linux-cve-announce - CVE-2022-50068: drm/ttm: Fix dummy res NULL ptr deref bug

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Message-ID: <2025061852-CVE-2022-50068-25c3@gregkh>
Date: Wed, 18 Jun 2025 13:02:13 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2022-50068: drm/ttm: Fix dummy res NULL ptr deref bug

From: Greg Kroah-Hartman <gregkh@...nel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

drm/ttm: Fix dummy res NULL ptr deref bug

Check the bo->resource value before accessing the resource
mem_type.

v2: Fix commit description unwrapped warning

<log snip>
[   40.191227][  T184] general protection fault, probably for non-canonical address 0xdffffc0000000002: 0000 [#1] SMP KASAN PTI
[   40.192995][  T184] KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]
[   40.194411][  T184] CPU: 1 PID: 184 Comm: systemd-udevd Not tainted 5.19.0-rc4-00721-gb297c22b7070 #1
[   40.196063][  T184] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-debian-1.16.0-4 04/01/2014
[   40.199605][  T184] RIP: 0010:ttm_bo_validate+0x1b3/0x240 [ttm]
[   40.200754][  T184] Code: e8 72 c5 ff ff 83 f8 b8 74 d4 85 c0 75 54 49 8b 9e 58 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d 7b 10 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 04 3c 03 7e 44 8b 53 10 31 c0 85 d2 0f 85 58
[   40.203685][  T184] RSP: 0018:ffffc900006df0c8 EFLAGS: 00010202
[   40.204630][  T184] RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 1ffff1102f4bb71b
[   40.205864][  T184] RDX: 0000000000000002 RSI: ffffc900006df208 RDI: 0000000000000010
[   40.207102][  T184] RBP: 1ffff920000dbe1a R08: ffffc900006df208 R09: 0000000000000000
[   40.208394][  T184] R10: ffff88817a5f0000 R11: 0000000000000001 R12: ffffc900006df110
[   40.209692][  T184] R13: ffffc900006df0f0 R14: ffff88817a5db800 R15: ffffc900006df208
[   40.210862][  T184] FS:  00007f6b1d16e8c0(0000) GS:ffff88839d700000(0000) knlGS:0000000000000000
[   40.212250][  T184] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   40.213275][  T184] CR2: 000055a1001d4ff0 CR3: 00000001700f4000 CR4: 00000000000006e0
[   40.214469][  T184] Call Trace:
[   40.214974][  T184]  <TASK>
[   40.215438][  T184]  ? ttm_bo_bounce_temp_buffer+0x140/0x140 [ttm]
[   40.216572][  T184]  ? mutex_spin_on_owner+0x240/0x240
[   40.217456][  T184]  ? drm_vma_offset_add+0xaa/0x100 [drm]
[   40.218457][  T184]  ttm_bo_init_reserved+0x3d6/0x540 [ttm]
[   40.219410][  T184]  ? shmem_get_inode+0x744/0x980
[   40.220231][  T184]  ttm_bo_init_validate+0xb1/0x200 [ttm]
[   40.221172][  T184]  ? bo_driver_evict_flags+0x340/0x340 [drm_vram_helper]
[   40.222530][  T184]  ? ttm_bo_init_reserved+0x540/0x540 [ttm]
[   40.223643][  T184]  ? __do_sys_finit_module+0x11a/0x1c0
[   40.224654][  T184]  ? __shmem_file_setup+0x102/0x280
[   40.234764][  T184]  drm_gem_vram_create+0x305/0x480 [drm_vram_helper]
[   40.235766][  T184]  ? bo_driver_evict_flags+0x340/0x340 [drm_vram_helper]
[   40.236846][  T184]  ? __kasan_slab_free+0x108/0x180
[   40.237650][  T184]  drm_gem_vram_fill_create_dumb+0x134/0x340 [drm_vram_helper]
[   40.238864][  T184]  ? local_pci_probe+0xdf/0x180
[   40.239674][  T184]  ? drmm_vram_helper_init+0x400/0x400 [drm_vram_helper]
[   40.240826][  T184]  drm_client_framebuffer_create+0x19c/0x400 [drm]
[   40.241955][  T184]  ? drm_client_buffer_delete+0x200/0x200 [drm]
[   40.243001][  T184]  ? drm_client_pick_crtcs+0x554/0xb80 [drm]
[   40.244030][  T184]  drm_fb_helper_generic_probe+0x23f/0x940 [drm_kms_helper]
[   40.245226][  T184]  ? __cond_resched+0x1c/0xc0
[   40.245987][  T184]  ? drm_fb_helper_memory_range_to_clip+0x180/0x180 [drm_kms_helper]
[   40.247316][  T184]  ? mutex_unlock+0x80/0x100
[   40.248005][  T184]  ? __mutex_unlock_slowpath+0x2c0/0x2c0
[   40.249083][  T184]  drm_fb_helper_single_fb_probe+0x907/0xf00 [drm_kms_helper]
[   40.250314][  T184]  ? drm_fb_helper_check_var+0x1180/0x1180 [drm_kms_helper]
