session_t structure. |
|
recv_ptr |
is the value for the pull function |
|
send_ptr |
is the value for the push function |
gnutls_transport_ptr_t
gnutls_transport_get_ptr (gnutls_session_t session
);
Used to get the first argument of the transport function (like
PUSH and PULL). This must have been set using
gnutls_transport_set_ptr()
.
void gnutls_transport_get_ptr2 (gnutls_session_t session
,gnutls_transport_ptr_t *recv_ptr
,gnutls_transport_ptr_t *send_ptr
);
Used to get the arguments of the transport functions (like PUSH
and PULL). These should have been set using
gnutls_transport_set_ptr2()
.
session |
is a gnutls_session_t structure. |
|
recv_ptr |
will hold the value for the pull function |
|
send_ptr |
will hold the value for the push function |
void gnutls_transport_set_push_function (gnutls_session_t session
,gnutls_push_func push_func
);
This is the function where you set a push function for gnutls to use in order to send data. If you are going to use berkeley style sockets, you do not need to use this function since the default (send(2)) will probably be ok. Otherwise you should specify this function for gnutls to be able to send data.
PUSH_FUNC is of the form, ssize_t (*gnutls_push_func)(gnutls_transport_ptr_t, const void*, size_t);
session |
is a gnutls_session_t structure. |
|
push_func |
a callback function similar to |
void gnutls_transport_set_pull_function (gnutls_session_t session
,gnutls_pull_func pull_func
);
This is the function where you set a function for gnutls to receive data. Normally, if you use berkeley style sockets, do not need to use this function since the default (recv(2)) will probably be ok.
PULL_FUNC is of the form, ssize_t (*gnutls_pull_func)(gnutls_transport_ptr_t, void*, size_t);
void gnutls_transport_set_errno_function (gnutls_session_t session
,gnutls_errno_func errno_func
);
This is the function where you set a function to retrieve errno after a failed push or pull operation.
errno_func is of the form, int (*gnutls_errno_func)(gnutls_transport_ptr_t); and should return the errno.
session |
is a gnutls_session_t structure. |
|
errno_func |
a callback function similar to |
void gnutls_transport_set_errno (gnutls_session_t session
,int err
);
Store err
in the session-specific errno variable. Useful values
for err
is EAGAIN and EINTR, other values are treated will be
treated as real errors in the push/pull function.
This function is useful in replacement push/pull functions set by
gnutls_transport_set_push_function and
gnutls_transport_set_pullpush_function under Windows, where the
replacement push/pull may not have access to the same errno
variable that is used by GnuTLS (e.g., the application is linked to
msvcr71.dll and gnutls is linked to msvcrt.dll).
If you don't have the session
variable easily accessible from the
push/pull function, and don't worry about thread conflicts, you can
also use gnutls_transport_set_global_errno()
.
session |
is a gnutls_session_t structure. |
|
err |
error value to store in session-specific errno variable. |
void gnutls_session_set_ptr (gnutls_session_t session
,void *ptr
);
This function will set (associate) the user given pointer ptr
to
the session structure. This is pointer can be accessed with
gnutls_session_get_ptr()
.
void *
gnutls_session_get_ptr (gnutls_session_t session
);
Get user pointer for session. Useful in callbacks. This is the
pointer set with gnutls_session_set_ptr()
.
void gnutls_openpgp_send_cert (gnutls_session_t session
,gnutls_openpgp_crt_status_t status
);
This function will order gnutls to send the key fingerprint instead of the key in the initial handshake procedure. This should be used with care and only when there is indication or knowledge that the server can obtain the client's key.
session |
is a pointer to a gnutls_session_t structure. |
|
status |
is one of GNUTLS_OPENPGP_CERT, or GNUTLS_OPENPGP_CERT_FINGERPRINT |
int gnutls_fingerprint (gnutls_digest_algorithm_t algo
,const gnutls_datum_t *data
,void *result
,size_t *result_size
);
This function will calculate a fingerprint (actually a hash), of the given data. The result is not printable data. You should convert it to hex, or to something else printable.
