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res_srtp: Enable AES-256 and AES-GCM.

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ASTERISK-26190 #close

Change-Id: I11326d80edd656524a51a19450e586c583aa0a0b
changes/83/3183/5
Alexander Traud 9 years ago
parent c2a72e6aa6
commit 1d2173c7ae
9 changed files with 805 additions and 113 deletions
Show Stats Download Patch File Download Diff File

28
channels/chan_sip.c
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@ -284,6 +284,7 @@ ASTERISK_REGISTER_FILE()
#include "asterisk/features_config.h"
#include "asterisk/http_websocket.h"
#include "asterisk/format_cache.h"
#include "asterisk/linkedlists.h" /* for AST_LIST_NEXT */
/*** DOCUMENTATION
<application name="SIPDtmfMode" language="en_US">
@ -13220,21 +13221,34 @@ static void get_our_media_address(struct sip_pvt *p, int needvideo, int needtext
static char *crypto_get_attrib(struct ast_sdp_srtp *srtp, int dtls_enabled, int default_taglen_32)
{
struct ast_sdp_srtp *tmp = srtp;
char *a_crypto;
const char *orig_crypto;
if (!srtp || dtls_enabled) {
if (!tmp || dtls_enabled) {
return NULL;
}
orig_crypto = ast_sdp_srtp_get_attrib(srtp, dtls_enabled, default_taglen_32);
if (ast_strlen_zero(orig_crypto)) {
a_crypto = ast_strdup("");
if (!a_crypto) {
return NULL;
}
if (ast_asprintf(&a_crypto, "a=crypto:%s\r\n", orig_crypto) == -1) {
return NULL;
}
do {
char *copy = a_crypto;
const char *orig_crypto = ast_sdp_srtp_get_attrib(tmp, dtls_enabled, default_taglen_32);
if (ast_strlen_zero(orig_crypto)) {
ast_free(copy);
return NULL;
}
if (ast_asprintf(&a_crypto, "%sa=crypto:%s\r\n", copy, orig_crypto) == -1) {
ast_free(copy);
return NULL;
}
ast_free(copy);
} while ((tmp = AST_LIST_NEXT(tmp, sdp_srtp_list)));
return a_crypto;
}

374
configure vendored
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@ -778,6 +778,18 @@ PBX_SRTP_SHUTDOWN
SRTP_SHUTDOWN_DIR
SRTP_SHUTDOWN_INCLUDE
SRTP_SHUTDOWN_LIB
PBX_SRTP_GCM
SRTP_GCM_DIR
SRTP_GCM_INCLUDE
SRTP_GCM_LIB
PBX_SRTP_192
SRTP_192_DIR
SRTP_192_INCLUDE
SRTP_192_LIB
PBX_SRTP_256
SRTP_256_DIR
SRTP_256_INCLUDE
SRTP_256_LIB
PBX_SRTP
SRTP_DIR
SRTP_INCLUDE
@ -11395,6 +11407,42 @@ fi
SRTP_256_DESCRIP="SRTP Library AES-256 (ICM)"
SRTP_256_OPTION=srtp
SRTP_256_DIR=${SRTP_DIR}
PBX_SRTP_256=0
SRTP_192_DESCRIP="SRTP Library AES-192 (ICM)"
SRTP_192_OPTION=srtp
SRTP_192_DIR=${SRTP_DIR}
PBX_SRTP_192=0
SRTP_GCM_DESCRIP="SRTP Library AES-128 (GCM) and AES-256 (GCM)"
SRTP_GCM_OPTION=srtp
SRTP_GCM_DIR=${SRTP_DIR}
PBX_SRTP_GCM=0
SRTP_SHUTDOWN_DESCRIP="SRTP Library Shutdown Function"
SRTP_SHUTDOWN_OPTION=srtp
SRTP_SHUTDOWN_DIR=${SRTP_DIR}
@ -13802,7 +13850,7 @@ else
We can't simply define LARGE_OFF_T to be 9223372036854775807,
since some C++ compilers masquerading as C compilers
incorrectly reject 9223372036854775807. */
#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
#define LARGE_OFF_T ((((off_t) 1 << 31) << 31) - 1 + (((off_t) 1 << 31) << 31))
int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
&& LARGE_OFF_T % 2147483647 == 1)
? 1 : -1];
@ -13848,7 +13896,7 @@ else
We can't simply define LARGE_OFF_T to be 9223372036854775807,
since some C++ compilers masquerading as C compilers
incorrectly reject 9223372036854775807. */
#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
#define LARGE_OFF_T ((((off_t) 1 << 31) << 31) - 1 + (((off_t) 1 << 31) << 31))
int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
&& LARGE_OFF_T % 2147483647 == 1)
? 1 : -1];
@ -13872,7 +13920,7 @@ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
We can't simply define LARGE_OFF_T to be 9223372036854775807,
since some C++ compilers masquerading as C compilers
incorrectly reject 9223372036854775807. */
#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
#define LARGE_OFF_T ((((off_t) 1 << 31) << 31) - 1 + (((off_t) 1 << 31) << 31))
int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
&& LARGE_OFF_T % 2147483647 == 1)
? 1 : -1];
@ -13917,7 +13965,7 @@ else
We can't simply define LARGE_OFF_T to be 9223372036854775807,
since some C++ compilers masquerading as C compilers
incorrectly reject 9223372036854775807. */
#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
#define LARGE_OFF_T ((((off_t) 1 << 31) << 31) - 1 + (((off_t) 1 << 31) << 31))
int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
&& LARGE_OFF_T % 2147483647 == 1)
? 1 : -1];
@ -13941,7 +13989,7 @@ rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
We can't simply define LARGE_OFF_T to be 9223372036854775807,
since some C++ compilers masquerading as C compilers
incorrectly reject 9223372036854775807. */
#define LARGE_OFF_T (((off_t) 1 << 62) - 1 + ((off_t) 1 << 62))
#define LARGE_OFF_T ((((off_t) 1 << 31) << 31) - 1 + (((off_t) 1 << 31) << 31))
int off_t_is_large[(LARGE_OFF_T % 2147483629 == 721
&& LARGE_OFF_T % 2147483647 == 1)
? 1 : -1];
@ -31820,6 +31868,322 @@ rm -f core conftest.err conftest.$ac_objext \
CFLAGS="${saved_cflags}"
fi
if test "$PBX_SRTP" = "1";
then
if test "x${PBX_SRTP_256}" != "x1" -a "${USE_SRTP_256}" != "no"; then
pbxlibdir=""
# if --with-SRTP_256=DIR has been specified, use it.
if test "x${SRTP_256_DIR}" != "x"; then
if test -d ${SRTP_256_DIR}/lib; then
pbxlibdir="-L${SRTP_256_DIR}/lib"
else
pbxlibdir="-L${SRTP_256_DIR}"
fi
fi
pbxfuncname="crypto_policy_set_aes_cm_256_hmac_sha1_80"
if test "x${pbxfuncname}" = "x" ; then # empty lib, assume only headers
AST_SRTP_256_FOUND=yes
else
ast_ext_lib_check_save_CFLAGS="${CFLAGS}"
CFLAGS="${CFLAGS} "
as_ac_Lib=`$as_echo "ac_cv_lib_srtp_${pbxfuncname}" | $as_tr_sh`
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for ${pbxfuncname} in -lsrtp" >&5
$as_echo_n "checking for ${pbxfuncname} in -lsrtp... " >&6; }
if eval \${$as_ac_Lib+:} false; then :
$as_echo_n "(cached) " >&6
else
ac_check_lib_save_LIBS=$LIBS
LIBS="-lsrtp ${pbxlibdir} $LIBS"
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
/* Override any GCC internal prototype to avoid an error.
