From: Kurt Roeckx <kurt@roeckx.be>
Date: Sun, 19 Jun 2016 12:16:16 +0000 (+0200)
Subject: buf2hexstr: properly deal with empty string
X-Git-Tag: OpenSSL_1_1_0-pre6~372
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=01238aec4071eabf072f4e98e3fb84cbab3c7107;p=oweals%2Fopenssl.git

buf2hexstr: properly deal with empty string

It wrote before the start of the string

found by afl

Reviewed-by: Richard Levitte <levitte@openssl.org>

MR: #2994
---

diff --git a/crypto/o_str.c b/crypto/o_str.c
index 29c324f474..beabec0ddc 100644
--- a/crypto/o_str.c
+++ b/crypto/o_str.c
@@ -198,7 +198,12 @@ char *OPENSSL_buf2hexstr(const unsigned char *buffer, long len)
     const unsigned char *p;
     int i;
 
-    if ((tmp = OPENSSL_malloc(len * 3 + 1)) == NULL) {
+    if (len == 0)
+    {
+        return OPENSSL_zalloc(1);
+    }
+
+    if ((tmp = OPENSSL_malloc(len * 3)) == NULL) {
         CRYPTOerr(CRYPTO_F_OPENSSL_BUF2HEXSTR, ERR_R_MALLOC_FAILURE);
         return NULL;
     }
diff --git a/doc/crypto/OPENSSL_malloc.pod b/doc/crypto/OPENSSL_malloc.pod
index ba50221f1c..5d254f7b90 100644
--- a/doc/crypto/OPENSSL_malloc.pod
+++ b/doc/crypto/OPENSSL_malloc.pod
@@ -124,7 +124,7 @@ An odd number of hex digits is an error.
 
 OPENSSL_buf2hexstr() takes the specified buffer and length, and returns
 a hex string for value, or NULL on error.
-B<Buffer> cannot be NULL; if B<len> is NULL an empty string is returned.
+B<Buffer> cannot be NULL; if B<len> is 0 an empty string is returned.
 
 OPENSSL_hexchar2int() converts a character to the hexadecimal equivalent,
 or returns -1 on error.