This is the usual way to calculate a fingerprint of an X.509 DER encoded certificate. Note however that the fingerprint of an OpenPGP is not just a hash and cannot be calculated with this function.
void
gnutls_srp_free_client_credentials (gnutls_srp_client_credentials_t sc
);
This structure is complex enough to manipulate directly thus this helper function is provided in order to free (deallocate) it.
int
gnutls_srp_allocate_client_credentials
(gnutls_srp_client_credentials_t *sc
);
This structure is complex enough to manipulate directly thus this helper function is provided in order to allocate it.
int gnutls_srp_set_client_credentials (gnutls_srp_client_credentials_t res
,const char *username
,const char *password
);
This function sets the username and password, in a
gnutls_srp_client_credentials_t structure. Those will be used in
SRP authentication. username
and password
should be ASCII
strings or UTF-8 strings prepared using the "SASLprep" profile of
"stringprep".
void
gnutls_srp_free_server_credentials (gnutls_srp_server_credentials_t sc
);
This structure is complex enough to manipulate directly thus this helper function is provided in order to free (deallocate) it.
int
gnutls_srp_allocate_server_credentials
(gnutls_srp_server_credentials_t *sc
);
This structure is complex enough to manipulate directly thus this helper function is provided in order to allocate it.
int gnutls_srp_set_server_credentials_file (gnutls_srp_server_credentials_t res
,const char *password_file
,const char *password_conf_file
);
This function sets the password files, in a gnutls_srp_server_credentials_t structure. Those password files hold usernames and verifiers and will be used for SRP authentication.
const char *
gnutls_srp_server_get_username (gnutls_session_t session
);
This function will return the username of the peer. This should only be called in case of SRP authentication and in case of a server. Returns NULL in case of an error.
void gnutls_srp_set_prime_bits (gnutls_session_t session
,unsigned int bits
);
This function sets the minimum accepted number of bits, for use in an SRP key exchange. If zero, the default 2048 bits will be used.
In the client side it sets the minimum accepted number of bits. If
a server sends a prime with less bits than that
GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER
will be returned by the
handshake.
This function has no effect in server side.
Since: 2.6.0
int gnutls_srp_verifier (const char *username
,const char *password
,const gnutls_datum_t *salt
,const gnutls_datum_t *generator
,const gnutls_datum_t *prime
,gnutls_datum_t *res
);
This function will create an SRP verifier, as specified in
RFC2945. The prime
and generator
should be one of the static
parameters defined in gnutls/extra.h or may be generated using the
libgcrypt functions gcry_prime_generate()
and
gcry_prime_group_generator()
.
The verifier will be allocated with malloc
and will be stored in
res
using binary format.
void gnutls_srp_set_server_credentials_function (gnutls_srp_server_credentials_t cred
,gnutls_srp_server_credentials_function *func
);
This function can be used to set a callback to retrieve the user's SRP credentials. The callback's function form is:
int (*callback)(gnutls_session_t, const char* username, gnutls_datum_t* salt, gnutls_datum_t *verifier, gnutls_datum_t* g, gnutls_datum_t* n);
username
contains the actual username.
The salt
, verifier
, generator
and prime
must be filled
in using the gnutls_malloc()
. For convenience prime
and generator
may also be one of the static parameters defined in extra.h.
In case the callback returned a negative number then gnutls will assume that the username does not exist.
In order to prevent attackers from guessing valid usernames, if a user does not exist, g and n values should be filled in using a random user's parameters. In that case the callback must return the special value (1).
The callback function will only be called once per handshake. The callback function should return 0 on success, while -1 indicates an error.
void gnutls_srp_set_client_credentials_function (gnutls_srp_client_credentials_t cred
,gnutls_srp_client_credentials_function *func
);
This function can be used to set a callback to retrieve the username and password for client SRP authentication. The callback's function form is:
int (*callback)(gnutls_session_t, char** username, char**password);
The username
and password
must be allocated using
gnutls_malloc()
. username
and password
should be ASCII strings
or UTF-8 strings prepared using the "SASLprep" profile of
"stringprep".