[   40.251540][  T184]  ? __cond_resched+0x1c/0xc0
[   40.252321][  T184]  ? mutex_lock+0x9f/0x100
[   40.253062][  T184]  __drm_fb_helper_initial_config_and_unlock+0xb9/0x2c0 [drm_kms_helper]
[   40.254394][  T184]  drm_fbdev_client_hotplug+0x56f/0x840 [drm_kms_helper]
[   40.255477][  T184]  drm_fbdev_generic_setup+0x165/0x3c0 [drm_kms_helper]
[   40.256607][  T184]  bochs_pci_probe+0x6b7/0x900 [bochs]
[   40.257515][  T184]  ? _raw_spin_lock_irqsave+0x87/0x100
[   40.258312][  T184]  ? bochs_hw_init+0x480/0x480 [bochs]
[   40.259244][  T184]  ? bochs_hw_init+0x480/0x480 [bochs]
[   40.260186][  T184]  local_pci_probe+0xdf/0x180
[   40.260928][  T184]  pci_call_probe+0x15f/0x500
[   40.265798][  T184]  ? _raw_spin_lock+0x81/0x100
[   40.266508][  T184]  ? pci_pm_suspend_noirq+0x980/0x980
[   40.267322][  T184]  ? pci_assign_irq+0x81/0x280
[   40.268096][  T184]  ? pci_match_device+0x351/0x6c0
[   40.268883][  T184]  ? kernfs_put+0x18/0x40
[   40.269611][  T184]  pci_device_probe+0xee/0x240
[   40.270352][  T184]  really_probe+0x435/0xa80
[   40.271021][  T184]  __driver_probe_device+0x2ab/0x480
[   40.271828][  T184]  driver_probe_device+0x49/0x140
[   40.272627][  T184]  __driver_attach+0x1bd/0x4c0
[   40.273372][  T184]  ? __device_attach_driver+0x240/0x240
[   40.274273][  T184]  bus_for_each_dev+0x11e/0x1c0
[   40.275080][  T184]  ? subsys_dev_iter_exit+0x40/0x40
[   40.275951][  T184]  ? klist_add_tail+0x132/0x280
[   40.276767][  T184]  bus_add_driver+0x39b/0x580
[   40.277574][  T184]  driver_register+0x20f/0x3c0
[   40.278281][  T184]  ? 0xffffffffc04a2000
[   40.278894][  T184]  do_one_initcall+0x8a/0x300
[   40.279642][  T184]  ? trace_event_raw_event_initcall_level+0x1c0/0x1c0
[   40.280707][  T184]  ? kasan_unpoison+0x23/0x80
[   40.281479][  T184]  ? kasan_unpoison+0x23/0x80
[   40.282197][  T184]  do_init_module+0x190/0x640
[   40.282926][  T184]  load_module+0x221b/0x2780
[   40.283611][  T184]  ? layout_and_allocate+0x5c0/0x5c0
[   40.284401][  T184]  ? kernel_read_file+0x286/0x6c0
[   40.285216][  T184]  ? __x64_sys_fspick+0x2c0/0x2c0
[   40.286043][  T184]  ? mmap_region+0x4e7/0x1300
[   40.286832][  T184]  ? __do_sys_finit_module+0x11a/0x1c0
[   40.287743][  T184]  __do_sys_finit_module+0x11a/0x1c0
[   40.288636][  T184]  ? __ia32_sys_init_module+0xc0/0xc0
[   40.289557][  T184]  ? __seccomp_filter+0x15e/0xc80
[   40.290341][  T184]  ? vm_mmap_pgoff+0x185/0x240
[   40.291060][  T184]  do_syscall_64+0x3b/0xc0
[   40.291763][  T184]  entry_SYSCALL_64_after_hwframe+0x46/0xb0
[   40.292678][  T184] RIP: 0033:0x7f6b1d6279b9
[   40.293438][  T184] Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d a7 54 0c 00 f7 d8 64 89 01 48
[   40.296302][  T184] RSP: 002b:00007ffe7f51b798 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
[   40.297633][  T184] RAX: ffffffffffffffda RBX: 00005642dcca2880 RCX: 00007f6b1d6279b9
[   40.298890][  T184] RDX: 0000000000000000 RSI: 00007f6b1d7b2e2d RDI: 0000000000000016
[   40.300199][  T184] RBP: 0000000000020000 R08: 0000000000000000 R09: 00005642dccd5530
[   40.301547][  T184] R10: 0000000000000016 R11: 0000000000000246 R12: 00007f6b1d7b2e2d
[   40.302698][  T184] R13: 0000000000000000 R14: 00005642dcca4230 R15: 00005642dcca2880

The Linux kernel CVE team has assigned CVE-2022-50068 to this issue.


Affected and fixed versions
===========================

	Fixed in 5.15.63 with commit 76672cd326c146ded2c2712ff257b8908dcf23d8
	Fixed in 5.19.4 with commit 9bd970d4097287778a4449452e70b35d0bfaa3aa
	Fixed in 6.0 with commit cf4b7387c0a842d64bdd7c353e6d3298174a7740

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2022-50068
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/gpu/drm/ttm/ttm_bo.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/76672cd326c146ded2c2712ff257b8908dcf23d8
	https://git.kernel.org/stable/c/9bd970d4097287778a4449452e70b35d0bfaa3aa
	https://git.kernel.org/stable/c/cf4b7387c0a842d64bdd7c353e6d3298174a7740