git.ipfire.org Git - thirdparty/openembedded/openembedded-core-contrib.git/blob

   1 CVE: CVE-2022-3550
   2 Upstream-Status: Backport
   3 Signed-off-by: Ross Burton <ross.burton@arm.com>
   4
   5 From 11beef0b7f1ed290348e45618e5fa0d2bffcb72e Mon Sep 17 00:00:00 2001
   6 From: Peter Hutterer <peter.hutterer@who-t.net>
   7 Date: Tue, 5 Jul 2022 12:06:20 +1000
   8 Subject: [PATCH] xkb: proof GetCountedString against request length attacks
   9
  10 GetCountedString did a check for the whole string to be within the
  11 request buffer but not for the initial 2 bytes that contain the length
  12 field. A swapped client could send a malformed request to trigger a
  13 swaps() on those bytes, writing into random memory.
  14
  15 Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
  16 ---
  17  xkb/xkb.c | 5 +++++
  18  1 file changed, 5 insertions(+)
  19
  20 diff --git a/xkb/xkb.c b/xkb/xkb.c
  21 index f42f59ef3..1841cff26 100644
  22 --- a/xkb/xkb.c
  23 +++ b/xkb/xkb.c
  24 @@ -5137,6 +5137,11 @@ _GetCountedString(char **wire_inout, ClientPtr client, char **str)
  25      CARD16 len;
  26
  27      wire = *wire_inout;
  28 +
  29 +    if (client->req_len <
  30 +        bytes_to_int32(wire + 2 - (char *) client->requestBuffer))
  31 +        return BadValue;
  32 +
  33      len = *(CARD16 *) wire;
  34      if (client->swapped) {
  35          swaps(&len);
  36 --
  37 2.34.1
  38