| 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-2024-45020: bpf: Fix a kernel verifier crash in stacksafe() |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| bpf: Fix a kernel verifier crash in stacksafe() |
| |
| Daniel Hodges reported a kernel verifier crash when playing with sched-ext. |
| Further investigation shows that the crash is due to invalid memory access |
| in stacksafe(). More specifically, it is the following code: |
| |
| if (exact != NOT_EXACT && |
| old->stack[spi].slot_type[i % BPF_REG_SIZE] != |
| cur->stack[spi].slot_type[i % BPF_REG_SIZE]) |
| return false; |
| |
| The 'i' iterates old->allocated_stack. |
| If cur->allocated_stack < old->allocated_stack the out-of-bound |
| access will happen. |
| |
| To fix the issue add 'i >= cur->allocated_stack' check such that if |
| the condition is true, stacksafe() should fail. Otherwise, |
| cur->stack[spi].slot_type[i % BPF_REG_SIZE] memory access is legal. |
| |
| The Linux kernel CVE team has assigned CVE-2024-45020 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.6.15 with commit ab470fefce2837e66b771c60858118d50bb5bb10 and fixed in 6.6.48 with commit 7cad3174cc79519bf5f6c4441780264416822c08 |
| Issue introduced in 6.7 with commit 2793a8b015f7f1caadb9bce9c63dc659f7522676 and fixed in 6.10.7 with commit 6e3987ac310c74bb4dd6a2fa8e46702fe505fb2b |
| Issue introduced in 6.7 with commit 2793a8b015f7f1caadb9bce9c63dc659f7522676 and fixed in 6.11 with commit bed2eb964c70b780fb55925892a74f26cb590b25 |
| |
| 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-2024-45020 |
| 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/verifier.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/7cad3174cc79519bf5f6c4441780264416822c08 |
| https://git.kernel.org/stable/c/6e3987ac310c74bb4dd6a2fa8e46702fe505fb2b |
| https://git.kernel.org/stable/c/bed2eb964c70b780fb55925892a74f26cb590b25 |
