Linux Kernel up to 6.8.x amdgpu amdgpu_gem_userptr_ioctl use after free

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.8.x. It has been declared as problematic. This affects the function amdgpu_gem_userptr_ioctl of the component amdgpu. Executing a manipulation can lead to use after free. The identification of this vulnerability is CVE-2024-26656. There is no exploit available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.8.x. It has been declared as problematic. This vulnerability affects the function amdgpu_gem_userptr_ioctl of the component amdgpu. The manipulation with an unknown input leads to a use after free vulnerability. The CWE definition for the vulnerability is CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. The impact remains unknown. CVE summarizes:

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 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: dffffc0000000000 RSI: 0000000000000004 RDI: ffff8881a9f78260 [ +0.000010] RBP: ffffc90002657a70 R08: 0000000000000001 R09: fffff520004caf25 [ +0.000010] R10: 0000000000000003 R11: ffffffff8161d1d6 R12: ffff88810e988c00 [ +0.000010] R13: ffff888126fb5a00 R14: ffff88810e988c0c R15: ffff8881a9f78260 [ +0.000011] FS: 00007ff9ec848540(0000) GS:ffff8883cc880000(0000) knlGS:0000000000000000 [ +0.000012] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ +0.000010] CR2: 000055b3f7e14328 CR3: 00000001b5770000 CR4: 0000000000350ef0 [ +0.000010] Call Trace: [ +0.000006] [ +0.000007] ? show_regs+0x6a/0x80 [ +0.000018] ? __warn+0xa5/0x1b0 [ +0.000019] ? mmu_interval_notifier_remove+0x327/0x340 [ +0.000018] ? report_bug+0x24a/0x290 [ +0.000022] ? handle_bug+0x46/0x90 [ +0.000015] ? exc_invalid_op+0x19/0x50 [ +0.000016] ? asm_exc_invalid_op+0x1b/0x20 [ +0.000017] ? kasan_save_stack+0x26/0x50 [ +0.000017] ? mmu_interval_notifier_remove+0x23b/0x340 [ +0.000019] ? mmu_interval_notifier_remove+0x327/0x340 [ +0.000019] ? mmu_interval_notifier_remove+0x23b/0x340 [ +0.000020] ? __pfx_mmu_interval_notifier_remove+0x10/0x10 [ +0.000017] ? kasan_save_alloc_info+0x1e/0x30 [ +0.000018] ? srso_return_thunk+0x5/0x5f [ +0.000014] ? __kasan_kmalloc+0xb1/0xc0 [ +0.000018] ? srso_return_thunk+0x5/0x5f [ +0.000013] ? __kasan_check_read+0x11/0x20 [ +0.000020] amdgpu_hmm_unregister+0x34/0x50 [amdgpu] [ +0.004695] amdgpu_gem_object_free+0x66/0xa0 [amdgpu] [ +0.004534] ? __pfx_amdgpu_gem_object_free+0x10/0x10 [amdgpu] [ +0.004291] ? do_syscall_64+0x5f/0xe0 [ +0.000023] ? srso_return_thunk+0x5/0x5f [ +0.000017] drm_gem_object_free+0x3b/0x50 [drm] [ +0.000489] amdgpu_gem_userptr_ioctl+0x306/0x500 [amdgpu] [ +0.004295] ? __pfx_amdgpu_gem_userptr_ioctl+0x10/0x10 [amdgpu] [ +0.004270] ? srso_return_thunk+0x5/0x5f [ +0.000014] ? __this_cpu_preempt_check+0x13/0x20 [ +0.000015] ? srso_return_thunk+0x5/0x5f [ +0.000013] ? sysvec_apic_timer_interrupt+0x57/0xc0 [ +0.000020] ? srso_return_thunk+0x5/0x5f [ +0.000014] ? asm_sysvec_apic_timer_interrupt+0x1b/0x20 [ +0.000022] ? drm_ioctl_kernel+0x17b/0x1f0 [drm] [ +0.000496] ? __pfx_amdgpu_gem_userptr_ioctl+0x10/0x10 [amdgpu] [ +0.004272] ? drm_ioctl_kernel+0x190/0x1f0 [drm] [ +0.000492] drm_ioctl_kernel+0x140/0x1f0 [drm] [ +0.000497] ? __pfx_amdgpu_gem_userptr_ioctl+0x10/0x10 [amdgpu] [ +0.004297] ? __pfx_drm_ioctl_kernel+0x10/0x10 [d ---truncated---

The advisory is shared for download at git.kernel.org. This vulnerability was named CVE-2024-26656 since 02/19/2024. The exploitation appears to be difficult. There are known technical details, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 210888 (RHEL 9 : kernel (RHSA-2024:9497)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.9-rc1 eliminates this vulnerability. Applying the patch 22207fd5c801 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (210888). Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.0
• 6.1
• 6.2
• 6.3
• 6.4
• 6.5
• 6.6
• 6.7
• 6.8

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

• 🔍
• 🔍
• 🔍

CPE 2.2info

• 🔍
• 🔍
• 🔍

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Once again VulDB remains the best source for vulnerability data.

Discussion