Use char because int might match the return type of a GCC
builtin and then its argument prototype would still apply. */
#ifdef __cplusplus
extern "C"
#endif
char ${pbxfuncname} ();
int
main ()
{
return ${pbxfuncname} ();
;
return 0;
}
_ACEOF
if ac_fn_c_try_link "$LINENO"; then :
eval "$as_ac_Lib=yes"
else
eval "$as_ac_Lib=no"
fi
rm -f core conftest.err conftest.$ac_objext \
conftest$ac_exeext conftest.$ac_ext
LIBS=$ac_check_lib_save_LIBS
fi
eval ac_res=\$$as_ac_Lib
{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
$as_echo "$ac_res" >&6; }
if eval test \"x\$"$as_ac_Lib"\" = x"yes"; then :
AST_SRTP_256_FOUND=yes
else
AST_SRTP_256_FOUND=no
fi
CFLAGS="${ast_ext_lib_check_save_CFLAGS}"
fi
# now check for the header.
if test "${AST_SRTP_256_FOUND}" = "yes"; then
SRTP_256_LIB="${pbxlibdir} -lsrtp "
# if --with-SRTP_256=DIR has been specified, use it.
if test "x${SRTP_256_DIR}" != "x"; then
SRTP_256_INCLUDE="-I${SRTP_256_DIR}/include"
fi
SRTP_256_INCLUDE="${SRTP_256_INCLUDE} "
if test "x" = "x" ; then # no header, assume found
SRTP_256_HEADER_FOUND="1"
else # check for the header
ast_ext_lib_check_saved_CPPFLAGS="${CPPFLAGS}"
CPPFLAGS="${CPPFLAGS} ${SRTP_256_INCLUDE}"
ac_fn_c_check_header_mongrel "$LINENO" "" "ac_cv_header_" "$ac_includes_default"
if test "x$ac_cv_header_" = xyes; then :
SRTP_256_HEADER_FOUND=1
else
SRTP_256_HEADER_FOUND=0
fi
CPPFLAGS="${ast_ext_lib_check_saved_CPPFLAGS}"
fi
if test "x${SRTP_256_HEADER_FOUND}" = "x0" ; then
SRTP_256_LIB=""
SRTP_256_INCLUDE=""
else
if test "x${pbxfuncname}" = "x" ; then # only checking headers -> no library
SRTP_256_LIB=""
fi
PBX_SRTP_256=1
cat >>confdefs.h <<_ACEOF
#define HAVE_SRTP_256 1
_ACEOF
fi
fi
fi
if test "x${PBX_SRTP_192}" != "x1" -a "${USE_SRTP_192}" != "no"; then
pbxlibdir=""
# if --with-SRTP_192=DIR has been specified, use it.
if test "x${SRTP_192_DIR}" != "x"; then
if test -d ${SRTP_192_DIR}/lib; then
pbxlibdir="-L${SRTP_192_DIR}/lib"
else
pbxlibdir="-L${SRTP_192_DIR}"
fi
fi
pbxfuncname="crypto_policy_set_aes_cm_192_hmac_sha1_80"
if test "x${pbxfuncname}" = "x" ; then # empty lib, assume only headers
AST_SRTP_192_FOUND=yes
else
ast_ext_lib_check_save_CFLAGS="${CFLAGS}"
CFLAGS="${CFLAGS} "
as_ac_Lib=`$as_echo "ac_cv_lib_srtp_${pbxfuncname}" | $as_tr_sh`
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for ${pbxfuncname} in -lsrtp" >&5
$as_echo_n "checking for ${pbxfuncname} in -lsrtp... " >&6; }
if eval \${$as_ac_Lib+:} false; then :
$as_echo_n "(cached) " >&6
else
ac_check_lib_save_LIBS=$LIBS
LIBS="-lsrtp ${pbxlibdir} $LIBS"
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
/* Override any GCC internal prototype to avoid an error.
Use char because int might match the return type of a GCC
builtin and then its argument prototype would still apply. */
#ifdef __cplusplus
extern "C"
#endif
char ${pbxfuncname} ();
int
main ()
{
return ${pbxfuncname} ();
;
return 0;
}
_ACEOF
if ac_fn_c_try_link "$LINENO"; then :
eval "$as_ac_Lib=yes"
else
eval "$as_ac_Lib=no"
fi
rm -f core conftest.err conftest.$ac_objext \
conftest$ac_exeext conftest.$ac_ext
LIBS=$ac_check_lib_save_LIBS
fi
eval ac_res=\$$as_ac_Lib
{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
$as_echo "$ac_res" >&6; }
if eval test \"x\$"$as_ac_Lib"\" = x"yes"; then :
AST_SRTP_192_FOUND=yes
else
AST_SRTP_192_FOUND=no
fi
CFLAGS="${ast_ext_lib_check_save_CFLAGS}"
fi
# now check for the header.
if test "${AST_SRTP_192_FOUND}" = "yes"; then
SRTP_192_LIB="${pbxlibdir} -lsrtp "
# if --with-SRTP_192=DIR has been specified, use it.
if test "x${SRTP_192_DIR}" != "x"; then
SRTP_192_INCLUDE="-I${SRTP_192_DIR}/include"
fi
SRTP_192_INCLUDE="${SRTP_192_INCLUDE} "
if test "x" = "x" ; then # no header, assume found
SRTP_192_HEADER_FOUND="1"
else # check for the header
ast_ext_lib_check_saved_CPPFLAGS="${CPPFLAGS}"
CPPFLAGS="${CPPFLAGS} ${SRTP_192_INCLUDE}"
ac_fn_c_check_header_mongrel "$LINENO" "" "ac_cv_header_" "$ac_includes_default"
if test "x$ac_cv_header_" = xyes; then :
SRTP_192_HEADER_FOUND=1
else
SRTP_192_HEADER_FOUND=0
fi
CPPFLAGS="${ast_ext_lib_check_saved_CPPFLAGS}"
fi
if test "x${SRTP_192_HEADER_FOUND}" = "x0" ; then
SRTP_192_LIB=""
SRTP_192_INCLUDE=""
else
if test "x${pbxfuncname}" = "x" ; then # only checking headers -> no library
SRTP_192_LIB=""
fi
PBX_SRTP_192=1
cat >>confdefs.h <<_ACEOF
#define HAVE_SRTP_192 1
_ACEOF
fi
fi
fi
if test "x${PBX_SRTP_GCM}" != "x1" -a "${USE_SRTP_GCM}" != "no"; then
pbxlibdir=""
