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authorMatt Caswell <matt@openssl.org>2015-05-19 16:03:02 +0100
committerMatt Caswell <matt@openssl.org>2015-05-22 23:43:07 +0100
commitc6eb1cbd1e2afbf0e0e9170cb9b5df1ff25bfd14 (patch)
tree582be98a19c77a791fdf08f3e67413c44c35eeaf /crypto/bn
parent1a9499cf23dfd441628f37c29cfe5ac615255ee1 (diff)
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@openssl.org>
Diffstat (limited to 'crypto/bn')
-rw-r--r--crypto/bn/bn.h1
-rw-r--r--crypto/bn/bn_err.c3
-rw-r--r--crypto/bn/bn_rand.c7
3 files changed, 9 insertions, 2 deletions
diff --git a/crypto/bn/bn.h b/crypto/bn/bn.h
index 7311c0a8cf..5696965e9a 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 a9b7f5193b..e7a703826e 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 9e78d4d42a..f9fb2e9e45 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;