CVE-2022-50168
In the Linux kernel, the following vulnerability has been resolved: bpf, x86: fix freeing of not-finalized bpf_prog_pack syzbot reported a few issues with bpf_prog_pack [1], [2].
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.23%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
In the Linux kernel, the following vulnerability has been resolved: bpf, x86: fix freeing of not-finalized bpf_prog_pack syzbot reported a few issues with bpf_prog_pack [1], [2]. This only happens with multiple subprogs. In jit_subprogs(), we first call bpf_int_jit_compile() on each sub program. And then, we call it on each sub program again. jit_data is not freed in the first call of bpf_int_jit_compile(). Similarly we don't call bpf_jit_binary_pack_finalize() in the first call of bpf_int_jit_compile(). If bpf_int_jit_compile() failed for one sub program, we will call bpf_jit_binary_pack_finalize() for this sub program. However, we don't have a chance to call it for other sub programs. Then we will hit "goto out_free" in jit_subprogs(), and call bpf_jit_free on some subprograms that haven't got bpf_jit_binary_pack_finalize() yet. At this point, bpf_jit_binary_pack_free() is called and the whole 2MB page is freed erroneously. Fix this with a custom bpf_jit_free() for x86_64, which calls bpf_jit_binary_pack_finalize() if necessary. Also, with custom bpf_jit_free(), bpf_prog_aux->use_bpf_prog_pack is not needed any more, remove it. [1] https://syzkaller.appspot.com/bug?extid=2f649ec6d2eea1495a8f [2] https://syzkaller.appspot.com/bug?extid=87f65c75f4a72db05445
- CVSS 3.1
- 7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.23% probability · 14th percentile
- CISA KEV
- Not listed
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.