CVE-2023-54086
Description
From CVE.org
In the Linux kernel, the following vulnerability has been resolved: bpf: Add preempt_count_{sub,add} into btf id deny list The recursion check in __bpf_prog_enter* and __bpf_prog_exit* leave preempt_count_{sub,add} unprotected. When attaching trampoline to them we get panic as follows, [ 867.843050] BUG: TASK stack guard page was hit at 0000000009d325cf (stack is 0000000046a46a15..00000000537e7b28) [ 867.843064] stack guard page: 0000 [#1] PREEMPT SMP NOPTI [ 867.843067] CPU: 8 PID: 11009 Comm: trace Kdump: loaded Not tainted 6.2.0+ #4 [ 867.843100] Call Trace: [ 867.843101] <TASK> [ 867.843104] asm_exc_int3+0x3a/0x40 [ 867.843108] RIP: 0010:preempt_count_sub+0x1/0xa0 [ 867.843135] __bpf_prog_enter_recur+0x17/0x90 [ 867.843148] bpf_trampoline_6442468108_0+0x2e/0x1000 [ 867.843154] ? preempt_count_sub+0x1/0xa0 [ 867.843157] preempt_count_sub+0x5/0xa0 [ 867.843159] ? migrate_enable+0xac/0xf0 [ 867.843164] __bpf_prog_exit_recur+0x2d/0x40 [ 867.843168] bpf_trampoline_6442468108_0+0x55/0x1000 ... [ 867.843788] preempt_count_sub+0x5/0xa0 [ 867.843793] ? migrate_enable+0xac/0xf0 [ 867.843829] __bpf_prog_exit_recur+0x2d/0x40 [ 867.843837] BUG: IRQ stack guard page was hit at 0000000099bd8228 (stack is 00000000b23e2bc4..000000006d95af35) [ 867.843841] BUG: IRQ stack guard page was hit at 000000005ae07924 (stack is 00000000ffd69623..0000000014eb594c) [ 867.843843] BUG: IRQ stack guard page was hit at 00000000028320f0 (stack is 00000000034b6438..0000000078d1bcec) [ 867.843842] bpf_trampoline_6442468108_0+0x55/0x1000 ... That is because in __bpf_prog_exit_recur, the preempt_count_{sub,add} are called after prog->active is decreased. Fixing this by adding these two functions into btf ids deny list.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert: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.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 4.4 | N/A | N/A |
| Attack Vector | Local | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | High | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | None | N/A | N/A |
| Integrity Impact | None | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Integrity,Confidentiality,Other
Technical Impact: Modify Application Data; Read Application Data; Alter Execution Logic
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