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