| 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-2024-40913: cachefiles: defer exposing anon_fd until after copy_to_user() succeeds |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| cachefiles: defer exposing anon_fd until after copy_to_user() succeeds |
| |
| After installing the anonymous fd, we can now see it in userland and close |
| it. However, at this point we may not have gotten the reference count of |
| the cache, but we will put it during colse fd, so this may cause a cache |
| UAF. |
| |
| So grab the cache reference count before fd_install(). In addition, by |
| kernel convention, fd is taken over by the user land after fd_install(), |
| and the kernel should not call close_fd() after that, i.e., it should call |
| fd_install() after everything is ready, thus fd_install() is called after |
| copy_to_user() succeeds. |
| |
| The Linux kernel CVE team has assigned CVE-2024-40913 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.19 with commit c8383054506c77b814489c09877b5db83fd4abf2 and fixed in 6.1.95 with commit eac51d9daacd61dcc93333ff6a890cf3efc8c1c0 |
| Issue introduced in 5.19 with commit c8383054506c77b814489c09877b5db83fd4abf2 and fixed in 6.6.35 with commit d2d3eb377a5d081bf2bed177d354a4f59b74da88 |
| Issue introduced in 5.19 with commit c8383054506c77b814489c09877b5db83fd4abf2 and fixed in 6.9.6 with commit b9f58cdae6a364a3270fd6b6a46e0fd4f7f8ce32 |
| Issue introduced in 5.19 with commit c8383054506c77b814489c09877b5db83fd4abf2 and fixed in 6.10 with commit 4b4391e77a6bf24cba2ef1590e113d9b73b11039 |
| |
| 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-2024-40913 |
| 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/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/eac51d9daacd61dcc93333ff6a890cf3efc8c1c0 |
| https://git.kernel.org/stable/c/d2d3eb377a5d081bf2bed177d354a4f59b74da88 |
| https://git.kernel.org/stable/c/b9f58cdae6a364a3270fd6b6a46e0fd4f7f8ce32 |
| https://git.kernel.org/stable/c/4b4391e77a6bf24cba2ef1590e113d9b73b11039 |
