Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: landlock: Fix use-after-free of the source's parent directory current_check_refer_path() reads old_dentry->d_parent without holding a reference nor a lock on it, and then dereferences it in collect_domain_accesses() and in the audit record. A reference on a child does not pin its parent: __d_move() reassigns dentry->d_parent and drops the reference the child held on its former parent. hook_path_rename() is not affected because the rename path calls lock_rename() before the hook, so the source cannot be reparented under it. hook_path_link() has no such protection: filename_linkat() holds a reference on the source dentry but neither locks nor references its parent, so a concurrent rename(2) can reparent the source while security_path_link() runs, and the former parent can then be removed and freed while the hook walks it. A process can trigger this after entering a Landlock domain that handles at least one filesystem access right. The process can then race a linkat(2) loop against rename(2) and rmdir(2): BUG: KASAN: slab-use-after-free in collect_domain_accesses+0x278/0x290 Read of size 4 at addr ffff888160bd53f4 by task llrepro2/549 collect_domain_accesses+0x278/0x290 current_check_refer_path+0x952/0x1120 security_path_link+0x1be/0x320 filename_linkat+0x342/0x6d0 __x64_sys_linkat+0xfa/0x150 Freed by task 562: kmem_cache_free+0x139/0x4c0 i_callback+0x4b/0x80 rcu_core+0x7dc/0x10a0 Take a reference on the dentry selected as the source parent, using dget() for the common-mount-root case and dget_parent() otherwise. Release it after the hierarchy walk and synchronous audit logging. [mic: Clarify the caller, reachability, and reference handling]
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected b91c3e4ea756b12b7d992529226edce1cfd854d7 before 48fc1c74052c956c59d5b16b5e18e0dd36b76aa2; affected b91c3e4ea756b12b7d992529226edce1cfd854d7 before 4c37992b9668c4f37aae41dd95c369f7b6009915; affected b91c3e4ea756b12b7d992529226edce1cfd854d7 before 379efd2ce8b26fd35feb13ccc2f671ff105a5052; affected b91c3e4ea756b12b7d992529226edce1cfd854d7 before ba29c46ccfe3ebadfb8aa18149186c49f84b14f8; affected b91c3e4ea756b12b7d992529226edce1cfd854d7 before 2c6dc792538260a8087ac5b22c31b3b8e47c85d6 |
| Linux / Linux | affected 5.19; unaffected 0 before 5.19; unaffected 6.6.160 through 6.6.*; unaffected 6.12.112 through 6.12.*; unaffected 6.18.53 through 6.18.*; unaffected 7.2.7 through 7.2.*; unaffected 7.3 through * |
CWE
No CWE identifiers supplied.
References
- https://git.kernel.org/stable/c/48fc1c74052c956c59d5b16b5e18e0dd36b76aa2
- https://git.kernel.org/stable/c/4c37992b9668c4f37aae41dd95c369f7b6009915
- https://git.kernel.org/stable/c/379efd2ce8b26fd35feb13ccc2f671ff105a5052
- https://git.kernel.org/stable/c/ba29c46ccfe3ebadfb8aa18149186c49f84b14f8
- https://git.kernel.org/stable/c/2c6dc792538260a8087ac5b22c31b3b8e47c85d6