[PATCH 6.1 486/609] mount: honour SB_NOUSER in the new mount API

Greg Kroah-Hartman <[email protected]>
Newsgroups dev.linux.lists.patches,org.kernel.vger.stable
Message-ID <[email protected]>
6.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Al Viro <[email protected]>

[ Upstream commit 6dd3c6884cd9defb511284b566cef5ac8f657dbf ]

One should *not* be allowed to mount one of those, new API or not.

Reported-by: Denis Arefev <[email protected]>
Signed-off-by: Al Viro <[email protected]>
Link: https://patch.msgid.link/20260602020444.GP2636677@ZenIV
Signed-off-by: Christian Brauner (Amutable) <[email protected]>
[Denis: rename new_mnt -> newmount.mnt]
[Denis: use goto err_unlock instead of direct return]
Signed-off-by: Denis Arefev <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
---
 fs/namespace.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/fs/namespace.c b/fs/namespace.c
index f22f76d9c22f9..ed5e9e7251e34 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -3744,6 +3744,11 @@ SYSCALL_DEFINE3(fsmount, int, fs_fd, unsigned int, flags,
 		ret = PTR_ERR(newmount.mnt);
 		goto err_unlock;
 	}
+	if (newmount.mnt->mnt_sb->s_flags & SB_NOUSER) {
+		mntput(newmount.mnt);
+		ret = -EINVAL;
+		goto err_unlock;
+	}
 	newmount.dentry = dget(fc->root);
 	newmount.mnt->mnt_flags = mnt_flags;
 
-- 
2.53.0
lmpx.com only provides a reader for public news (NNTP) servers. It is not affiliated with the servers or forums shown here and is not responsible for the content of articles, which is written by their respective authors.