[PATCH] f2fs: use the mount idmap for the owner check in f2fs_xattr_advise_set()

[Zhan Xusheng <zhanxusheng1024@gmail.com>]

f2fs_xattr_advise_set() calls inode_owner_or_capable() with &nop_mnt_idmap
before allowing the "system.advise" xattr to be set, instead of the idmap
that the VFS passes to the ->set() handler.

f2fs supports idmapped mounts, so on such a mount this checks the caller's
fsuid against the unmapped on-disk owner rather than the mapped owner: the
actual owner can be wrongly denied with -EPERM and an unrelated caller
wrongly allowed.  Pass the handler's idmap instead.

Fixes: 01beba7957a2 ("fs: port inode_owner_or_capable() to mnt_idmap")
Cc: stable@vger.kernel.org
Signed-off-by: Zhan Xusheng <zhanxusheng@xiaomi.com>
---
 fs/f2fs/xattr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c
index ed33e5110f2a..6728d1488cad 100644
--- a/fs/f2fs/xattr.c
+++ b/fs/f2fs/xattr.c
@@ -119,7 +119,7 @@ static int f2fs_xattr_advise_set(const struct xattr_handler *handler,
 	unsigned char old_advise = F2FS_I(inode)->i_advise;
 	unsigned char new_advise;
 
-	if (!inode_owner_or_capable(&nop_mnt_idmap, inode))
+	if (!inode_owner_or_capable(idmap, inode))
 		return -EPERM;
 	if (value == NULL)
 		return -EINVAL;
-- 
2.43.0