CVE-2022-48762 arm64: extable: fix load_unaligned_zeropad() reg indices
A bug in the Linux kernel arm64 exception handler causes arbitrary register corruption and null pointer dereferences, leading to system crashes.
- 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-2022-48762?
CVE-2022-48762 is a high-severity vulnerability in Linux kernel, published on 20 Jun 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:
arm64: extable: fix load_unaligned_zeropad() reg indices
In ex_handler_load_unaligned_zeropad() we erroneously extract the data and addr register indices from ex->type rather than ex->data. As ex->type will contain EX_TYPE_LOAD_UNALIGNED_ZEROPAD (i.e. 4): * We'll always treat X0 as the address register, since EX_DATA_REG_ADDR is extracted from bits [9:5]. Thus, we may attempt to dereference an arbitrary address as X0 may hold an arbitrary value. * We'll always treat X4 as the data register, since EX_DATA_REG_DATA is extracted from bits [4:0]. Thus we will corrupt X4 and cause arbitrary behaviour within load_unaligned_zeropad() and its caller.
Fix this by extracting both values from ex->data as originally intended.
On an MTE-enabled QEMU image we are hitting the following crash: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 Call trace: fixup_exception+0xc4/0x108 __do_kernel_fault+0x3c/0x268 do_tag_check_fault+0x3c/0x104 do_mem_abort+0x44/0xf4 el1_abort+0x40/0x64 el1h_64_sync_handler+0x60/0xa0 el1h_64_sync+0x7c/0x80 link_path_walk+0x150/0x344 path_openat+0xa0/0x7dc do_filp_open+0xb8/0x168 do_sys_openat2+0x88/0x17c __arm64_sys_openat+0x74/0xa0 invoke_syscall+0x48/0x148 el0_svc_common+0xb8/0xf8 do_el0_svc+0x28/0x88 el0_svc+0x24/0x84 el0t_64_sync_handler+0x88/0xec el0t_64_sync+0x1b4/0x1b8 Code: f8695a69 71007d1f 540000e0 927df12a (f940014a)
Weakness: CWE-476
Which versions are affected by CVE-2022-48762?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2022-48762?
Apply the vendor's patch.
Is CVE-2022-48762 being exploited?
There is no known exploitation of CVE-2022-48762 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2022-48762, GHSA-vj7w-cq55-7h2m, UBUNTU-CVE-2022-48762.