CVE-2022-48633

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

drm/gma500: Fix WARN_ON(lock->magic != lock) error

psb_gem_unpin() calls dma_resv_lock() but the underlying ww_mutex gets destroyed by drm_gem_object_release() move the drm_gem_object_release() call in psb_gem_free_object() to after the unpin to fix the below warning:

[ 79.693962] ————[ cut here ]———— [ 79.693992] DEBUG_LOCKS_WARN_ON(lock->magic != lock) [ 79.694015] WARNING: CPU: 0 PID: 240 at kernel/locking/mutex.c:582 __ww_mutex_lock.constprop.0+0x569/0xfb0 [ 79.694052] Modules linked in: rfcomm snd_seq_dummy snd_hrtimer qrtr bnep ath9k ath9k_common ath9k_hw snd_hda_codec_realtek snd_hda_codec_generic ledtrig_audio snd_hda_codec_hdmi snd_hda_intel ath3k snd_intel_dspcfg mac80211 snd_intel_sdw_acpi btusb snd_hda_codec btrtl btbcm btintel btmtk bluetooth at24 snd_hda_core snd_hwdep uvcvideo snd_seq libarc4 videobuf2_vmalloc ath videobuf2_memops videobuf2_v4l2 videobuf2_common snd_seq_device videodev acer_wmi intel_powerclamp coretemp mc snd_pcm joydev sparse_keymap ecdh_generic pcspkr wmi_bmof cfg80211 i2c_i801 i2c_smbus snd_timer snd r8169 rfkill lpc_ich soundcore acpi_cpufreq zram rtsx_pci_sdmmc mmc_core serio_raw rtsx_pci gma500_gfx(E) video wmi ip6_tables ip_tables i2c_dev fuse [ 79.694436] CPU: 0 PID: 240 Comm: plymouthd Tainted: G W E 6.0.0-rc3+ #490 [ 79.694457] Hardware name: Packard Bell dot s/SJE01_CT, BIOS V1.10 07/23/2013 [ 79.694469] RIP: 0010:__ww_mutex_lock.constprop.0+0x569/0xfb0 [ 79.694496] Code: ff 85 c0 0f 84 15 fb ff ff 8b 05 ca 3c 11 01 85 c0 0f 85 07 fb ff ff 48 c7 c6 30 cb 84 aa 48 c7 c7 a3 e1 82 aa e8 ac 29 f8 ff <0f> 0b e9 ed fa ff ff e8 5b 83 8a ff 85 c0 74 10 44 8b 0d 98 3c 11 [ 79.694513] RSP: 0018:ffffad1dc048bbe0 EFLAGS: 00010282 [ 79.694623] RAX: 0000000000000028 RBX: 0000000000000000 RCX: 0000000000000000 [ 79.694636] RDX: 0000000000000001 RSI: ffffffffaa8b0ffc RDI: 00000000ffffffff [ 79.694650] RBP: ffffad1dc048bc80 R08: 0000000000000000 R09: ffffad1dc048ba90 [ 79.694662] R10: 0000000000000003 R11: ffffffffaad62fe8 R12: ffff9ff302103138 [ 79.694675] R13: ffff9ff306ec8000 R14: ffff9ff307779078 R15: ffff9ff3014c0270 [ 79.694690] FS: 00007ff1cccf1740(0000) GS:ffff9ff3bc200000(0000) knlGS:0000000000000000 [ 79.694705] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 79.694719] CR2: 0000559ecbcb4420 CR3: 0000000013210000 CR4: 00000000000006f0 [ 79.694734] Call Trace: [ 79.694749] [ 79.694761] ? __schedule+0x47f/0x1670 [ 79.694796] ? psb_gem_unpin+0x27/0x1a0 [gma500_gfx] [ 79.694830] ? lock_is_held_type+0xe3/0x140 [ 79.694864] ? ww_mutex_lock+0x38/0xa0 [ 79.694885] ? __cond_resched+0x1c/0x30 [ 79.694902] ww_mutex_lock+0x38/0xa0 [ 79.694925] psb_gem_unpin+0x27/0x1a0 [gma500_gfx] [ 79.694964] psb_gem_unpin+0x199/0x1a0 [gma500_gfx] [ 79.694996] drm_gem_object_release_handle+0x50/0x60 [ 79.695020] ? drm_gem_object_handle_put_unlocked+0xf0/0xf0 [ 79.695042] idr_for_each+0x4b/0xb0 [ 79.695066] ? _raw_spin_unlock_irqrestore+0x30/0x60 [ 79.695095] drm_gem_release+0x1c/0x30 [ 79.695118] drm_file_free.part.0+0x1ea/0x260 [ 79.695150] drm_release+0x6a/0x120 [ 79.695175] __fput+0x9f/0x260 [ 79.695203] task_work_run+0x59/0xa0 [ 79.695227] do_exit+0x387/0xbe0 [ 79.695250] ? seqcount_lockdep_reader_access.constprop.0+0x82/0x90 [ 79.695275] ? lockdep_hardirqs_on+0x7d/0x100 [ 79.695304] do_group_exit+0x33/0xb0 [ 79.695331] __x64_sys_exit_group+0x14/0x20 [ 79.695353] do_syscall_64+0x58/0x80 [ 79.695376] ? up_read+0x17/0x20 [ 79.695401] ? lock_is_held_type+0xe3/0x140 [ 79.695429] ? asm_exc_page_fault+0x22/0x30 [ 79.695450] ? lockdep_hardirqs_on+0x7d/0x100 [ 79.695473] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 79.695493] RIP: 0033:0x7ff1ccefe3f1 [ 79.695516] Code: Unable to access opcode bytes at RIP 0x7ff1ccefe3c7. [ 79.695607] RSP: 002b:00007ffed4413378 EFLAGS: —truncated—

Weakness

The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.

Affected Software

Extended Description

While assertion is good for catching logic errors and reducing the chances of reaching more serious vulnerability conditions, it can still lead to a denial of service. For example, if a server handles multiple simultaneous connections, and an assert() occurs in one single connection that causes all other connections to be dropped, this is a reachable assertion that leads to a denial of service.

Potential Mitigations

References

• https://git.kernel.org/stable/c/55c077d97fa67e9f19952bb24122a8316b089474
• https://git.kernel.org/stable/c/b6f25c3b94f2aadbf5cbef954db4073614943d74
• https://git.kernel.org/stable/c/55c077d97fa67e9f19952bb24122a8316b089474
• https://git.kernel.org/stable/c/b6f25c3b94f2aadbf5cbef954db4073614943d74