# if --with-SRTP_GCM=DIR has been specified, use it.
if test "x${SRTP_GCM_DIR}" != "x"; then
if test -d ${SRTP_GCM_DIR}/lib; then
pbxlibdir="-L${SRTP_GCM_DIR}/lib"
else
pbxlibdir="-L${SRTP_GCM_DIR}"
fi
fi
pbxfuncname="aes_gcm_128_openssl"
if test "x${pbxfuncname}" = "x" ; then # empty lib, assume only headers
AST_SRTP_GCM_FOUND=yes
else
ast_ext_lib_check_save_CFLAGS="${CFLAGS}"
CFLAGS="${CFLAGS} "
as_ac_Lib=`$as_echo "ac_cv_lib_srtp_${pbxfuncname}" | $as_tr_sh`
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for ${pbxfuncname} in -lsrtp" >&5
$as_echo_n "checking for ${pbxfuncname} in -lsrtp... " >&6; }
if eval \${$as_ac_Lib+:} false; then :
$as_echo_n "(cached) " >&6
else
ac_check_lib_save_LIBS=$LIBS
LIBS="-lsrtp ${pbxlibdir} $LIBS"
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
/* Override any GCC internal prototype to avoid an error.
Use char because int might match the return type of a GCC
builtin and then its argument prototype would still apply. */
#ifdef __cplusplus
extern "C"
#endif
char ${pbxfuncname} ();
int
main ()
{
return ${pbxfuncname} ();
;
return 0;
}
_ACEOF
if ac_fn_c_try_link "$LINENO"; then :
eval "$as_ac_Lib=yes"
else
eval "$as_ac_Lib=no"
fi
rm -f core conftest.err conftest.$ac_objext \
conftest$ac_exeext conftest.$ac_ext
LIBS=$ac_check_lib_save_LIBS
fi
eval ac_res=\$$as_ac_Lib
{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
$as_echo "$ac_res" >&6; }
if eval test \"x\$"$as_ac_Lib"\" = x"yes"; then :
AST_SRTP_GCM_FOUND=yes
else
AST_SRTP_GCM_FOUND=no
fi
CFLAGS="${ast_ext_lib_check_save_CFLAGS}"
fi
# now check for the header.
if test "${AST_SRTP_GCM_FOUND}" = "yes"; then
SRTP_GCM_LIB="${pbxlibdir} -lsrtp "
# if --with-SRTP_GCM=DIR has been specified, use it.
if test "x${SRTP_GCM_DIR}" != "x"; then
SRTP_GCM_INCLUDE="-I${SRTP_GCM_DIR}/include"
fi
SRTP_GCM_INCLUDE="${SRTP_GCM_INCLUDE} "
if test "x" = "x" ; then # no header, assume found
SRTP_GCM_HEADER_FOUND="1"
else # check for the header
ast_ext_lib_check_saved_CPPFLAGS="${CPPFLAGS}"
CPPFLAGS="${CPPFLAGS} ${SRTP_GCM_INCLUDE}"
ac_fn_c_check_header_mongrel "$LINENO" "" "ac_cv_header_" "$ac_includes_default"
if test "x$ac_cv_header_" = xyes; then :
SRTP_GCM_HEADER_FOUND=1
else
SRTP_GCM_HEADER_FOUND=0
fi
CPPFLAGS="${ast_ext_lib_check_saved_CPPFLAGS}"
fi
if test "x${SRTP_GCM_HEADER_FOUND}" = "x0" ; then
SRTP_GCM_LIB=""
SRTP_GCM_INCLUDE=""
else
if test "x${pbxfuncname}" = "x" ; then # only checking headers -> no library
SRTP_GCM_LIB=""
fi
PBX_SRTP_GCM=1
cat >>confdefs.h <<_ACEOF
#define HAVE_SRTP_GCM 1
_ACEOF
fi
fi
fi
fi
if test "x${PBX_SRTP_SHUTDOWN}" != "x1" -a "${USE_SRTP_SHUTDOWN}" != "no"; then
pbxlibdir=""

10
configure.ac
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@ -530,6 +530,9 @@ AST_EXT_LIB_SETUP_DEPENDENT([SPEEX_PREPROCESS], [speex_preprocess_ctl], [], [spe
AST_EXT_LIB_SETUP([SQLITE], [SQLite], [sqlite])
AST_EXT_LIB_SETUP([SQLITE3], [SQLite], [sqlite3])
AST_EXT_LIB_SETUP([SRTP], [Secure RTP], [srtp])
AST_EXT_LIB_SETUP_OPTIONAL([SRTP_256], [SRTP Library AES-256 (ICM)], [SRTP], [srtp])
AST_EXT_LIB_SETUP_OPTIONAL([SRTP_192], [SRTP Library AES-192 (ICM)], [SRTP], [srtp])
AST_EXT_LIB_SETUP_OPTIONAL([SRTP_GCM], [SRTP Library AES-128 (GCM) and AES-256 (GCM)], [SRTP], [srtp])
AST_EXT_LIB_SETUP_OPTIONAL([SRTP_SHUTDOWN], [SRTP Library Shutdown Function], [SRTP], [srtp])
AST_EXT_LIB_SETUP([OPENSSL], [OpenSSL Secure Sockets Layer], [ssl])
AST_EXT_LIB_SETUP_OPTIONAL([RT], [Realtime functions], [rt])
@ -2461,6 +2464,13 @@ then
CFLAGS="${saved_cflags}"
fi
if test "$PBX_SRTP" = "1";
then
AST_EXT_LIB_CHECK([SRTP_256], [srtp], [crypto_policy_set_aes_cm_256_hmac_sha1_80])
AST_EXT_LIB_CHECK([SRTP_192], [srtp], [crypto_policy_set_aes_cm_192_hmac_sha1_80])
AST_EXT_LIB_CHECK([SRTP_GCM], [srtp], [aes_gcm_128_openssl])
fi
AST_EXT_LIB_CHECK([SRTP_SHUTDOWN], [srtp], [srtp_shutdown], [srtp/srtp.h])
for ver in 2.0 2.2 2.4 2.6; do

10
include/asterisk/autoconfig.h.in
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@ -838,6 +838,16 @@
/* Define to 1 if you have the Secure RTP library. */
#undef HAVE_SRTP
/* Define to 1 if SRTP has the SRTP Library AES-192 (ICM) feature. */
#undef HAVE_SRTP_192
/* Define to 1 if SRTP has the SRTP Library AES-256 (ICM) feature. */
#undef HAVE_SRTP_256
/* Define to 1 if SRTP has the SRTP Library AES-128 (GCM) and AES-256 (GCM)
feature. */
#undef HAVE_SRTP_GCM
/* Define to 1 if SRTP has the SRTP Library Shutdown Function feature. */
#undef HAVE_SRTP_SHUTDOWN

14
include/asterisk/res_srtp.h
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@ -21,6 +21,8 @@
#ifndef _ASTERISK_RES_SRTP_H
#define _ASTERISK_RES_SRTP_H
#include "asterisk.h" /* for size_t */
struct ast_srtp;
