Ensure that we zero memory that contiansthe ASN.1 encoded session, since

this contains the session master key.

ok deraadt@ doug@

1 files changed, 29 insertions, 26 deletions

diff --git a/src/lib/libssl/s3_srvr.c b/src/lib/libssl/s3_srvr.c
index c979031933..3dd085115d 100644
--- a/src/lib/libssl/s3_srvr.c
+++ b/src/lib/libssl/s3_srvr.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: s3_srvr.c,v 1.136 2016/12/06 13:17:52 jsing Exp $ */
+/* $OpenBSD: s3_srvr.c,v 1.137 2016/12/07 13:18:38 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -2564,18 +2564,19 @@ ssl3_send_server_certificate(SSL *s)
 int
 ssl3_send_newsession_ticket(SSL *s)
 {
-        if (s->state == SSL3_ST_SW_SESSION_TICKET_A) {
-                unsigned char *d, *p, *senc, *macstart;
-                const unsigned char *const_p;
-                int len, slen_full, slen;
-                SSL_SESSION *sess;
-                unsigned int hlen;
-                EVP_CIPHER_CTX ctx;
-                HMAC_CTX hctx;
-                SSL_CTX *tctx = s->initial_ctx;
-                unsigned char iv[EVP_MAX_IV_LENGTH];
-                unsigned char key_name[16];
+        unsigned char *d, *p, *macstart;
+        unsigned char *senc = NULL;
+        const unsigned char *const_p;
+        int len, slen_full, slen;
+        SSL_SESSION *sess;
+        unsigned int hlen;
+        EVP_CIPHER_CTX ctx;
+        HMAC_CTX hctx;
+        SSL_CTX *tctx = s->initial_ctx;
+        unsigned char iv[EVP_MAX_IV_LENGTH];
+        unsigned char key_name[16];
 
+        if (s->state == SSL3_ST_SW_SESSION_TICKET_A) {
                 /* get session encoding length */
                 slen_full = i2d_SSL_SESSION(s->session, NULL);
                 /*
@@ -2583,10 +2584,10 @@ ssl3_send_newsession_ticket(SSL *s)
                  * too long
                  */
                 if (slen_full > 0xFF00)
-                        return (-1);
+                        goto err;
                 senc = malloc(slen_full);
                 if (!senc)
-                        return (-1);
+                        goto err;
                 p = senc;
                 i2d_SSL_SESSION(s->session, &p);
 
@@ -2596,10 +2597,8 @@ ssl3_send_newsession_ticket(SSL *s)
                  */
                 const_p = senc;
                 sess = d2i_SSL_SESSION(NULL, &const_p, slen_full);
-                if (sess == NULL) {
-                        free(senc);
-                        return (-1);
-                }
+                if (sess == NULL)
+                        goto err;
 
                 /* ID is irrelevant for the ticket */
                 sess->session_id_length = 0;
@@ -2607,8 +2606,7 @@ ssl3_send_newsession_ticket(SSL *s)
                 slen = i2d_SSL_SESSION(sess, NULL);
                 if (slen > slen_full) {
                         /* shouldn't ever happen */
-                        free(senc);
-                        return (-1);
+                        goto err;
                 }
                 p = senc;
                 i2d_SSL_SESSION(sess, &p);
@@ -2624,10 +2622,8 @@ ssl3_send_newsession_ticket(SSL *s)
                  */
                 if (!BUF_MEM_grow(s->init_buf, ssl3_handshake_msg_hdr_len(s) +
                     22 + EVP_MAX_IV_LENGTH + EVP_MAX_BLOCK_LENGTH +
-                    EVP_MAX_MD_SIZE + slen)) {
-                        free(senc);
-                        return (-1);
-                }
+                    EVP_MAX_MD_SIZE + slen))
+                        goto err;
 
                 d = p = ssl3_handshake_msg_start(s, SSL3_MT_NEWSESSION_TICKET);
 
@@ -2642,9 +2638,8 @@ ssl3_send_newsession_ticket(SSL *s)
                 if (tctx->tlsext_ticket_key_cb) {
                         if (tctx->tlsext_ticket_key_cb(s, key_name, iv, &ctx,
                             &hctx, 1) < 0) {
-                                free(senc);
                                 EVP_CIPHER_CTX_cleanup(&ctx);
-                                return (-1);
+                                goto err;
                         }
                 } else {
                         arc4random_buf(iv, 16);
@@ -2696,11 +2691,19 @@ ssl3_send_newsession_ticket(SSL *s)
 
                 s->state = SSL3_ST_SW_SESSION_TICKET_B;
 
+                explicit_bzero(senc, slen_full);
                 free(senc);
         }
 
         /* SSL3_ST_SW_SESSION_TICKET_B */
         return (ssl3_handshake_write(s));
+
+ err:
+        if (senc != NULL)
+                explicit_bzero(senc, slen_full);
+        free(senc);
+
+        return (-1);
 }
 
 int