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

[Matt Caswell]

The branch OpenSSL_1_0_2-stable has been updated
       via  361071993182c0a37d421e2ea9a1f84ec4f1ac4f (commit)
      from  af3aa2b5ef741a35394c92872cbdbab4d46b9c90 (commit)


- Log -----------------------------------------------------------------
commit 361071993182c0a37d421e2ea9a1f84ec4f1ac4f
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;