[sr-dev] git:master: tls: new parameter 'renegotiation' to enable/ disable client renegotiation
Daniel-Constantin Mierla
miconda at gmail.com
Sat Dec 17 22:23:43 CET 2011
Module: sip-router
Branch: master
Commit: 5731486ac973324f25b091367a573d710f4fe71f
URL: http://git.sip-router.org/cgi-bin/gitweb.cgi/sip-router/?a=commit;h=5731486ac973324f25b091367a573d710f4fe71f
Author: Daniel-Constantin Mierla <miconda at gmail.com>
Committer: Daniel-Constantin Mierla <miconda at gmail.com>
Date: Sat Dec 17 22:22:04 2011 +0100
tls: new parameter 'renegotiation' to enable/disable client renegotiation
- default is 0 (renegotiation disabled), to protect against SSL
renegotiation attack
- can be enabled by setting it to 1
---
modules/tls/tls_domain.c | 36 ++++++++++++++++++++++++++++++++++++
modules/tls/tls_mod.c | 3 +++
modules/tls/tls_mod.h | 2 ++
modules/tls/tls_server.c | 32 ++++++++++++++++++++++++--------
modules/tls/tls_server.h | 4 +++-
5 files changed, 68 insertions(+), 9 deletions(-)
diff --git a/modules/tls/tls_domain.c b/modules/tls/tls_domain.c
index a61149d..d353b81 100644
--- a/modules/tls/tls_domain.c
+++ b/modules/tls/tls_domain.c
@@ -591,6 +591,40 @@ static int set_verification(tls_domain_t* d)
}
+/* This callback function is executed when libssl processes the SSL
+ * handshake and does SSL record layer stuff. It's used to trap
+ * client-initiated renegotiations.
+ */
+
+static void sr_ssl_ctx_info_callback(const SSL *ssl, int event, int ret)
+{
+ struct tls_extra_data* data = 0;
+ int tls_dbg;
+
+ if (event & SSL_CB_HANDSHAKE_START) {
+ tls_dbg = cfg_get(tls, tls_cfg, debug);
+ LOG(tls_dbg, "SSL handshake started\n");
+ if(data==0)
+ data = (struct tls_extra_data*)SSL_get_app_data(ssl);
+ if(data->flags & F_TLS_CON_HANDSHAKED) {
+ LOG(tls_dbg, "SSL renegotiation initiated by client\n");
+ data->flags |= F_TLS_CON_RENEGOTIATION;
+ }
+ }
+ if (event & SSL_CB_HANDSHAKE_DONE) {
+ tls_dbg = cfg_get(tls, tls_cfg, debug);
+ if(data==0)
+ data = (struct tls_extra_data*)SSL_get_app_data(ssl);
+ LOG(tls_dbg, "SSL handshake done\n");
+ /* CVE-2009-3555 - disable renegotiation */
+ if (ssl->s3) {
+ LOG(tls_dbg, "SSL disable renegotiation\n");
+ ssl->s3->flags |= SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS;
+ }
+ data->flags |= F_TLS_CON_HANDSHAKED;
+ }
+}
+
/**
* @brief Configure generic SSL parameters
* @param d domain
@@ -635,6 +669,8 @@ static int set_ssl_options(tls_domain_t* d)
#endif
for(i = 0; i < procs_no; i++) {
SSL_CTX_set_options(d->ctx[i], options);
+ if(sr_tls_renegotiation==0)
+ SSL_CTX_set_info_callback(d->ctx[i], sr_ssl_ctx_info_callback);
}
return 0;
}
diff --git a/modules/tls/tls_mod.c b/modules/tls/tls_mod.c
index 2f7d626..e0c05d8 100644
--- a/modules/tls/tls_mod.c
+++ b/modules/tls/tls_mod.c
@@ -175,6 +175,8 @@ tls_domains_cfg_t** tls_domains_cfg = NULL;
gen_lock_t* tls_domains_cfg_lock = NULL;
+int sr_tls_renegotiation = 0;
+
/*
* Exported functions
*/
