In the Linux kernel, the following vulnerability has been resolved: drm/virtio: fix NULL pointer dereference in virtio_gpu_conn_get_modes drm_cvt_mode may return NULL and we should check it. This bug is found by syzkaller: FAULT_INJECTION stacktrace: [ 168.567394] FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 1 [ 168.567403] CPU: 1 PID: 6425 Comm: syz Kdump: loaded Not tainted 4.19.90-vhulk2201.1.0.h1035.kasan.eulerosv2r10.aarch64 #1 [ 168.567406] Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 [ 168.567408] Call trace: [ 168.567414] dump_backtrace+0x0/0x310 [ 168.567418] show_stack+0x28/0x38 [ 168.567423] dump_stack+0xec/0x15c [ 168.567427] should_fail+0x3ac/0x3d0 [ 168.567437] __should_failslab+0xb8/0x120 [ 168.567441] should_failslab+0x28/0xc0 [ 168.567445] kmem_cache_alloc_trace+0x50/0x640 [ 168.567454] drm_mode_create+0x40/0x90 [ 168.567458] drm_cvt_mode+0x48/0xc78 [ 168.567477] virtio_gpu_conn_get_modes+0xa8/0x140 [virtio_gpu] [ 168.567485] drm_helper_probe_single_connector_modes+0x3a4/0xd80 [ 168.567492] drm_mode_getconnector+0x2e0/0xa70 [ 168.567496] drm_ioctl_kernel+0x11c/0x1d8 [ 168.567514] drm_ioctl+0x558/0x6d0 [ 168.567522] do_vfs_ioctl+0x160/0xf30 [ 168.567525] ksys_ioctl+0x98/0xd8 [ 168.567530] __arm64_sys_ioctl+0x50/0xc8 [ 168.567536] el0_svc_common+0xc8/0x320 [ 168.567540] el0_svc_handler+0xf8/0x160 [ 168.567544] el0_svc+0x10/0x218 KASAN stacktrace: [ 168.567561] BUG: KASAN: null-ptr-deref in virtio_gpu_conn_get_modes+0xb4/0x140 [virtio_gpu] [ 168.567565] Read of size 4 at addr 0000000000000054 by task syz/6425 [ 168.567566] [ 168.567571] CPU: 1 PID: 6425 Comm: syz Kdump: loaded Not tainted 4.19.90-vhulk2201.1.0.h1035.kasan.eulerosv2r10.aarch64 #1 [ 168.567573] Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 [ 168.567575] Call trace: [ 168.567578] dump_backtrace+0x0/0x310 [ 168.567582] show_stack+0x28/0x38 [ 168.567586] dump_stack+0xec/0x15c [ 168.567591] kasan_report+0x244/0x2f0 [ 168.567594] __asan_load4+0x58/0xb0 [ 168.567607] virtio_gpu_conn_get_modes+0xb4/0x140 [virtio_gpu] [ 168.567612] drm_helper_probe_single_connector_modes+0x3a4/0xd80 [ 168.567617] drm_mode_getconnector+0x2e0/0xa70 [ 168.567621] drm_ioctl_kernel+0x11c/0x1d8 [ 168.567624] drm_ioctl+0x558/0x6d0 [ 168.567628] do_vfs_ioctl+0x160/0xf30 [ 168.567632] ksys_ioctl+0x98/0xd8 [ 168.567636] __arm64_sys_ioctl+0x50/0xc8 [ 168.567641] el0_svc_common+0xc8/0x320 [ 168.567645] el0_svc_handler+0xf8/0x160 [ 168.567649] el0_svc+0x10/0x218
| Métrique | Valeur | Interprétation |
|---|---|---|
|
AV (Vecteur d'Attaque)
Attack Vector
|
Local (L)
|
Exploit nécessite un accès local au système |
|
AC (Complexité d'Attaque)
Attack Complexity
|
Low (L)
|
Peu de conditions requises pour exploiter |
|
PR (Privilèges Requis)
Privileges Required
|
Low (L)
|
Authentifié avec compte utilisateur basique |
|
UI (Interaction Utilisateur)
User Interaction
|
None (N)
|
Aucune interaction utilisateur nécessaire |
|
S (Périmètre)
Scope
|
Unchanged (U)
|
Impact reste dans le périmètre du composant compromis |
|
C (Impact Confidentialité)
Confidentiality Impact
|
None (N)
|
Aucune divulgation d'informations |
|
I (Impact Intégrité)
Integrity Impact
|
None (N)
|
Aucune modification de données possible |
|
A (Impact Disponibilité)
Availability Impact
|
High (H)
|
Interruption totale du service possible |