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Convert the SRTP extension to the new system

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Change-Id: I12f1d06562c34d357d82bbde7e5d0c15096046e6
Reviewed-on: https://boringssl-review.googlesource.com/5463
Reviewed-by: Adam Langley <agl@google.com>
This commit is contained in:
Adam Langley 2015-07-15 19:06:07 -07:00
parent 49c7af1c42
commit 391250d255
4 changed files with 167 additions and 257 deletions
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2
include/openssl/tls1.h
View File

@ -209,7 +209,7 @@ extern "C" {
#define TLSEXT_TYPE_signature_algorithms 13
/* ExtensionType value from RFC5764 */
#define TLSEXT_TYPE_use_srtp 14
#define TLSEXT_TYPE_srtp 14
/* ExtensionType value from RFC5620 */
#define TLSEXT_TYPE_heartbeat 15

202
ssl/d1_srtp.c
View File

@ -125,12 +125,12 @@
#include <openssl/srtp.h>
static const SRTP_PROTECTION_PROFILE srtp_known_profiles[] = {
const SRTP_PROTECTION_PROFILE kSRTPProfiles[] = {
{
"SRTP_AES128_CM_SHA1_80", SRTP_AES128_CM_SHA1_80,
"SRTP_AES128_CM_SHA1_80", SRTP_AES128_CM_SHA1_80,
},
{
"SRTP_AES128_CM_SHA1_32", SRTP_AES128_CM_SHA1_32,
"SRTP_AES128_CM_SHA1_32", SRTP_AES128_CM_SHA1_32,
},
{0},
};
@ -140,7 +140,7 @@ static int find_profile_by_name(const char *profile_name,
size_t len) {
const SRTP_PROTECTION_PROFILE *p;
p = srtp_known_profiles;
p = kSRTPProfiles;
while (p->name) {
if (len == strlen(p->name) && !strncmp(p->name, profile_name, len)) {
*pptr = p;
@ -153,22 +153,6 @@ static int find_profile_by_name(const char *profile_name,
return 0;
}
static int find_profile_by_num(unsigned profile_num,
const SRTP_PROTECTION_PROFILE **pptr) {
const SRTP_PROTECTION_PROFILE *p;
p = srtp_known_profiles;
while (p->name) {
if (p->id == profile_num) {
*pptr = p;
return 1;
}
p++;
}
return 0;
}
static int ssl_ctx_make_profiles(const char *profiles_string,
STACK_OF(SRTP_PROTECTION_PROFILE) **out) {
STACK_OF(SRTP_PROTECTION_PROFILE) *profiles;
@ -240,181 +224,3 @@ int SSL_set_tlsext_use_srtp(SSL *s, const char *profiles) {
/* This API inverts its return value. */
return !SSL_set_srtp_profiles(s, profiles);
}
/* Note: this function returns 0 length if there are no profiles specified */
int ssl_add_clienthello_use_srtp_ext(SSL *s, uint8_t *p, int *len, int maxlen) {
int ct = 0;
int i;
STACK_OF(SRTP_PROTECTION_PROFILE) *clnt = 0;
const SRTP_PROTECTION_PROFILE *prof;
clnt = SSL_get_srtp_profiles(s);
ct = sk_SRTP_PROTECTION_PROFILE_num(clnt); /* -1 if clnt == 0 */
if (p) {
if (ct == 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_EMPTY_SRTP_PROTECTION_PROFILE_LIST);
return 0;
}
if (2 + ct * 2 + 1 > maxlen) {
OPENSSL_PUT_ERROR(SSL, SSL_R_SRTP_PROTECTION_PROFILE_LIST_TOO_LONG);
return 0;
}
/* Add the length */
s2n(ct * 2, p);
for (i = 0; i < ct; i++) {
prof = sk_SRTP_PROTECTION_PROFILE_value(clnt, i);
s2n(prof->id, p);
}
/* Add an empty use_mki value */
*p++ = 0;
}
*len = 2 + ct * 2 + 1;
return 1;
}
int ssl_parse_clienthello_use_srtp_ext(SSL *s, CBS *cbs, int *out_alert) {
CBS profile_ids, srtp_mki;
const SRTP_PROTECTION_PROFILE *cprof, *sprof;
STACK_OF(SRTP_PROTECTION_PROFILE) *client_profiles = 0, *server_profiles;
size_t i, j;
int ret = 0;
if (!CBS_get_u16_length_prefixed(cbs, &profile_ids) ||
CBS_len(&profile_ids) < 2 ||
!CBS_get_u8_length_prefixed(cbs, &srtp_mki) ||
CBS_len(cbs) != 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
*out_alert = SSL_AD_DECODE_ERROR;
goto done;
}
client_profiles = sk_SRTP_PROTECTION_PROFILE_new_null();
