From: Stefan Hajnoczi <stefanha@redhat.com>
Date: Thu, 18 Feb 2016 18:55:54 +0000 (+0000)
Subject: sunrpc/cache: fix off-by-one in qword_get()
X-Git-Tag: v3.16.35~337
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=db35046f115513ec04312fbc41d05bb5f7a41efa;p=thirdparty%2Fkernel%2Fstable.git

sunrpc/cache: fix off-by-one in qword_get()

commit b7052cd7bcf3c1478796e93e3dff2b44c9e82943 upstream.

The qword_get() function NUL-terminates its output buffer.  If the input
string is in hex format \xXXXX... and the same length as the output
buffer, there is an off-by-one:

  int qword_get(char **bpp, char *dest, int bufsize)
  {
      ...
      while (len < bufsize) {
          ...
          *dest++ = (h << 4) | l;
          len++;
      }
      ...
      *dest = '\0';
      return len;
  }

This patch ensures the NUL terminator doesn't fall outside the output
buffer.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---

diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index 48f14003af104..14d38ec5e53de 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -1230,7 +1230,7 @@ int qword_get(char **bpp, char *dest, int bufsize)
 	if (bp[0] == '\\' && bp[1] == 'x') {
 		/* HEX STRING */
 		bp += 2;
-		while (len < bufsize) {
+		while (len < bufsize - 1) {
 			int h, l;
 
 			h = hex_to_bin(bp[0]);