| From bippy-1.2.0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@kernel.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2025-22036: exfat: fix random stack corruption after get_block |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| exfat: fix random stack corruption after get_block |
| |
| When get_block is called with a buffer_head allocated on the stack, such |
| as do_mpage_readpage, stack corruption due to buffer_head UAF may occur in |
| the following race condition situation. |
| |
| <CPU 0> <CPU 1> |
| mpage_read_folio |
| <<bh on stack>> |
| do_mpage_readpage |
| exfat_get_block |
| bh_read |
| __bh_read |
| get_bh(bh) |
| submit_bh |
| wait_on_buffer |
| ... |
| end_buffer_read_sync |
| __end_buffer_read_notouch |
| unlock_buffer |
| <<keep going>> |
| ... |
| ... |
| ... |
| ... |
| <<bh is not valid out of mpage_read_folio>> |
| . |
| . |
| another_function |
| <<variable A on stack>> |
| put_bh(bh) |
| atomic_dec(bh->b_count) |
| * stack corruption here * |
| |
| This patch returns -EAGAIN if a folio does not have buffers when bh_read |
| needs to be called. By doing this, the caller can fallback to functions |
| like block_read_full_folio(), create a buffer_head in the folio, and then |
| call get_block again. |
| |
| Let's do not call bh_read() with on-stack buffer_head. |
| |
| The Linux kernel CVE team has assigned CVE-2025-22036 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.8 with commit 11a347fb6cef62ce47e84b97c45f2b2497c7593b and fixed in 6.12.23 with commit 49b0a6ab8e528a0c1c50e37cef9b9c7c121365f2 |
| Issue introduced in 6.8 with commit 11a347fb6cef62ce47e84b97c45f2b2497c7593b and fixed in 6.13.11 with commit f7447286363dc1e410bf30b87d75168f3519f9cc |
| Issue introduced in 6.8 with commit 11a347fb6cef62ce47e84b97c45f2b2497c7593b and fixed in 6.14.2 with commit f807a6bf2005740fa26b4f59c4a003dc966b9afd |
| Issue introduced in 6.8 with commit 11a347fb6cef62ce47e84b97c45f2b2497c7593b and fixed in 6.15 with commit 1bb7ff4204b6d4927e982cd256286c09ed4fd8ca |
| |
| 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-2025-22036 |
| 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: |
| fs/exfat/inode.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/49b0a6ab8e528a0c1c50e37cef9b9c7c121365f2 |
| https://git.kernel.org/stable/c/f7447286363dc1e410bf30b87d75168f3519f9cc |
| https://git.kernel.org/stable/c/f807a6bf2005740fa26b4f59c4a003dc966b9afd |
| https://git.kernel.org/stable/c/1bb7ff4204b6d4927e982cd256286c09ed4fd8ca |
