CVE-2024-49942 drm/xe: Prevent null pointer access in xe_migrate_copy

Medium 5.5 Published Updated

A null pointer dereference in the Linux kernel's xe_migrate_copy function allows local attackers to cause a system crash.

Exploited in the wild
Not known
Login needed
Any signed-in user
Attackable
Local or same network only
Victim action needed
Not needed
Fix
Available

What is CVE-2024-49942?

CVE-2024-49942 is a medium-severity vulnerability in Linux kernel, published on 21 Oct 2024. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

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

drm/xe: Prevent null pointer access in xe_migrate_copy

xe_migrate_copy designed to copy content of TTM resources. When source resource is null, it will trigger a NULL pointer dereference in xe_migrate_copy. To avoid this situation, update lacks source flag to true for this case, the flag will trigger xe_migrate_clear rather than xe_migrate_copy.

Issue trace: <7> [317.089847] xe 0000:00:02.0: [drm:xe_migrate_copy [xe]] Pass 14, sizes: 4194304 & 4194304 <7> [317.089945] xe 0000:00:02.0: [drm:xe_migrate_copy [xe]] Pass 15, sizes: 4194304 & 4194304 <1> [317.128055] BUG: kernel NULL pointer dereference, address: 0000000000000010 <1> [317.128064] #PF: supervisor read access in kernel mode <1> [317.128066] #PF: error_code(0x0000) - not-present page <6> [317.128069] PGD 0 P4D 0 <4> [317.128071] Oops: Oops: 0000 [#1] PREEMPT SMP NOPTI <4> [317.128074] CPU: 1 UID: 0 PID: 1440 Comm: kunit_try_catch Tainted: G U N 6.11.0-rc7-xe #1 <4> [317.128078] Tainted: [U]=USER, [N]=TEST <4> [317.128080] Hardware name: Intel Corporation Lunar Lake Client Platform/LNL-M LP5 RVP1, BIOS LNLMFWI1.R00.3221.D80.2407291239 07/29/2024 <4> [317.128082] RIP: 0010:xe_migrate_copy+0x66/0x13e0 [xe] <4> [317.128158] Code: 00 00 48 89 8d e0 fe ff ff 48 8b 40 10 4c 89 85 c8 fe ff ff 44 88 8d bd fe ff ff 65 48 8b 3c 25 28 00 00 00 48 89 7d d0 31 ff <8b> 79 10 48 89 85 a0 fe ff ff 48 8b 00 48 89 b5 d8 fe ff ff 83 ff <4> [317.128162] RSP: 0018:ffffc9000167f9f0 EFLAGS: 00010246 <4> [317.128164] RAX: ffff8881120d8028 RBX: ffff88814d070428 RCX: 0000000000000000 <4> [317.128166] RDX: ffff88813cb99c00 RSI: 0000000004000000 RDI: 0000000000000000 <4> [317.128168] RBP: ffffc9000167fbb8 R08: ffff88814e7b1f08 R09: 0000000000000001 <4> [317.128170] R10: 0000000000000001 R11: 0000000000000001 R12: ffff88814e7b1f08 <4> [317.128172] R13: ffff88814e7b1f08 R14: ffff88813cb99c00 R15: 0000000000000001 <4> [317.128174] FS: 0000000000000000(0000) GS:ffff88846f280000(0000) knlGS:0000000000000000 <4> [317.128176] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 <4> [317.128178] CR2: 0000000000000010 CR3: 000000011f676004 CR4: 0000000000770ef0 <4> [317.128180] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 <4> [317.128182] DR3: 0000000000000000 DR6: 00000000ffff07f0 DR7: 0000000000000400 <4> [317.128184] PKRU: 55555554 <4> [317.128185] Call Trace: <4> [317.128187] <TASK> <4> [317.128189] ? show_regs+0x67/0x70 <4> [317.128194] ? __die_body+0x20/0x70 <4> [317.128196] ? __die+0x2b/0x40 <4> [317.128198] ? page_fault_oops+0x15f/0x4e0 <4> [317.128203] ? do_user_addr_fault+0x3fb/0x970 <4> [317.128205] ? lock_acquire+0xc7/0x2e0 <4> [317.128209] ? exc_page_fault+0x87/0x2b0 <4> [317.128212] ? asm_exc_page_fault+0x27/0x30 <4> [317.128216] ? xe_migrate_copy+0x66/0x13e0 [xe] <4> [317.128263] ? __lock_acquire+0xb9d/0x26f0 <4> [317.128265] ? __lock_acquire+0xb9d/0x26f0 <4> [317.128267] ? sg_free_append_table+0x20/0x80 <4> [317.128271] ? lock_acquire+0xc7/0x2e0 <4> [317.128273] ? mark_held_locks+0x4d/0x80 <4> [317.128275] ? trace_hardirqs_on+0x1e/0xd0 <4> [317.128278] ? _raw_spin_unlock_irqrestore+0x31/0x60 <4> [317.128281] ? __pm_runtime_resume+0x60/0xa0 <4> [317.128284] xe_bo_move+0x682/0xc50 [xe] <4> [317.128315] ? lock_is_held_type+0xaa/0x120 <4> [317.128318] ttm_bo_handle_move_mem+0xe5/0x1a0 [ttm] <4> [317.128324] ttm_bo_validate+0xd1/0x1a0 [ttm] <4> [317.128328] shrink_test_run_device+0x721/0xc10 [xe] <4> [317.128360] ? find_held_lock+0x31/0x90 <4> [317.128363] ? lock_release+0xd1/0x2a0 <4> [317.128365] ? __pfx_kunit_generic_run_threadfn_adapter+0x10/0x10 [kunit] <4> [317.128370] xe_bo_shrink_kunit+0x11/0x20 [xe] <4> [317.128397] kunit_try_run_case+0x6e/0x150 [kunit] <4> [317.128400] ? trace_hardirqs_on+0x1e/0xd0 <4> [317.128402] ? _raw_spin_unlock_irqrestore+0x31/0x60 <4> [317.128404] kunit_generic_run_threadfn_adapter+0x1e/0x40 [ku ---truncated---

Weakness: CWE-476

Which versions are affected by CVE-2024-49942?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2024-49942?

Apply the vendor's patch.

Is CVE-2024-49942 being exploited?

There is no known exploitation of CVE-2024-49942 in the wild and no public exploit code.

All Linux kernel vulnerabilities

Sources

Also known as BELL-CVE-2024-49942, DEBIAN-CVE-2024-49942, GHSA-9gj6-xqgx-pv89, UBUNTU-CVE-2024-49942.

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