File openssl-CVE-2016-2181.patch of Package openssl

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File openssl-CVE-2016-2181.patch of Package openssl (Revision 03cac06d7a7c85e7ad3def593ef00f2d)

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commit b77ab018b79a00f789b0fb85596b446b08be4c9d
Author: Matt Caswell <matt@openssl.org>
Date:   Tue Jul 5 12:04:37 2016 +0100

Fix DTLS replay protection
    
    The DTLS implementation provides some protection against replay attacks
    in accordance with RFC6347 section 4.1.2.6.
    
    A sliding "window" of valid record sequence numbers is maintained with
    the "right" hand edge of the window set to the highest sequence number we
    have received so far. Records that arrive that are off the "left" hand
    edge of the window are rejected. Records within the window are checked
    against a list of records received so far. If we already received it then
    we also reject the new record.
    
    If we have not already received the record, or the sequence number is off
    the right hand edge of the window then we verify the MAC of the record.
    If MAC verification fails then we discard the record. Otherwise we mark
    the record as received. If the sequence number was off the right hand edge
    of the window, then we slide the window along so that the right hand edge
    is in line with the newly received sequence number.
    
    Records may arrive for future epochs, i.e. a record from after a CCS being
    sent, can arrive before the CCS does if the packets get re-ordered. As we
    have not yet received the CCS we are not yet in a position to decrypt or
    validate the MAC of those records. OpenSSL places those records on an
    unprocessed records queue. It additionally updates the window immediately,
    even though we have not yet verified the MAC. This will only occur if
    currently in a handshake/renegotiation.
    
    This could be exploited by an attacker by sending a record for the next
    epoch (which does not have to decrypt or have a valid MAC), with a very
    large sequence number. This means the right hand edge of the window is
    moved very far to the right, and all subsequent legitimate packets are
    dropped causing a denial of service.
    
    A similar effect can be achieved during the initial handshake. In this
    case there is no MAC key negotiated yet. Therefore an attacker can send a
    message for the current epoch with a very large sequence number. The code
    will process the record as normal. If the hanshake message sequence number
    (as opposed to the record sequence number that we have been talking about
    so far) is in the future then the injected message is bufferred to be
    handled later, but the window is still updated. Therefore all subsequent
    legitimate handshake records are dropped. This aspect is not considered a
    security issue because there are many ways for an attacker to disrupt the
    initial handshake and prevent it from completing successfully (e.g.
    injection of a handshake message will cause the Finished MAC to fail and
    the handshake to be aborted). This issue comes about as a result of trying
    to do replay protection, but having no integrity mechanism in place yet.
    Does it even make sense to have replay protection in epoch 0? That
    issue isn't addressed here though.
    
    This addressed an OCAP Audit issue.
    
    CVE-2016-2181
    
    Reviewed-by: Richard Levitte <levitte@openssl.org>

commit 5802758eb480c5f14a768f6a061df1dd20aec8c4
Author: Matt Caswell <matt@openssl.org>
Date:   Wed Aug 17 17:55:36 2016 +0100

Update function error code
    
    A function error code needed updating due to merge issues.
    
    Reviewed-by: Richard Levitte <levitte@openssl.org>

commit fa75569758298e2930c78989b516cac937118acc
Author: Matt Caswell <matt@openssl.org>
Date:   Tue Jul 5 11:46:26 2016 +0100

Fix DTLS unprocessed records bug
    
    During a DTLS handshake we may get records destined for the next epoch
    arrive before we have processed the CCS. In that case we can't decrypt or
    verify the record yet, so we buffer it for later use. When we do receive
    the CCS we work through the queue of unprocessed records and process them.
    
    Unfortunately the act of processing wipes out any existing packet data
    that we were still working through. This includes any records from the new
    epoch that were in the same packet as the CCS. We should only process the
    buffered records if we've not got any data left.
    
