Emilio Pozuelo Monfort pushed to branch debian-unstable at X Strike Force / 
xserver / xorg-server


Commits:
a75aebff by Emilio Pozuelo Monfort at 2022-11-10T12:30:06+01:00
Security update

* xkb: proof GetCountedString against request length attacks (CVE-2022-3550)
* xkb: fix some possible memleaks in XkbGetKbdByName (CVE-2022-3551)

- - - - -
936c993b by Emilio Pozuelo Monfort at 2022-11-11T13:35:45+01:00
Release to sid

- - - - -


4 changed files:

- debian/changelog
- + debian/patches/08_xkb-proof-GetCountedString-against-request-length-at.patch
- + debian/patches/09_xkb-fix-some-possible-memleaks-in-XkbGetKbdByName.patch
- debian/patches/series


Changes:

=====================================
debian/changelog
=====================================
@@ -1,3 +1,10 @@
+xorg-server (2:21.1.4-3) unstable; urgency=medium
+
+  * xkb: proof GetCountedString against request length attacks (CVE-2022-3550)
+  * xkb: fix some possible memleaks in XkbGetKbdByName (CVE-2022-3551)
+
+ -- Emilio Pozuelo Monfort <[email protected]>  Fri, 11 Nov 2022 13:35:13 +0100
+
 xorg-server (2:21.1.4-2) unstable; urgency=medium
 
   * 001_fedora_extramodes.patch: Dropped, apparently obsolete since


=====================================
debian/patches/08_xkb-proof-GetCountedString-against-request-length-at.patch
=====================================
@@ -0,0 +1,34 @@
+From 11beef0b7f1ed290348e45618e5fa0d2bffcb72e Mon Sep 17 00:00:00 2001
+From: Peter Hutterer <[email protected]>
+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 <[email protected]>
+---
+ 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);
+-- 
+2.30.2
+


=====================================
debian/patches/09_xkb-fix-some-possible-memleaks-in-XkbGetKbdByName.patch
=====================================
@@ -0,0 +1,59 @@
+From 18f91b950e22c2a342a4fbc55e9ddf7534a707d2 Mon Sep 17 00:00:00 2001
+From: Peter Hutterer <[email protected]>
+Date: Wed, 13 Jul 2022 11:23:09 +1000
+Subject: [PATCH] xkb: fix some possible memleaks in XkbGetKbdByName
+
+GetComponentByName returns an allocated string, so let's free that if we
+fail somewhere.
+
+Signed-off-by: Peter Hutterer <[email protected]>
+---
+ xkb/xkb.c | 26 ++++++++++++++++++++------
+ 1 file changed, 20 insertions(+), 6 deletions(-)
+
+diff --git a/xkb/xkb.c b/xkb/xkb.c
+index 4692895db..b79a269e3 100644
+--- a/xkb/xkb.c
++++ b/xkb/xkb.c
+@@ -5935,18 +5935,32 @@ ProcXkbGetKbdByName(ClientPtr client)
+     xkb = dev->key->xkbInfo->desc;
+     status = Success;
+     str = (unsigned char *) &stuff[1];
+-    if (GetComponentSpec(&str, TRUE, &status))  /* keymap, unsupported */
+-        return BadMatch;
++    {
++        char *keymap = GetComponentSpec(&str, TRUE, &status);  /* keymap, 
unsupported */
++        if (keymap) {
++            free(keymap);
++            return BadMatch;
++        }
++    }
+     names.keycodes = GetComponentSpec(&str, TRUE, &status);
+     names.types = GetComponentSpec(&str, TRUE, &status);
+     names.compat = GetComponentSpec(&str, TRUE, &status);
+     names.symbols = GetComponentSpec(&str, TRUE, &status);
+     names.geometry = GetComponentSpec(&str, TRUE, &status);
+-    if (status != Success)
++    if (status == Success) {
++        len = str - ((unsigned char *) stuff);
++        if ((XkbPaddedSize(len) / 4) != stuff->length)
++            status = BadLength;
++    }
++
++    if (status != Success) {
++        free(names.keycodes);
++        free(names.types);
++        free(names.compat);
++        free(names.symbols);
++        free(names.geometry);
+         return status;
+-    len = str - ((unsigned char *) stuff);
+-    if ((XkbPaddedSize(len) / 4) != stuff->length)
+-        return BadLength;
++    }
+ 
+     CHK_MASK_LEGAL(0x01, stuff->want, XkbGBN_AllComponentsMask);
+     CHK_MASK_LEGAL(0x02, stuff->need, XkbGBN_AllComponentsMask);
+-- 
+2.30.2
+


=====================================
debian/patches/series
=====================================
@@ -6,3 +6,5 @@
 06_use-intel-only-on-pre-gen4.diff
 07_use-modesetting-driver-by-default-on-GeForce.diff
 present-Check-for-NULL-to-prevent-crash.patch
+08_xkb-proof-GetCountedString-against-request-length-at.patch
+09_xkb-fix-some-possible-memleaks-in-XkbGetKbdByName.patch



View it on GitLab: 
https://salsa.debian.org/xorg-team/xserver/xorg-server/-/compare/4456e97e011ac0c6f23f2845a66636d1a7057aa9...936c993b435c641a3696ca292d9169297df8ba3b

-- 
View it on GitLab: 
https://salsa.debian.org/xorg-team/xserver/xorg-server/-/compare/4456e97e011ac0c6f23f2845a66636d1a7057aa9...936c993b435c641a3696ca292d9169297df8ba3b
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