Message-ID: <2025022641-CVE-2022-49341-b0e9@gregkh>
Date: Wed, 26 Feb 2025 03:10:15 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: CVE-2022-49341: bpf, arm64: Clear prog->jited_len along prog->jited

Description
===========

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

bpf, arm64: Clear prog->jited_len along prog->jited

syzbot reported an illegal copy_to_user() attempt
from bpf_prog_get_info_by_fd() [1]

There was no repro yet on this bug, but I think
that commit 0aef499f3172 ("mm/usercopy: Detect vmalloc overruns")
is exposing a prior bug in bpf arm64.

bpf_prog_get_info_by_fd() looks at prog->jited_len
to determine if the JIT image can be copied out to user space.

My theory is that syzbot managed to get a prog where prog->jited_len
has been set to 43, while prog->bpf_func has ben cleared.

It is not clear why copy_to_user(uinsns, NULL, ulen) is triggering
this particular warning.

I thought find_vma_area(NULL) would not find a vm_struct.
As we do not hold vmap_area_lock spinlock, it might be possible
that the found vm_struct was garbage.

[1]
usercopy: Kernel memory exposure attempt detected from vmalloc (offset 792633534417210172, size 43)!
kernel BUG at mm/usercopy.c:101!
Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 25002 Comm: syz-executor.1 Not tainted 5.18.0-syzkaller-10139-g8291eaafed36 #0
Hardware name: linux,dummy-virt (DT)
pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : usercopy_abort+0x90/0x94 mm/usercopy.c:101
lr : usercopy_abort+0x90/0x94 mm/usercopy.c:89
sp : ffff80000b773a20
x29: ffff80000b773a30 x28: faff80000b745000 x27: ffff80000b773b48
x26: 0000000000000000 x25: 000000000000002b x24: 0000000000000000
x23: 00000000000000e0 x22: ffff80000b75db67 x21: 0000000000000001
x20: 000000000000002b x19: ffff80000b75db3c x18: 00000000fffffffd
x17: 2820636f6c6c616d x16: 76206d6f72662064 x15: 6574636574656420
x14: 74706d6574746120 x13: 2129333420657a69 x12: 73202c3237313031
x11: 3237313434333533 x10: 3336323937207465 x9 : 657275736f707865
x8 : ffff80000a30c550 x7 : ffff80000b773830 x6 : ffff80000b773830
x5 : 0000000000000000 x4 : ffff00007fbbaa10 x3 : 0000000000000000
x2 : 0000000000000000 x1 : f7ff000028fc0000 x0 : 0000000000000064
Call trace:
 usercopy_abort+0x90/0x94 mm/usercopy.c:89
 check_heap_object mm/usercopy.c:186 [inline]
 __check_object_size mm/usercopy.c:252 [inline]
 __check_object_size+0x198/0x36c mm/usercopy.c:214
 check_object_size include/linux/thread_info.h:199 [inline]
 check_copy_size include/linux/thread_info.h:235 [inline]
 copy_to_user include/linux/uaccess.h:159 [inline]
 bpf_prog_get_info_by_fd.isra.0+0xf14/0xfdc kernel/bpf/syscall.c:3993
 bpf_obj_get_info_by_fd+0x12c/0x510 kernel/bpf/syscall.c:4253
 __sys_bpf+0x900/0x2150 kernel/bpf/syscall.c:4956
 __do_sys_bpf kernel/bpf/syscall.c:5021 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5019 [inline]
 __arm64_sys_bpf+0x28/0x40 kernel/bpf/syscall.c:5019
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x48/0x114 arch/arm64/kernel/syscall.c:52
 el0_svc_common.constprop.0+0x44/0xec arch/arm64/kernel/syscall.c:142
 do_el0_svc+0xa0/0xc0 arch/arm64/kernel/syscall.c:206
 el0_svc+0x44/0xb0 arch/arm64/kernel/entry-common.c:624
 el0t_64_sync_handler+0x1ac/0x1b0 arch/arm64/kernel/entry-common.c:642
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:581
Code: aa0003e3 d00038c0 91248000 97fff65f (d4210000)

The Linux kernel CVE team has assigned CVE-2022-49341 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 4.16 with commit db496944fdaaf2a67d2f60529f5dc23abf809506 and fixed in 4.19.247 with commit aaf61a312af63e1cfe2264c4c5b8cd4ea3626025
	Issue introduced in 4.16 with commit db496944fdaaf2a67d2f60529f5dc23abf809506 and fixed in 5.4.198 with commit e412b3d178ea4bf746f6b8ee086761613704c6be
	Issue introduced in 4.16 with commit db496944fdaaf2a67d2f60529f5dc23abf809506 and fixed in 5.10.122 with commit 0cf7aaff290cdc4d7cee683d4a18138b0dacac48
	Issue introduced in 4.16 with commit db496944fdaaf2a67d2f60529f5dc23abf809506 and fixed in 5.15.47 with commit 3f4d5e727aeaa610688d46c9f101f78b7f712583
	Issue introduced in 4.16 with commit db496944fdaaf2a67d2f60529f5dc23abf809506 and fixed in 5.17.15 with commit 5c25a3040bc0486c41a7b63a1fb0de7cdb846ad7
	Issue introduced in 4.16 with commit db496944fdaaf2a67d2f60529f5dc23abf809506 and fixed in 5.18.4 with commit 41f7c4f85d402043687e863627a1a84fa867c62d
	Issue introduced in 4.16 with commit db496944fdaaf2a67d2f60529f5dc23abf809506 and fixed in 5.19 with commit 10f3b29c65bb2fe0d47c2945cd0b4087be1c5218

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2022-49341
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	arch/arm64/net/bpf_jit_comp.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/aaf61a312af63e1cfe2264c4c5b8cd4ea3626025
	https://git.kernel.org/stable/c/e412b3d178ea4bf746f6b8ee086761613704c6be
	https://git.kernel.org/stable/c/0cf7aaff290cdc4d7cee683d4a18138b0dacac48
	https://git.kernel.org/stable/c/3f4d5e727aeaa610688d46c9f101f78b7f712583
	https://git.kernel.org/stable/c/5c25a3040bc0486c41a7b63a1fb0de7cdb846ad7
	https://git.kernel.org/stable/c/41f7c4f85d402043687e863627a1a84fa867c62d
	https://git.kernel.org/stable/c/10f3b29c65bb2fe0d47c2945cd0b4087be1c5218

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