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In the Linux kernel, the following vulnerability has been...

Moderate severity Unreviewed Published Aug 22, 2024 to the GitHub Advisory Database • Updated Aug 22, 2024

Package

No package listedSuggest a package

Affected versions

Unknown

Patched versions

Unknown

Description

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

bpf: Fix crash due to incorrect copy_map_value

When both bpf_spin_lock and bpf_timer are present in a BPF map value,
copy_map_value needs to skirt both objects when copying a value into and
out of the map. However, the current code does not set both s_off and
t_off in copy_map_value, which leads to a crash when e.g. bpf_spin_lock
is placed in map value with bpf_timer, as bpf_map_update_elem call will
be able to overwrite the other timer object.

When the issue is not fixed, an overwriting can produce the following
splat:

[root@(none) bpf]# ./test_progs -t timer_crash
[ 15.930339] bpf_testmod: loading out-of-tree module taints kernel.
[ 16.037849] ==================================================================
[ 16.038458] BUG: KASAN: user-memory-access in __pv_queued_spin_lock_slowpath+0x32b/0x520
[ 16.038944] Write of size 8 at addr 0000000000043ec0 by task test_progs/325
[ 16.039399]
[ 16.039514] CPU: 0 PID: 325 Comm: test_progs Tainted: G OE 5.16.0+ #278
[ 16.039983] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ArchLinux 1.15.0-1 04/01/2014
[ 16.040485] Call Trace:
[ 16.040645]
[ 16.040805] dump_stack_lvl+0x59/0x73
[ 16.041069] ? __pv_queued_spin_lock_slowpath+0x32b/0x520
[ 16.041427] kasan_report.cold+0x116/0x11b
[ 16.041673] ? __pv_queued_spin_lock_slowpath+0x32b/0x520
[ 16.042040] __pv_queued_spin_lock_slowpath+0x32b/0x520
[ 16.042328] ? memcpy+0x39/0x60
[ 16.042552] ? pv_hash+0xd0/0xd0
[ 16.042785] ? lockdep_hardirqs_off+0x95/0xd0
[ 16.043079] __bpf_spin_lock_irqsave+0xdf/0xf0
[ 16.043366] ? bpf_get_current_comm+0x50/0x50
[ 16.043608] ? jhash+0x11a/0x270
[ 16.043848] bpf_timer_cancel+0x34/0xe0
[ 16.044119] bpf_prog_c4ea1c0f7449940d_sys_enter+0x7c/0x81
[ 16.044500] bpf_trampoline_6442477838_0+0x36/0x1000
[ 16.044836] __x64_sys_nanosleep+0x5/0x140
[ 16.045119] do_syscall_64+0x59/0x80
[ 16.045377] ? lock_is_held_type+0xe4/0x140
[ 16.045670] ? irqentry_exit_to_user_mode+0xa/0x40
[ 16.046001] ? mark_held_locks+0x24/0x90
[ 16.046287] ? asm_exc_page_fault+0x1e/0x30
[ 16.046569] ? asm_exc_page_fault+0x8/0x30
[ 16.046851] ? lockdep_hardirqs_on+0x7e/0x100
[ 16.047137] entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 16.047405] RIP: 0033:0x7f9e4831718d
[ 16.047602] Code: b4 0c 00 0f 05 eb a9 66 0f 1f 44 00 00 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d b3 6c 0c 00 f7 d8 64 89 01 48
[ 16.048764] RSP: 002b:00007fff488086b8 EFLAGS: 00000206 ORIG_RAX: 0000000000000023
[ 16.049275] RAX: ffffffffffffffda RBX: 00007f9e48683740 RCX: 00007f9e4831718d
[ 16.049747] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007fff488086d0
[ 16.050225] RBP: 00007fff488086f0 R08: 00007fff488085d7 R09: 00007f9e4cb594a0
[ 16.050648] R10: 0000000000000000 R11: 0000000000000206 R12: 00007f9e484cde30
[ 16.051124] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[ 16.051608]
[ 16.051762] ==================================================================

References

Published by the National Vulnerability Database Aug 22, 2024
Published to the GitHub Advisory Database Aug 22, 2024
Last updated Aug 22, 2024

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS score

0.042%
(5th percentile)

Weaknesses

CVE ID

CVE-2022-48940

GHSA ID

GHSA-rc9p-g2q3-x488

Source code

No known source code

Dependabot alerts are not supported on this advisory because it does not have a package from a supported ecosystem with an affected and fixed version.

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