| 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-2024-50301: security/keys: fix slab-out-of-bounds in key_task_permission |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| security/keys: fix slab-out-of-bounds in key_task_permission |
| |
| KASAN reports an out of bounds read: |
| BUG: KASAN: slab-out-of-bounds in __kuid_val include/linux/uidgid.h:36 |
| BUG: KASAN: slab-out-of-bounds in uid_eq include/linux/uidgid.h:63 [inline] |
| BUG: KASAN: slab-out-of-bounds in key_task_permission+0x394/0x410 |
| security/keys/permission.c:54 |
| Read of size 4 at addr ffff88813c3ab618 by task stress-ng/4362 |
| |
| CPU: 2 PID: 4362 Comm: stress-ng Not tainted 5.10.0-14930-gafbffd6c3ede #15 |
| Call Trace: |
| __dump_stack lib/dump_stack.c:82 [inline] |
| dump_stack+0x107/0x167 lib/dump_stack.c:123 |
| print_address_description.constprop.0+0x19/0x170 mm/kasan/report.c:400 |
| __kasan_report.cold+0x6c/0x84 mm/kasan/report.c:560 |
| kasan_report+0x3a/0x50 mm/kasan/report.c:585 |
| __kuid_val include/linux/uidgid.h:36 [inline] |
| uid_eq include/linux/uidgid.h:63 [inline] |
| key_task_permission+0x394/0x410 security/keys/permission.c:54 |
| search_nested_keyrings+0x90e/0xe90 security/keys/keyring.c:793 |
| |
| This issue was also reported by syzbot. |
| |
| It can be reproduced by following these steps(more details [1]): |
| 1. Obtain more than 32 inputs that have similar hashes, which ends with the |
| pattern '0xxxxxxxe6'. |
| 2. Reboot and add the keys obtained in step 1. |
| |
| The reproducer demonstrates how this issue happened: |
| 1. In the search_nested_keyrings function, when it iterates through the |
| slots in a node(below tag ascend_to_node), if the slot pointer is meta |
| and node->back_pointer != NULL(it means a root), it will proceed to |
| descend_to_node. However, there is an exception. If node is the root, |
| and one of the slots points to a shortcut, it will be treated as a |
| keyring. |
| 2. Whether the ptr is keyring decided by keyring_ptr_is_keyring function. |
| However, KEYRING_PTR_SUBTYPE is 0x2UL, the same as |
| ASSOC_ARRAY_PTR_SUBTYPE_MASK. |
| 3. When 32 keys with the similar hashes are added to the tree, the ROOT |
| has keys with hashes that are not similar (e.g. slot 0) and it splits |
| NODE A without using a shortcut. When NODE A is filled with keys that |
| all hashes are xxe6, the keys are similar, NODE A will split with a |
| shortcut. Finally, it forms the tree as shown below, where slot 6 points |
| to a shortcut. |
| |
| NODE A |
| +------>+---+ |
| ROOT | | 0 | xxe6 |
| +---+ | +---+ |
| xxxx | 0 | shortcut : : xxe6 |
| +---+ | +---+ |
| xxe6 : : | | | xxe6 |
| +---+ | +---+ |
| | 6 |---+ : : xxe6 |
| +---+ +---+ |
| xxe6 : : | f | xxe6 |
| +---+ +---+ |
| xxe6 | f | |
| +---+ |
| |
| 4. As mentioned above, If a slot(slot 6) of the root points to a shortcut, |
| it may be mistakenly transferred to a key*, leading to a read |
| out-of-bounds read. |
| |
| To fix this issue, one should jump to descend_to_node if the ptr is a |
| shortcut, regardless of whether the node is root or not. |
| |
| [1] https://lore.kernel.org/linux-kernel/1cfa878e-8c7b-4570-8606-21daf5e13ce7@huaweicloud.com/ |
| |
| [jarkko: tweaked the commit message a bit to have an appropriate closes |
| tag.] |
| |
| The Linux kernel CVE team has assigned CVE-2024-50301 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 3.13 with commit b2a4df200d570b2c33a57e1ebfa5896e4bc81b69 and fixed in 4.19.324 with commit c3ce634ad953ce48c75c39bdfd8b711dd95f346f |
| Issue introduced in 3.13 with commit b2a4df200d570b2c33a57e1ebfa5896e4bc81b69 and fixed in 5.4.286 with commit 4efb69a0e294ef201bcdf7ce3d6202cd0a545a5d |
| Issue introduced in 3.13 with commit b2a4df200d570b2c33a57e1ebfa5896e4bc81b69 and fixed in 5.10.230 with commit 1e4332581cd4eed75aea77af6f66cdcdda8b49b9 |
| Issue introduced in 3.13 with commit b2a4df200d570b2c33a57e1ebfa5896e4bc81b69 and fixed in 5.15.172 with commit 199c20fb7499c79557a075dc24e9a7dae7d9f1ce |
| Issue introduced in 3.13 with commit b2a4df200d570b2c33a57e1ebfa5896e4bc81b69 and fixed in 6.1.117 with commit bbad2d5b6c99db468d8f88b6ba6a56ed409b4881 |
| Issue introduced in 3.13 with commit b2a4df200d570b2c33a57e1ebfa5896e4bc81b69 and fixed in 6.6.61 with commit 3e79ad156bedf2da0ab909a118d2cec6c9c22b79 |
| Issue introduced in 3.13 with commit b2a4df200d570b2c33a57e1ebfa5896e4bc81b69 and fixed in 6.11.8 with commit e0a317ad68e4ea48a0158187238c5407e4fdec8b |
| Issue introduced in 3.13 with commit b2a4df200d570b2c33a57e1ebfa5896e4bc81b69 and fixed in 6.12 with commit 4a74da044ec9ec8679e6beccc4306b936b62873f |
| |
| 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-2024-50301 |
| 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: |
| security/keys/keyring.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/c3ce634ad953ce48c75c39bdfd8b711dd95f346f |
| https://git.kernel.org/stable/c/4efb69a0e294ef201bcdf7ce3d6202cd0a545a5d |
| https://git.kernel.org/stable/c/1e4332581cd4eed75aea77af6f66cdcdda8b49b9 |
| https://git.kernel.org/stable/c/199c20fb7499c79557a075dc24e9a7dae7d9f1ce |
| https://git.kernel.org/stable/c/bbad2d5b6c99db468d8f88b6ba6a56ed409b4881 |
| https://git.kernel.org/stable/c/3e79ad156bedf2da0ab909a118d2cec6c9c22b79 |
| https://git.kernel.org/stable/c/e0a317ad68e4ea48a0158187238c5407e4fdec8b |
| https://git.kernel.org/stable/c/4a74da044ec9ec8679e6beccc4306b936b62873f |
