Shailend ChandandgVisor bot e428bbea51 Fix creds check in linkat(AT_EMPTY_PATH) ...

linkat(AT_EMPTY_PATH) needs to check for CAP_DAC_READ_SEARCH in the userns in
which the fd was opened, not the userns of the task running linkat().

To get at that userns, vfs.FileDescription now saves a pointer to the creds
at the time of its creation: plumbing these creds in accounts for much of the
diff. This is similar to how `struct file` stores creds in `f_cred` in Linux.

Moreover, since the Linux patch "vfs: relax linkat() AT_EMPTY_PATH..." [1], the
need for this cap is excused if the creds of the calling task are literally
the same as the one stored in the fd.

[1] https://github.com/torvalds/linux/commit/42bd2af5950456d

PiperOrigin-RevId: 853374474

2026-01-07 12:48:17 -08:00

..

BUILD

Fix creds check in linkat(AT_EMPTY_PATH)

2026-01-07 12:48:17 -08:00

timerfd.go

Fix creds check in linkat(AT_EMPTY_PATH)

2026-01-07 12:48:17 -08:00