struct ast_srtp_policy;
struct ast_rtp_instance;
@ -52,9 +54,17 @@ struct ast_srtp_res {
/* Crypto suites */
enum ast_srtp_suite {
/* https://www.iana.org/assignments/srtp-protection/srtp-protection.xhtml */
AST_AES_CM_128_HMAC_SHA1_80 = 1,
AST_AES_CM_128_HMAC_SHA1_32 = 2,
AST_F8_128_HMAC_SHA1_80 = 3
AST_AES_CM_128_HMAC_SHA1_32,
AST_AES_CM_256_HMAC_SHA1_80,
AST_AES_CM_256_HMAC_SHA1_32,
AST_AES_GCM_128 = 7,
AST_AES_GCM_256,
AST_AES_GCM_128_8,
AST_AES_GCM_256_8,
AST_AES_CM_192_HMAC_SHA1_80,
AST_AES_CM_192_HMAC_SHA1_32,
};
struct ast_srtp_policy_res {

18
include/asterisk/sdp_srtp.h
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@ -20,8 +20,7 @@
*
* \brief SRTP and SDP Security descriptions
*
* Specified in RFC 4568
* Specified in RFC 3711
* Specified in RFC 3711, 6188, 7714, and 4568
*
* \author Mikael Magnusson <mikma@users.sourceforge.net>
*/
@ -29,7 +28,8 @@
#ifndef _SDP_SRTP_H
#define _SDP_SRTP_H
#include <asterisk/rtp_engine.h>
#include "asterisk/linkedlists.h" /* for AST_LIST_ENTRY */
#include "asterisk/rtp_engine.h" /* for ast_rtp_instance */
struct ast_sdp_crypto;
@ -37,12 +37,18 @@ struct ast_sdp_crypto;
struct ast_sdp_srtp {
unsigned int flags;
struct ast_sdp_crypto *crypto;
AST_LIST_ENTRY(ast_sdp_srtp) sdp_srtp_list;
};
/* SRTP flags */
#define AST_SRTP_CRYPTO_OFFER_OK (1 << 1)
#define AST_SRTP_CRYPTO_TAG_32 (1 << 2)
#define AST_SRTP_CRYPTO_TAG_80 (1 << 3)
#define AST_SRTP_CRYPTO_OFFER_OK (1 << 1)
#define AST_SRTP_CRYPTO_TAG_32 (1 << 2)
#define AST_SRTP_CRYPTO_TAG_80 (1 << 3)
#define AST_SRTP_CRYPTO_TAG_16 (1 << 4)
#define AST_SRTP_CRYPTO_TAG_8 (1 << 5)
#define AST_SRTP_CRYPTO_AES_192 (1 << 6)
#define AST_SRTP_CRYPTO_AES_256 (1 << 7)
#define AST_SRTP_CRYPTO_OLD_NAME (1 << 8)
/*!
* \brief allocate a ast_sdp_srtp structure

373
main/sdp_srtp.c
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@ -20,8 +20,7 @@
*
* \brief SRTP and SDP Security descriptions
*
* Specified in RFC 3711
* Specified in RFC 4568
* Specified in RFC 3711, 6188, 7714, and 4568
*
* \author Mikael Magnusson <mikma@users.sourceforge.net>
*/
@ -34,15 +33,15 @@
ASTERISK_REGISTER_FILE()
#include <math.h>
#include "asterisk/options.h"
#include "asterisk/utils.h"
#include "asterisk/sdp_srtp.h"
#include <math.h> /* for pow */
#include <srtp/srtp.h> /* for SRTP_MAX_KEY_LEN, etc */
#define SRTP_MASTER_LEN 30
#define SRTP_MASTERKEY_LEN 16
#define SRTP_MASTERSALT_LEN ((SRTP_MASTER_LEN) - (SRTP_MASTERKEY_LEN))
#define SRTP_MASTER_LEN64 (((SRTP_MASTER_LEN) * 8 + 5) / 6 + 1)
#include "asterisk/linkedlists.h" /* for AST_LIST_NEXT, etc */
#include "asterisk/logger.h" /* for ast_log, LOG_ERROR, etc */
#include "asterisk/rtp_engine.h" /* for ast_rtp_engine_dtls, etc */
#include "asterisk/sdp_srtp.h" /* for ast_sdp_srtp, etc */
#include "asterisk/strings.h" /* for ast_strlen_zero */
#include "asterisk/utils.h" /* for ast_set_flag, ast_test_flag, etc */
extern struct ast_srtp_res *res_srtp;
extern struct ast_srtp_policy_res *res_srtp_policy;
@ -59,22 +58,31 @@ struct ast_sdp_srtp *ast_sdp_srtp_alloc(void)
void ast_sdp_srtp_destroy(struct ast_sdp_srtp *srtp)
{
if (srtp->crypto) {
ast_sdp_crypto_destroy(srtp->crypto);
struct ast_sdp_srtp *next;
for (next = AST_LIST_NEXT(srtp, sdp_srtp_list);
srtp;
srtp = next, next = srtp ? AST_LIST_NEXT(srtp, sdp_srtp_list) : NULL) {
if (srtp->crypto) {
ast_sdp_crypto_destroy(srtp->crypto);
}
srtp->crypto = NULL;
ast_free(srtp);
}
srtp->crypto = NULL;
ast_free(srtp);
}
struct ast_sdp_crypto {
char *a_crypto;
unsigned char local_key[SRTP_MASTER_LEN];
unsigned char local_key[SRTP_MAX_KEY_LEN];
int tag;
char local_key64[SRTP_MASTER_LEN64];
unsigned char remote_key[SRTP_MASTER_LEN];
char local_key64[((SRTP_MAX_KEY_LEN) * 8 + 5) / 6 + 1];
unsigned char remote_key[SRTP_MAX_KEY_LEN];
int key_len;
};
static int set_crypto_policy(struct ast_srtp_policy *policy, int suite_val, const unsigned char *master_key, unsigned long ssrc, int inbound);
static struct ast_sdp_crypto *sdp_crypto_alloc(const int key_len);
static struct ast_sdp_crypto *crypto_init_keys(struct ast_sdp_crypto *p, const int key_len);
static int set_crypto_policy(struct ast_srtp_policy *policy, int suite_val, const unsigned char *master_key, int key_len, unsigned long ssrc, int inbound);
void ast_sdp_crypto_destroy(struct ast_sdp_crypto *crypto)
{
@ -83,57 +91,67 @@ void ast_sdp_crypto_destroy(struct ast_sdp_crypto *crypto)
ast_free(crypto);
}
struct ast_sdp_crypto *ast_sdp_crypto_alloc(void)
static struct ast_sdp_crypto *crypto_init_keys(struct ast_sdp_crypto *p, const int key_len)
{
struct ast_sdp_crypto *p;
int key_len;
unsigned char remote_key[SRTP_MASTER_LEN];
unsigned char remote_key[key_len];
if (!ast_rtp_engine_srtp_is_registered()) {