The callback function will be called once per handshake before the initial hello message is sent.
The callback should not return a negative error code the second time called, since the handshake procedure will be aborted.
The callback function should return 0 on success. -1 indicates an error.
int gnutls_srp_base64_encode (const gnutls_datum_t *data
,char *result
,size_t *result_size
);
This function will convert the given data to printable data, using the base64 encoding, as used in the libsrp. This is the encoding used in SRP password files. If the provided buffer is not long enough GNUTLS_E_SHORT_MEMORY_BUFFER is returned.
Warning! This base64 encoding is not the "standard" encoding, so do not use it for non-SRP purposes.
int gnutls_srp_base64_encode_alloc (const gnutls_datum_t *data
,gnutls_datum_t *result
);
This function will convert the given data to printable data, using the base64 encoding. This is the encoding used in SRP password files. This function will allocate the required memory to hold the encoded data.
You should use gnutls_free()
to free the returned data.
Warning! This base64 encoding is not the "standard" encoding, so do not use it for non-SRP purposes.
int gnutls_srp_base64_decode (const gnutls_datum_t *b64_data
,char *result
,size_t *result_size
);
This function will decode the given encoded data, using the base64 encoding found in libsrp.
Note that b64_data
should be null terminated.
Warning! This base64 encoding is not the "standard" encoding, so do not use it for non-SRP purposes.
int gnutls_srp_base64_decode_alloc (const gnutls_datum_t *b64_data
,gnutls_datum_t *result
);
This function will decode the given encoded data. The decoded data will be allocated, and stored into result. It will decode using the base64 algorithm as used in libsrp.
You should use gnutls_free()
to free the returned data.
Warning! This base64 encoding is not the "standard" encoding, so do not use it for non-SRP purposes.
void
gnutls_psk_free_client_credentials (gnutls_psk_client_credentials_t sc
);
This structure is complex enough to manipulate directly thus this helper function is provided in order to free (deallocate) it.
int
gnutls_psk_allocate_client_credentials
(gnutls_psk_client_credentials_t *sc
);
This structure is complex enough to manipulate directly thus this helper function is provided in order to allocate it.
int gnutls_psk_set_client_credentials (gnutls_psk_client_credentials_t res
,const char *username
,const gnutls_datum_t *key
,gnutls_psk_key_flags format
);
This function sets the username and password, in a
gnutls_psk_client_credentials_t structure. Those will be used in
PSK authentication. username
should be an ASCII string or UTF-8
strings prepared using the "SASLprep" profile of "stringprep". The
key can be either in raw byte format or in Hex format (without the
0x prefix).
res |
is a gnutls_psk_client_credentials_t structure. |
|
username |
is the user's zero-terminated userid |
|
key |
is the user's key |
|
format |
indicate the format of the key, either
|
void
gnutls_psk_free_server_credentials (gnutls_psk_server_credentials_t sc
);
This structure is complex enough to manipulate directly thus this helper function is provided in order to free (deallocate) it.
int
gnutls_psk_allocate_server_credentials
(gnutls_psk_server_credentials_t *sc
);
This structure is complex enough to manipulate directly thus this helper function is provided in order to allocate it.
int gnutls_psk_set_server_credentials_file (gnutls_psk_server_credentials_t res
,const char *password_file
);
This function sets the password file, in a
gnutls_psk_server_credentials_t
structure. This password file
holds usernames and keys and will be used for PSK authentication.
int gnutls_psk_set_server_credentials_hint (gnutls_psk_server_credentials_t res
,const char *hint
);
This function sets the identity hint, in a
gnutls_psk_server_credentials_t
structure. This hint is sent to
the client to help it chose a good PSK credential (i.e., username
and password).
Since: 2.4.0
const char *
gnutls_psk_server_get_username (gnutls_session_t session
);
This should only be called in case of PSK authentication and in case of a server.
const char *
gnutls_psk_client_get_hint (gnutls_session_t session
);
The PSK identity hint may give the client help in deciding which username to use. This should only be called in case of PSK authentication and in case of a client.
