Fix DTLS failure when used in a build which has SCTP enabled

The value of BIO_CTRL_DGRAM_SET_PEEK_MODE was clashing with the value for
BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE. In an SCTP enabled build
BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE was used unconditionally with
the reasoning that it would be ignored if SCTP wasn't in use. Unfortunately
due to this clash, this wasn't the case. The BIO ended up going into peek
mode and was continually reading the same data over and over - throwing it
away as a replay.

Fixes #3723

Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3724)

(cherry picked from commit 9924087573cfbc8d2bc97088f36d1a81ca00cda3)

diff --git a/crypto/bio/bss_dgram.c b/crypto/bio/bss_dgram.c
index 81730abe4403ade1c40f67e85021e1b11b4dcb4d..2358289dd12cb48b5aa4dbca04125b484251b9eb 100644 (file)
--- a/crypto/bio/bss_dgram.c
+++ b/crypto/bio/bss_dgram.c
@@ -782,6 +782,15 @@ static long dgram_ctrl(BIO *b, int cmd, long num, void *ptr)
     case BIO_CTRL_DGRAM_GET_MTU_OVERHEAD:
         ret = dgram_get_mtu_overhead(data);
         break;
+
+    /*
+     * BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE is used here for compatibility
+     * reasons. When BIO_CTRL_DGRAM_SET_PEEK_MODE was first defined its value
+     * was incorrectly clashing with BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE. The
+     * value has been updated to a non-clashing value. However to preserve
+     * binary compatiblity we now respond to both the old value and the new one
+     */
+    case BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE:
     case BIO_CTRL_DGRAM_SET_PEEK_MODE:
         data->peekmode = (unsigned int)num;
         break;

diff --git a/include/openssl/bio.h b/include/openssl/bio.h
index 781285157b9da5b08e2e79941f61e5205ecd5100..31fd91c728e8db2e944735681320dc13d5a1edcd 100644 (file)
--- a/include/openssl/bio.h
+++ b/include/openssl/bio.h
@@ -125,11 +125,10 @@ extern "C" {
 
 # define BIO_CTRL_DGRAM_GET_MTU_OVERHEAD   49
 
-# define BIO_CTRL_DGRAM_SET_PEEK_MODE      50
-
+/* Deliberately outside of OPENSSL_NO_SCTP - used in bss_dgram.c */
+#  define BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE    50
 # ifndef OPENSSL_NO_SCTP
 /* SCTP stuff */
-#  define BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE    50
 #  define BIO_CTRL_DGRAM_SCTP_ADD_AUTH_KEY                51
 #  define BIO_CTRL_DGRAM_SCTP_NEXT_AUTH_KEY               52
 #  define BIO_CTRL_DGRAM_SCTP_AUTH_CCS_RCVD               53
@@ -142,6 +141,8 @@ extern "C" {
 #  define BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN               70
 # endif
 
+# define BIO_CTRL_DGRAM_SET_PEEK_MODE      71
+
 /* modifiers */
 # define BIO_FP_READ             0x02
 # define BIO_FP_WRITE            0x04

diff --git a/ssl/statem/statem.c b/ssl/statem/statem.c
index 691bfbbb2a18b666fcc1a241d56fdf2df6542bb3..e6dc3b10954cec7e4f7de639ded01aae35b089b4 100644 (file)
--- a/ssl/statem/statem.c
+++ b/ssl/statem/statem.c
@@ -241,10 +241,10 @@ static int state_machine(SSL *s, int server)
             return -1;
     }
 #ifndef OPENSSL_NO_SCTP
-    if (SSL_IS_DTLS(s)) {
+    if (SSL_IS_DTLS(s) && BIO_dgram_is_sctp(SSL_get_wbio(s))) {
         /*
          * Notify SCTP BIO socket to enter handshake mode and prevent stream
-         * identifier other than 0. Will be ignored if no SCTP is used.
+         * identifier other than 0.
          */
         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE,
                  st->in_handshake, NULL);
@@ -417,10 +417,10 @@ static int state_machine(SSL *s, int server)
     st->in_handshake--;
 
 #ifndef OPENSSL_NO_SCTP
-    if (SSL_IS_DTLS(s)) {
+    if (SSL_IS_DTLS(s) && BIO_dgram_is_sctp(SSL_get_wbio(s))) {
         /*
          * Notify SCTP BIO socket to leave handshake mode and allow stream
-         * identifier other than 0. Will be ignored if no SCTP is used.
+         * identifier other than 0.
          */
         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SET_IN_HANDSHAKE,
                  st->in_handshake, NULL);