*/
/*** MODULEINFO
- <depend>srtp</depend>
+ <depend>srtp</depend>
+ <support_level>core</support_level>
***/
-/* The SIP channel will automatically use sdescriptions if received in a SDP offer,
- and res_srtp is loaded. SRTP with sdescriptions key exchange can be activated
- in outgoing offers by setting _SIPSRTP_CRYPTO=enable in extension.conf before executing Dial
-
- The dial fails if the callee doesn't support SRTP and sdescriptions.
-
- exten => 2345,1,Set(_SIPSRTP_CRYPTO=enable)
- exten => 2345,2,Dial(SIP/1001)
-*/
+/* See https://wiki.asterisk.org/wiki/display/AST/Secure+Calling */
#include "asterisk.h"
#include "asterisk/module.h"
#include "asterisk/options.h"
#include "asterisk/rtp_engine.h"
+#include "asterisk/astobj2.h"
struct ast_srtp {
struct ast_rtp_instance *rtp;
+ struct ao2_container *policies;
srtp_t session;
const struct ast_srtp_cb *cb;
void *data;
+ int warned;
unsigned char buf[8192 + AST_FRIENDLY_OFFSET];
- unsigned int has_stream:1;
+ unsigned char rtcpbuf[8192 + AST_FRIENDLY_OFFSET];
};
struct ast_srtp_policy {
static int ast_srtp_create(struct ast_srtp **srtp, struct ast_rtp_instance *rtp, struct ast_srtp_policy *policy);
static void ast_srtp_destroy(struct ast_srtp *srtp);
static int ast_srtp_add_stream(struct ast_srtp *srtp, struct ast_srtp_policy *policy);
+static int ast_srtp_change_source(struct ast_srtp *srtp, unsigned int from_ssrc, unsigned int to_ssrc);
static int ast_srtp_unprotect(struct ast_srtp *srtp, void *buf, int *len, int rtcp);
static int ast_srtp_protect(struct ast_srtp *srtp, void **buf, int *len, int rtcp);
.create = ast_srtp_create,
.destroy = ast_srtp_destroy,
.add_stream = ast_srtp_add_stream,
+ .change_source = ast_srtp_change_source,
.set_cb = ast_srtp_set_cb,
.unprotect = ast_srtp_unprotect,
.protect = ast_srtp_protect,
}
}
+static int policy_hash_fn(const void *obj, const int flags)
+{
+ const struct ast_srtp_policy *policy = obj;
+
+ return policy->sp.ssrc.type == ssrc_specific ? policy->sp.ssrc.value : policy->sp.ssrc.type;
+}
+
+static int policy_cmp_fn(void *obj, void *arg, int flags)
+{
+ const struct ast_srtp_policy *one = obj, *two = arg;
+
+ return one->sp.ssrc.type == two->sp.ssrc.type && one->sp.ssrc.value == two->sp.ssrc.value;
+}
+
+static struct ast_srtp_policy *find_policy(struct ast_srtp *srtp, const srtp_policy_t *policy, int flags)
+{
+ struct ast_srtp_policy tmp = {
+ .sp = {
+ .ssrc.type = policy->ssrc.type,
+ .ssrc.value = policy->ssrc.value,
+ },
+ };
+
+ return ao2_t_find(srtp->policies, &tmp, flags, "Looking for policy");
+}
+
static struct ast_srtp *res_srtp_new(void)
{
struct ast_srtp *srtp;
return NULL;
}
+ if (!(srtp->policies = ao2_t_container_alloc(5, policy_hash_fn, policy_cmp_fn, "SRTP policy container"))) {
+ ast_free(srtp);
+ return NULL;
+ }
+
+ srtp->warned = 1;
+
return srtp;
}
}
}
+static void policy_destructor(void *obj)
+{
+ struct ast_srtp_policy *policy = obj;
+
+ if (policy->sp.key) {
+ ast_free(policy->sp.key);
+ policy->sp.key = NULL;
+ }
+}
+
static struct ast_srtp_policy *ast_srtp_policy_alloc()
{
struct ast_srtp_policy *tmp;
- if (!(tmp = ast_calloc(1, sizeof(*tmp)))) {
+ if (!(tmp = ao2_t_alloc(sizeof(*tmp), policy_destructor, "Allocating policy"))) {
ast_log(LOG_ERROR, "Unable to allocate memory for srtp_policy\n");
}
static void ast_srtp_policy_destroy(struct ast_srtp_policy *policy)
{
- if (policy->sp.key) {
- ast_free(policy->sp.key);
- policy->sp.key = NULL;
- }
- ast_free(policy);
+ ao2_t_ref(policy, -1, "Destroying policy");
}
static int policy_set_suite(crypto_policy_t *p, enum ast_srtp_suite suite)
{
int res = 0;
int i;
+ int retry = 0;
struct ast_rtp_instance_stats stats = {0,};
+ tryagain:
+
for (i = 0; i < 2; i++) {
res = rtcp ? srtp_unprotect_rtcp(srtp->session, buf, len) : srtp_unprotect(srtp->session, buf, len);
if (res != err_status_no_ctx) {
}
}
+ if (retry == 0 && res == err_status_replay_old) {
+ ast_log(LOG_WARNING, "SRTP unprotect: %s\n", srtp_errstr(res));
+
+ if (srtp->session) {
+ struct ast_srtp_policy *policy;
+ struct ao2_iterator it;
+ int policies_count = 0;
+
+ // dealloc first
+ ast_log(LOG_WARNING, "SRTP destroy before re-create\n");
+ srtp_dealloc(srtp->session);
+
+ // get the count
+ policies_count = ao2_container_count(srtp->policies);
+
