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authorAlexey Gladkov <legion@kernel.org>2024-01-15 18:46:43 +0300
committerAndrew Morton <akpm@linux-foundation.org>2024-02-23 02:38:52 +0300
commitf9436a5d0497f759330d07e1189565edd4456be8 (patch)
tree5099a974b5272d85b648e1c8122abd4bb0dde424 /ipc
parent9220066ea807e3efce21476bffcac16743e9db22 (diff)
downloadlinux-f9436a5d0497f759330d07e1189565edd4456be8.tar.xz
sysctl: allow to change limits for posix messages queues
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. Link: https://lkml.kernel.org/r/6ad67f23d1459a4f4339f74aa73bac0ecf3995e1.1705333426.git.legion@kernel.org Signed-off-by: Alexey Gladkov <legion@kernel.org> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Link: https://lkml.kernel.org/r/7eb21211c8622e91d226e63416b1b93c079f60ee.1663756794.git.legion@kernel.org Cc: Christian Brauner <brauner@kernel.org> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Joel Granados <joel.granados@gmail.com> Cc: Kees Cook <keescook@chromium.org> Cc: Luis Chamberlain <mcgrof@kernel.org> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'ipc')
-rw-r--r--ipc/mq_sysctl.c36
1 files changed, 36 insertions, 0 deletions
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 &current->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)