Bug#1081338: xorg-server: diff for NMU version 2:21.1.16-1.1
Control: tags 1081338 + pending
Dear maintainer,
I've prepared an NMU for xorg-server (versioned as 2:21.1.16-1.1) and
uploaded it to DELAYED/5. Please feel free to tell me if I
should cancel it.
Regards,
Salvatore
diffstat for xorg-server_21.1.16-1 xorg-server_21.1.16-1.1
debian/patches/09_dix-Hold-input-lock-for-AttachDevice.diff | 91 ++++++++++++
xorg-server-21.1.16/debian/changelog | 8 +
xorg-server-21.1.16/debian/patches/series | 1
3 files changed, 100 insertions(+)
diff -u xorg-server-21.1.16/debian/changelog xorg-server-21.1.16/debian/changelog
--- xorg-server-21.1.16/debian/changelog
+++ xorg-server-21.1.16/debian/changelog
@@ -1,3 +1,11 @@
+xorg-server (2:21.1.16-1.1) unstable; urgency=medium
+
+ * Non-maintainer upload.
+ * dix: Hold input lock for AttachDevice() (CVE-2022-49737)
+ (Closes: #1081338)
+
+ -- Salvatore Bonaccorso <carnil@debian.org> Fri, 02 May 2025 15:04:19 +0200
+
xorg-server (2:21.1.16-1) unstable; urgency=medium
* New upstream release. Fixes:
diff -u xorg-server-21.1.16/debian/patches/series xorg-server-21.1.16/debian/patches/series
--- xorg-server-21.1.16/debian/patches/series
+++ xorg-server-21.1.16/debian/patches/series
@@ -3,3 +3,4 @@
06_use-intel-only-on-pre-gen4.diff
07_use-modesetting-driver-by-default-on-GeForce.diff
08_apple_silicon_config.diff
+09_dix-Hold-input-lock-for-AttachDevice.diff
only in patch2:
unchanged:
--- xorg-server-21.1.16.orig/debian/patches/09_dix-Hold-input-lock-for-AttachDevice.diff
+++ xorg-server-21.1.16/debian/patches/09_dix-Hold-input-lock-for-AttachDevice.diff
@@ -0,0 +1,91 @@
+From: tholin <thomas.lindroth@gmail.com>
+Date: Tue, 4 Jan 2022 12:08:11 +0000
+Subject: dix: Hold input lock for AttachDevice()
+Origin: https://gitlab.freedesktop.org/xorg/xserver/-/commit/ba830583e6a8e9a78f09e2d723813c03142b11f6
+Bug-Debian: https://bugs.debian.org/1081338
+Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2022-49737
+
+Fix the following race:
+
+Possible data race during read of size 8 at 0xA112510 by thread #6
+Locks held: 1, at address 0x366B40
+ at 0x14C8B9: GetMaster (devices.c:2691)
+ by 0x15CFC5: IsFloating (events.c:346)
+ by 0x2B9554: miPointerGetScreen (mipointer.c:527)
+ by 0x1A5136: xf86PostButtonEventM (xf86Xinput.c:1379)
+ by 0x1A52BD: xf86PostButtonEvent (xf86Xinput.c:1345)
+ by 0x485F45B: EvdevProcessEvent (in /usr/lib64/xorg/modules/input/evdev_drv.so)
+ by 0x485FDAC: EvdevReadInput (in /usr/lib64/xorg/modules/input/evdev_drv.so)
+ by 0x195427: xf86ReadInput (xf86Events.c:247)
+ by 0x2CC113: InputReady (inputthread.c:180)
+ by 0x2CE4EA: ospoll_wait (ospoll.c:657)
+ by 0x2CC077: InputThreadDoWork (inputthread.c:369)
+ by 0x484A336: mythread_wrapper (hg_intercepts.c:406)
+
+This conflicts with a previous write of size 8 by thread #1
+Locks held: none
+ at 0x14D2C6: AttachDevice (devices.c:2609)
+ by 0x15CF85: ReattachToOldMaster (events.c:1457)
+ by 0x1647DD: DeactivateKeyboardGrab (events.c:1700)
+ by 0x25D7F1: ProcXIUngrabDevice (xigrabdev.c:169)
+ by 0x2552AD: ProcIDispatch (extinit.c:398)
+ by 0x155291: Dispatch (dispatch.c:479)
+ by 0x158CBA: dix_main (main.c:276)
+ by 0x143A3D: main (stubmain.c:34)
+ Address 0xa112510 is 336 bytes inside a block of size 904 alloc'd
+ at 0x4846571: calloc (vg_replace_malloc.c:1328)
+ by 0x14A0B3: AddInputDevice (devices.c:260)
+ by 0x1A31A0: xf86ActivateDevice (xf86Xinput.c:365)
+ by 0x1A4549: xf86NewInputDevice (xf86Xinput.c:948)
+ by 0x1A4B44: NewInputDeviceRequest (xf86Xinput.c:1090)
+ by 0x1B81FE: device_added (udev.c:282)
+ by 0x1B8516: config_udev_init (udev.c:439)
+ by 0x1B7091: config_init (config.c:50)
+ by 0x197970: InitInput (xf86Init.c:814)
+ by 0x158C6B: dix_main (main.c:250)
+ by 0x143A3D: main (stubmain.c:34)
+ Block was alloc'd by thread #1
+
+The steps to trigger the race are:
+1. Main thread does cleanup at mipointer.c:360 setting the slave device's
+ miPointerPtr to null.
+2. Input thread use MIPOINTER in mipointer.c and get the slave's
+ miPointerPtr = null.
+3. Main thread updates dev->master at devices.c:2609.
+4. MIPOINTER would now return the master's miPointerPtr but the input
+ thread already got the slave's miPointerPtr in step 2 and segfaults by
+ null ptr deref.
+
+Closes: https://gitlab.freedesktop.org/xorg/xserver/-/issues/1260
+Signed-off-by: Thomas Lindroth <thomas.lindroth@gmail.com>
+(cherry picked from commit dc7cb45482cea6ccec22d117ca0b489500b4d0a0)
+
+Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1874>
+---
+ dix/devices.c | 3 +++
+ 1 file changed, 3 insertions(+)
+
+diff --git a/dix/devices.c b/dix/devices.c
+index 77bac49242d6..5f6d32e537a6 100644
+--- a/dix/devices.c
++++ b/dix/devices.c
+@@ -2672,6 +2672,8 @@ AttachDevice(ClientPtr client, DeviceIntPtr dev, DeviceIntPtr master)
+ if (IsFloating(dev) && !master && dev->enabled)
+ return Success;
+
++ input_lock();
++
+ /* free the existing sprite. */
+ if (IsFloating(dev) && dev->spriteInfo->paired == dev) {
+ screen = miPointerGetScreen(dev);
+@@ -2715,6 +2717,7 @@ AttachDevice(ClientPtr client, DeviceIntPtr dev, DeviceIntPtr master)
+ RecalculateMasterButtons(master);
+ }
+
++ input_unlock();
+ /* XXX: in theory, the MD should change back to its old, original
+ * classes when the last SD is detached. Thanks to the XTEST devices,
+ * we'll always have an SD attached until the MD is removed.
+--
+2.49.0
+
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