[openssl-commits] [openssl] OpenSSL_1_0_2-stable update

[Matt Caswell]

The branch OpenSSL_1_0_2-stable has been updated
       via  c6eb1cbd1e2afbf0e0e9170cb9b5df1ff25bfd14 (commit)
      from  1a9499cf23dfd441628f37c29cfe5ac615255ee1 (commit)


- Log -----------------------------------------------------------------
commit c6eb1cbd1e2afbf0e0e9170cb9b5df1ff25bfd14
Author: Matt Caswell <matt at openssl.org>
Date:   Tue May 19 16:03:02 2015 +0100

    Fix off-by-one in BN_rand
    
    If BN_rand is called with |bits| set to 1 and |top| set to 1 then a 1 byte
    buffer overflow can occur. There are no such instances within the OpenSSL at
    the moment.
    
    Thanks to Mateusz Kocielski (LogicalTrust), Marek Kroemeke, Filip Palian for
    discovering and reporting this issue.
    
    Reviewed-by: Kurt Roeckx <kurt at openssl.org>

-----------------------------------------------------------------------

Summary of changes:
 crypto/bn/bn.h         | 1 +
 crypto/bn/bn_err.c     | 3 ++-
 crypto/bn/bn_rand.c    | 7 ++++++-
 doc/crypto/BN_rand.pod | 3 ++-
 4 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/crypto/bn/bn.h b/crypto/bn/bn.h
index 7311c0a..5696965 100644
--- a/crypto/bn/bn.h
+++ b/crypto/bn/bn.h
@@ -916,6 +916,7 @@ void ERR_load_BN_strings(void);
 # define BN_R_ARG2_LT_ARG3                                100
 # define BN_R_BAD_RECIPROCAL                              101
 # define BN_R_BIGNUM_TOO_LONG                             114
+# define BN_R_BITS_TOO_SMALL                              118
 # define BN_R_CALLED_WITH_EVEN_MODULUS                    102
 # define BN_R_DIV_BY_ZERO                                 103
 # define BN_R_ENCODING_ERROR                              104
diff --git a/crypto/bn/bn_err.c b/crypto/bn/bn_err.c
index a9b7f51..e7a7038 100644
--- a/crypto/bn/bn_err.c
+++ b/crypto/bn/bn_err.c
@@ -1,6 +1,6 @@
 /* crypto/bn/bn_err.c */
 /* ====================================================================
- * Copyright (c) 1999-2007 The OpenSSL Project.  All rights reserved.
+ * Copyright (c) 1999-2015 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
@@ -119,6 +119,7 @@ static ERR_STRING_DATA BN_str_reasons[] = {
     {ERR_REASON(BN_R_ARG2_LT_ARG3), "arg2 lt arg3"},
     {ERR_REASON(BN_R_BAD_RECIPROCAL), "bad reciprocal"},
     {ERR_REASON(BN_R_BIGNUM_TOO_LONG), "bignum too long"},
+    {ERR_REASON(BN_R_BITS_TOO_SMALL), "bits too small"},
     {ERR_REASON(BN_R_CALLED_WITH_EVEN_MODULUS), "called with even modulus"},
     {ERR_REASON(BN_R_DIV_BY_ZERO), "div by zero"},
     {ERR_REASON(BN_R_ENCODING_ERROR), "encoding error"},
diff --git a/crypto/bn/bn_rand.c b/crypto/bn/bn_rand.c
index 9e78d4d..f9fb2e9 100644
--- a/crypto/bn/bn_rand.c
+++ b/crypto/bn/bn_rand.c
@@ -121,6 +121,11 @@ static int bnrand(int pseudorand, BIGNUM *rnd, int bits, int top, int bottom)
     int ret = 0, bit, bytes, mask;
     time_t tim;
 
+    if (bits < 0 || (bits == 1 && top > 0)) {
+        BNerr(BN_F_BNRAND, BN_R_BITS_TOO_SMALL);
+        return 0;
+    }
+
     if (bits == 0) {
         BN_zero(rnd);
         return 1;
@@ -169,7 +174,7 @@ static int bnrand(int pseudorand, BIGNUM *rnd, int bits, int top, int bottom)
     }
 #endif
 
-    if (top != -1) {
+    if (top >= 0) {
         if (top) {
             if (bit == 0) {
                 buf[0] = 1;
diff --git a/doc/crypto/BN_rand.pod b/doc/crypto/BN_rand.pod
index d6b975c..bd6bc86 100644
--- a/doc/crypto/BN_rand.pod
+++ b/doc/crypto/BN_rand.pod
@@ -24,7 +24,8 @@ most significant bit of the random number can be zero. If B<top> is 0,
 it is set to 1, and if B<top> is 1, the two most significant bits of
 the number will be set to 1, so that the product of two such random
 numbers will always have 2*B<bits> length.  If B<bottom> is true, the
-number will be odd.
+number will be odd. The value of B<bits> must be zero or greater. If B<bits> is
+1 then B<top> cannot also be 1.
 
 BN_pseudo_rand() does the same, but pseudo-random numbers generated by
 this function are not necessarily unpredictable. They can be used for