fuse: readdirplus: sanity checks

commit a28ef45cbb1e7fadd5159deb17b02de15c6e4aaf upstream.

Add sanity checks before adding or updating an entry with data received
from readdirplus.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 11 insertions, 1 deletions

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index a71df0206f6f..5b1274699b08 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -1225,6 +1225,12 @@ static int fuse_direntplus_link(struct file *file,
                 if (name.name[1] == '.' && name.len == 2)
                         return 0;
         }
+
+        if (invalid_nodeid(o->nodeid))
+                return -EIO;
+        if (!fuse_valid_type(o->attr.mode))
+                return -EIO;
+
         fc = get_fuse_conn(dir);
 
         name.hash = full_name_hash(name.name, name.len);
@@ -1233,10 +1239,14 @@ static int fuse_direntplus_link(struct file *file,
                 inode = dentry->d_inode;
                 if (!inode) {
                         d_drop(dentry);
-                } else if (get_node_id(inode) != o->nodeid) {
+                } else if (get_node_id(inode) != o->nodeid ||
+                           ((o->attr.mode ^ inode->i_mode) & S_IFMT)) {
                         err = d_invalidate(dentry);
                         if (err)
                                 goto out;
+                } else if (is_bad_inode(inode)) {
+                        err = -EIO;
+                        goto out;
                 } else {
                         struct fuse_inode *fi;
                         fi = get_fuse_inode(inode);