Fix read_ahead

[openssl.git] / ssl / record / rec_layer_s3.c

diff --git a/ssl/record/rec_layer_s3.c b/ssl/record/rec_layer_s3.c
index 46870c054b82b9ba1ac2365bed6d1cb1d36e72cf..4535f89a1e3f346b64bf28915c81ce873c4a72d5 100644 (file)
--- a/ssl/record/rec_layer_s3.c
+++ b/ssl/record/rec_layer_s3.c
@@ -177,6 +177,12 @@ const char *SSL_rstate_string(const SSL *s)
     }
 }
 
+/*
+ * Return values are as per SSL_read(), i.e.
+ * >0 The number of read bytes
+ *  0 Failure (not retryable)
+ * <0 Failure (may be retryable)
+ */
 int ssl3_read_n(SSL *s, int n, int max, int extend, int clearold)
 {
     /*
@@ -235,6 +241,18 @@ int ssl3_read_n(SSL *s, int n, int max, int extend, int clearold)
         /* ... now we can act as if 'extend' was set */
     }
 
+    len = s->rlayer.packet_length;
+    pkt = rb->buf + align;
+    /*
+     * Move any available bytes to front of buffer: 'len' bytes already
+     * pointed to by 'packet', 'left' extra ones at the end
+     */
+    if (s->rlayer.packet != pkt && clearold == 1) {
+        memmove(pkt, s->rlayer.packet, len + left);
+        s->rlayer.packet = pkt;
+        rb->offset = len + align;
+    }
+
     /*
      * For DTLS/UDP reads should not span multiple packets because the read
      * operation returns the whole packet at once (as long as it fits into
@@ -257,18 +275,6 @@ int ssl3_read_n(SSL *s, int n, int max, int extend, int clearold)
 
     /* else we need to read more data */
 
-    len = s->rlayer.packet_length;
-    pkt = rb->buf + align;
-    /*
-     * Move any available bytes to front of buffer: 'len' bytes already
-     * pointed to by 'packet', 'left' extra ones at the end
-     */
-    if (s->rlayer.packet != pkt && clearold == 1) { /* len > 0 */
-        memmove(pkt, s->rlayer.packet, len + left);
-        s->rlayer.packet = pkt;
-        rb->offset = len + align;
-    }
-
     if (n > (int)(rb->len - rb->offset)) { /* does not happen */
         SSLerr(SSL_F_SSL3_READ_N, ERR_R_INTERNAL_ERROR);
         return -1;
@@ -306,7 +312,7 @@ int ssl3_read_n(SSL *s, int n, int max, int extend, int clearold)
             if (s->mode & SSL_MODE_RELEASE_BUFFERS && !SSL_IS_DTLS(s))
                 if (len + left == 0)
                     ssl3_release_read_buffer(s);
-            return (i);
+            return -1;
         }
         left += i;
         /*
@@ -874,7 +880,13 @@ int do_ssl3_write(SSL *s, int type, const unsigned char *buf,
     return -1;
 }
 
-/* if s->s3->wbuf.left != 0, we need to call this */
+/* if s->s3->wbuf.left != 0, we need to call this
+ *
+ * Return values are as per SSL_read(), i.e.
+ * >0 The number of read bytes
+ *  0 Failure (not retryable)
+ * <0 Failure (may be retryable)
+ */
 int ssl3_write_pending(SSL *s, int type, const unsigned char *buf,
                        unsigned int len)
 {
@@ -924,7 +936,7 @@ int ssl3_write_pending(SSL *s, int type, const unsigned char *buf,
                  */
                 SSL3_BUFFER_set_left(&wb[currbuf], 0);
             }
-            return (i);
+            return -1;
         }
         SSL3_BUFFER_add_offset(&wb[currbuf], i);
         SSL3_BUFFER_add_left(&wb[currbuf], -i);
@@ -1063,6 +1075,14 @@ int ssl3_read_bytes(SSL *s, int type, int *recvd_type, unsigned char *buf,
     } while (num_recs == 0);
     rr = &rr[curr_rec];
 
+    /*
+     * Reset the count of consecutive warning alerts if we've got a non-empty
+     * record that isn't an alert.
+     */
+    if (SSL3_RECORD_get_type(rr) != SSL3_RT_ALERT
+            && SSL3_RECORD_get_length(rr) != 0)
+        s->rlayer.alert_count = 0;
+
     /* we now have a packet which can be read and processed */
 
     if (s->s3->change_cipher_spec /* set when we receive ChangeCipherSpec,
@@ -1125,7 +1145,11 @@ int ssl3_read_bytes(SSL *s, int type, int *recvd_type, unsigned char *buf,
 
             memcpy(buf, &(rr->data[rr->off]), n);
             buf += n;
-            if (!peek) {
+            if (peek) {
+                /* Mark any zero length record as consumed CVE-2016-6305 */
+                if (SSL3_RECORD_get_length(rr) == 0)
+                    SSL3_RECORD_set_read(rr);
+            } else {
                 SSL3_RECORD_sub_length(rr, n);
                 SSL3_RECORD_add_off(rr, n);
                 if (SSL3_RECORD_get_length(rr) == 0) {
@@ -1333,6 +1357,14 @@ int ssl3_read_bytes(SSL *s, int type, int *recvd_type, unsigned char *buf,
         if (alert_level == SSL3_AL_WARNING) {
             s->s3->warn_alert = alert_descr;
             SSL3_RECORD_set_read(rr);
+
+            s->rlayer.alert_count++;
+            if (s->rlayer.alert_count == MAX_WARN_ALERT_COUNT) {
+                al = SSL_AD_UNEXPECTED_MESSAGE;
+                SSLerr(SSL_F_SSL3_READ_BYTES, SSL_R_TOO_MANY_WARN_ALERTS);
+                goto f_err;
+            }
+
             if (alert_descr == SSL_AD_CLOSE_NOTIFY) {
                 s->shutdown |= SSL_RECEIVED_SHUTDOWN;
                 return (0);