DEBIAN-CVE-2026-99225: Debian/linux vulnerability
In the Linux kernel, the following vulnerability has been resolved: keys: Check the authorization payload in process keyring searches An authorization payload and its saved credentials must remain valid while searchprocesskeyringsrcu() searches the requestor's keyrings. The function validates the authorization key, then separately loads payload.data[0] and unconditionally reads rka->cred. Validation does not prevent requestkeyauthrevoke() from clearing the payload. A request-key helper can assume authority and fork a descendant that inherits the authorization key. If the descendant misses in its own keyrings, it falls back to the saved requestor credentials. Successful target instantiation invalidates the authorization key without clearing the payload. After the helper exits, UMHWAITPROC returns to the requester, which calls completerequestkey() and revokes that key. With the descendant paused after validation, the paths can interleave as follows: 1. The descendant enters searchprocesskeyringsrcu() under RCU and keyvalidate() succeeds. 2. The helper instantiates the target, invalidates the authorization key, and exits. 3. The requester resumes from UMHWAITPROC, calls completerequestkey(), and revokes the authorization key. requestkeyauthrevoke() sets its payload pointer to NULL. 4. The descendant loads NULL and dereferences rka->cred. This NULL dereference can oops the kernel. RCU delays payload disposal but does not prevent the pointer from being cleared. Load the payload with dereferencekeyrcu() and require a non-NULL result before validating the authorization key and searching its saved credentials. A non-NULL payload and its credentials remain alive for the caller's RCU read-side section; a cleared payload skips the fallback search and follows the existing error selection. KASAN report as below: Oops: general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f] RIP: 0010:searchprocesskeyringsrcu+0x32b/0x790