@@ -218,6 +220,7 @@ static param_export_t params[] = {
{"tls_force_run", PARAM_INT, &default_tls_cfg.force_run},
{"low_mem_threshold1", PARAM_INT, &default_tls_cfg.low_mem_threshold1},
{"low_mem_threshold2", PARAM_INT, &default_tls_cfg.low_mem_threshold2},
+ {"renegotiation", PARAM_INT, &sr_tls_renegotiation},
{0, 0, 0}
};
diff --git a/modules/tls/tls_mod.h b/modules/tls/tls_mod.h
index a19e9aa..462e5d0 100644
--- a/modules/tls/tls_mod.h
+++ b/modules/tls/tls_mod.h
@@ -53,4 +53,6 @@ extern tls_domain_t srv_defaults;
extern str tls_domains_cfg_file;
+extern int sr_tls_renegotiation;
+
#endif /* _TLS_MOD_H */
diff --git a/modules/tls/tls_server.c b/modules/tls/tls_server.c
index 5ccf545..e3d0a61 100644
--- a/modules/tls/tls_server.c
+++ b/modules/tls/tls_server.c
@@ -209,6 +209,10 @@ static int tls_complete_init(struct tcp_connection* c)
#endif
SSL_set_bio(data->ssl, data->rwbio, data->rwbio);
c->extra_data = data;
+
+ /* link the extra data struct inside ssl connection*/
+ SSL_set_app_data(data->ssl, data);
+
return 0;
error:
@@ -908,6 +912,7 @@ int tls_read_f(struct tcp_connection* c, int* flags)
int n, flush_flags;
char* err_src;
int x;
+ int tls_dbg;
TLS_RD_TRACE("(%p, %p (%d)) start (%s -> %s:%d*)\n",
c, flags, *flags,
@@ -1092,15 +1097,26 @@ continue_ssl_read:
* In the later case, this whole function should be called again
* once there is more output space (set RD_CONN_REPEAT_READ).
*/
- if (unlikely(n <= 0)) {
- ssl_error = SSL_get_error(ssl, n);
- err_src = "TLS read:";
- /* errors handled below, outside the lock */
+
+ if (unlikely(tls_c->flags & F_TLS_CON_RENEGOTIATION)) {
+ /* Fix CVE-2009-3555 - disable renegotiation if started by client
+ * - simulate SSL EOF to force close connection*/
+ tls_dbg = cfg_get(tls, tls_cfg, debug);
+ LOG(tls_dbg, "Reading on a renegotiation of connection (n:%d) (%d)\n",
+ n, SSL_get_error(ssl, n));
+ err_src = "TLS R-N read:";
+ ssl_error = SSL_ERROR_ZERO_RETURN;
} else {
- ssl_error = SSL_ERROR_NONE;
- r->pos += n;
- ssl_read += n;
- bytes_free -=n;
+ if (unlikely(n <= 0)) {
+ ssl_error = SSL_get_error(ssl, n);
+ err_src = "TLS read:";
+ /* errors handled below, outside the lock */
+ } else {
+ ssl_error = SSL_ERROR_NONE;
+ r->pos += n;
+ ssl_read += n;
+ bytes_free -=n;
+ }
}
TLS_RD_TRACE("(%p, %p) SSL_read() => %d (err=%d) ssl_read=%d"
" *flags=%d tls_c->flags=%d\n",
diff --git a/modules/tls/tls_server.h b/modules/tls/tls_server.h
index 62047d5..4b00d06 100644
--- a/modules/tls/tls_server.h
+++ b/modules/tls/tls_server.h
@@ -49,7 +49,9 @@ struct tls_rd_buf {
};
/* tls conn flags */
-#define F_TLS_CON_WR_WANTS_RD 1 /* write wants read */
+#define F_TLS_CON_WR_WANTS_RD 1 /* write wants read */
+#define F_TLS_CON_HANDSHAKED 2 /* connection is handshaked */
+#define F_TLS_CON_RENEGOTIATION 4 /* renegotiation by clinet */
struct tls_extra_data {
tls_domains_cfg_t* cfg; /* Configuration used for this connection */
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