From: Alexey Gladkov <legion@kernel.org>
To: LKML <linux-kernel@vger.kernel.org>,
Linux Containers <containers@lists.linux.dev>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Christian Brauner <brauner@kernel.org>,
"Eric W . Biederman" <ebiederm@xmission.com>,
Joel Granados <joel.granados@gmail.com>,
Kees Cook <keescook@chromium.org>,
Luis Chamberlain <mcgrof@kernel.org>,
Manfred Spraul <manfred@colorfullife.com>
Subject: [RESEND PATCH v3 3/3] sysctl: Allow to change limits for posix messages queues
Date: Mon, 15 Jan 2024 15:46:43 +0000 [thread overview]
Message-ID: <6ad67f23d1459a4f4339f74aa73bac0ecf3995e1.1705333426.git.legion@kernel.org> (raw)
In-Reply-To: <cover.1705333426.git.legion@kernel.org>
All parameters of posix messages queues (queues_max/msg_max/msgsize_max)
end up being limited by RLIMIT_MSGQUEUE. The code in mqueue_get_inode is
where that limiting happens.
The RLIMIT_MSGQUEUE is bound to the user namespace and is counted
hierarchically.
We can allow root in the user namespace to modify the posix messages
queues parameters.
Signed-off-by: Alexey Gladkov <legion@kernel.org>
Link: https://lkml.kernel.org/r/7eb21211c8622e91d226e63416b1b93c079f60ee.1663756794.git.legion@kernel.org
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
---
ipc/mq_sysctl.c | 36 ++++++++++++++++++++++++++++++++++++
1 file changed, 36 insertions(+)
diff --git a/ipc/mq_sysctl.c b/ipc/mq_sysctl.c
index ebb5ed81c151..21fba3a6edaf 100644
--- a/ipc/mq_sysctl.c
+++ b/ipc/mq_sysctl.c
@@ -12,6 +12,7 @@
#include <linux/stat.h>
#include <linux/capability.h>
#include <linux/slab.h>
+#include <linux/cred.h>
static int msg_max_limit_min = MIN_MSGMAX;
static int msg_max_limit_max = HARD_MSGMAX;
@@ -76,8 +77,43 @@ static int set_is_seen(struct ctl_table_set *set)
return ¤t->nsproxy->ipc_ns->mq_set == set;
}
+static void mq_set_ownership(struct ctl_table_header *head,
+ struct ctl_table *table,
+ kuid_t *uid, kgid_t *gid)
+{
+ struct ipc_namespace *ns =
+ container_of(head->set, struct ipc_namespace, mq_set);
+
+ kuid_t ns_root_uid = make_kuid(ns->user_ns, 0);
+ kgid_t ns_root_gid = make_kgid(ns->user_ns, 0);
+
+ *uid = uid_valid(ns_root_uid) ? ns_root_uid : GLOBAL_ROOT_UID;
+ *gid = gid_valid(ns_root_gid) ? ns_root_gid : GLOBAL_ROOT_GID;
+}
+
+static int mq_permissions(struct ctl_table_header *head, struct ctl_table *table)
+{
+ int mode = table->mode;
+ kuid_t ns_root_uid;
+ kgid_t ns_root_gid;
+
+ mq_set_ownership(head, table, &ns_root_uid, &ns_root_gid);
+
+ if (uid_eq(current_euid(), ns_root_uid))
+ mode >>= 6;
+
+ else if (in_egroup_p(ns_root_gid))
+ mode >>= 3;
+
+ mode &= 7;
+
+ return (mode << 6) | (mode << 3) | mode;
+}
+
static struct ctl_table_root set_root = {
.lookup = set_lookup,
+ .permissions = mq_permissions,
+ .set_ownership = mq_set_ownership,
};
bool setup_mq_sysctls(struct ipc_namespace *ns)
--
2.43.0
next prev parent reply other threads:[~2024-01-15 15:48 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-12 16:17 [PATCH v1] sysctl: Allow change system v ipc sysctls inside ipc namespace Alexey Gladkov
2022-07-25 16:16 ` Eric W. Biederman
2022-08-16 15:42 ` Alexey Gladkov
2022-08-16 15:42 ` [PATCH v1 1/3] " Alexey Gladkov
2022-09-19 15:26 ` Eric W. Biederman
2022-09-20 16:15 ` Alexey Gladkov
2022-09-20 18:08 ` [PATCH v2 0/3] Allow to change ipc/mq " Alexey Gladkov
2022-09-20 18:08 ` [PATCH v2 1/3] sysctl: Allow change system v ipc " Alexey Gladkov
2022-09-21 9:38 ` kernel test robot
2022-09-21 10:41 ` [PATCH v3 0/3] Allow to change ipc/mq " Alexey Gladkov
2022-09-21 10:41 ` [PATCH v3 1/3] sysctl: Allow change system v ipc " Alexey Gladkov
2022-09-21 10:41 ` [PATCH v3 2/3] sysctl: Allow to change limits for posix messages queues Alexey Gladkov
2022-09-21 10:41 ` [PATCH v3 3/3] docs: Add information about ipc sysctls limitations Alexey Gladkov
2024-01-15 15:46 ` [RESEND PATCH v3 0/3] Allow to change ipc/mq sysctls inside ipc namespace Alexey Gladkov
2024-01-15 15:46 ` [RESEND PATCH v3 1/3] sysctl: Allow change system v ipc " Alexey Gladkov
2024-01-15 15:46 ` [RESEND PATCH v3 2/3] docs: Add information about ipc sysctls limitations Alexey Gladkov
2024-01-15 15:46 ` Alexey Gladkov [this message]
2022-09-20 18:08 ` [PATCH v2 2/3] sysctl: Allow to change limits for posix messages queues Alexey Gladkov
2022-09-20 18:08 ` [PATCH v2 3/3] docs: Add information about ipc sysctls limitations Alexey Gladkov
2022-08-16 15:42 ` [PATCH v1 2/3] sysctl: Allow to change limits for posix messages queues Alexey Gladkov
2022-09-19 15:27 ` Eric W. Biederman
2022-08-16 15:42 ` [PATCH v1 3/3] docs: Add information about ipc sysctls limitations Alexey Gladkov
2022-09-19 15:29 ` Eric W. Biederman
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