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

[Matt Caswell]

The branch OpenSSL_1_0_2-stable has been updated
       via  02a02319ea6cde904e4bfa3a05fe128fd9b6675c (commit)
      from  6d69dc56de8f0535be9ccabea7a8d4e61c04c2f1 (commit)


- Log -----------------------------------------------------------------
commit 02a02319ea6cde904e4bfa3a05fe128fd9b6675c
Author: Matt Caswell <matt at openssl.org>
Date:   Wed Oct 12 16:43:03 2016 +0100

    Ensure we handle len == 0 in ERR_err_string_n
    
    If len == 0 in a call to ERR_error_string_n() then we can read beyond the
    end of the buffer. Really applications should not be calling this function
    with len == 0, but we shouldn't be letting it through either!
    
    Thanks to Agostino Sarubbo for reporting this issue. Agostino's blog on
    this issue is available here:
    https://blogs.gentoo.org/ago/2016/10/14/openssl-libcrypto-stack-based-buffer-overflow-in-err_error_string_n-err-c/
    
    Reviewed-by: Richard Levitte <levitte at openssl.org>
    (cherry picked from commit e5c1361580d8de79682958b04a5f0d262e680f8b)

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

Summary of changes:
 crypto/err/err.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/crypto/err/err.c b/crypto/err/err.c
index e77d963..52dc9a5 100644
--- a/crypto/err/err.c
+++ b/crypto/err/err.c
@@ -868,6 +868,9 @@ void ERR_error_string_n(unsigned long e, char *buf, size_t len)
     const char *ls, *fs, *rs;
     unsigned long l, f, r;
 
+    if (len == 0)
+        return;
+
     l = ERR_GET_LIB(e);
     f = ERR_GET_FUNC(e);
     r = ERR_GET_REASON(e);