Since: 2.4.0
void gnutls_psk_set_server_credentials_function (gnutls_psk_server_credentials_t cred
,gnutls_psk_server_credentials_function *func
);
This function can be used to set a callback to retrieve the user's PSK credentials. The callback's function form is: int (*callback)(gnutls_session_t, const char* username, gnutls_datum_t* key);
username
contains the actual username.
The key
must be filled in using the gnutls_malloc()
.
In case the callback returned a negative number then gnutls will assume that the username does not exist.
The callback function will only be called once per handshake. The callback function should return 0 on success, while -1 indicates an error.
void gnutls_psk_set_client_credentials_function (gnutls_psk_client_credentials_t cred
,gnutls_psk_client_credentials_function *func
);
This function can be used to set a callback to retrieve the username and password for client PSK authentication. The callback's function form is: int (*callback)(gnutls_session_t, char** username, gnutls_datum_t* key);
The username
and key->data
must be allocated using gnutls_malloc()
.
username
should be ASCII strings or UTF-8 strings prepared using
the "SASLprep" profile of "stringprep".
The callback function will be called once per handshake.
The callback function should return 0 on success. -1 indicates an error.
int gnutls_hex_encode (const gnutls_datum_t *data
,char *result
,size_t *result_size
);
This function will convert the given data to printable data, using the hex encoding, as used in the PSK password files.
int gnutls_hex_decode (const gnutls_datum_t *hex_data
,char *result
,size_t *result_size
);
This function will decode the given encoded data, using the hex encoding used by PSK password files.
Note that hex_data should be null terminated.
void gnutls_psk_set_server_dh_params (gnutls_psk_server_credentials_t res
,gnutls_dh_params_t dh_params
);
This function will set the Diffie-Hellman parameters for an anonymous server to use. These parameters will be used in Diffie-Hellman exchange with PSK cipher suites.
void gnutls_psk_set_server_params_function (gnutls_psk_server_credentials_t res
,gnutls_params_function *func
);
This function will set a callback in order for the server to get the Diffie-Hellman parameters for PSK authentication. The callback should return zero on success.
gnutls_credentials_type_t
gnutls_auth_get_type (gnutls_session_t session
);
Returns type of credentials for the current authentication schema. The returned information is to be used to distinguish the function used to access authentication data.
Eg. for CERTIFICATE ciphersuites (key exchange algorithms:
GNUTLS_KX_RSA
, GNUTLS_KX_DHE_RSA
), the same function are to be
used to access the authentication data.
The type of credentials for the current authentication schema, a gnutls_credentials_type_t type.
gnutls_credentials_type_t
gnutls_auth_server_get_type (gnutls_session_t session
);
Returns the type of credentials that were used for server authentication. The returned information is to be used to distinguish the function used to access authentication data.
The type of credentials for the server authentication schema, a gnutls_credentials_type_t type.
gnutls_credentials_type_t
gnutls_auth_client_get_type (gnutls_session_t session
);
Returns the type of credentials that were used for client authentication. The returned information is to be used to distinguish the function used to access authentication data.
The type of credentials for the client authentication schema, a gnutls_credentials_type_t type.
void gnutls_dh_set_prime_bits (gnutls_session_t session
,unsigned int bits
);
This function sets the number of bits, for use in an Diffie-Hellman key exchange. This is used both in DH ephemeral and DH anonymous cipher suites. This will set the minimum size of the prime that will be used for the handshake.
In the client side it sets the minimum accepted number of bits. If
a server sends a prime with less bits than that
GNUTLS_E_DH_PRIME_UNACCEPTABLE
will be returned by the handshake.