if (res_srtp->get_random(p->local_key, key_len) < 0) {
return NULL;
}
if (!(p = ast_calloc(1, sizeof(*p)))) {
ast_base64encode(p->local_key64, p->local_key, key_len, sizeof(p->local_key64));
p->key_len = ast_base64decode(remote_key, p->local_key64, sizeof(remote_key));
if (p->key_len != key_len) {
ast_log(LOG_ERROR, "base64 encode/decode bad len %d != %d\n", p->key_len, key_len);
return NULL;
}
p->tag = 1;
if (res_srtp->get_random(p->local_key, sizeof(p->local_key)) < 0) {
ast_sdp_crypto_destroy(p);
if (memcmp(remote_key, p->local_key, p->key_len)) {
ast_log(LOG_ERROR, "base64 encode/decode bad key\n");
return NULL;
}
ast_base64encode(p->local_key64, p->local_key, SRTP_MASTER_LEN, sizeof(p->local_key64));
ast_debug(1 , "local_key64 %s len %zu\n", p->local_key64, strlen(p->local_key64));
key_len = ast_base64decode(remote_key, p->local_key64, sizeof(remote_key));
return p;
}
if (key_len != SRTP_MASTER_LEN) {
ast_log(LOG_ERROR, "base64 encode/decode bad len %d != %d\n", key_len, SRTP_MASTER_LEN);
ast_sdp_crypto_destroy(p);
static struct ast_sdp_crypto *sdp_crypto_alloc(const int key_len)
{
struct ast_sdp_crypto *p, *result;
if (!ast_rtp_engine_srtp_is_registered()) {
return NULL;
}
if (memcmp(remote_key, p->local_key, SRTP_MASTER_LEN)) {
ast_log(LOG_ERROR, "base64 encode/decode bad key\n");
ast_sdp_crypto_destroy(p);
if (!(p = ast_calloc(1, sizeof(*p)))) {
return NULL;
}
p->tag = 1;
ast_debug(1 , "local_key64 %s len %zu\n", p->local_key64, strlen(p->local_key64));
/* default is a key which uses AST_AES_CM_128_HMAC_SHA1_xx */
result = crypto_init_keys(p, key_len);
if (!result) {
ast_sdp_crypto_destroy(p);
}
return p;
return result;
}
static int set_crypto_policy(struct ast_srtp_policy *policy, int suite_val, const unsigned char *master_key, unsigned long ssrc, int inbound)
struct ast_sdp_crypto *ast_sdp_crypto_alloc(void)
{
const unsigned char *master_salt = NULL;
return sdp_crypto_alloc(SRTP_MASTER_KEY_LEN);
}
static int set_crypto_policy(struct ast_srtp_policy *policy, int suite_val, const unsigned char *master_key, int key_len, unsigned long ssrc, int inbound)
{
if (!ast_rtp_engine_srtp_is_registered()) {
return -1;
}
master_salt = master_key + SRTP_MASTERKEY_LEN;
if (res_srtp_policy->set_master_key(policy, master_key, SRTP_MASTERKEY_LEN, master_salt, SRTP_MASTERSALT_LEN) < 0) {
if (res_srtp_policy->set_master_key(policy, master_key, key_len, NULL, 0) < 0) {
return -1;
}
@ -147,7 +165,7 @@ static int set_crypto_policy(struct ast_srtp_policy *policy, int suite_val, cons
return 0;
}
static int crypto_activate(struct ast_sdp_crypto *p, int suite_val, unsigned char *remote_key, struct ast_rtp_instance *rtp)
static int crypto_activate(struct ast_sdp_crypto *p, int suite_val, unsigned char *remote_key, int key_len, struct ast_rtp_instance *rtp)
{
struct ast_srtp_policy *local_policy = NULL;
struct ast_srtp_policy *remote_policy = NULL;
@ -174,11 +192,11 @@ static int crypto_activate(struct ast_sdp_crypto *p, int suite_val, unsigned cha
goto err;
}
if (set_crypto_policy(local_policy, suite_val, p->local_key, stats.local_ssrc, 0) < 0) {
if (set_crypto_policy(local_policy, suite_val, p->local_key, key_len, stats.local_ssrc, 0) < 0) {
goto err;
}
if (set_crypto_policy(remote_policy, suite_val, remote_key, 0, 1) < 0) {
if (set_crypto_policy(remote_policy, suite_val, remote_key, key_len, 0, 1) < 0) {
goto err;
}
@ -215,12 +233,15 @@ int ast_sdp_crypto_process(struct ast_rtp_instance *rtp, struct ast_sdp_srtp *sr
char *lifetime = NULL; /* Key lifetime (# of RTP packets) */
char *mki = NULL; /* Master Key Index */
int found = 0;
int key_len = 0;
int key_len_from_sdp;
int key_len_expected;
int tag_from_sdp;
int suite_val = 0;
unsigned char remote_key[SRTP_MASTER_LEN];
int taglen = 0;
unsigned char remote_key[SRTP_MAX_KEY_LEN];
int taglen;
double sdes_lifetime;
struct ast_sdp_crypto *crypto = srtp->crypto;
struct ast_sdp_crypto *crypto;
struct ast_sdp_srtp *tmp;
if (!ast_rtp_engine_srtp_is_registered()) {
return -1;
@ -239,7 +260,7 @@ int ast_sdp_crypto_process(struct ast_rtp_instance *rtp, struct ast_sdp_srtp *sr
}
/* RFC4568 9.1 - tag is 1-9 digits, greater than zero */
if (sscanf(tag, "%30d", &crypto->tag) != 1 || crypto->tag <= 0 || crypto->tag > 999999999) {
if (sscanf(tag, "%30d", &tag_from_sdp) != 1 || tag_from_sdp <= 0 || tag_from_sdp > 999999999) {
ast_log(LOG_WARNING, "Unacceptable a=crypto tag: %s\n", tag);
return -1;
}
@ -249,16 +270,107 @@ int ast_sdp_crypto_process(struct ast_rtp_instance *rtp, struct ast_sdp_srtp *sr
return -1;
}
/* On egress, Asterisk sent several crypto lines in the SIP/SDP offer
The remote party might have choosen another line than the first */
