fscrypt: Add missing superblock check in find_or_insert_direct_key()
- 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- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean?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 6.1.183, 6.6.148, 6.12.101, 6.18.42, 7.1.6
- 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
- Exploitation: none
- Automatable: no
- Technical impact: total
Summary
In the Linux kernel, the following vulnerability has been resolved: fscrypt: Add missing superblock check in find_or_insert_direct_key() The legacy 'fscrypt_direct_keys' table caches master keys that are used by v1 encryption policies that have FSCRYPT_POLICY_FLAG_DIRECT_KEY. It's just a global table for all filesystems (since the keys can be provided by the legacy process-subscribed keyrings mechanism, which makes it difficult to reuse super_block::s_master_keys). The entries in it ('struct fscrypt_direct_key') do contain a super_block pointer, though, for passing to fscrypt_destroy_inline_crypt_key() when the last inode that references the key is evicted. However, when finding the fscrypt_direct_key for an inode, we weren't actually comparing the super_block pointer. As a result, inodes with different super_blocks could point to the same fscrypt_direct_key. That could extend the lifetime of a fscrypt_direct_key beyond the super_block it points to, causing a use-after-free later. Fix this by creating distinct fscrypt_direct_key structs for distinct super_block structs. Note that this problem doesn't exist in the v2 policy equivalent ("per-mode keys"), since the data structures there are per super_block.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: total
- Record last updated
Affected versions
- Linux Linux
From 22e9947a4b2ba255888541bd0111cf00b9b16586 · fixed in 965b5bc8cf5031225e057979ce660fec2bd5fbfc; From 22e9947a4b2ba255888541bd0111cf00b9b16586 · fixed in 330249609b70778094a7a36f5b6bcfa6362121d4; From 22e9947a4b2ba255888541bd0111cf00b9b16586 · fixed in deff41898a5ae3a47db5fa1896a494aa95efda5d; From 22e9947a4b2ba255888541bd0111cf00b9b16586 · fixed in 95376fe9c145be35566991df99c53134943d992f; From 22e9947a4b2ba255888541bd0111cf00b9b16586 · fixed in 466f187b501a5ac8e1ea2ccf3ccd5c46108d8830; From 22e9947a4b2ba255888541bd0111cf00b9b16586 · fixed in b5fa40226e71c17847b9ff2816c6ca4133d0d994
- Linux Linux
6.1
- KernelLinux
From 6.1.0 · fixed in 6.1.183; From 6.2.0 · fixed in 6.6.148; From 6.7.0 · fixed in 6.12.101; From 6.13.0 · fixed in 6.18.42; From 6.19.0 · fixed in 7.1.6