This function has no effect in server side.
int
gnutls_dh_get_secret_bits (gnutls_session_t session
);
This function will return the bits used in the last Diffie-Hellman key exchange with the peer. Should be used for both anonymous and ephemeral Diffie-Hellman.
int
gnutls_dh_get_peers_public_bits (gnutls_session_t session
);
Get the Diffie-Hellman public key bit size. Can be used for both anonymous and ephemeral Diffie-Hellman.
int
gnutls_dh_get_prime_bits (gnutls_session_t session
);
This function will return the bits of the prime used in the last Diffie-Hellman key exchange with the peer. Should be used for both anonymous and ephemeral Diffie-Hellman. Note that some ciphers, like RSA and DSA without DHE, does not use a Diffie-Hellman key exchange, and then this function will return 0.
int gnutls_dh_get_group (gnutls_session_t session
,gnutls_datum_t *raw_gen
,gnutls_datum_t *raw_prime
);
This function will return the group parameters used in the last
Diffie-Hellman key exchange with the peer. These are the prime and
the generator used. This function should be used for both
anonymous and ephemeral Diffie-Hellman. The output parameters must
be freed with gnutls_free()
.
int gnutls_dh_get_pubkey (gnutls_session_t session
,gnutls_datum_t *raw_key
);
This function will return the peer's public key used in the last
Diffie-Hellman key exchange. This function should be used for both
anonymous and ephemeral Diffie-Hellman. The output parameters must
be freed with gnutls_free()
.
int gnutls_rsa_export_get_pubkey (gnutls_session_t session
,gnutls_datum_t *exponent
,gnutls_datum_t *modulus
);
This function will return the peer's public key exponent and
modulus used in the last RSA-EXPORT authentication. The output
parameters must be freed with gnutls_free()
.
int
gnutls_rsa_export_get_modulus_bits (gnutls_session_t session
);
Get the export RSA parameter's modulus size.
void gnutls_certificate_set_retrieve_function (gnutls_certificate_credentials_t cred
,gnutls_certificate_retrieve_function *func
);
This function sets a callback to be called in order to retrieve the certificate to be used in the handshake.
The callback's function prototype is: int (*callback)(gnutls_session_t, const gnutls_datum_t* req_ca_dn, int nreqs, const gnutls_pk_algorithm_t* pk_algos, int pk_algos_length, gnutls_retr2_st* st);
req_ca_cert
is only used in X.509 certificates.
Contains a list with the CA names that the server considers trusted.
Normally we should send a certificate that is signed
by one of these CAs. These names are DER encoded. To get a more
meaningful value use the function gnutls_x509_rdn_get()
.
pk_algos
contains a list with server's acceptable signature algorithms.
The certificate returned should support the server's given algorithms.
st
should contain the certificates and private keys.
If the callback function is provided then gnutls will call it, in the handshake, after the certificate request message has been received.
In server side pk_algos and req_ca_dn are NULL.
The callback function should set the certificate list to be sent, and return 0 on success. If no certificate was selected then the number of certificates should be set to zero. The value (-1) indicates error and the handshake will be terminated.
void gnutls_certificate_set_verify_function (gnutls_certificate_credentials_t cred
,gnutls_certificate_verify_function *func
);
This function sets a callback to be called when peer's certificate has been received in order to verify it on receipt rather than doing after the handshake is completed.
The callback's function prototype is: int (*callback)(gnutls_session_t);
If the callback function is provided then gnutls will call it, in the
handshake, just after the certificate message has been received.
To verify or obtain the certificate the gnutls_certificate_verify_peers2()
,
gnutls_certificate_type_get()
, gnutls_certificate_get_peers()
functions
can be used.
The callback function should return 0 for the handshake to continue or non-zero to terminate.
Since: 2.10.0
void gnutls_certificate_server_set_request (gnutls_session_t session
,gnutls_certificate_request_t req
);
This function specifies if we (in case of a server) are going to
send a certificate request message to the client. If req
is
GNUTLS_CERT_REQUIRE then the server will return an error if the
peer does not provide a certificate. If you do not call this
function then the client will not be asked to send a certificate.
session |
is a gnutls_session_t structure. |
|
req |
is one of GNUTLS_CERT_REQUEST, GNUTLS_CERT_REQUIRE |
const gnutls_datum_t * gnutls_certificate_get_peers (gnutls_session_t session
,unsigned int *list_size
);
Get the peer's raw certificate (chain) as sent by the peer. These certificates are in raw format (DER encoded for X.509). In case of a X.509 then a certificate list may be present. The first certificate in the list is the peer's certificate, following the issuer's certificate, then the issuer's issuer etc.
