CVE-2022-48940
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Description
The CVE Program describes this issue as:
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] ==================================================================
Additional information
- Bugzilla 2307196: kernel: bpf: Fix crash due to incorrect copy_map_value
- CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer
- FAQ: Frequently asked questions about CVE-2022-48940
Common Vulnerability Scoring System (CVSS) Score Details
Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
Red Hat | NVD | |
---|---|---|
CVSS v3 Base Score | 5.5 | 5.5 |
Attack Vector | Local | Local |
Attack Complexity | Low | Low |
Privileges Required | Low | Low |
User Interaction | None | None |
Scope | Unchanged | Unchanged |
Confidentiality Impact | None | None |
Integrity Impact | None | None |
Availability Impact | High | High |
CVSS v3 Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Frequently Asked Questions
Why is Red Hat's CVSS v3 score or Impact different from other vendors?
For more information, see https://access.redhat.com/solutions/762393.
My product is listed as "Under investigation" or "Affected", when will Red Hat release a fix for this vulnerability?
- "Under investigation" doesn't necessarily mean that the product is affected by this vulnerability. It only means that our Analysis Team is still working on determining whether the product is affected and how it is affected.
- "Affected" means that our Analysis Team has determined that this product is affected by this vulnerability and might release a fix to address this in the near future.
What can I do if my product is listed as "Will not fix"?
Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
- Upgrade to a supported product version that includes a fix for this vulnerability (recommended).
- Apply a mitigation (if one exists).
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What can I do if my product is listed as "Fix deferred"?
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- Apply a mitigation (if one exists).
- Open a support case to request a prioritization of releasing a fix for this vulnerability.
- Red Hat Engineering focuses on addressing high-priority issues based on their complexity or limited lifecycle support. Therefore, lower-priority issues will not receive immediate fixes.
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