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* [PATCH AUTOSEL 4.19 01/38] drm/virtio: fix NULL pointer dereference in virtio_gpu_conn_get_modes
@ 2022-05-30 13:48 Sasha Levin
  2022-05-30 13:48 ` [PATCH AUTOSEL 4.19 07/38] fbcon: Consistently protect deferred_takeover with console_lock() Sasha Levin
                   ` (4 more replies)
  0 siblings, 5 replies; 7+ messages in thread
From: Sasha Levin @ 2022-05-30 13:48 UTC (permalink / raw)
  To: linux-kernel, stable
  Cc: Sasha Levin, airlied, Liu Zixian, dri-devel, virtualization,
	Gerd Hoffmann

From: Liu Zixian <liuzixian4@huawei.com>

[ Upstream commit 194d250cdc4a40ccbd179afd522a9e9846957402 ]

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

Signed-off-by: Liu Zixian <liuzixian4@huawei.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20220322091730.1653-1-liuzixian4@huawei.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/virtio/virtgpu_display.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/virtio/virtgpu_display.c b/drivers/gpu/drm/virtio/virtgpu_display.c
index 25503b933599..7511f416eb67 100644
--- a/drivers/gpu/drm/virtio/virtgpu_display.c
+++ b/drivers/gpu/drm/virtio/virtgpu_display.c
@@ -180,6 +180,8 @@ static int virtio_gpu_conn_get_modes(struct drm_connector *connector)
 		DRM_DEBUG("add mode: %dx%d\n", width, height);
 		mode = drm_cvt_mode(connector->dev, width, height, 60,
 				    false, false, false);
+		if (!mode)
+			return count;
 		mode->type |= DRM_MODE_TYPE_PREFERRED;
 		drm_mode_probed_add(connector, mode);
 		count++;
-- 
2.35.1


^ permalink raw reply related	[flat|nested] 7+ messages in thread

end of thread, other threads:[~2022-06-05 13:28 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-05-30 13:48 [PATCH AUTOSEL 4.19 01/38] drm/virtio: fix NULL pointer dereference in virtio_gpu_conn_get_modes Sasha Levin
2022-05-30 13:48 ` [PATCH AUTOSEL 4.19 07/38] fbcon: Consistently protect deferred_takeover with console_lock() Sasha Levin
2022-05-30 13:48 ` [PATCH AUTOSEL 4.19 10/38] drm/amd/pm: fix double free in si_parse_power_table() Sasha Levin
2022-05-30 13:49 ` [PATCH AUTOSEL 4.19 18/38] drm/plane: Move range check for format_count earlier Sasha Levin
2022-05-30 13:49 ` [PATCH AUTOSEL 4.19 19/38] drm/amd/pm: fix the compile warning Sasha Levin
     [not found] ` <20220530134924.1936816-16-sashal@kernel.org>
2022-05-30 14:41   ` [PATCH AUTOSEL 4.19 16/38] drm/sun4i: Add support for D1 TCONs Samuel Holland
2022-06-05 13:28     ` Sasha Levin

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