🇰🇷 한글 설명
Linux 커널의 drm/gma500 드라이버에서 발생하는 취약점으로, psb_gem_unpin() 함수가 이미 파괴된 ww_mutex를 호출하여 발생하는 오류입니다. 이로 인해 커널 경고(WARN_ON)가 발생하거나 시스템 안정성에 영향을 줄 수 있습니다.
💡 쉬운 설명
그래픽 드라이버가 이미 사라진 메모리 잠금 장치를 사용하려고 시도하면서 발생하는 문제입니다. 이로 인해 컴퓨터 시스템이 불안정해지거나 오류 메시지가 나타날 수 있습니다.
🇺🇸 원문 (English)
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] <TASK>
[ 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---
📍 영향받는 시스템
Linux kernel (gma500_gfx driver module)
⚔️ 공격 벡터
로컬 공격자가 특정 그래픽 자원 해제 과정을 유도하여 커널 경고를 발생시킬 수 있음
🛡️ 대응 방법
Linux 커널을 최신 보안 패치가 적용된 버전으로 업데이트하십시오.
🔧 검증 코드
명령어 실행 결과로 'lock->magic != lock' 또는 'psb_gem_unpin' 관련 경고 메시지가 출력되면 취약한 상태입니다.
dmesg | grep -i 'gma500' | grep -i 'WARN_ON'