In case of OpenPGP keys a single key will be returned in raw format.
const gnutls_datum_t *
gnutls_certificate_get_ours (gnutls_session_t session
);
Get the certificate as sent to the peer, in the last handshake. These certificates are in raw format. In X.509 this is a certificate list. In OpenPGP this is a single certificate.
time_t
gnutls_certificate_activation_time_peers
(gnutls_session_t session
);
gnutls_certificate_activation_time_peers
is deprecated and should not be used in newly-written code.
gnutls_certificate_verify_peers2() now verifies activation times.
This function will return the peer's certificate activation time. This is the creation time for openpgp keys.
time_t
gnutls_certificate_expiration_time_peers
(gnutls_session_t session
);
gnutls_certificate_expiration_time_peers
is deprecated and should not be used in newly-written code.
gnutls_certificate_verify_peers2() now verifies expiration times.
This function will return the peer's certificate expiration time.
int
gnutls_certificate_client_get_request_status
(gnutls_session_t session
);
Get whether client certificate is requested or not.
int gnutls_certificate_verify_peers2 (gnutls_session_t session
,unsigned int *status
);
This function will try to verify the peer's certificate and return
its status (trusted, invalid etc.). The value of status
should
be one or more of the gnutls_certificate_status_t enumerated
elements bitwise or'd. To avoid denial of service attacks some
default upper limits regarding the certificate key size and chain
size are set. To override them use
gnutls_certificate_set_verify_limits()
.
Note that you must also check the peer's name in order to check if the verified certificate belongs to the actual peer.
This function uses gnutls_x509_crt_list_verify()
with the CAs in
the credentials as trusted CAs.
int gnutls_pem_base64_encode (const char *msg
,const gnutls_datum_t *data
,char *result
,size_t *result_size
);
This function will convert the given data to printable data, using the base64 encoding. This is the encoding used in PEM messages.
The output string will be null terminated, although the size will not include the terminating null.
msg |
is a message to be put in the header |
|
data |
contain the raw data |
|
result |
the place where base64 data will be copied |
|
result_size |
holds the size of the result |
On success GNUTLS_E_SUCCESS
(0) is returned,
GNUTLS_E_SHORT_MEMORY_BUFFER
is returned if the buffer given is
not long enough, or 0 on success.
int gnutls_pem_base64_decode (const char *header
,const gnutls_datum_t *b64_data
,unsigned char *result
,size_t *result_size
);
This function will decode the given encoded data. If the header given is non null this function will search for "-----BEGIN header" and decode only this part. Otherwise it will decode the first PEM packet found.
header |
A null terminated string with the PEM header (eg. CERTIFICATE) |
|
b64_data |
contain the encoded data |
|
result |
the place where decoded data will be copied |
|
result_size |
holds the size of the result |
On success GNUTLS_E_SUCCESS
(0) is returned,
GNUTLS_E_SHORT_MEMORY_BUFFER
is returned if the buffer given is
not long enough, or 0 on success.
int gnutls_pem_base64_encode_alloc (const char *msg
,const gnutls_datum_t *data
,gnutls_datum_t *result
);
This function will convert the given data to printable data, using the base64 encoding. This is the encoding used in PEM messages. This function will allocate the required memory to hold the encoded data.
You should use gnutls_free()
to free the returned data.
int gnutls_pem_base64_decode_alloc (const char *header
,const gnutls_datum_t *b64_data
,gnutls_datum_t *result
);
This function will decode the given encoded data. The decoded data will be allocated, and stored into result. If the header given is non null this function will search for "-----BEGIN header" and decode only this part. Otherwise it will decode the first PEM packet found.