    Reviewed-by: Richard Levitte <levitte@openssl.org>

Index: openssl-1.0.1i/ssl/d1_pkt.c
===================================================================
--- openssl-1.0.1i.orig/ssl/d1_pkt.c	2016-08-22 14:05:29.476566452 +0200
+++ openssl-1.0.1i/ssl/d1_pkt.c	2016-08-22 14:06:57.157942683 +0200
@@ -178,7 +178,7 @@ static int dtls1_record_needs_buffering(
 #endif
 static int dtls1_buffer_record(SSL *s, record_pqueue *q,
 	unsigned char *priority);
-static int dtls1_process_record(SSL *s);
+static int dtls1_process_record(SSL *s, DTLS1_BITMAP *bitmap);
 
 /* copy buffered record into SSL structure */
 static int
@@ -304,6 +304,11 @@ static int
 dtls1_process_buffered_records(SSL *s)
     {
     pitem *item;
+    SSL3_BUFFER *rb;
+    SSL3_RECORD *rr;
+    DTLS1_BITMAP *bitmap;
+    unsigned int is_next_epoch;
+    int replayok = 1;
     
     item = pqueue_peek(s->d1->unprocessed_rcds.q);
     if (item)
@@ -311,16 +316,59 @@ dtls1_process_buffered_records(SSL *s)
         /* Check if epoch is current. */
         if (s->d1->unprocessed_rcds.epoch != s->d1->r_epoch)
             return(1);  /* Nothing to do. */
+
+        rr = &s->s3->rrec;
+        rb = &s->s3->rbuf;
+
+        if (rb->left > 0) {
+            /*
+             * We've still got data from the current packet to read. There could
+             * be a record from the new epoch in it - so don't overwrite it
+             * with the unprocessed records yet (we'll do it when we've
+             * finished reading the current packet).
+             */
+            return 1;
+        }
         
         /* Process all the records. */
         while (pqueue_peek(s->d1->unprocessed_rcds.q))
             {
             dtls1_get_unprocessed_record(s);
-            if ( ! dtls1_process_record(s))
-                return(0);
+            bitmap = dtls1_get_bitmap(s, rr, &is_next_epoch);
+            if (bitmap == NULL) {
+                /*
+                 * Should not happen. This will only ever be NULL when the
+                 * current record is from a different epoch. But that cannot
+                 * be the case because we already checked the epoch above
+                 */
+                 SSLerr(SSL_F_DTLS1_PROCESS_BUFFERED_RECORDS,
+                        ERR_R_INTERNAL_ERROR);
+                 return 0;
+            }
+#ifndef OPENSSL_NO_SCTP
+            /* Only do replay check if no SCTP bio */
+            if (!BIO_dgram_is_sctp(SSL_get_rbio(s)))
+#endif
+            {
+                /*
+                 * Check whether this is a repeat, or aged record. We did this
+                 * check once already when we first received the record - but
+                 * we might have updated the window since then due to
+                 * records we subsequently processed.
+                 */
+                replayok = dtls1_record_replay_check(s, bitmap);
+            }
+
+            if (!replayok || !dtls1_process_record(s, bitmap)) {
+                /* dump this record */
+                rr->length = 0;
+                s->packet_length = 0;
+                continue;
+            }
+
             if(dtls1_buffer_record(s, &(s->d1->processed_rcds),
                 s->s3->rrec.seq_num)<0)
-                return -1;
+                return 0;
             }
         }
 
@@ -379,7 +427,7 @@ dtls1_get_buffered_record(SSL *s)
 #endif
 
 static int
-dtls1_process_record(SSL *s)
+dtls1_process_record(SSL *s, DTLS1_BITMAP *bitmap)
 {
 	int i,al;
 	int enc_err;
@@ -535,6 +583,10 @@ printf("\n");
 
 	/* we have pulled in a full packet so zero things */
 	s->packet_length=0;
+
+    /* Mark receipt of record. */
+    dtls1_record_bitmap_update(s, bitmap);
+
 	return(1);
 
 f_err:
@@ -565,9 +617,10 @@ int dtls1_get_record(SSL *s)
 
 	rr= &(s->s3->rrec);
 
+again:
 	/* The epoch may have changed.  If so, process all the
 	 * pending records.  This is a non-blocking operation. */
-	if(dtls1_process_buffered_records(s)<0)
+	if(!dtls1_process_buffered_records(s))
 		return -1;
 
 	/* if we're renegotiating, then there may be buffered records */
@@ -575,7 +628,6 @@ int dtls1_get_record(SSL *s)
 		return 1;
 
