| 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-2024-53125: bpf: sync_linked_regs() must preserve subreg_def |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| bpf: sync_linked_regs() must preserve subreg_def |
| |
| Range propagation must not affect subreg_def marks, otherwise the |
| following example is rewritten by verifier incorrectly when |
| BPF_F_TEST_RND_HI32 flag is set: |
| |
| 0: call bpf_ktime_get_ns call bpf_ktime_get_ns |
| 1: r0 &= 0x7fffffff after verifier r0 &= 0x7fffffff |
| 2: w1 = w0 rewrites w1 = w0 |
| 3: if w0 < 10 goto +0 --------------> r11 = 0x2f5674a6 (r) |
| 4: r1 >>= 32 r11 <<= 32 (r) |
| 5: r0 = r1 r1 |= r11 (r) |
| 6: exit; if w0 < 0xa goto pc+0 |
| r1 >>= 32 |
| r0 = r1 |
| exit |
| |
| (or zero extension of w1 at (2) is missing for architectures that |
| require zero extension for upper register half). |
| |
| The following happens w/o this patch: |
| - r0 is marked as not a subreg at (0); |
| - w1 is marked as subreg at (2); |
| - w1 subreg_def is overridden at (3) by copy_register_state(); |
| - w1 is read at (5) but mark_insn_zext() does not mark (2) |
| for zero extension, because w1 subreg_def is not set; |
| - because of BPF_F_TEST_RND_HI32 flag verifier inserts random |
| value for hi32 bits of (2) (marked (r)); |
| - this random value is read at (5). |
| |
| The Linux kernel CVE team has assigned CVE-2024-53125 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.10 with commit 75748837b7e56919679e02163f45d5818c644d03 and fixed in 5.10.232 with commit dadf82c1b2608727bcc306843b540cd7414055a7 |
| Issue introduced in 5.10 with commit 75748837b7e56919679e02163f45d5818c644d03 and fixed in 5.15.175 with commit b57ac2d92c1f565743f6890a5b9cf317ed856b09 |
| Issue introduced in 5.10 with commit 75748837b7e56919679e02163f45d5818c644d03 and fixed in 6.1.121 with commit 60fd3538d2a8fd44c41d25088c0ece3e1fd30659 |
| Issue introduced in 5.10 with commit 75748837b7e56919679e02163f45d5818c644d03 and fixed in 6.6.67 with commit bfe9446ea1d95f6cb7848da19dfd58d2eec6fd84 |
| Issue introduced in 5.10 with commit 75748837b7e56919679e02163f45d5818c644d03 and fixed in 6.11.6 with commit e2ef0f317a52e678fe8fa84b94d6a15b466d6ff0 |
| Issue introduced in 5.10 with commit 75748837b7e56919679e02163f45d5818c644d03 and fixed in 6.12 with commit e9bd9c498cb0f5843996dbe5cbce7a1836a83c70 |
| |
| 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-2024-53125 |
| 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/dadf82c1b2608727bcc306843b540cd7414055a7 |
| https://git.kernel.org/stable/c/b57ac2d92c1f565743f6890a5b9cf317ed856b09 |
| https://git.kernel.org/stable/c/60fd3538d2a8fd44c41d25088c0ece3e1fd30659 |
| https://git.kernel.org/stable/c/bfe9446ea1d95f6cb7848da19dfd58d2eec6fd84 |
| https://git.kernel.org/stable/c/e2ef0f317a52e678fe8fa84b94d6a15b466d6ff0 |
| https://git.kernel.org/stable/c/e9bd9c498cb0f5843996dbe5cbce7a1836a83c70 |