You should use gnutls_free()
to free the returned data.
void gnutls_certificate_set_params_function (gnutls_certificate_credentials_t res
,gnutls_params_function *func
);
This function will set a callback in order for the server to get the Diffie-Hellman or RSA parameters for certificate authentication. The callback should return zero on success.
void gnutls_anon_set_params_function (gnutls_anon_server_credentials_t res
,gnutls_params_function *func
);
This function will set a callback in order for the server to get the Diffie-Hellman or RSA parameters for anonymous authentication. The callback should return zero on success.
void gnutls_psk_set_params_function (gnutls_psk_server_credentials_t res
,gnutls_params_function *func
);
This function will set a callback in order for the server to get the Diffie-Hellman or RSA parameters for PSK authentication. The callback should return zero on success.
int gnutls_hex2bin (const char *hex_data
,size_t hex_size
,char *bin_data
,size_t *bin_size
);
Convert a buffer with hex data to binary data.
hex_data |
string with data in hex format |
|
hex_size |
size of hex data |
|
bin_data |
output array with binary data |
|
bin_size |
when calling * |
Since: 2.4.0
Enumeration of different symmetric encryption algorithms.
Unknown algorithm. |
||
NULL algorithm. |
||
ARCFOUR stream cipher with 128-bit keys. |
||
3DES in CBC mode. |
||
AES in CBC mode with 128-bit keys. |
||
AES in CBC mode with 256-bit keys. |
||
ARCFOUR stream cipher with 40-bit keys. |
||
Camellia in CBC mode with 128-bit keys. |
||
Camellia in CBC mode with 256-bit keys. |
||
RC2 in CBC mode with 40-bit keys. |
||
DES in CBC mode (56-bit keys). |
||
AES in CBC mode with 192-bit keys. |
||
IDEA in CFB mode. |
||
3DES in CFB mode. |
||
CAST5 in CFB mode. |
||
Blowfish in CFB mode. |
||
Safer-SK in CFB mode with 128-bit keys. |
||
AES in CFB mode with 128-bit keys. |
||
AES in CFB mode with 192-bit keys. |
||
AES in CFB mode with 256-bit keys. |
||
Twofish in CFB mode. |
Enumeration of different key exchange algorithms.
Unknown key-exchange algorithm. |
||
RSA key-exchange algorithm. |
||
DHE-DSS key-exchange algorithm. |
||
DHE-RSA key-exchange algorithm. |
||
Anon-DH key-exchange algorithm. |
||
SRP key-exchange algorithm. |
||
RSA-EXPORT key-exchange algorithm. |
||
SRP-RSA key-exchange algorithm. |
||
SRP-DSS key-exchange algorithm. |
||
PSK key-exchange algorithm. |
||
DHE-PSK key-exchange algorithm. |
Enumeration of different Message Authentication Code (MAC) algorithms.
Enumeration of different digest (hash) algorithms.
Enumeration of different TLS compression methods.
Unknown compression method. |
||
The NULL compression method (uncompressed). |
||
The deflate/zlib compression method. |
||
Same as |
||
The non-standard LZO compression method. |
Enumeration of different TLS alerts.
Close notify. |
||
Unexpected message. |
||
Bad record MAC. |
||
Decryption failed. |
||
Record overflow. |
||
Decompression failed. |
||
Handshake failed. |
||
No certificate. |
||
Certificate is bad. |
||
Certificate is not supported. |
||
Certificate was revoked. |
||
Certificate is expired. |
||
Unknown certificate. |
||
Illegal parameter. |
||
CA is unknown. |
||
Access was denied. |
||
Decode error. |
||
Decrypt error. |
||
Export restriction. |
||
Error in protocol version. |
||
Insufficient security. |
||
Internal error. |
||
User canceled. |
||
No renegotiation is allowed. |
||
An unsupported extension was sent. |
||
Could not retrieve the specified certificate. |
||
The server name sent was not recognized. |
||
The SRP/PSK username is missing or not known. |
||
Inner application negotiation failed. |
||
Inner application verification failed. |
Enumeration of different TLS handshake packets.
Enumeration of certificate status codes. Note that the status bits have different meanings in OpenPGP keys and X.509 certificate verification.
