From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-cve-announce@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: CVE-2022-49552: bpf: Fix combination of jit blinding and pointers to bpf subprogs.
Date: Wed, 26 Feb 2025 03:13:46 +0100 [thread overview]
Message-ID: <2025022616-CVE-2022-49552-e30f@gregkh> (raw)
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix combination of jit blinding and pointers to bpf subprogs.
The combination of jit blinding and pointers to bpf subprogs causes:
[ 36.989548] BUG: unable to handle page fault for address: 0000000100000001
[ 36.990342] #PF: supervisor instruction fetch in kernel mode
[ 36.990968] #PF: error_code(0x0010) - not-present page
[ 36.994859] RIP: 0010:0x100000001
[ 36.995209] Code: Unable to access opcode bytes at RIP 0xffffffd7.
[ 37.004091] Call Trace:
[ 37.004351] <TASK>
[ 37.004576] ? bpf_loop+0x4d/0x70
[ 37.004932] ? bpf_prog_3899083f75e4c5de_F+0xe3/0x13b
The jit blinding logic didn't recognize that ld_imm64 with an address
of bpf subprogram is a special instruction and proceeded to randomize it.
By itself it wouldn't have been an issue, but jit_subprogs() logic
relies on two step process to JIT all subprogs and then JIT them
again when addresses of all subprogs are known.
Blinding process in the first JIT phase caused second JIT to miss
adjustment of special ld_imm64.
Fix this issue by ignoring special ld_imm64 instructions that don't have
user controlled constants and shouldn't be blinded.
The Linux kernel CVE team has assigned CVE-2022-49552 to this issue.
Affected and fixed versions
===========================
Issue introduced in 5.13 with commit 69c087ba6225b574afb6e505b72cb75242a3d844 and fixed in 5.17.13 with commit a029b02b47dd5bb87a21550d9d9a80cb4dd3f714
Issue introduced in 5.13 with commit 69c087ba6225b574afb6e505b72cb75242a3d844 and fixed in 5.18.2 with commit d106a3e96fca30e44081eae9c27aab28fc132a46
Issue introduced in 5.13 with commit 69c087ba6225b574afb6e505b72cb75242a3d844 and fixed in 5.19 with commit 4b6313cf99b0d51b49aeaea98ec76ca8161ecb80
Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.
Unaffected versions might change over time as fixes are backported to
older supported kernel versions. The official CVE entry at
https://cve.org/CVERecord/?id=CVE-2022-49552
will be updated if fixes are backported, please check that for the most
up to date information about this issue.
Affected files
==============
The file(s) affected by this issue are:
kernel/bpf/core.c
Mitigation
==========
The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes. Individual
changes are never tested alone, but rather are part of a larger kernel
release. Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all. If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
https://git.kernel.org/stable/c/a029b02b47dd5bb87a21550d9d9a80cb4dd3f714
https://git.kernel.org/stable/c/d106a3e96fca30e44081eae9c27aab28fc132a46
https://git.kernel.org/stable/c/4b6313cf99b0d51b49aeaea98ec76ca8161ecb80
reply other threads:[~2025-02-26 2:15 UTC|newest]
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