1 files changed, 41 insertions, 11 deletions

diff --git a/ipc/ipc_sysctl.c b/ipc/ipc_sysctl.c
index 8c62e443f78b..15b17e86e198 100644
--- a/ipc/ipc_sysctl.c
+++ b/ipc/ipc_sysctl.c
@@ -14,9 +14,10 @@
 #include <linux/ipc_namespace.h>
 #include <linux/msg.h>
 #include <linux/slab.h>
+#include <linux/cred.h>
 #include "util.h"
 
-static int proc_ipc_dointvec_minmax_orphans(struct ctl_table *table, int write,
+static int proc_ipc_dointvec_minmax_orphans(const struct ctl_table *table, int write,
 		void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct ipc_namespace *ns =
@@ -32,7 +33,7 @@ static int proc_ipc_dointvec_minmax_orphans(struct ctl_table *table, int write,
 	return err;
 }
 
-static int proc_ipc_auto_msgmni(struct ctl_table *table, int write,
+static int proc_ipc_auto_msgmni(const struct ctl_table *table, int write,
 		void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct ctl_table ipc_table;
@@ -47,7 +48,7 @@ static int proc_ipc_auto_msgmni(struct ctl_table *table, int write,
 	return proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos);
 }
 
-static int proc_ipc_sem_dointvec(struct ctl_table *table, int write,
+static int proc_ipc_sem_dointvec(const struct ctl_table *table, int write,
 	void *buffer, size_t *lenp, loff_t *ppos)
 {
 	struct ipc_namespace *ns =
@@ -72,7 +73,7 @@ int ipc_mni = IPCMNI;
 int ipc_mni_shift = IPCMNI_SHIFT;
 int ipc_min_cycle = RADIX_TREE_MAP_SIZE;
 
-static struct ctl_table ipc_sysctls[] = {
+static const struct ctl_table ipc_sysctls[] = {
 	{
 		.procname	= "shmmax",
 		.data		= &init_ipc_ns.shm_ctlmax,
@@ -177,7 +178,6 @@ static struct ctl_table ipc_sysctls[] = {
 		.extra2		= SYSCTL_INT_MAX,
 	},
 #endif
-	{}
 };
 
 static struct ctl_table_set *set_lookup(struct ctl_table_root *root)
@@ -190,25 +190,56 @@ static int set_is_seen(struct ctl_table_set *set)
 	return &current->nsproxy->ipc_ns->ipc_set == set;
 }
 
-static int ipc_permissions(struct ctl_table_header *head, struct ctl_table *table)
+static void ipc_set_ownership(struct ctl_table_header *head,
+			      kuid_t *uid, kgid_t *gid)
+{
+	struct ipc_namespace *ns =
+		container_of(head->set, struct ipc_namespace, ipc_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 ipc_permissions(struct ctl_table_header *head, const struct ctl_table *table)
 {
 	int mode = table->mode;
 
 #ifdef CONFIG_CHECKPOINT_RESTORE
-	struct ipc_namespace *ns = current->nsproxy->ipc_ns;
+	struct ipc_namespace *ns =
+		container_of(head->set, struct ipc_namespace, ipc_set);
 
 	if (((table->data == &ns->ids[IPC_SEM_IDS].next_id) ||
 	     (table->data == &ns->ids[IPC_MSG_IDS].next_id) ||
 	     (table->data == &ns->ids[IPC_SHM_IDS].next_id)) &&
 	    checkpoint_restore_ns_capable(ns->user_ns))
 		mode = 0666;
+	else
 #endif
-	return mode;
+	{
+		kuid_t ns_root_uid;
+		kgid_t ns_root_gid;
+
+		ipc_set_ownership(head, &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 = ipc_permissions,
+	.set_ownership = ipc_set_ownership,
 };
 
 bool setup_ipc_sysctls(struct ipc_namespace *ns)
@@ -259,8 +290,7 @@ bool setup_ipc_sysctls(struct ipc_namespace *ns)
 				tbl[i].data = NULL;
 		}
 
-		ns->ipc_sysctls = __register_sysctl_table(&ns->ipc_set,
-							  "kernel", tbl,
+		ns->ipc_sysctls = __register_sysctl_table(&ns->ipc_set, "kernel", tbl,
 							  ARRAY_SIZE(ipc_sysctls));
 	}
 	if (!ns->ipc_sysctls) {
@@ -274,7 +304,7 @@ bool setup_ipc_sysctls(struct ipc_namespace *ns)
 
 void retire_ipc_sysctls(struct ipc_namespace *ns)
 {
-	struct ctl_table *tbl;
+	const struct ctl_table *tbl;
 
 	tbl = ns->ipc_sysctls->ctl_table_arg;
 	unregister_sysctl_table(ns->ipc_sysctls);