+ // get the first to build up
+ it = ao2_iterator_init(srtp->policies, 0);
+ policy = ao2_iterator_next(&it);
+
+ ast_log(LOG_WARNING, "SRTP try to re-create\n");
+ if (srtp_create(&srtp->session, &policy->sp) == err_status_ok) {
+ ast_log(LOG_WARNING, "SRTP re-created with first policy\n");
+
+ // unref first element
+ ao2_t_ref(policy, -1, "Unreffing first policy for re-creating srtp session");
+
+ // if we have more than one policy, add them afterwards
+ if (policies_count > 1) {
+ ast_log(LOG_WARNING, "Add all the other %d policies\n", policies_count-1);
+ while ((policy = ao2_iterator_next(&it))) {
+ srtp_add_stream(srtp->session, &policy->sp);
+ ao2_t_ref(policy, -1, "Unreffing n-th policy for re-creating srtp session");
+ }
+ }
+
+ retry++;
+ ao2_iterator_destroy(&it);
+ goto tryagain;
+ }
+ ao2_iterator_destroy(&it);
+ }
+ }
+
if (res != err_status_ok && res != err_status_replay_fail ) {
- ast_debug(1, "SRTP unprotect: %s\n", srtp_errstr(res));
+ if ((srtp->warned >= 10) && !((srtp->warned - 10) % 100)) {
+ ast_log(LOG_WARNING, "SRTP unprotect: %s %d\n", srtp_errstr(res), srtp->warned);
+ srtp->warned = 11;
+ } else {
+ srtp->warned++;
+ }
+ errno = EAGAIN;
return -1;
}
static int ast_srtp_protect(struct ast_srtp *srtp, void **buf, int *len, int rtcp)
{
int res;
+ unsigned char *localbuf;
if ((*len + SRTP_MAX_TRAILER_LEN) > sizeof(srtp->buf)) {
return -1;
}
+
+ localbuf = rtcp ? srtp->rtcpbuf : srtp->buf;
- memcpy(srtp->buf, *buf, *len);
+ memcpy(localbuf, *buf, *len);
- if ((res = rtcp ? srtp_protect_rtcp(srtp->session, srtp->buf, len) : srtp_protect(srtp->session, srtp->buf, len)) != err_status_ok && res != err_status_replay_fail) {
- ast_debug(1, "SRTP protect: %s\n", srtp_errstr(res));
+ if ((res = rtcp ? srtp_protect_rtcp(srtp->session, localbuf, len) : srtp_protect(srtp->session, localbuf, len)) != err_status_ok && res != err_status_replay_fail) {
+ ast_log(LOG_WARNING, "SRTP protect: %s\n", srtp_errstr(res));
return -1;
}
- *buf = srtp->buf;
+ *buf = localbuf;
return *len;
}
return -1;
}
+ ast_module_ref(ast_module_info->self);
temp->rtp = rtp;
*srtp = temp;
+ ao2_t_link((*srtp)->policies, policy, "Created initial policy");
+
return 0;
}
srtp_dealloc(srtp->session);
}
+ ao2_t_callback(srtp->policies, OBJ_UNLINK | OBJ_NODATA | OBJ_MULTIPLE, NULL, NULL, "Unallocate policy");
+ ao2_t_ref(srtp->policies, -1, "Destroying container");
+
ast_free(srtp);
+ ast_module_unref(ast_module_info->self);
}
static int ast_srtp_add_stream(struct ast_srtp *srtp, struct ast_srtp_policy *policy)
{
- if (!srtp->has_stream && srtp_add_stream(srtp->session, &policy->sp) != err_status_ok) {
+ struct ast_srtp_policy *match;
+
+ if ((match = find_policy(srtp, &policy->sp, OBJ_POINTER))) {
+ ast_debug(3, "Policy already exists, not re-adding\n");
+ ao2_t_ref(match, -1, "Unreffing already existing policy");
+ return -1;
+ }
+
+ if (srtp_add_stream(srtp->session, &policy->sp) != err_status_ok) {
return -1;
}
- srtp->has_stream = 1;
+ ao2_t_link(srtp->policies, policy, "Added additional stream");
+
+ return 0;
+}
+
+static int ast_srtp_change_source(struct ast_srtp *srtp, unsigned int from_ssrc, unsigned int to_ssrc)
+{
+ struct ast_srtp_policy *match;
+ struct srtp_policy_t sp = {
+ .ssrc.type = ssrc_specific,
+ .ssrc.value = from_ssrc,
+ };
+ err_status_t status;
+
+ /* If we find a mach, return and unlink it from the container so we
+ * can change the SSRC (which is part of the hash) and then have
+ * ast_srtp_add_stream link it back in if all is well */
+ if ((match = find_policy(srtp, &sp, OBJ_POINTER | OBJ_UNLINK))) {
+ match->sp.ssrc.value = to_ssrc;
+ if (ast_srtp_add_stream(srtp, match)) {
+ ast_log(LOG_WARNING, "Couldn't add stream\n");
+ } else if ((status = srtp_remove_stream(srtp->session, from_ssrc))) {
+ ast_debug(3, "Couldn't remove stream (%d)\n", status);
+ }
+ ao2_t_ref(match, -1, "Unreffing found policy in change_source");
+ }
return 0;
}
return 0;
}
-AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_GLOBAL_SYMBOLS, "Secure RTP (SRTP)",
+AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_GLOBAL_SYMBOLS | AST_MODFLAG_LOAD_ORDER, "Secure RTP (SRTP)",
.load = load_module,
.unload = unload_module,
+ .load_pri = AST_MODPRI_CHANNEL_DEPEND,
);
projects / asterisk/asterisk.git / blobdiff