if (client_profiles == NULL) {
OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
*out_alert = SSL_AD_INTERNAL_ERROR;
goto done;
}
while (CBS_len(&profile_ids) > 0) {
uint16_t profile_id;
if (!CBS_get_u16(&profile_ids, &profile_id)) {
*out_alert = SSL_AD_DECODE_ERROR;
goto done;
}
if (find_profile_by_num(profile_id, &cprof)) {
sk_SRTP_PROTECTION_PROFILE_push(client_profiles, cprof);
}
}
/* Discard the MKI value for now. */
server_profiles = SSL_get_srtp_profiles(s);
/* Pick the server's most preferred profile. */
for (i = 0; i < sk_SRTP_PROTECTION_PROFILE_num(server_profiles); i++) {
sprof = sk_SRTP_PROTECTION_PROFILE_value(server_profiles, i);
for (j = 0; j < sk_SRTP_PROTECTION_PROFILE_num(client_profiles); j++) {
cprof = sk_SRTP_PROTECTION_PROFILE_value(client_profiles, j);
if (cprof->id == sprof->id) {
s->srtp_profile = sprof;
ret = 1;
goto done;
}
}
}
ret = 1;
done:
if (client_profiles) {
sk_SRTP_PROTECTION_PROFILE_free(client_profiles);
}
return ret;
}
int ssl_add_serverhello_use_srtp_ext(SSL *s, unsigned char *p, int *len,
int maxlen) {
if (p) {
if (maxlen < 5) {
OPENSSL_PUT_ERROR(SSL, SSL_R_SRTP_PROTECTION_PROFILE_LIST_TOO_LONG);
return 0;
}
if (s->srtp_profile == 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_USE_SRTP_NOT_NEGOTIATED);
return 0;
}
s2n(2, p);
s2n(s->srtp_profile->id, p);
*p++ = 0;
}
*len = 5;
return 1;
}
int ssl_parse_serverhello_use_srtp_ext(SSL *s, CBS *cbs, int *out_alert) {
CBS profile_ids, srtp_mki;
uint16_t profile_id;
size_t i;
STACK_OF(SRTP_PROTECTION_PROFILE) *client_profiles;
const SRTP_PROTECTION_PROFILE *prof;
/* The extension consists of a u16-prefixed profile ID list containing a
* single uint16_t profile ID, then followed by a u8-prefixed srtp_mki field.
*
* See https://tools.ietf.org/html/rfc5764#section-4.1.1 */
if (!CBS_get_u16_length_prefixed(cbs, &profile_ids) ||
!CBS_get_u16(&profile_ids, &profile_id) || CBS_len(&profile_ids) != 0 ||
!CBS_get_u8_length_prefixed(cbs, &srtp_mki) || CBS_len(cbs) != 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
if (CBS_len(&srtp_mki) != 0) {
/* Must be no MKI, since we never offer one. */
OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SRTP_MKI_VALUE);
*out_alert = SSL_AD_ILLEGAL_PARAMETER;
return 0;
}
client_profiles = SSL_get_srtp_profiles(s);
/* Throw an error if the server gave us an unsolicited extension */
if (client_profiles == NULL) {
OPENSSL_PUT_ERROR(SSL, SSL_R_NO_SRTP_PROFILES);
*out_alert = SSL_AD_DECODE_ERROR;
return 0;
}
/* Check to see if the server gave us something we support
(and presumably offered). */
for (i = 0; i < sk_SRTP_PROTECTION_PROFILE_num(client_profiles); i++) {
prof = sk_SRTP_PROTECTION_PROFILE_value(client_profiles, i);
if (prof->id == profile_id) {
s->srtp_profile = prof;
*out_alert = 0;
return 1;
}
}
OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
*out_alert = SSL_AD_ILLEGAL_PARAMETER;
return 0;
}

5
ssl/internal.h
View File

@ -1168,9 +1168,4 @@ int tls12_check_peer_sigalg(const EVP_MD **out_md, int *out_alert, SSL *s,
CBS *cbs, EVP_PKEY *pkey);
void ssl_set_client_disabled(SSL *s);
int ssl_add_clienthello_use_srtp_ext(SSL *s, uint8_t *p, int *len, int maxlen);
int ssl_parse_clienthello_use_srtp_ext(SSL *s, CBS *cbs, int *out_alert);
int ssl_add_serverhello_use_srtp_ext(SSL *s, uint8_t *p, int *len, int maxlen);
int ssl_parse_serverhello_use_srtp_ext(SSL *s, CBS *cbs, int *out_alert);
#endif /* OPENSSL_HEADER_SSL_INTERNAL_H */

