CVE-2022-49985
bpf: Don't use tnum_range on array range checking for poke descriptors
- Published
- Updated
- Reserved
- Assigned by
- Linux
Description
In the Linux kernel, the following vulnerability has been resolved: bpf: Don't use tnum_range on array range checking for poke descriptors Hsin-Wei reported a KASAN splat triggered by their BPF runtime fuzzer which is based on a customized syzkaller: BUG: KASAN: slab-out-of-bounds in bpf_int_jit_compile+0x1257/0x13f0 Read of size 8 at addr ffff888004e90b58 by task syz-executor.0/1489 CPU: 1 PID: 1489 Comm: syz-executor.0 Not tainted 5.19.0 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x9c/0xc9 print_address_description.constprop.0+0x1f/0x1f0 ? bpf_int_jit_compile+0x1257/0x13f0 kasan_report.cold+0xeb/0x197 ? kvmalloc_node+0x170/0x200 ? bpf_int_jit_compile+0x1257/0x13f0 bpf_int_jit_compile+0x1257/0x13f0 ? arch_prepare_bpf_dispatcher+0xd0/0xd0 ? rcu_read_lock_sched_held+0x43/0x70 bpf_prog_select_runtime+0x3e8/0x640 ? bpf_obj_name_cpy+0x149/0x1b0 bpf_prog_load+0x102f/0x2220 ? __bpf_prog_put.constprop.0+0x220/0x220 ? find_held_lock+0x2c/0x110 ? __might_fault+0xd6/0x180 ? lock_downgrade+0x6e0/0x6e0 ? lock_is_held_type+0xa6/0x120 ? __might_fault+0x147/0x180 __sys_bpf+0x137b/0x6070 ? bpf_perf_link_attach+0x530/0x530 ? new_sync_read+0x600/0x600 ? __fget_files+0x255/0x450 ? lock_downgrade+0x6e0/0x6e0 ? fput+0x30/0x1a0 ? ksys_write+0x1a8/0x260 __x64_sys_bpf+0x7a/0xc0 ? syscall_enter_from_user_mode+0x21/0x70 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f917c4e2c2d The problem here is that a range of tnum_range(0, map->max_entries - 1) has limited ability to represent the concrete tight range with the tnum as the set of resulting states from value + mask can result in a superset of the actual intended range, and as such a tnum_in(range, reg->var_off) check may yield true when it shouldn't, for example tnum_range(0, 2) would result in 00XX -> v = 0000, m = 0011 such that the intended set of {0, 1, 2} is here represented by a less precise superset of {0, 1, 2, 3}. As the register is known const scalar, really just use the concrete reg->var_off.value for the upper index check.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Modified | 3.1 | High7.1 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.26% · top 82% of all CVEs (7 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.8.
Weakness
Affected products
- affected d2e4c1e6c2947269346054ac8937ccfe9e0bcc6b – < e8979807178434db8ceaa84dfcd44363e71e50bb
- affected d2e4c1e6c2947269346054ac8937ccfe9e0bcc6b – < 4f672112f8665102a5842c170be1713f8ff95919
- affected d2e4c1e6c2947269346054ac8937ccfe9e0bcc6b – < a36df92c7ff7ecde2fb362241d0ab024dddd0597
- affected d2e4c1e6c2947269346054ac8937ccfe9e0bcc6b – < a657182a5c5150cdfacb6640aad1d2712571a409
- affected 5.5
- unaffected < 5.5
- unaffected 5.10.140 – ≤ 5.10.*
- unaffected 5.15.64 – ≤ 5.15.*
- unaffected 5.19.6 – ≤ 5.19.*
- unaffected 6.0 – ≤ *
References (4)
- https://git.kernel.org/stable/c/e8979807178434db8ceaa84dfcd44363e71e50bb (opens in a new tab)
- https://git.kernel.org/stable/c/4f672112f8665102a5842c170be1713f8ff95919 (opens in a new tab)
- https://git.kernel.org/stable/c/a36df92c7ff7ecde2fb362241d0ab024dddd0597 (opens in a new tab)
- https://git.kernel.org/stable/c/a657182a5c5150cdfacb6640aad1d2712571a409 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
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[](https://trackcve.app/cve/CVE-2022-49985)Record last updated .