[PATCH 1/2] fs: require inode_owner_or_capable for F_SET_RW_HINT

[Christoph Hellwig <hch@xxxxxx>]

F_SET_RW_HINT controls data placement in the file system and / or
device and should not be available to everyone who can read a given file.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
 fs/fcntl.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/fcntl.c b/fs/fcntl.c
index 22dd9dcce7ec..7fc6190da342 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -375,6 +375,9 @@ static long fcntl_set_rw_hint(struct file *file, unsigned int cmd,
 	u64 __user *argp = (u64 __user *)arg;
 	u64 hint;
 
+	if (!inode_owner_or_capable(file_mnt_idmap(file), inode))
+		return -EPERM;
+
 	if (copy_from_user(&hint, argp, sizeof(hint)))
 		return -EFAULT;
 	if (!rw_hint_valid(hint))
-- 
2.45.2