ncpfs: Support interacting with multiple user namespaces

ncpfs does not natively support uids and gids so this conversion was
simply a matter of updating the the type of the mounteduid, the uid
and the gid on the superblock. Fixing the ioctls that read them,
updating the mount option parser and the mount option printer.

Cc: Petr Vandrovec <petr@vandrovec.name>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

3 files changed, 50 insertions, 36 deletions

diff --git a/fs/ncpfs/inode.c b/fs/ncpfs/inode.c
index 1acdad7..e2be336 100644
--- a/fs/ncpfs/inode.c
+++ b/fs/ncpfs/inode.c
@@ -331,12 +331,15 @@ static int  ncp_show_options(struct seq_file *seq, struct dentry *root)
 	struct ncp_server *server = NCP_SBP(root->d_sb);
 	unsigned int tmp;
 
-	if (server->m.uid != 0)
-		seq_printf(seq, ",uid=%u", server->m.uid);
-	if (server->m.gid != 0)
-		seq_printf(seq, ",gid=%u", server->m.gid);
-	if (server->m.mounted_uid != 0)
-		seq_printf(seq, ",owner=%u", server->m.mounted_uid);
+	if (!uid_eq(server->m.uid, GLOBAL_ROOT_UID))
+		seq_printf(seq, ",uid=%u",
+			   from_kuid_munged(&init_user_ns, server->m.uid));
+	if (!gid_eq(server->m.gid, GLOBAL_ROOT_GID))
+		seq_printf(seq, ",gid=%u",
+			   from_kgid_munged(&init_user_ns, server->m.gid));
+	if (!uid_eq(server->m.mounted_uid, GLOBAL_ROOT_UID))
+		seq_printf(seq, ",owner=%u",
+			   from_kuid_munged(&init_user_ns, server->m.mounted_uid));
 	tmp = server->m.file_mode & S_IALLUGO;
 	if (tmp != NCP_DEFAULT_FILE_MODE)
 		seq_printf(seq, ",mode=0%o", tmp);
@@ -381,13 +384,13 @@ static int ncp_parse_options(struct ncp_mount_data_kernel *data, char *options)
 
 	data->flags = 0;
 	data->int_flags = 0;
-	data->mounted_uid = 0;
+	data->mounted_uid = GLOBAL_ROOT_UID;
 	data->wdog_pid = NULL;
 	data->ncp_fd = ~0;
 	data->time_out = NCP_DEFAULT_TIME_OUT;
 	data->retry_count = NCP_DEFAULT_RETRY_COUNT;
-	data->uid = 0;
-	data->gid = 0;
+	data->uid = GLOBAL_ROOT_UID;
+	data->gid = GLOBAL_ROOT_GID;
 	data->file_mode = NCP_DEFAULT_FILE_MODE;
 	data->dir_mode = NCP_DEFAULT_DIR_MODE;
 	data->info_fd = -1;
@@ -399,13 +402,19 @@ static int ncp_parse_options(struct ncp_mount_data_kernel *data, char *options)
 			goto err;
 		switch (optval) {
 			case 'u':
-				data->uid = optint;
+				data->uid = make_kuid(current_user_ns(), optint);
+				if (!uid_valid(data->uid))
+					goto err;
 				break;
 			case 'g':
-				data->gid = optint;
+				data->gid = make_kgid(current_user_ns(), optint);
+				if (!gid_valid(data->gid))
+					goto err;
 				break;
 			case 'o':
-				data->mounted_uid = optint;
+				data->mounted_uid = make_kuid(current_user_ns(), optint);
+				if (!uid_valid(data->mounted_uid))
+					goto err;
 				break;
 			case 'm':
 				data->file_mode = optint;
@@ -480,13 +489,13 @@ static int ncp_fill_super(struct super_block *sb, void *raw_data, int silent)
 
