| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2022-49552: bpf: Fix combination of jit blinding and pointers to bpf subprogs. |
| |
| 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 |
