CVE-2022-48940

MEDIUM
Published Aug 22, 2024 Modified Aug 22, 2024 CWE-119

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] <TASK> [ 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] </TASK> [ 16.051762] ==================================================================

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CVSS v3.1 Score

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

Weakness Type (CWE)

CWE-119 Buffer Overflow

Affected Products

Vendor Product
linux linux_kernel
linux linux_kernel

References

Frequently Asked Questions

What is CVE-2022-48940? +
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] <TASK> [ 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] </TASK> [ 16.051762] ================================================================== It has a CVSS v3.1 base score of 5.5 (MEDIUM).
How severe is CVE-2022-48940? +
CVE-2022-48940 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.
What products are affected by CVE-2022-48940? +
CVE-2022-48940 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2022-48940? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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