 				data.flags = md->flags;
 				data.int_flags = NCP_IMOUNT_LOGGEDIN_POSSIBLE;
-				data.mounted_uid = md->mounted_uid;
+				data.mounted_uid = make_kuid(current_user_ns(), md->mounted_uid);
 				data.wdog_pid = find_get_pid(md->wdog_pid);
 				data.ncp_fd = md->ncp_fd;
 				data.time_out = md->time_out;
 				data.retry_count = md->retry_count;
-				data.uid = md->uid;
-				data.gid = md->gid;
+				data.uid = make_kuid(current_user_ns(), md->uid);
+				data.gid = make_kgid(current_user_ns(), md->gid);
 				data.file_mode = md->file_mode;
 				data.dir_mode = md->dir_mode;
 				data.info_fd = -1;
@@ -499,13 +508,13 @@ static int ncp_fill_super(struct super_block *sb, void *raw_data, int silent)
 				struct ncp_mount_data_v4* md = (struct ncp_mount_data_v4*)raw_data;
 
 				data.flags = md->flags;
-				data.mounted_uid = md->mounted_uid;
+				data.mounted_uid = make_kuid(current_user_ns(), md->mounted_uid);
 				data.wdog_pid = find_get_pid(md->wdog_pid);
 				data.ncp_fd = md->ncp_fd;
 				data.time_out = md->time_out;
 				data.retry_count = md->retry_count;
-				data.uid = md->uid;
-				data.gid = md->gid;
+				data.uid = make_kuid(current_user_ns(), md->uid);
+				data.gid = make_kgid(current_user_ns(), md->gid);
 				data.file_mode = md->file_mode;
 				data.dir_mode = md->dir_mode;
 				data.info_fd = -1;
@@ -520,6 +529,10 @@ static int ncp_fill_super(struct super_block *sb, void *raw_data, int silent)
 				goto out;
 			break;
 	}
+	error = -EINVAL;
+	if (!uid_valid(data.mounted_uid) || !uid_valid(data.uid) ||
+	    !gid_valid(data.gid))
+		goto out;
 	error = -EBADF;
 	ncp_filp = fget(data.ncp_fd);
 	if (!ncp_filp)
@@ -886,12 +899,10 @@ int ncp_notify_change(struct dentry *dentry, struct iattr *attr)
 		goto out;
 
 	result = -EPERM;
-	if (((attr->ia_valid & ATTR_UID) &&
-	     (attr->ia_uid != server->m.uid)))
+	if ((attr->ia_valid & ATTR_UID) && !uid_eq(attr->ia_uid, server->m.uid))
 		goto out;
 
-	if (((attr->ia_valid & ATTR_GID) &&
-	     (attr->ia_gid != server->m.gid)))
+	if ((attr->ia_valid & ATTR_GID) && !gid_eq(attr->ia_gid, server->m.gid))
 		goto out;
 
 	if (((attr->ia_valid & ATTR_MODE) &&
diff --git a/fs/ncpfs/ioctl.c b/fs/ncpfs/ioctl.c
index 6958adf..d44318d 100644
--- a/fs/ncpfs/ioctl.c
+++ b/fs/ncpfs/ioctl.c
@@ -45,7 +45,7 @@ ncp_get_fs_info(struct ncp_server * server, struct inode *inode,
 		return -EINVAL;
 	}
 	/* TODO: info.addr = server->m.serv_addr; */
-	SET_UID(info.mounted_uid, server->m.mounted_uid);
+	SET_UID(info.mounted_uid, from_kuid_munged(current_user_ns(), server->m.mounted_uid));
 	info.connection		= server->connection;
 	info.buffer_size	= server->buffer_size;
 	info.volume_number	= NCP_FINFO(inode)->volNumber;
@@ -69,7 +69,7 @@ ncp_get_fs_info_v2(struct ncp_server * server, struct inode *inode,
 		DPRINTK("info.version invalid: %d\n", info2.version);
 		return -EINVAL;
 	}
-	info2.mounted_uid   = server->m.mounted_uid;
+	info2.mounted_uid   = from_kuid_munged(current_user_ns(), server->m.mounted_uid);
 	info2.connection    = server->connection;
 	info2.buffer_size   = server->buffer_size;
 	info2.volume_number = NCP_FINFO(inode)->volNumber;
@@ -135,7 +135,7 @@ ncp_get_compat_fs_info_v2(struct ncp_server * server, struct inode *inode,
 		DPRINTK("info.version invalid: %d\n", info2.version);
 		return -EINVAL;
 	}
-	info2.mounted_uid   = server->m.mounted_uid;
+	info2.mounted_uid   = from_kuid_munged(current_user_ns(), server->m.mounted_uid);
 	info2.connection    = server->connection;
 	info2.buffer_size   = server->buffer_size;
 	info2.volume_number = NCP_FINFO(inode)->volNumber;
@@ -348,22 +348,25 @@ static long __ncp_ioctl(struct inode *inode, unsigned int cmd, unsigned long arg
 		{
 			u16 uid;
 
