pidfd: hold exec_update_lock around namespace ioctl
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 6.12.112, 6.18.51, 7.2.4
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
In the Linux kernel, the following vulnerability has been resolved: pidfd: hold exec_update_lock around namespace ioctl The PIDFD_GET_*_NAMESPACE ioctls in pidfd_ioctl() perform a filesystem credentials ptrace access check before handing out a namespace file descriptor. The accompanying comment states that the code "mirrors nsfs behavior", but, unlike the corresponding procfs paths, it does so without holding the target task's exec_update_lock. proc_ns_get_link() and proc_ns_readlink() both take exec_update_lock for reading around the ptrace check and the namespace lookup, so that the credentials used for the access decision match those of the task when its namespace is read. Without it, a caller can pass the check against the target's old credentials and then read the namespace after the target has execve()'d a setuid binary and committed new credentials -- accessing namespace information it should have been denied. Hold exec_update_lock for reading around the ptrace check and the namespace lookup so that pidfd truly mirrors nsfs behavior, as the comment already claims. open_namespace() itself runs outside the lock: once a namespace reference is obtained it carries its own refcount and is opened with the caller's own credentials, so a concurrent execve() on the target can no longer affect the outcome.
Timeline
- CVE published
- Record last updated
Affected versions
- Linux Linux
From 5b08bd408534bfb3a7cf5778da5b27d4e4fffe12 · fixed in bac2f1913a216677c2c220d7bb352dd0330065ca; From 5b08bd408534bfb3a7cf5778da5b27d4e4fffe12 · fixed in cf24ce48d60225fdbee68ed2058763a1fd172ff3; From 5b08bd408534bfb3a7cf5778da5b27d4e4fffe12 · fixed in e89318aa8629969e86548b05e7c19283af3f0efb; From 5b08bd408534bfb3a7cf5778da5b27d4e4fffe12 · fixed in 9688a46802939da28f00cb40e8129615d5d4af39
- Linux Linux
6.11
- KernelLinux
From 6.11.0 · fixed in 6.12.112; From 6.13.0 · fixed in 6.18.51; From 6.19.0 · fixed in 7.2.4