Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
orangefs: fix xattr related buffer overflow…
Willy Tarreau [email protected] forwarded me a message from Disclosure [email protected] with the following warning:
The helper
xattr_key()uses the pointer variable in the loop condition rather than dereferencing it. Askeyis incremented, it remains non-NULL (until it runs into unmapped memory), so the loop does not terminate on valid C strings and will walk memory indefinitely, consuming CPU or hanging the thread.
I easily reproduced this with setfattr and getfattr, causing a kernel oops, hung user processes and corrupted orangefs files. Disclosure sent along a diff (not a patch) with a suggested fix, which I based this patch on.
After xattr_key started working right, xfstest generic/069 exposed an xattr related memory leak that lead to OOM. xattr_key returns a hashed key. When adding xattrs to the orangefs xattr cache, orangefs used hash_add, a kernel hashing macro. hash_add also hashes the key using hash_log which resulted in additions to the xattr cache going to the wrong hash bucket. generic/069 tortures a single file and orangefs does a getattr for the xattr “security.capability” every time. Orangefs negative caches on xattrs which includes a kmalloc. Since adds to the xattr cache were going to the wrong bucket, every getattr for “security.capability” resulted in another kmalloc, none of which were ever freed.
I changed the two uses of hash_add to hlist_add_head instead and the memory leak ceased and generic/069 quit throwing furniture.
Details
- Affected product:
- Oracle Linux 7 ELS , Ubuntu 20.04 ELS
- Affected packages:
- linux @ 5.4.0 (+1 more)
Fixes
KernelCare state
Live-patch status from KernelCare for each operating system.
| Operating system | Status | Covered kernels |
|---|---|---|
| Debian 11 | Released |
36 kernels
|
| Debian 11 cloud | Released |
16 kernels
|
| Debian 12 | Released |
32 kernels
|
| Debian 13 | Will Not Fix | — |
| Proxmox VE 7 5.15 | Released |
47 kernels
|
| Ubuntu 20.04 HWE AWS | Released |
57 kernels
|
| Ubuntu 20.04 HWE Azure | Released |
40 kernels
|
| Ubuntu 22.04 | Released |
90 kernels
|
| Ubuntu 22.04 AWS | Released |
81 kernels
|
| Ubuntu 22.04 Azure | Released |
73 kernels
|
| Ubuntu 24.04 | Planned | — |
| Ubuntu 24.04 AWS | Planned | — |