215
ssl/t1_lib.c
View File

@ -1760,6 +1760,160 @@ static int ext_channel_id_add_serverhello(SSL *ssl, CBB *out) {
return 1;
}
/* Secure Real-time Transport Protocol (SRTP) extension.
*
* https://tools.ietf.org/html/rfc5764 */
extern const SRTP_PROTECTION_PROFILE kSRTPProfiles[];
static void ext_srtp_init(SSL *ssl) {
ssl->srtp_profile = NULL;
}
static int ext_srtp_add_clienthello(SSL *ssl, CBB *out) {
STACK_OF(SRTP_PROTECTION_PROFILE) *profiles = SSL_get_srtp_profiles(ssl);
if (profiles == NULL) {
return 1;
}
const size_t num_profiles = sk_SRTP_PROTECTION_PROFILE_num(profiles);
if (num_profiles == 0) {
return 1;
}
CBB contents, profile_ids;
if (!CBB_add_u16(out, TLSEXT_TYPE_srtp) ||
!CBB_add_u16_length_prefixed(out, &contents) ||
!CBB_add_u16_length_prefixed(&contents, &profile_ids)) {
return 0;
}
size_t i;
for (i = 0; i < num_profiles; i++) {
if (!CBB_add_u16(&profile_ids,
sk_SRTP_PROTECTION_PROFILE_value(profiles, i)->id)) {
return 0;
}
}
if (!CBB_add_u8(&contents, 0 /* empty use_mki value */) ||
!CBB_flush(out)) {
return 0;
}
return 1;
}
static int ext_srtp_parse_serverhello(SSL *ssl, uint8_t *out_alert,
CBS *contents) {
if (contents == NULL) {
return 1;
}
/* The extension consists of a u16-prefixed profile ID list containing a
* single uint16_t profile ID, then followed by a u8-prefixed srtp_mki field.
*
* See https://tools.ietf.org/html/rfc5764#section-4.1.1 */
CBS profile_ids, srtp_mki;
uint16_t profile_id;
if (!CBS_get_u16_length_prefixed(contents, &profile_ids) ||
!CBS_get_u16(&profile_ids, &profile_id) ||
CBS_len(&profile_ids) != 0 ||
!CBS_get_u8_length_prefixed(contents, &srtp_mki) ||
CBS_len(contents) != 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
return 0;
}
if (CBS_len(&srtp_mki) != 0) {
/* Must be no MKI, since we never offer one. */
OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SRTP_MKI_VALUE);
*out_alert = SSL_AD_ILLEGAL_PARAMETER;
return 0;
}
STACK_OF(SRTP_PROTECTION_PROFILE) *profiles = SSL_get_srtp_profiles(ssl);
/* Check to see if the server gave us something we support (and presumably
* offered). */
size_t i;
for (i = 0; i < sk_SRTP_PROTECTION_PROFILE_num(profiles); i++) {
const SRTP_PROTECTION_PROFILE *profile =
sk_SRTP_PROTECTION_PROFILE_value(profiles, i);
if (profile->id == profile_id) {
ssl->srtp_profile = profile;
return 1;
}
}
OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
*out_alert = SSL_AD_ILLEGAL_PARAMETER;
return 0;
}
static int ext_srtp_parse_clienthello(SSL *ssl, uint8_t *out_alert,
CBS *contents) {
if (contents == NULL) {
return 1;
}
CBS profile_ids, srtp_mki;
if (!CBS_get_u16_length_prefixed(contents, &profile_ids) ||
CBS_len(&profile_ids) < 2 ||
!CBS_get_u8_length_prefixed(contents, &srtp_mki) ||
CBS_len(contents) != 0) {
OPENSSL_PUT_ERROR(SSL, SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST);
return 0;
}
/* Discard the MKI value for now. */
const STACK_OF(SRTP_PROTECTION_PROFILE) *server_profiles =
SSL_get_srtp_profiles(ssl);
/* Pick the server's most preferred profile. */
size_t i;
for (i = 0; i < sk_SRTP_PROTECTION_PROFILE_num(server_profiles); i++) {
const SRTP_PROTECTION_PROFILE *server_profile =
sk_SRTP_PROTECTION_PROFILE_value(server_profiles, i);
CBS profile_ids_tmp;
CBS_init(&profile_ids_tmp, CBS_data(&profile_ids), CBS_len(&profile_ids));
while (CBS_len(&profile_ids_tmp) > 0) {
uint16_t profile_id;
if (!CBS_get_u16(&profile_ids_tmp, &profile_id)) {
return 0;
}
if (server_profile->id == profile_id) {
