Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

Pull user namespace rlimit handling update from Eric Biederman:
 "This is the work mainly by Alexey Gladkov to limit rlimits to the
  rlimits of the user that created a user namespace, and to allow users
  to have stricter limits on the resources created within a user
  namespace."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  cred: add missing return error code when set_cred_ucounts() failed
  ucounts: Silence warning in dec_rlimit_ucounts
  ucounts: Set ucount_max to the largest positive value the type can hold
  kselftests: Add test to check for rlimit changes in different user namespaces
  Reimplement RLIMIT_MEMLOCK on top of ucounts
  Reimplement RLIMIT_SIGPENDING on top of ucounts
  Reimplement RLIMIT_MSGQUEUE on top of ucounts
  Reimplement RLIMIT_NPROC on top of ucounts
  Use atomic_t for ucounts reference counting
  Add a reference to ucounts for each cred
  Increase size of ucounts to atomic_long_t

2 files changed, 34 insertions, 32 deletions

diff --git a/ipc/mqueue.c b/ipc/mqueue.c
index 4e4e61111500..5becca9be867 100644
--- a/ipc/mqueue.c
+++ b/ipc/mqueue.c
@@ -144,7 +144,7 @@ struct mqueue_inode_info {
 	struct pid *notify_owner;
 	u32 notify_self_exec_id;
 	struct user_namespace *notify_user_ns;
-	struct user_struct *user;	/* user who created, for accounting */
+	struct ucounts *ucounts;	/* user who created, for accounting */
 	struct sock *notify_sock;
 	struct sk_buff *notify_cookie;
 
@@ -292,7 +292,6 @@ static struct inode *mqueue_get_inode(struct super_block *sb,
 		struct ipc_namespace *ipc_ns, umode_t mode,
 		struct mq_attr *attr)
 {
-	struct user_struct *u = current_user();
 	struct inode *inode;
 	int ret = -ENOMEM;
 
@@ -321,7 +320,7 @@ static struct inode *mqueue_get_inode(struct super_block *sb,
 		info->notify_owner = NULL;
 		info->notify_user_ns = NULL;
 		info->qsize = 0;
-		info->user = NULL;	/* set when all is ok */
+		info->ucounts = NULL;	/* set when all is ok */
 		info->msg_tree = RB_ROOT;
 		info->msg_tree_rightmost = NULL;
 		info->node_cache = NULL;
@@ -371,19 +370,23 @@ static struct inode *mqueue_get_inode(struct super_block *sb,
 		if (mq_bytes + mq_treesize < mq_bytes)
 			goto out_inode;
 		mq_bytes += mq_treesize;
-		spin_lock(&mq_lock);
-		if (u->mq_bytes + mq_bytes < u->mq_bytes ||
-		    u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) {
+		info->ucounts = get_ucounts(current_ucounts());
+		if (info->ucounts) {
+			long msgqueue;
+
+			spin_lock(&mq_lock);
+			msgqueue = inc_rlimit_ucounts(info->ucounts, UCOUNT_RLIMIT_MSGQUEUE, mq_bytes);
+			if (msgqueue == LONG_MAX || msgqueue > rlimit(RLIMIT_MSGQUEUE)) {
+				dec_rlimit_ucounts(info->ucounts, UCOUNT_RLIMIT_MSGQUEUE, mq_bytes);
+				spin_unlock(&mq_lock);
+				put_ucounts(info->ucounts);
+				info->ucounts = NULL;
+				/* mqueue_evict_inode() releases info->messages */
+				ret = -EMFILE;
+				goto out_inode;
+			}
 			spin_unlock(&mq_lock);
-			/* mqueue_evict_inode() releases info->messages */
-			ret = -EMFILE;
-			goto out_inode;
 		}
-		u->mq_bytes += mq_bytes;
-		spin_unlock(&mq_lock);
-
-		/* all is ok */
-		info->user = get_uid(u);
 	} else if (S_ISDIR(mode)) {
 		inc_nlink(inode);
 		/* Some things misbehave if size == 0 on a directory */
@@ -497,7 +500,6 @@ static void mqueue_free_inode(struct inode *inode)
 static void mqueue_evict_inode(struct inode *inode)
 {
 	struct mqueue_inode_info *info;
-	struct user_struct *user;
 	struct ipc_namespace *ipc_ns;
 	struct msg_msg *msg, *nmsg;
 	LIST_HEAD(tmp_msg);
@@ -520,8 +522,7 @@ static void mqueue_evict_inode(struct inode *inode)
 		free_msg(msg);
 	}
 
-	user = info->user;
-	if (user) {
+	if (info->ucounts) {
 		unsigned long mq_bytes, mq_treesize;
 