for (tmp = srtp; tmp && tmp->crypto && tmp->crypto->tag != tag_from_sdp;) {
tmp = AST_LIST_NEXT(tmp, sdp_srtp_list);
}
if (tmp) { /* tag matched an already created crypto line */
unsigned int flags = tmp->flags;
/* Make that crypto line the head of the list, not by changing the
list structure but by exchanging the content of the list members */
crypto = tmp->crypto;
tmp->crypto = srtp->crypto;
tmp->flags = srtp->flags;
srtp->crypto = crypto;
srtp->flags = flags;
} else {
crypto = srtp->crypto;
crypto->tag = tag_from_sdp;
}
if (!strcmp(suite, "AES_CM_128_HMAC_SHA1_80")) {
suite_val = AST_AES_CM_128_HMAC_SHA1_80;
ast_set_flag(srtp, AST_SRTP_CRYPTO_TAG_80);
taglen = 80;
key_len_expected = 30;
} else if (!strcmp(suite, "AES_CM_128_HMAC_SHA1_32")) {
suite_val = AST_AES_CM_128_HMAC_SHA1_32;
ast_set_flag(srtp, AST_SRTP_CRYPTO_TAG_32);
taglen = 32;
key_len_expected = 30;
#ifdef HAVE_SRTP_192
} else if (!strcmp(suite, "AES_192_CM_HMAC_SHA1_80")) {
suite_val = AST_AES_CM_192_HMAC_SHA1_80;
ast_set_flag(srtp, AST_SRTP_CRYPTO_TAG_80);
ast_set_flag(srtp, AST_SRTP_CRYPTO_AES_192);
key_len_expected = 38;
} else if (!strcmp(suite, "AES_192_CM_HMAC_SHA1_32")) {
suite_val = AST_AES_CM_192_HMAC_SHA1_32;
ast_set_flag(srtp, AST_SRTP_CRYPTO_TAG_32);
ast_set_flag(srtp, AST_SRTP_CRYPTO_AES_192);
key_len_expected = 38;
/* RFC used a different name while in draft, some still use that */
} else if (!strcmp(suite, "AES_CM_192_HMAC_SHA1_80")) {
suite_val = AST_AES_CM_192_HMAC_SHA1_80;
ast_set_flag(srtp, AST_SRTP_CRYPTO_TAG_80);
ast_set_flag(srtp, AST_SRTP_CRYPTO_AES_192);
ast_set_flag(srtp, AST_SRTP_CRYPTO_OLD_NAME);
key_len_expected = 38;
} else if (!strcmp(suite, "AES_CM_192_HMAC_SHA1_32")) {
suite_val = AST_AES_CM_192_HMAC_SHA1_32;
ast_set_flag(srtp, AST_SRTP_CRYPTO_TAG_32);
ast_set_flag(srtp, AST_SRTP_CRYPTO_AES_192);
ast_set_flag(srtp, AST_SRTP_CRYPTO_OLD_NAME);
key_len_expected = 38;
#endif
#ifdef HAVE_SRTP_256
} else if (!strcmp(suite, "AES_256_CM_HMAC_SHA1_80")) {
suite_val = AST_AES_CM_256_HMAC_SHA1_80;
ast_set_flag(srtp, AST_SRTP_CRYPTO_TAG_80);
ast_set_flag(srtp, AST_SRTP_CRYPTO_AES_256);
key_len_expected = 46;
} else if (!strcmp(suite, "AES_256_CM_HMAC_SHA1_32")) {
suite_val = AST_AES_CM_256_HMAC_SHA1_32;
ast_set_flag(srtp, AST_SRTP_CRYPTO_TAG_32);
ast_set_flag(srtp, AST_SRTP_CRYPTO_AES_256);
key_len_expected = 46;
/* RFC used a different name while in draft, some still use that */
} else if (!strcmp(suite, "AES_CM_256_HMAC_SHA1_80")) {
suite_val = AST_AES_CM_256_HMAC_SHA1_80;
ast_set_flag(srtp, AST_SRTP_CRYPTO_TAG_80);
ast_set_flag(srtp, AST_SRTP_CRYPTO_AES_256);
ast_set_flag(srtp, AST_SRTP_CRYPTO_OLD_NAME);
key_len_expected = 46;
} else if (!strcmp(suite, "AES_CM_256_HMAC_SHA1_32")) {
suite_val = AST_AES_CM_256_HMAC_SHA1_32;
ast_set_flag(srtp, AST_SRTP_CRYPTO_TAG_32);
ast_set_flag(srtp, AST_SRTP_CRYPTO_AES_256);
ast_set_flag(srtp, AST_SRTP_CRYPTO_OLD_NAME);
key_len_expected = 46;
#endif
#ifdef HAVE_SRTP_GCM
} else if (!strcmp(suite, "AEAD_AES_128_GCM")) {
suite_val = AST_AES_GCM_128;
ast_set_flag(srtp, AST_SRTP_CRYPTO_TAG_16);
key_len_expected = AES_128_GCM_KEYSIZE_WSALT;
} else if (!strcmp(suite, "AEAD_AES_256_GCM")) {
suite_val = AST_AES_GCM_256;
ast_set_flag(srtp, AST_SRTP_CRYPTO_TAG_16);
ast_set_flag(srtp, AST_SRTP_CRYPTO_AES_256);
key_len_expected = AES_256_GCM_KEYSIZE_WSALT;
/* RFC contained a (too) short auth tag for RTP media, some still use that */
} else if (!strcmp(suite, "AEAD_AES_128_GCM_8")) {
suite_val = AST_AES_GCM_128_8;
ast_set_flag(srtp, AST_SRTP_CRYPTO_TAG_8);
key_len_expected = AES_128_GCM_KEYSIZE_WSALT;
} else if (!strcmp(suite, "AEAD_AES_256_GCM_8")) {
suite_val = AST_AES_GCM_256_8;
ast_set_flag(srtp, AST_SRTP_CRYPTO_TAG_8);
ast_set_flag(srtp, AST_SRTP_CRYPTO_AES_256);
key_len_expected = AES_256_GCM_KEYSIZE_WSALT;
#endif
} else {
ast_log(LOG_WARNING, "Unsupported crypto suite: %s\n", suite);
ast_verb(1, "Unsupported crypto suite: %s\n", suite);
return -1;
}
@ -341,23 +453,55 @@ int ast_sdp_crypto_process(struct ast_rtp_instance *rtp, struct ast_sdp_srtp *sr
return -1;
}
key_len = ast_base64decode(remote_key, key_salt, sizeof(remote_key));
if (key_len != SRTP_MASTER_LEN) {
ast_log(LOG_WARNING, "SRTP descriptions key length '%d' != master length '%d'\n",
key_len, SRTP_MASTER_LEN);
key_len_from_sdp = ast_base64decode(remote_key, key_salt, sizeof(remote_key));
if (key_len_from_sdp != key_len_expected) {
ast_log(LOG_WARNING, "SRTP descriptions key length is '%d', not '%d'\n",
key_len_from_sdp, key_len_expected);
return -1;
}
if (!memcmp(crypto->remote_key, remote_key, sizeof(crypto->remote_key))) {
/* on default, the key is 30 (AES-128); throw that away (only) when the suite changed actually */