-			SET_UID(uid, server->m.mounted_uid);
+			SET_UID(uid, from_kuid_munged(current_user_ns(), server->m.mounted_uid));
 			if (put_user(uid, (u16 __user *)argp))
 				return -EFAULT;
 			return 0;
 		}
 	case NCP_IOC_GETMOUNTUID32:
-		if (put_user(server->m.mounted_uid,
-			     (u32 __user *)argp))
+	{
+		uid_t uid = from_kuid_munged(current_user_ns(), server->m.mounted_uid);
+		if (put_user(uid, (u32 __user *)argp))
 			return -EFAULT;
 		return 0;
+	}
 	case NCP_IOC_GETMOUNTUID64:
-		if (put_user(server->m.mounted_uid,
-			     (u64 __user *)argp))
+	{
+		uid_t uid = from_kuid_munged(current_user_ns(), server->m.mounted_uid);
+		if (put_user(uid, (u64 __user *)argp))
 			return -EFAULT;
 		return 0;
-
+	}
 	case NCP_IOC_GETROOT:
 		{
 			struct ncp_setroot_ioctl sr;
@@ -810,7 +813,7 @@ long ncp_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
 	struct inode *inode = filp->f_dentry->d_inode;
 	struct ncp_server *server = NCP_SERVER(inode);
-	uid_t uid = current_uid();
+	kuid_t uid = current_uid();
 	int need_drop_write = 0;
 	long ret;
 
@@ -824,7 +827,7 @@ long ncp_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 		}
 		break;
 	}
-	if (server->m.mounted_uid != uid) {
+	if (!uid_eq(server->m.mounted_uid, uid)) {
 		switch (cmd) {
 		/*
 		 * Only mount owner can issue these ioctls.  Information
diff --git a/fs/ncpfs/ncp_fs_sb.h b/fs/ncpfs/ncp_fs_sb.h
index 54cc0cd..c51b2c5 100644
--- a/fs/ncpfs/ncp_fs_sb.h
+++ b/fs/ncpfs/ncp_fs_sb.h
@@ -23,15 +23,15 @@ struct ncp_mount_data_kernel {
 	unsigned long    flags;		/* NCP_MOUNT_* flags */
 	unsigned int	 int_flags;	/* internal flags */
 #define NCP_IMOUNT_LOGGEDIN_POSSIBLE	0x0001
-	uid_t		 mounted_uid;	/* Who may umount() this filesystem? */
+	kuid_t		 mounted_uid;	/* Who may umount() this filesystem? */
 	struct pid      *wdog_pid;	/* Who cares for our watchdog packets? */
 	unsigned int     ncp_fd;	/* The socket to the ncp port */
 	unsigned int     time_out;	/* How long should I wait after
 					   sending a NCP request? */
 	unsigned int     retry_count;	/* And how often should I retry? */
 	unsigned char	 mounted_vol[NCP_VOLNAME_LEN + 1];
-	uid_t		 uid;
-	gid_t		 gid;
+	kuid_t		 uid;
+	kgid_t		 gid;
 	umode_t		 file_mode;
 	umode_t		 dir_mode;
 	int		 info_fd;