 		/* Total amount of bytes accounted for the mqueue */
@@ -533,7 +534,7 @@ static void mqueue_evict_inode(struct inode *inode)
 					  info->attr.mq_msgsize);
 
 		spin_lock(&mq_lock);
-		user->mq_bytes -= mq_bytes;
+		dec_rlimit_ucounts(info->ucounts, UCOUNT_RLIMIT_MSGQUEUE, mq_bytes);
 		/*
 		 * get_ns_from_inode() ensures that the
 		 * (ipc_ns = sb->s_fs_info) is either a valid ipc_ns
@@ -543,7 +544,8 @@ static void mqueue_evict_inode(struct inode *inode)
 		if (ipc_ns)
 			ipc_ns->mq_queues_count--;
 		spin_unlock(&mq_lock);
-		free_uid(user);
+		put_ucounts(info->ucounts);
+		info->ucounts = NULL;
 	}
 	if (ipc_ns)
 		put_ipc_ns(ipc_ns);
diff --git a/ipc/shm.c b/ipc/shm.c
index febd88daba8c..003234fbbd17 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -60,7 +60,7 @@ struct shmid_kernel /* private to the kernel */
 	time64_t		shm_ctim;
 	struct pid		*shm_cprid;
 	struct pid		*shm_lprid;
-	struct user_struct	*mlock_user;
+	struct ucounts		*mlock_ucounts;
 
 	/* The task created the shm object.  NULL if the task is dead. */
 	struct task_struct	*shm_creator;
@@ -286,10 +286,10 @@ static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
 	shm_rmid(ns, shp);
 	shm_unlock(shp);
 	if (!is_file_hugepages(shm_file))
-		shmem_lock(shm_file, 0, shp->mlock_user);
-	else if (shp->mlock_user)
+		shmem_lock(shm_file, 0, shp->mlock_ucounts);
+	else if (shp->mlock_ucounts)
 		user_shm_unlock(i_size_read(file_inode(shm_file)),
-				shp->mlock_user);
+				shp->mlock_ucounts);
 	fput(shm_file);
 	ipc_update_pid(&shp->shm_cprid, NULL);
 	ipc_update_pid(&shp->shm_lprid, NULL);
@@ -625,7 +625,7 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
 
 	shp->shm_perm.key = key;
 	shp->shm_perm.mode = (shmflg & S_IRWXUGO);
-	shp->mlock_user = NULL;
+	shp->mlock_ucounts = NULL;
 
 	shp->shm_perm.security = NULL;
 	error = security_shm_alloc(&shp->shm_perm);
@@ -650,7 +650,7 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
 		if (shmflg & SHM_NORESERVE)
 			acctflag = VM_NORESERVE;
 		file = hugetlb_file_setup(name, hugesize, acctflag,
-				  &shp->mlock_user, HUGETLB_SHMFS_INODE,
+				  &shp->mlock_ucounts, HUGETLB_SHMFS_INODE,
 				(shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
 	} else {
 		/*
@@ -698,8 +698,8 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
 no_id:
 	ipc_update_pid(&shp->shm_cprid, NULL);
 	ipc_update_pid(&shp->shm_lprid, NULL);
-	if (is_file_hugepages(file) && shp->mlock_user)
-		user_shm_unlock(size, shp->mlock_user);
+	if (is_file_hugepages(file) && shp->mlock_ucounts)
+		user_shm_unlock(size, shp->mlock_ucounts);
 	fput(file);
 	ipc_rcu_putref(&shp->shm_perm, shm_rcu_free);
 	return error;
@@ -1105,12 +1105,12 @@ static int shmctl_do_lock(struct ipc_namespace *ns, int shmid, int cmd)
 		goto out_unlock0;
 
 	if (cmd == SHM_LOCK) {
-		struct user_struct *user = current_user();
+		struct ucounts *ucounts = current_ucounts();
 
-		err = shmem_lock(shm_file, 1, user);
+		err = shmem_lock(shm_file, 1, ucounts);
 		if (!err && !(shp->shm_perm.mode & SHM_LOCKED)) {
 			shp->shm_perm.mode |= SHM_LOCKED;
-			shp->mlock_user = user;
+			shp->mlock_ucounts = ucounts;
 		}
 		goto out_unlock0;
 	}
@@ -1118,9 +1118,9 @@ static int shmctl_do_lock(struct ipc_namespace *ns, int shmid, int cmd)
 	/* SHM_UNLOCK */
 	if (!(shp->shm_perm.mode & SHM_LOCKED))
 		goto out_unlock0;
-	shmem_lock(shm_file, 0, shp->mlock_user);
+	shmem_lock(shm_file, 0, shp->mlock_ucounts);
 	shp->shm_perm.mode &= ~SHM_LOCKED;
-	shp->mlock_user = NULL;
+	shp->mlock_ucounts = NULL;
 	get_file(shm_file);
 	ipc_unlock_object(&shp->shm_perm);
 	rcu_read_unlock();