| 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-2022-48929: bpf: Fix crash due to out of bounds access into reg2btf_ids. |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| bpf: Fix crash due to out of bounds access into reg2btf_ids. |
| |
| When commit e6ac2450d6de ("bpf: Support bpf program calling kernel function") added |
| kfunc support, it defined reg2btf_ids as a cheap way to translate the verifier |
| reg type to the appropriate btf_vmlinux BTF ID, however |
| commit c25b2ae13603 ("bpf: Replace PTR_TO_XXX_OR_NULL with PTR_TO_XXX | PTR_MAYBE_NULL") |
| moved the __BPF_REG_TYPE_MAX from the last member of bpf_reg_type enum to after |
| the base register types, and defined other variants using type flag |
| composition. However, now, the direct usage of reg->type to index into |
| reg2btf_ids may no longer fall into __BPF_REG_TYPE_MAX range, and hence lead to |
| out of bounds access and kernel crash on dereference of bad pointer. |
| |
| The Linux kernel CVE team has assigned CVE-2022-48929 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.16.11 with commit 77459bc4d5e2c6f24db845780b4d9d60cf82d06a and fixed in 5.16.12 with commit f0ce1bc9e0235dd7412240be493d7ea65ed9eadc |
| |
| 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-2022-48929 |
| 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/btf.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/8c39925e98d498b9531343066ef82ae39e41adae |
| https://git.kernel.org/stable/c/f0ce1bc9e0235dd7412240be493d7ea65ed9eadc |
| https://git.kernel.org/stable/c/45ce4b4f9009102cd9f581196d480a59208690c1 |