/* ingress: optional, but saves one expensive call to get_random(.) */
/* egress: required, because the local key was communicated before the remote key is processed */
if (crypto->key_len != key_len_from_sdp) {
if (!crypto_init_keys(crypto, key_len_from_sdp)) {
return -1;
}
} else if (!memcmp(crypto->remote_key, remote_key, key_len_from_sdp)) {
ast_debug(1, "SRTP remote key unchanged; maintaining current policy\n");
ast_set_flag(srtp, AST_SRTP_CRYPTO_OFFER_OK);
return 0;
}
memcpy(crypto->remote_key, remote_key, sizeof(crypto->remote_key));
if (crypto_activate(crypto, suite_val, remote_key, rtp) < 0) {
if (key_len_from_sdp > sizeof(crypto->remote_key)) {
ast_log(LOG_ERROR,
"SRTP key buffer is %zu although it must be at least %d bytes\n",
sizeof(crypto->remote_key), key_len_from_sdp);
return -1;
}
memcpy(crypto->remote_key, remote_key, key_len_from_sdp);
if (crypto_activate(crypto, suite_val, remote_key, key_len_from_sdp, rtp) < 0) {
return -1;
}
if (ast_test_flag(srtp, AST_SRTP_CRYPTO_TAG_32)) {
taglen = 32;
} else if (ast_test_flag(srtp, AST_SRTP_CRYPTO_TAG_16)) {
taglen = 16;
} else if (ast_test_flag(srtp, AST_SRTP_CRYPTO_TAG_8)) {
taglen = 8;
} else {
taglen = 80;
}
if (ast_test_flag(srtp, AST_SRTP_CRYPTO_AES_256)) {
taglen |= 0x0200;
} else if (ast_test_flag(srtp, AST_SRTP_CRYPTO_AES_192)) {
taglen |= 0x0100;
}
if (ast_test_flag(srtp, AST_SRTP_CRYPTO_OLD_NAME)) {
taglen |= 0x0080;
}
/* Finally, rebuild the crypto line */
if (ast_sdp_crypto_build_offer(crypto, taglen)) {
@ -375,10 +519,30 @@ int ast_sdp_crypto_build_offer(struct ast_sdp_crypto *p, int taglen)
ast_free(p->a_crypto);
}
if (ast_asprintf(&p->a_crypto, "%d AES_CM_128_HMAC_SHA1_%i inline:%s",
p->tag, taglen, p->local_key64) == -1) {
ast_log(LOG_ERROR, "Could not allocate memory for crypto line\n");
return -1;
if ((taglen & 0x007f) == 8) {
if (ast_asprintf(&p->a_crypto, "%d AEAD_AES_%d_GCM_%d inline:%s",
p->tag, 128 + ((taglen & 0x0300) >> 2), taglen & 0x007f, p->local_key64) == -1) {
ast_log(LOG_ERROR, "Could not allocate memory for crypto line\n");
return -1;
}
} else if ((taglen & 0x007f) == 16) {
if (ast_asprintf(&p->a_crypto, "%d AEAD_AES_%d_GCM inline:%s",
p->tag, 128 + ((taglen & 0x0300) >> 2), p->local_key64) == -1) {
ast_log(LOG_ERROR, "Could not allocate memory for crypto line\n");
return -1;
}
} else if ((taglen & 0x0300) && !(taglen & 0x0080)) {
if (ast_asprintf(&p->a_crypto, "%d AES_%d_CM_HMAC_SHA1_%d inline:%s",
p->tag, 128 + ((taglen & 0x0300) >> 2), taglen & 0x007f, p->local_key64) == -1) {
ast_log(LOG_ERROR, "Could not allocate memory for crypto line\n");
return -1;
}
} else {
if (ast_asprintf(&p->a_crypto, "%d AES_CM_%d_HMAC_SHA1_%d inline:%s",
p->tag, 128 + ((taglen & 0x0300) >> 2), taglen & 0x007f, p->local_key64) == -1) {
ast_log(LOG_ERROR, "Could not allocate memory for crypto line\n");
return -1;
}
}
ast_debug(1, "Crypto line: a=crypto:%s\n", p->a_crypto);
@ -388,7 +552,7 @@ int ast_sdp_crypto_build_offer(struct ast_sdp_crypto *p, int taglen)
const char *ast_sdp_srtp_get_attrib(struct ast_sdp_srtp *srtp, int dtls_enabled, int default_taglen_32)
{
int taglen = default_taglen_32 ? 32 : 80;
int taglen;
if (!srtp) {
return NULL;
@ -396,7 +560,72 @@ const char *ast_sdp_srtp_get_attrib(struct ast_sdp_srtp *srtp, int dtls_enabled,
/* Set encryption properties */
if (!srtp->crypto) {
srtp->crypto = ast_sdp_crypto_alloc();
if (AST_LIST_NEXT(srtp, sdp_srtp_list)) {
srtp->crypto = ast_sdp_crypto_alloc();
ast_log(LOG_ERROR, "SRTP SDP list was not empty\n");
} else {
const int len = default_taglen_32 ? AST_SRTP_CRYPTO_TAG_32 : AST_SRTP_CRYPTO_TAG_80;
const int attr[][3] = {
/* This array creates the following list:
* a=crypto:1 AES_CM_128_HMAC_SHA1_ ...
* a=crypto:2 AEAD_AES_128_GCM ...
* a=crypto:3 AES_256_CM_HMAC_SHA1_ ...
* a=crypto:4 AEAD_AES_256_GCM ...
* a=crypto:5 AES_192_CM_HMAC_SHA1_ ...
* something like 'AEAD_AES_192_GCM' is not specified by the RFCs
*
* If you want to prefer another crypto suite or you want to
* exclude a suite, change this array and recompile Asterisk.
* This list cannot be changed from rtp.conf because you should
* know what you are doing. Especially AES-192 and AES-GCM are
* broken in many VoIP clients, see
* https://github.com/cisco/libsrtp/pull/170
* https://github.com/cisco/libsrtp/pull/184
* Furthermore, AES-GCM uses a shorter crypto-suite string which
* causes Nokia phones based on Symbian/S60 to reject the whole
* INVITE with status 500, even if a matching suite was offered.
* AES-256 might just waste your processor cycles, especially if
* your TLS transport is not secured with equivalent grade, see
* https://security.stackexchange.com/q/61361
* Therefore, AES-128 was preferred here.