 	/* get something from the wire */
-again:
 	/* check if we have the header */
 	if (	(s->rstate != SSL_ST_READ_BODY) ||
 		(s->packet_length < DTLS1_RT_HEADER_LENGTH)) 
@@ -707,20 +759,18 @@ again:
 			{
 			if(dtls1_buffer_record(s, &(s->d1->unprocessed_rcds), rr->seq_num)<0)
 				return -1;
-			dtls1_record_bitmap_update(s, bitmap);/* Mark receipt of record. */
 			}
 		rr->length = 0;
 		s->packet_length = 0;
 		goto again;
 		}
 
-	if (!dtls1_process_record(s))
+	if (!dtls1_process_record(s, bitmap))
 		{
 		rr->length = 0;
 		s->packet_length = 0;  /* dump this record */
 		goto again;   /* get another record */
 		}
-	dtls1_record_bitmap_update(s, bitmap);/* Mark receipt of record. */
 
 	return(1);
 
@@ -1811,8 +1861,13 @@ dtls1_get_bitmap(SSL *s, SSL3_RECORD *rr
     if (rr->epoch == s->d1->r_epoch)
         return &s->d1->bitmap;
 
-    /* Only HM and ALERT messages can be from the next epoch */
+    /*
+     * Only HM and ALERT messages can be from the next epoch and only if we
+     * have already processed all of the unprocessed records from the last
+     * epoch
+     */
     else if (rr->epoch == (unsigned long)(s->d1->r_epoch + 1) &&
+        s->d1->unprocessed_rcds.epoch != s->d1->r_epoch &&
         (rr->type == SSL3_RT_HANDSHAKE ||
             rr->type == SSL3_RT_ALERT))
         {
Index: openssl-1.0.1i/ssl/ssl_err.c
===================================================================
--- openssl-1.0.1i.orig/ssl/ssl_err.c	2016-08-22 14:05:29.692569841 +0200
+++ openssl-1.0.1i/ssl/ssl_err.c	2016-08-22 14:06:57.157942683 +0200
@@ -1,6 +1,6 @@
 /* ssl/ssl_err.c */
 /* ====================================================================
- * Copyright (c) 1999-2011 The OpenSSL Project.  All rights reserved.
+ * Copyright (c) 1999-2016 The OpenSSL Project.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -92,6 +92,8 @@ static ERR_STRING_DATA SSL_str_functs[]=
 {ERR_FUNC(SSL_F_DTLS1_HEARTBEAT),	"DTLS1_HEARTBEAT"},
 {ERR_FUNC(SSL_F_DTLS1_OUTPUT_CERT_CHAIN),	"DTLS1_OUTPUT_CERT_CHAIN"},
 {ERR_FUNC(SSL_F_DTLS1_PREPROCESS_FRAGMENT),	"DTLS1_PREPROCESS_FRAGMENT"},
+{ERR_FUNC(SSL_F_DTLS1_PROCESS_BUFFERED_RECORDS),
+ "DTLS1_PROCESS_BUFFERED_RECORDS"},
 {ERR_FUNC(SSL_F_DTLS1_PROCESS_OUT_OF_SEQ_MESSAGE),	"DTLS1_PROCESS_OUT_OF_SEQ_MESSAGE"},
 {ERR_FUNC(SSL_F_DTLS1_PROCESS_RECORD),	"DTLS1_PROCESS_RECORD"},
 {ERR_FUNC(SSL_F_DTLS1_READ_BYTES),	"DTLS1_READ_BYTES"},
Index: openssl-1.0.1i/ssl/ssl.h
===================================================================
--- openssl-1.0.1i.orig/ssl/ssl.h	2016-08-22 14:05:29.692569841 +0200
+++ openssl-1.0.1i/ssl/ssl.h	2016-08-22 14:06:57.157942683 +0200
@@ -2101,6 +2101,7 @@ void ERR_load_SSL_strings(void);
 #define SSL_F_DTLS1_HEARTBEAT				 305
 #define SSL_F_DTLS1_OUTPUT_CERT_CHAIN			 255
 #define SSL_F_DTLS1_PREPROCESS_FRAGMENT			 288
+#define SSL_F_DTLS1_PROCESS_BUFFERED_RECORDS             424
 #define SSL_F_DTLS1_PROCESS_OUT_OF_SEQ_MESSAGE		 256
 #define SSL_F_DTLS1_PROCESS_RECORD			 257
 #define SSL_F_DTLS1_READ_BYTES				 258

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File openssl-CVE-2016-2181.patch of Package openssl (Revision 03cac06d7a7c85e7ad3def593ef00f2d)

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