#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master Add early validation of file handle type in nsfs_fh_to_dentry() to prevent processing of handles with incorrect types. This fixes a warning triggered when open_by_handle_at() is called with non-nsfs handle types on nsfs files. The issue occurs when a user provides a file handle with a type like FILEID_INO32_GEN_PARENT (0xf1) instead of FILEID_NSFS when calling open_by_handle_at() on an nsfs file. The generic export code routes this to nsfs_fh_to_dentry(), which then processes the incorrectly formatted handle data, leading to validation warnings. Reported-by: syzbot+9eefe09bedd093f156c2@syzkaller.appspotmail.com Signed-off-by: Deepanshu Kartikey --- fs/nsfs.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/nsfs.c b/fs/nsfs.c index 32cb8c835a2b..050e7db80297 100644 --- a/fs/nsfs.c +++ b/fs/nsfs.c @@ -461,6 +461,8 @@ static int nsfs_encode_fh(struct inode *inode, u32 *fh, int *max_len, static struct dentry *nsfs_fh_to_dentry(struct super_block *sb, struct fid *fh, int fh_len, int fh_type) { + if (fh_type != FILEID_NSFS) + return ERR_PTR(-EINVAL); struct path path __free(path_put) = {}; struct nsfs_file_handle *fid = (struct nsfs_file_handle *)fh; struct user_namespace *owning_ns = NULL; -- 2.43.0