Commit f9c82a4e authored by Alexey Gladkov's avatar Alexey Gladkov Committed by Eric W. Biederman
Browse files

Increase size of ucounts to atomic_long_t 



RLIMIT_MSGQUEUE and RLIMIT_MEMLOCK use unsigned long to store their
counters. As a preparation for moving rlimits based on ucounts, we need
to increase the size of the variable to long.

Signed-off-by: default avatarAlexey Gladkov <legion@kernel.org>
Link: https://lkml.kernel.org/r/257aa5fb1a7d81cf0f4c34f39ada2320c4284771.1619094428.git.legion@kernel.org


Signed-off-by: default avatarEric W. Biederman <ebiederm@xmission.com>
parent 9f4ad9e4

include/linux/user_namespace.h

+2 −2
Original line number Diff line number Diff line
@@ -88,7 +88,7 @@ struct user_namespace { 
	struct ctl_table_header *sysctls;

#endif

	struct ucounts		*ucounts;

	int ucount_max[UCOUNT_COUNTS];

	long ucount_max[UCOUNT_COUNTS];

} __randomize_layout;



struct ucounts {
@@ -96,7 +96,7 @@ struct ucounts { 
	struct user_namespace *ns;

	kuid_t uid;

	int count;

	atomic_t ucount[UCOUNT_COUNTS];

	atomic_long_t ucount[UCOUNT_COUNTS];

};



extern struct user_namespace init_user_ns;

kernel/ucount.c

+8 −8
Original line number Diff line number Diff line
@@ -175,14 +175,14 @@ static void put_ucounts(struct ucounts *ucounts) 
	kfree(ucounts);

}



static inline bool atomic_inc_below(atomic_t *v, int u)

static inline bool atomic_long_inc_below(atomic_long_t *v, int u)

{

	int c, old;

	c = atomic_read(v);

	long c, old;

	c = atomic_long_read(v);

	for (;;) {

		if (unlikely(c >= u))

			return false;

		old = atomic_cmpxchg(v, c, c+1);

		old = atomic_long_cmpxchg(v, c, c+1);

		if (likely(old == c))

			return true;

		c = old;
@@ -196,17 +196,17 @@ struct ucounts *inc_ucount(struct user_namespace *ns, kuid_t uid, 
	struct user_namespace *tns;

	ucounts = get_ucounts(ns, uid);

	for (iter = ucounts; iter; iter = tns->ucounts) {

		int max;

		long max;

		tns = iter->ns;

		max = READ_ONCE(tns->ucount_max[type]);

		if (!atomic_inc_below(&iter->ucount[type], max))

		if (!atomic_long_inc_below(&iter->ucount[type], max))

			goto fail;

	}

	return ucounts;

fail:

	bad = iter;

	for (iter = ucounts; iter != bad; iter = iter->ns->ucounts)

		atomic_dec(&iter->ucount[type]);

		atomic_long_dec(&iter->ucount[type]);



	put_ucounts(ucounts);

	return NULL;
@@ -216,7 +216,7 @@ void dec_ucount(struct ucounts *ucounts, enum ucount_type type) 
{

	struct ucounts *iter;

	for (iter = ucounts; iter; iter = iter->ns->ucounts) {

		int dec = atomic_dec_if_positive(&iter->ucount[type]);

		long dec = atomic_long_dec_if_positive(&iter->ucount[type]);

		WARN_ON_ONCE(dec < 0);

	}

	put_ucounts(ucounts);