Will be set if the certificate was not verified. |
||
Certificate revoked. In X.509 this will be set only if CRLs are checked. |
||
Certificate not verified. Signer not found. |
||
Certificate not verified. Signer not a CA certificate. |
||
Certificate not verified, insecure algorithm. |
||
Certificate not yet activated. |
||
Certificate expired. |
Enumeration of different SSL/TLS protocol versions.
SSL version 3.0. |
||
TLS version 1.0. |
||
Same as |
||
TLS version 1.1. |
||
TLS version 1.2. |
||
Maps to the highest supported TLS version. |
||
Unknown SSL/TLS version. |
Enumeration of different digital signature algorithms.
Unknown signature algorithm. |
||
Digital signature algorithm RSA with SHA-1 |
||
Same as |
||
Digital signature algorithm DSA with SHA-1 |
||
Same as |
||
Digital signature algorithm RSA with MD5. |
||
Digital signature algorithm RSA with MD2. |
||
Digital signature algorithm RSA with RMD-160. |
||
Digital signature algorithm RSA with SHA-256. |
||
Digital signature algorithm RSA with SHA-384. |
||
Digital signature algorithm RSA with SHA-512. |
||
Digital signature algorithm RSA with SHA-224. |
||
Digital signature algorithm DSA with SHA-224 |
||
Digital signature algorithm DSA with SHA-256 |
Enumeration of different TLS extension types. This flag indicates for an extension whether it is useful to application level or TLS level only. This is (only) used to parse the application level extensions before the "client_hello" callback is called.
Enumeration of different supplemental data types (RFC 4680).
extern gnutls_alloc_function gnutls_malloc;
This function will allocate 's' bytes data, and return a pointer to memory. This function is supposed to be used by callbacks.
The allocation function used is the one set by
gnutls_global_set_mem_functions()
.
extern gnutls_free_function gnutls_free;
This function will free data pointed by ptr.
The deallocation function used is the one set by
gnutls_global_set_mem_functions()
.
Enumeration of different subject alternative names types.
DNS-name SAN. |
||
E-mail address SAN. |
||
URI SAN. |
||
IP address SAN. |
||
OtherName SAN. |
||
DN SAN. |
||
Virtual SAN, used by
|
#define GNUTLS_E_UNSUPPORTED_VERSION_PACKET -8 /* GNUTLS_A_PROTOCOL_VERSION */
#define GNUTLS_E_UNEXPECTED_PACKET_LENGTH -9 /* GNUTLS_A_RECORD_OVERFLOW */
#define GNUTLS_E_UNKNOWN_CIPHER_SUITE -21 /* GNUTLS_A_HANDSHAKE_FAILURE */
#define GNUTLS_E_DECRYPTION_FAILED -24 /* GNUTLS_A_DECRYPTION_FAILED, GNUTLS_A_BAD_RECORD_MAC */
#define GNUTLS_E_DECOMPRESSION_FAILED -26 /* GNUTLS_A_DECOMPRESSION_FAILURE */
#define GNUTLS_E_INSUFICIENT_CREDENTIALS GNUTLS_E_INSUFFICIENT_CREDENTIALS /* for backwards compatibility only */
#define GNUTLS_E_INSUFICIENT_CRED GNUTLS_E_INSUFFICIENT_CREDENTIALS /* for backwards compatibility only */
#define GNUTLS_E_X509_UNSUPPORTED_CRITICAL_EXTENSION -47
#define GNUTLS_E_NO_CERTIFICATE_FOUND -49 /* GNUTLS_A_BAD_CERTIFICATE */
#define GNUTLS_E_RECEIVED_ILLEGAL_PARAMETER -55 /* GNUTLS_A_ILLEGAL_PARAMETER */
#define GNUTLS_E_UNSUPPORTED_CERTIFICATE_TYPE -61 /* GNUTLS_A_UNSUPPORTED_CERTIFICATE */
#define GNUTLS_E_INCOMPATIBLE_GCRYPT_LIBRARY -202 /* obsolete */