*
* If you want to enable one of those defines, please, go for
* CFLAGS='-DENABLE_SRTP_AES_GCM' ./configure && sudo make install
*/
{ len, 0, 30 },
#if defined(HAVE_SRTP_GCM) && defined(ENABLE_SRTP_AES_GCM)
{ AST_SRTP_CRYPTO_TAG_16, 0, AES_128_GCM_KEYSIZE_WSALT },
#endif
#if defined(HAVE_SRTP_256) && defined(ENABLE_SRTP_AES_256)
{ len, AST_SRTP_CRYPTO_AES_256, 46 },
#endif
#if defined(HAVE_SRTP_GCM) && defined(ENABLE_SRTP_AES_GCM) && defined(ENABLE_SRTP_AES_256)
{ AST_SRTP_CRYPTO_TAG_16, AST_SRTP_CRYPTO_AES_256, AES_256_GCM_KEYSIZE_WSALT },
#endif
#if defined(HAVE_SRTP_192) && defined(ENABLE_SRTP_AES_192)
{ len, AST_SRTP_CRYPTO_AES_192, 38 },
#endif
};
struct ast_sdp_srtp *tmp = srtp;
int i;
for (i = 0; i < ARRAY_LEN(attr); i++) {
if (attr[i][0]) {
ast_set_flag(tmp, attr[i][0]);
}
if (attr[i][1]) {
ast_set_flag(tmp, attr[i][1]);
}
tmp->crypto = sdp_crypto_alloc(attr[i][2]); /* key_len */
tmp->crypto->tag = (i + 1); /* tag starts at 1 */
if (i < ARRAY_LEN(attr) - 1) {
AST_LIST_NEXT(tmp, sdp_srtp_list) = ast_sdp_srtp_alloc();
tmp = AST_LIST_NEXT(tmp, sdp_srtp_list);
}
}
}
}
if (dtls_enabled) {
@ -409,6 +638,20 @@ const char *ast_sdp_srtp_get_attrib(struct ast_sdp_srtp *srtp, int dtls_enabled,
taglen = 80;
} else if (ast_test_flag(srtp, AST_SRTP_CRYPTO_TAG_32)) {
taglen = 32;
} else if (ast_test_flag(srtp, AST_SRTP_CRYPTO_TAG_16)) {
taglen = 16;
} else if (ast_test_flag(srtp, AST_SRTP_CRYPTO_TAG_8)) {
taglen = 8;
} else {
taglen = default_taglen_32 ? 32 : 80;
}
if (ast_test_flag(srtp, AST_SRTP_CRYPTO_AES_256)) {
taglen |= 0x0200;
} else if (ast_test_flag(srtp, AST_SRTP_CRYPTO_AES_192)) {
taglen |= 0x0100;
}
if (ast_test_flag(srtp, AST_SRTP_CRYPTO_OLD_NAME)) {
taglen |= 0x0080;
}
if (srtp->crypto && (ast_sdp_crypto_build_offer(srtp->crypto, taglen) >= 0)) {

26
res/res_pjsip_sdp_rtp.c
Unescape View File

@ -51,6 +51,7 @@ ASTERISK_REGISTER_FILE()
#include "asterisk/acl.h"
#include "asterisk/sdp_srtp.h"
#include "asterisk/dsp.h"
#include "asterisk/linkedlists.h" /* for AST_LIST_NEXT */
#include "asterisk/res_pjsip.h"
#include "asterisk/res_pjsip_session.h"
@ -938,6 +939,7 @@ static int add_crypto_to_stream(struct ast_sip_session *session,
enum ast_rtp_dtls_hash hash;
const char *crypto_attribute;
struct ast_rtp_engine_dtls *dtls;
struct ast_sdp_srtp *tmp;
static const pj_str_t STR_NEW = { "new", 3 };
static const pj_str_t STR_EXISTING = { "existing", 8 };
static const pj_str_t STR_ACTIVE = { "active", 6 };
@ -957,16 +959,22 @@ static int add_crypto_to_stream(struct ast_sip_session *session,
}
}
crypto_attribute = ast_sdp_srtp_get_attrib(session_media->srtp,
0 /* DTLS running? No */,
session->endpoint->media.rtp.srtp_tag_32 /* 32 byte tag length? */);
if (!crypto_attribute) {
/* No crypto attribute to add, bad news */
return -1;
}
tmp = session_media->srtp;
do {
crypto_attribute = ast_sdp_srtp_get_attrib(tmp,
0 /* DTLS running? No */,
session->endpoint->media.rtp.srtp_tag_32 /* 32 byte tag length? */);
if (!crypto_attribute) {
/* No crypto attribute to add, bad news */
return -1;
}
attr = pjmedia_sdp_attr_create(pool, "crypto",
pj_cstr(&stmp, crypto_attribute));
media->attr[media->attr_count++] = attr;
} while ((tmp = AST_LIST_NEXT(tmp, sdp_srtp_list)));
attr = pjmedia_sdp_attr_create(pool, "crypto", pj_cstr(&stmp, crypto_attribute));
media->attr[media->attr_count++] = attr;
break;
case AST_SIP_MEDIA_ENCRYPT_DTLS:
if (setup_dtls_srtp(session, session_media)) {

65
res/res_srtp.c
Unescape View File

@ -35,7 +35,7 @@
/* See https://wiki.asterisk.org/wiki/display/AST/Secure+Calling */
#include "asterisk.h"
#include "asterisk.h" /* for NULL, size_t, memcpy, etc */
ASTERISK_REGISTER_FILE()
@ -46,12 +46,13 @@ ASTERISK_REGISTER_FILE()
#include <srtp/crypto_kernel.h>
#endif
#include "asterisk/lock.h"
#include "asterisk/sched.h"
#include "asterisk/module.h"
#include "asterisk/options.h"
#include "asterisk/rtp_engine.h"
#include "asterisk/astobj2.h"
#include "asterisk/astobj2.h" /* for ao2_t_ref, etc */
#include "asterisk/frame.h" /* for AST_FRIENDLY_OFFSET */
#include "asterisk/logger.h" /* for ast_log, ast_debug, etc */
#include "asterisk/module.h" /* for ast_module_info, etc */
#include "asterisk/res_srtp.h" /* for ast_srtp_cb, ast_srtp_suite, etc */
#include "asterisk/rtp_engine.h" /* for ast_rtp_engine_register_srtp, etc */
#include "asterisk/utils.h" /* for ast_free, ast_calloc */
struct ast_srtp {
struct ast_rtp_instance *rtp;
@ -257,23 +258,49 @@ static int policy_set_suite(crypto_policy_t *p, enum ast_srtp_suite suite)
{
switch (suite) {
case AST_AES_CM_128_HMAC_SHA1_80:
p->cipher_type = AES_128_ICM;
p->cipher_key_len = 30;
p->auth_type = HMAC_SHA1;
p->auth_key_len = 20;
p->auth_tag_len = 10;
p->sec_serv = sec_serv_conf_and_auth;
crypto_policy_set_aes_cm_128_hmac_sha1_80(p);
return 0;
case AST_AES_CM_128_HMAC_SHA1_32:
p->cipher_type = AES_128_ICM;
p->cipher_key_len = 30;
p->auth_type = HMAC_SHA1;
p->auth_key_len = 20;
p->auth_tag_len = 4;
p->sec_serv = sec_serv_conf_and_auth;
crypto_policy_set_aes_cm_128_hmac_sha1_32(p);
return 0;
#ifdef HAVE_SRTP_192
case AST_AES_CM_192_HMAC_SHA1_80:
crypto_policy_set_aes_cm_192_hmac_sha1_80(p);
return 0;
case AST_AES_CM_192_HMAC_SHA1_32:
crypto_policy_set_aes_cm_192_hmac_sha1_32(p);
return 0;
#endif
#ifdef HAVE_SRTP_256
case AST_AES_CM_256_HMAC_SHA1_80:
crypto_policy_set_aes_cm_256_hmac_sha1_80(p);
return 0;
case AST_AES_CM_256_HMAC_SHA1_32:
crypto_policy_set_aes_cm_256_hmac_sha1_32(p);
return 0;
#endif
#ifdef HAVE_SRTP_GCM
case AST_AES_GCM_128:
crypto_policy_set_aes_gcm_128_16_auth(p);
return 0;
case AST_AES_GCM_256:
crypto_policy_set_aes_gcm_256_16_auth(p);
return 0;
case AST_AES_GCM_128_8:
crypto_policy_set_aes_gcm_128_8_auth(p);
return 0;
case AST_AES_GCM_256_8:
crypto_policy_set_aes_gcm_256_8_auth(p);
return 0;
#endif
default:
ast_log(LOG_ERROR, "Invalid crypto suite: %u\n", suite);
return -1;

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