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From: Alexey Gladkov <gladkov.alexey@gmail.com>
To: LKML <linux-kernel@vger.kernel.org>,
	Kernel Hardening <kernel-hardening@lists.openwall.com>,
	Linux Containers <containers@lists.linux-foundation.org>,
	linux-mm@kvack.org
Cc: Alexey Gladkov <legion@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Christian Brauner <christian.brauner@ubuntu.com>,
	"Eric W . Biederman" <ebiederm@xmission.com>,
	Jann Horn <jannh@google.com>, Jens Axboe <axboe@kernel.dk>,
	Kees Cook <keescook@chromium.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Oleg Nesterov <oleg@redhat.com>
Subject: [PATCH v10 1/9] Increase size of ucounts to atomic_long_t
Date: Wed,  7 Apr 2021 19:08:06 +0200	[thread overview]
Message-ID: <b39ae3fe6eca25870e88a8b0e336343e657403ee.1617814298.git.gladkov.alexey@gmail.com> (raw)
In-Reply-To: <cover.1617814298.git.gladkov.alexey@gmail.com>

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: Alexey Gladkov <gladkov.alexey@gmail.com>
---
 include/linux/user_namespace.h |  4 ++--
 kernel/ucount.c                | 16 ++++++++--------
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h
index 64cf8ebdc4ec..0bb833fd41f4 100644
--- a/include/linux/user_namespace.h
+++ b/include/linux/user_namespace.h
@@ -85,7 +85,7 @@ 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 {
@@ -93,7 +93,7 @@ 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;
diff --git a/kernel/ucount.c b/kernel/ucount.c
index 11b1596e2542..04c561751af1 100644
--- a/kernel/ucount.c
+++ b/kernel/ucount.c
@@ -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);
-- 
2.29.3


  reply	other threads:[~2021-04-07 17:09 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-07 17:08 [PATCH v10 0/9] Count rlimits in each user namespace Alexey Gladkov
2021-04-07 17:08 ` Alexey Gladkov [this message]
2021-04-07 17:08 ` [PATCH v10 2/9] Add a reference to ucounts for each cred Alexey Gladkov
2021-04-07 17:08 ` [PATCH v10 3/9] Use atomic_t for ucounts reference counting Alexey Gladkov
2021-04-07 17:08 ` [PATCH v10 4/9] Reimplement RLIMIT_NPROC on top of ucounts Alexey Gladkov
2021-04-07 17:08 ` [PATCH v10 5/9] Reimplement RLIMIT_MSGQUEUE " Alexey Gladkov
2021-04-07 17:08 ` [PATCH v10 6/9] Reimplement RLIMIT_SIGPENDING " Alexey Gladkov
2021-04-08  8:30   ` 08ed4efad6: stress-ng.sigsegv.ops_per_sec -41.9% regression kernel test robot
2021-04-08 16:22     ` Linus Torvalds
2021-04-08 16:44       ` Alexey Gladkov
2021-04-08 18:44       ` Eric W. Biederman
2021-04-16 11:33         ` Alexey Gladkov
2021-04-23  2:47         ` Oliver Sang
2021-04-23  7:44           ` Alexey Gladkov
2021-04-28 14:36             ` Oliver Sang
2021-04-28 15:09               ` Alexey Gladkov
2021-05-07  7:14                 ` Oliver Sang
2021-04-07 17:08 ` [PATCH v10 7/9] Reimplement RLIMIT_MEMLOCK on top of ucounts Alexey Gladkov
2021-04-07 21:37   ` kernel test robot
2021-04-07 17:08 ` [PATCH v10 8/9] kselftests: Add test to check for rlimit changes in different user namespaces Alexey Gladkov
2021-04-07 17:08 ` [PATCH v10 9/9] ucounts: Set ucount_max to the largest positive value the type can hold Alexey Gladkov

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