| 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-2024-56549: cachefiles: Fix NULL pointer dereference in object->file |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| cachefiles: Fix NULL pointer dereference in object->file |
| |
| At present, the object->file has the NULL pointer dereference problem in |
| ondemand-mode. The root cause is that the allocated fd and object->file |
| lifetime are inconsistent, and the user-space invocation to anon_fd uses |
| object->file. Following is the process that triggers the issue: |
| |
| [write fd] [umount] |
| cachefiles_ondemand_fd_write_iter |
| fscache_cookie_state_machine |
| cachefiles_withdraw_cookie |
| if (!file) return -ENOBUFS |
| cachefiles_clean_up_object |
| cachefiles_unmark_inode_in_use |
| fput(object->file) |
| object->file = NULL |
| // file NULL pointer dereference! |
| __cachefiles_write(..., file, ...) |
| |
| Fix this issue by add an additional reference count to the object->file |
| before write/llseek, and decrement after it finished. |
| |
| The Linux kernel CVE team has assigned CVE-2024-56549 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.19 with commit c8383054506c77b814489c09877b5db83fd4abf2 and fixed in 6.1.129 with commit d6bba3ece960129a553d4b16f1b00c884dc0993a |
| Issue introduced in 5.19 with commit c8383054506c77b814489c09877b5db83fd4abf2 and fixed in 6.6.78 with commit 785408bbafcfa24c9fc5b251f03fd0780ce182bd |
| Issue introduced in 5.19 with commit c8383054506c77b814489c09877b5db83fd4abf2 and fixed in 6.11.11 with commit f98770440c9bc468e2fd878212ec9526dbe08293 |
| Issue introduced in 5.19 with commit c8383054506c77b814489c09877b5db83fd4abf2 and fixed in 6.12.2 with commit 9582c7664103c9043e80a78f5c382aa6bdd67418 |
| Issue introduced in 5.19 with commit c8383054506c77b814489c09877b5db83fd4abf2 and fixed in 6.13 with commit 31ad74b20227ce6b40910ff78b1c604e42975cf1 |
| |
| 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-2024-56549 |
| 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/cachefiles/interface.c |
| fs/cachefiles/ondemand.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/d6bba3ece960129a553d4b16f1b00c884dc0993a |
| https://git.kernel.org/stable/c/785408bbafcfa24c9fc5b251f03fd0780ce182bd |
| https://git.kernel.org/stable/c/f98770440c9bc468e2fd878212ec9526dbe08293 |
| https://git.kernel.org/stable/c/9582c7664103c9043e80a78f5c382aa6bdd67418 |
| https://git.kernel.org/stable/c/31ad74b20227ce6b40910ff78b1c604e42975cf1 |
