Description
In the Linux kernel, the following vulnerability has been resolved: fsnotify: do not generate ACCESS/MODIFY events on child for special files inotify/fanotify do not allow users with no read access to a file to subscribe to events (e.g. IN_ACCESS/IN_MODIFY), but they do allow the same user to subscribe for watching events on children when the user has access to the parent directory (e.g. /dev). Users with no read access to a file but with read access to its parent directory can still stat the file and see if it was accessed/modified via atime/mtime change. The same is not true for special files (e.g. /dev/null). Users will not generally observe atime/mtime changes when other users read/write to special files, only when someone sets atime/mtime via utimensat(). Align fsnotify events with this stat behavior and do not generate ACCESS/MODIFY events to parent watchers on read/write of special files. The events are still generated to parent watchers on utimensat(). This closes some side-channels that could be possibly used for information exfiltration [1]. [1] https://snee.la/pdf/pubs/file-notification-attacks.pdf
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
72acc854427948efed7a83da27f7dc3239ac9afc to < df2711544b050aba703e6da418c53c7dc5d443caaffected72acc854427948efed7a83da27f7dc3239ac9afc to < 859bdf438f01d9aa7f84b09c1202d548c7cad9e8affected72acc854427948efed7a83da27f7dc3239ac9afc to < 6a7d7d96eeeab7af2bd01afbb3d9878a11a13d91affected72acc854427948efed7a83da27f7dc3239ac9afc to < e0643d46759db8b84c0504a676043e5e341b6c81affected72acc854427948efed7a83da27f7dc3239ac9afc to < 82f7416bcbd951549e758d15fc1a96a5afc2e900affected72acc854427948efed7a83da27f7dc3239ac9afc to < 7a93edb23bcf07a3aaf8b598edfc2faa8fbcc0b6affected72acc854427948efed7a83da27f7dc3239ac9afc to < 635bc4def026a24e071436f4f356ea08c0eed6ffaffected
Linux Linux
Default version status: affected
2.6.36affected0 to < 2.6.36unaffected5.10.248 to ≤ 5.10.*unaffected5.15.198 to ≤ 5.15.*unaffected6.1.160 to ≤ 6.1.*unaffected6.6.120 to ≤ 6.6.*unaffected6.12.64 to ≤ 6.12.*unaffected6.18.3 to ≤ 6.18.*unaffected6.19 to ≤ *unaffected
References
- https://git.kernel.org/stable/c/df2711544b050aba703e6da418c53c7dc5d443ca ↗
- https://git.kernel.org/stable/c/859bdf438f01d9aa7f84b09c1202d548c7cad9e8 ↗
- https://git.kernel.org/stable/c/6a7d7d96eeeab7af2bd01afbb3d9878a11a13d91 ↗
- https://git.kernel.org/stable/c/e0643d46759db8b84c0504a676043e5e341b6c81 ↗
- https://git.kernel.org/stable/c/82f7416bcbd951549e758d15fc1a96a5afc2e900 ↗
- https://git.kernel.org/stable/c/7a93edb23bcf07a3aaf8b598edfc2faa8fbcc0b6 ↗
- https://git.kernel.org/stable/c/635bc4def026a24e071436f4f356ea08c0eed6ff ↗
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html ↗
- https://cert-portal.siemens.com/productcert/html/ssa-457936.html ↗