| 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-2024-39276: ext4: fix mb_cache_entry's e_refcnt leak in ext4_xattr_block_cache_find() |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| ext4: fix mb_cache_entry's e_refcnt leak in ext4_xattr_block_cache_find() |
| |
| Syzbot reports a warning as follows: |
| |
| ============================================ |
| WARNING: CPU: 0 PID: 5075 at fs/mbcache.c:419 mb_cache_destroy+0x224/0x290 |
| Modules linked in: |
| CPU: 0 PID: 5075 Comm: syz-executor199 Not tainted 6.9.0-rc6-gb947cc5bf6d7 |
| RIP: 0010:mb_cache_destroy+0x224/0x290 fs/mbcache.c:419 |
| Call Trace: |
| <TASK> |
| ext4_put_super+0x6d4/0xcd0 fs/ext4/super.c:1375 |
| generic_shutdown_super+0x136/0x2d0 fs/super.c:641 |
| kill_block_super+0x44/0x90 fs/super.c:1675 |
| ext4_kill_sb+0x68/0xa0 fs/ext4/super.c:7327 |
| [...] |
| ============================================ |
| |
| This is because when finding an entry in ext4_xattr_block_cache_find(), if |
| ext4_sb_bread() returns -ENOMEM, the ce's e_refcnt, which has already grown |
| in the __entry_find(), won't be put away, and eventually trigger the above |
| issue in mb_cache_destroy() due to reference count leakage. |
| |
| So call mb_cache_entry_put() on the -ENOMEM error branch as a quick fix. |
| |
| The Linux kernel CVE team has assigned CVE-2024-39276 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 4.19.14 with commit b878c8a7f08f0c225b6a46ba1ac867e9c5d17807 and fixed in 4.19.316 with commit 9ad75e78747b5a50dc5a52f0f8e92e920a653f16 |
| Issue introduced in 5.0 with commit fb265c9cb49e2074ddcdd4de99728aefdd3b3592 and fixed in 5.4.278 with commit 896a7e7d0d555ad8b2b46af0c2fa7de7467f9483 |
| Issue introduced in 5.0 with commit fb265c9cb49e2074ddcdd4de99728aefdd3b3592 and fixed in 5.10.219 with commit 76dc776153a47372719d664e0fc50d6355791abb |
| Issue introduced in 5.0 with commit fb265c9cb49e2074ddcdd4de99728aefdd3b3592 and fixed in 5.15.161 with commit 681ff9a09accd8a4379f8bd30b7a1641ee19bb3e |
| Issue introduced in 5.0 with commit fb265c9cb49e2074ddcdd4de99728aefdd3b3592 and fixed in 6.1.94 with commit e941b712e758f615d311946bf98216e79145ccd9 |
| Issue introduced in 5.0 with commit fb265c9cb49e2074ddcdd4de99728aefdd3b3592 and fixed in 6.6.34 with commit a95df6f04f2c37291adf26a74205cde0314d4577 |
| Issue introduced in 5.0 with commit fb265c9cb49e2074ddcdd4de99728aefdd3b3592 and fixed in 6.9.5 with commit b37c0edef4e66fb21a2fbc211471195a383e5ab8 |
| Issue introduced in 5.0 with commit fb265c9cb49e2074ddcdd4de99728aefdd3b3592 and fixed in 6.10 with commit 0c0b4a49d3e7f49690a6827a41faeffad5df7e21 |
| Issue introduced in 4.14.92 with commit 9da1f6d06b7a6d068e68fcfd7cbbf6b586d888e1 |
| Issue introduced in 4.20.1 with commit 81313ed2c705d958744882a269bf4a5e3ddec95e |
| |
| 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-2024-39276 |
| 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/xattr.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/9ad75e78747b5a50dc5a52f0f8e92e920a653f16 |
| https://git.kernel.org/stable/c/896a7e7d0d555ad8b2b46af0c2fa7de7467f9483 |
| https://git.kernel.org/stable/c/76dc776153a47372719d664e0fc50d6355791abb |
| https://git.kernel.org/stable/c/681ff9a09accd8a4379f8bd30b7a1641ee19bb3e |
| https://git.kernel.org/stable/c/e941b712e758f615d311946bf98216e79145ccd9 |
| https://git.kernel.org/stable/c/a95df6f04f2c37291adf26a74205cde0314d4577 |
| https://git.kernel.org/stable/c/b37c0edef4e66fb21a2fbc211471195a383e5ab8 |
| https://git.kernel.org/stable/c/0c0b4a49d3e7f49690a6827a41faeffad5df7e21 |
