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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2021-10-21 17:27:17 -1000 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-10-21 17:27:17 -1000 |
| commit | 9d235ac01f54e8f8c1d967b25ac29e4313a41c5c (patch) | |
| tree | 6273fc22e76035e318308fd7f27b2234636cd529 /include | |
| parent | 6c2c712767ee1d74b2234c9caaf1920808333be6 (diff) | |
| parent | 5ebcbe342b1c12fae44b4f83cbeae1520e09857e (diff) | |
| download | linux-9d235ac01f54e8f8c1d967b25ac29e4313a41c5c.tar.bz2 | |
Merge branch 'ucount-fixes-for-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull ucounts fixes from Eric Biederman:
"There has been one very hard to track down bug in the ucount code that
we have been tracking since roughly v5.14 was released. Alex managed
to find a reliable reproducer a few days ago and then I was able to
instrument the code and figure out what the issue was.
It turns out the sigqueue_alloc single atomic operation optimization
did not play nicely with ucounts multiple level rlimits. It turned out
that either sigqueue_alloc or sigqueue_free could be operating on
multiple levels and trigger the conditions for the optimization on
more than one level at the same time.
To deal with that situation I have introduced inc_rlimit_get_ucounts
and dec_rlimit_put_ucounts that just focuses on the optimization and
the rlimit and ucount changes.
While looking into the big bug I found I couple of other little issues
so I am including those fixes here as well.
When I have time I would very much like to dig into process ownership
of the shared signal queue and see if we could pick a single owner for
the entire queue so that all of the rlimits can count to that owner.
That should entirely remove the need to call get_ucounts and
put_ucounts in sigqueue_alloc and sigqueue_free. It is difficult
because Linux unlike POSIX supports setuid that works on a single
thread"
* 'ucount-fixes-for-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
ucounts: Move get_ucounts from cred_alloc_blank to key_change_session_keyring
ucounts: Proper error handling in set_cred_ucounts
ucounts: Pair inc_rlimit_ucounts with dec_rlimit_ucoutns in commit_creds
ucounts: Fix signal ucount refcounting
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/user_namespace.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h index eb70cabe6e7f..33a4240e6a6f 100644 --- a/include/linux/user_namespace.h +++ b/include/linux/user_namespace.h @@ -127,6 +127,8 @@ static inline long get_ucounts_value(struct ucounts *ucounts, enum ucount_type t long inc_rlimit_ucounts(struct ucounts *ucounts, enum ucount_type type, long v); bool dec_rlimit_ucounts(struct ucounts *ucounts, enum ucount_type type, long v); +long inc_rlimit_get_ucounts(struct ucounts *ucounts, enum ucount_type type); +void dec_rlimit_put_ucounts(struct ucounts *ucounts, enum ucount_type type); bool is_ucounts_overlimit(struct ucounts *ucounts, enum ucount_type type, unsigned long max); static inline void set_rlimit_ucount_max(struct user_namespace *ns, |