CVE-2024-26656: drm/amdgpu: fix use-after-free bug

Description

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

drm/amdgpu: fix use-after-free bug

The bug can be triggered by sending a single amdgpu_gem_userptr_ioctl
to the AMDGPU DRM driver on any ASICs with an invalid address and size.
The bug was reported by Joonkyo Jung .
For example the following code:

static void Syzkaller1(int fd)
{
struct drm_amdgpu_gem_userptr arg;
int ret;

arg.addr = 0xffffffffffff0000;
arg.size = 0x80000000; /*2 Gb*/
arg.flags = 0x7;
ret = drmIoctl(fd, 0xc1186451/*amdgpu_gem_userptr_ioctl*/, &arg);
}

Due to the address and size are not valid there is a failure in
amdgpu_hmm_register->mmu_interval_notifier_insert->__mmu_interval_notifier_insert->
check_shl_overflow, but we even the amdgpu_hmm_register failure we still call
amdgpu_hmm_unregister into amdgpu_gem_object_free which causes access to a bad address.
The following stack is below when the issue is reproduced when Kazan is enabled:

[ +0.000014] Hardware name: ASUS System Product Name/ROG STRIX B550-F GAMING (WI-FI), BIOS 1401 12/03/2020
[ +0.000009] RIP: 0010:mmu_interval_notifier_remove+0x327/0x340
[ +0.000017] Code: ff ff 49 89 44 24 08 48 b8 00 01 00 00 00 00 ad de 4c 89 f7 49 89 47 40 48 83 c0 22 49 89 47 48 e8 ce d1 2d 01 e9 32 ff ff ff <0f> 0b e9 16 ff ff ff 4c 89 ef e8 fa 14 b3 ff e9 36 ff ff ff e8 80
[ +0.000014] RSP: 0018:ffffc90002657988 EFLAGS: 00010246
[ +0.000013] RAX: 0000000000000000 RBX: 1ffff920004caf35 RCX: ffffffff8160565b
[ +0.000011] RDX: dfff...

Classification

CVE ID: CVE-2024-26656

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.05% (probability of being exploited)

EPSS Percentile: 17.81% (scored less or equal to compared to others)

EPSS Date: 2025-02-03 (when was this score calculated)

References

https://git.kernel.org/stable/c/e87e08c94c9541b4e18c4c13f2f605935f512605
https://git.kernel.org/stable/c/af054a5fb24a144f99895afce9519d709891894c
https://git.kernel.org/stable/c/22f665ecfd1225afa1309ace623157d12bb9bb0c
https://git.kernel.org/stable/c/22207fd5c80177b860279653d017474b2812af5e

Timeline