[openssl-commits] [openssl] OpenSSL_1_0_1-stable update

[Matt Caswell]

The branch OpenSSL_1_0_1-stable has been updated
       via  05bdebb6e011459555795bab20f2e95786153dcc (commit)
      from  32b2ad7e071d0e766da6956f5b0c9cf2ccb18388 (commit)


- Log -----------------------------------------------------------------
commit 05bdebb6e011459555795bab20f2e95786153dcc
Author: Matt Caswell <matt at openssl.org>
Date:   Tue May 19 13:59:47 2015 +0100

    Fix off-by-one error in BN_bn2hex
    
    A BIGNUM can have the value of -0. The function BN_bn2hex fails to account
    for this and can allocate a buffer one byte too short in the event of -0
    being used, leading to a one byte buffer overrun. All usage within the
    OpenSSL library is considered safe. Any security risk is considered
    negligible.
    
    With thanks to Mateusz Kocielski (LogicalTrust), Marek Kroemeke and
    Filip Palian for discovering and reporting this issue.
    
    Reviewed-by: Tim Hudson <tjh at openssl.org>
    (cherry picked from commit c56353071d9849220714d8a556806703771b9269)
    
    Conflicts:
    	crypto/bn/bn_print.c

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

Summary of changes:
 crypto/bn/bn_print.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/crypto/bn/bn_print.c b/crypto/bn/bn_print.c
index 4dcaae3..ab10b95 100644
--- a/crypto/bn/bn_print.c
+++ b/crypto/bn/bn_print.c
@@ -71,7 +71,12 @@ char *BN_bn2hex(const BIGNUM *a)
     char *buf;
     char *p;
 
-    buf = (char *)OPENSSL_malloc(a->top * BN_BYTES * 2 + 2);
+    if (a->neg && BN_is_zero(a)) {
+        /* "-0" == 3 bytes including NULL terminator */
+        buf = OPENSSL_malloc(3);
+    } else {
+        buf = OPENSSL_malloc(a->top * BN_BYTES * 2 + 2);
+    }
     if (buf == NULL) {
         BNerr(BN_F_BN_BN2HEX, ERR_R_MALLOC_FAILURE);
         goto err;