Fix small OOB reads.

In ssl3_get_client_certificate, ssl3_get_server_certificate and
ssl3_get_certificate_request check we have enough room
before reading a length.

Thanks to Shi Lei (Gear Team, Qihoo 360 Inc.) for reporting these bugs.

CVE-2016-6306

Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
(cherry picked from commit ff553f837172ecb2b5c8eca257ec3c5619a4b299)

diff --git a/ssl/s3_clnt.c b/ssl/s3_clnt.c
index 9e5875f1f9ba8bd75099cb8288e9c78746a43282..40ca13da244287c1657410ebe95a0f9940af5fc7 100644 (file)
--- a/ssl/s3_clnt.c
+++ b/ssl/s3_clnt.c
@@ -1143,6 +1143,12 @@ int ssl3_get_server_certificate(SSL *s)
         goto f_err;
     }
     for (nc = 0; nc < llen;) {
+        if (nc + 3 > llen) {
+            al = SSL_AD_DECODE_ERROR;
+            SSLerr(SSL_F_SSL3_GET_SERVER_CERTIFICATE,
+                   SSL_R_CERT_LENGTH_MISMATCH);
+            goto f_err;
+        }
         n2l3(p, l);
         if ((l + nc + 3) > llen) {
             al = SSL_AD_DECODE_ERROR;
@@ -2072,6 +2078,11 @@ int ssl3_get_certificate_request(SSL *s)
     }
 
     for (nc = 0; nc < llen;) {
+        if (nc + 2 > llen) {
+            ssl3_send_alert(s, SSL3_AL_FATAL, SSL_AD_DECODE_ERROR);
+            SSLerr(SSL_F_SSL3_GET_CERTIFICATE_REQUEST, SSL_R_CA_DN_TOO_LONG);
+            goto err;
+        }
         n2s(p, l);
         if ((l + nc + 2) > llen) {
             if ((s->options & SSL_OP_NETSCAPE_CA_DN_BUG))

diff --git a/ssl/s3_srvr.c b/ssl/s3_srvr.c
index 591b13ecea2eed4f4fe164ebeea415151091c367..4f1a2e9aba80c8d8bda5903bdf63fe4c63bb2e0c 100644 (file)
--- a/ssl/s3_srvr.c
+++ b/ssl/s3_srvr.c
@@ -3234,6 +3234,12 @@ int ssl3_get_client_certificate(SSL *s)
         goto f_err;
     }
     for (nc = 0; nc < llen;) {
+        if (nc + 3 > llen) {
+            al = SSL_AD_DECODE_ERROR;
+            SSLerr(SSL_F_SSL3_GET_CLIENT_CERTIFICATE,
+                   SSL_R_CERT_LENGTH_MISMATCH);
+            goto f_err;
+        }
         n2l3(p, l);
         if ((l + nc + 3) > llen) {
             al = SSL_AD_DECODE_ERROR;