ssl->srtp_profile = server_profile;
return 1;
}
}
}
return 1;
}
static int ext_srtp_add_serverhello(SSL *ssl, CBB *out) {
if (ssl->srtp_profile == NULL) {
return 1;
}
CBB contents, profile_ids;
if (!CBB_add_u16(out, TLSEXT_TYPE_srtp) ||
!CBB_add_u16_length_prefixed(out, &contents) ||
!CBB_add_u16_length_prefixed(&contents, &profile_ids) ||
!CBB_add_u16(&profile_ids, ssl->srtp_profile->id) ||
!CBB_add_u8(&contents, 0 /* empty MKI */) ||
!CBB_flush(out)) {
return 0;
}
return 1;
}
/* kExtensions contains all the supported extensions. */
static const struct tls_extension kExtensions[] = {
{
@ -1845,6 +1999,14 @@ static const struct tls_extension kExtensions[] = {
ext_channel_id_parse_clienthello,
ext_channel_id_add_serverhello,
},
{
TLSEXT_TYPE_srtp,
ext_srtp_init,
ext_srtp_add_clienthello,
ext_srtp_parse_serverhello,
ext_srtp_parse_clienthello,
ext_srtp_add_serverhello,
},
};
#define kNumExtensions (sizeof(kExtensions) / sizeof(struct tls_extension))
@ -1941,25 +2103,6 @@ uint8_t *ssl_add_clienthello_tlsext(SSL *s, uint8_t *const buf,
ret += CBB_len(&cbb);
CBB_cleanup(&cbb);
if (SSL_get_srtp_profiles(s)) {
int el;
ssl_add_clienthello_use_srtp_ext(s, 0, &el, 0);
if ((limit - ret - 4 - el) < 0) {
return NULL;
}
s2n(TLSEXT_TYPE_use_srtp, ret);
s2n(el, ret);
if (!ssl_add_clienthello_use_srtp_ext(s, ret, &el, el)) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
return NULL;
}
ret += el;
}
if (using_ecc) {
/* Add TLS extension ECPointFormats to the ClientHello message */
long lenmax;
@ -2133,25 +2276,6 @@ uint8_t *ssl_add_serverhello_tlsext(SSL *s, uint8_t *const buf,
}
/* Currently the server should not respond with a SupportedCurves extension */
if (s->srtp_profile) {
int el;
ssl_add_serverhello_use_srtp_ext(s, 0, &el, 0);
if ((limit - ret - 4 - el) < 0) {
return NULL;
}
s2n(TLSEXT_TYPE_use_srtp, ret);
s2n(el, ret);
if (!ssl_add_serverhello_use_srtp_ext(s, ret, &el, el)) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
return NULL;
}
ret += el;
}
extdatalen = ret - orig - 2;
if (extdatalen == 0) {
return orig;
@ -2164,8 +2288,6 @@ uint8_t *ssl_add_serverhello_tlsext(SSL *s, uint8_t *const buf,
static int ssl_scan_clienthello_tlsext(SSL *s, CBS *cbs, int *out_alert) {
CBS extensions;
s->srtp_profile = NULL;
/* Clear ECC extensions */
OPENSSL_free(s->s3->tmp.peer_ecpointformatlist);
s->s3->tmp.peer_ecpointformatlist = NULL;
@ -2278,10 +2400,6 @@ static int ssl_scan_clienthello_tlsext(SSL *s, CBS *cbs, int *out_alert) {
}
s->s3->tmp.peer_ellipticcurvelist_length = num_curves;
} else if (type == TLSEXT_TYPE_use_srtp) {
if (!ssl_parse_clienthello_use_srtp_ext(s, &extension, out_alert)) {
return 0;
}
}
}
@ -2319,11 +2437,6 @@ int ssl_parse_clienthello_tlsext(SSL *s, CBS *cbs) {
static int ssl_scan_serverhello_tlsext(SSL *s, CBS *cbs, int *out_alert) {
CBS extensions;
/* TODO(davidben): Move all of these to some per-handshake state that gets
* systematically reset on a new handshake; perhaps allocate it fresh each
* time so it's not even kept around post-handshake. */
s->srtp_profile = NULL;
/* Clear ECC extensions */
OPENSSL_free(s->s3->tmp.peer_ecpointformatlist);
s->s3->tmp.peer_ecpointformatlist = NULL;
@ -2397,10 +2510,6 @@ static int ssl_scan_serverhello_tlsext(SSL *s, CBS *cbs, int *out_alert) {
*out_alert = SSL_AD_INTERNAL_ERROR;
return 0;
}
} else if (type == TLSEXT_TYPE_use_srtp) {
if (!ssl_parse_serverhello_use_srtp_ext(s, &extension, out_alert)) {
return 0;
}
}
}