| 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-2024-49889: ext4: avoid use-after-free in ext4_ext_show_leaf() |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| ext4: avoid use-after-free in ext4_ext_show_leaf() |
| |
| In ext4_find_extent(), path may be freed by error or be reallocated, so |
| using a previously saved *ppath may have been freed and thus may trigger |
| use-after-free, as follows: |
| |
| ext4_split_extent |
| path = *ppath; |
| ext4_split_extent_at(ppath) |
| path = ext4_find_extent(ppath) |
| ext4_split_extent_at(ppath) |
| // ext4_find_extent fails to free path |
| // but zeroout succeeds |
| ext4_ext_show_leaf(inode, path) |
| eh = path[depth].p_hdr |
| // path use-after-free !!! |
| |
| Similar to ext4_split_extent_at(), we use *ppath directly as an input to |
| ext4_ext_show_leaf(). Fix a spelling error by the way. |
| |
| Same problem in ext4_ext_handle_unwritten_extents(). Since 'path' is only |
| used in ext4_ext_show_leaf(), remove 'path' and use *ppath directly. |
| |
| This issue is triggered only when EXT_DEBUG is defined and therefore does |
| not affect functionality. |
| |
| The Linux kernel CVE team has assigned CVE-2024-49889 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Fixed in 5.10.227 with commit b0cb4561fc4284d04e69c8a66c8504928ab2484e |
| Fixed in 5.15.168 with commit 4999fed877bb64e3e7f9ab9996de2ca983c41928 |
| Fixed in 6.1.113 with commit 2eba3b0cc5b8de624918d21f32b5b8db59a90b39 |
| Fixed in 6.6.55 with commit 34b2096380ba475771971a778a478661a791aa15 |
| Fixed in 6.10.14 with commit 8b114f2cc7dd5d36729d040b68432fbd0f0a8868 |
| Fixed in 6.11.3 with commit d483c7cc1796bd6a80e7b3a8fd494996260f6b67 |
| Fixed in 6.12 with commit 4e2524ba2ca5f54bdbb9e5153bea00421ef653f5 |
| |
| 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-2024-49889 |
| 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/ext4/extents.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/b0cb4561fc4284d04e69c8a66c8504928ab2484e |
| https://git.kernel.org/stable/c/4999fed877bb64e3e7f9ab9996de2ca983c41928 |
| https://git.kernel.org/stable/c/2eba3b0cc5b8de624918d21f32b5b8db59a90b39 |
| https://git.kernel.org/stable/c/34b2096380ba475771971a778a478661a791aa15 |
| https://git.kernel.org/stable/c/8b114f2cc7dd5d36729d040b68432fbd0f0a8868 |
| https://git.kernel.org/stable/c/d483c7cc1796bd6a80e7b3a8fd494996260f6b67 |
| https://git.kernel.org/stable/c/4e2524ba2ca5f54bdbb9e5153bea00421ef653f5 |
