CVE-2022-48983

published 2024-10-21

CVE-2022-48983: In the Linux kernel, the following vulnerability has been resolved: io_uring: Fix a null-ptr-deref in io_tctx_exit_cb() Syzkaller reports a NULL deref bug as…

Priority P4 21 medium 5.5 CVSS 3.1

AV L AC L PR L UI N S U C N I N A H

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

io_uring: Fix a null-ptr-deref in io_tctx_exit_cb()

Syzkaller reports a NULL deref bug as follows:

BUG: KASAN: null-ptr-deref in io_tctx_exit_cb+0x53/0xd3
Read of size 4 at addr 0000000000000138 by task file1/1955

CPU: 1 PID: 1955 Comm: file1 Not tainted 6.1.0-rc7-00103-gef4d3ea40565 #75
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014
Call Trace:

dump_stack_lvl+0xcd/0x134
? io_tctx_exit_cb+0x53/0xd3
kasan_report+0xbb/0x1f0
? io_tctx_exit_cb+0x53/0xd3
kasan_check_range+0x140/0x190
io_tctx_exit_cb+0x53/0xd3
task_work_run+0x164/0x250
? task_work_cancel+0x30/0x30
get_signal+0x1c3/0x2440
? lock_downgrade+0x6e0/0x6e0
? lock_downgrade+0x6e0/0x6e0
? exit_signals+0x8b0/0x8b0
? do_raw_read_unlock+0x3b/0x70
? do_raw_spin_unlock+0x50/0x230
arch_do_signal_or_restart+0x82/0x2470
? kmem_cache_free+0x260/0x4b0
? putname+0xfe/0x140
? get_sigframe_size+0x10/0x10
? do_execveat_common.isra.0+0x226/0x710
? lockdep_hardirqs_on+0x79/0x100
? putname+0xfe/0x140
? do_execveat_common.isra.0+0x238/0x710
exit_to_user_mode_prepare+0x15f/0x250
syscall_exit_to_user_mode+0x19/0x50
do_syscall_64+0x42/0xb0
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0023:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 002b:00000000fffb7790 EFLAGS: 00000200 ORIG_RAX: 000000000000000b
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Kernel panic - not syncing: panic_on_warn set ...

This happens because the adding of task_work from io_ring_exit_work()
isn't synchronized with canceling all work items from eg exec. The
execution of the two are ordered in that they are both run by the task
itself, but if io_tctx_exit

Affected

11 ranges

Vendor	Product	Version range	Fixed in
debian	linux	< linux 6.1.4-1 (bookworm)	linux 6.1.4-1 (bookworm)
linux	linux	—	—
linux	linux	>= d56d938b4bef3e1421a42023cdcd6e13c1f50831 < f895511de9d27fff71dad2c234ad53b4afd2b06c	f895511de9d27fff71dad2c234ad53b4afd2b06c
linux	linux	>= d56d938b4bef3e1421a42023cdcd6e13c1f50831 < d91edca1943453aaaba4f380f6f364346222e5cf	d91edca1943453aaaba4f380f6f364346222e5cf
linux	linux	>= d56d938b4bef3e1421a42023cdcd6e13c1f50831 < 998b30c3948e4d0b1097e639918c5cff332acac5	998b30c3948e4d0b1097e639918c5cff332acac5
linux	linux_kernel	—	—
linux	linux_kernel	>= 0 < 6.1.4-1	6.1.4-1
linux	linux_kernel	>= 0 < 6.1.4-1	6.1.4-1
linux	linux_kernel	>= 0 < 6.1.4-1	6.1.4-1
linux	linux_kernel	>= 5.12 < 5.15.83	5.15.83
linux	linux_kernel	>= 5.16 < 6.0.13	6.0.13

CVSS provenance

nvd v3.1 5.5 MEDIUM CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

osv 5.5 MEDIUM

vendor_debian 5.5 MEDIUM

vendor_redhat 5.5 MEDIUM

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