afs: Fix updating of i_mode due to 3rd party change

[ Upstream commit 6e1eb04a87f954eb06a89ee6034c166351dfff6e ]

Fix afs_apply_status() to mask off the irrelevant bits from status->mode
when OR'ing them into i_mode.  This can happen when a 3rd party chmod
occurs.

Also fix afs_inode_init_from_status() to mask off the mode bits when
initialising i_mode.

Fixes: 260a980317da ("[AFS]: Add "directory write" support.")
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/afs/inode.c b/fs/afs/inode.c
index 1d03eb1920ec02ad1a88beeb3ebdb4f8bdce0ba3..bf44e245d7dc9f4ee554cbddeac4eb11c0836fed 100644 (file)
--- a/fs/afs/inode.c
+++ b/fs/afs/inode.c
@@ -102,13 +102,13 @@ static int afs_inode_init_from_status(struct afs_operation *op,
 
        switch (status->type) {
        case AFS_FTYPE_FILE:
-               inode->i_mode   = S_IFREG | status->mode;
+               inode->i_mode   = S_IFREG | (status->mode & S_IALLUGO);
                inode->i_op     = &afs_file_inode_operations;
                inode->i_fop    = &afs_file_operations;
                inode->i_mapping->a_ops = &afs_fs_aops;
                break;
        case AFS_FTYPE_DIR:
-               inode->i_mode   = S_IFDIR | status->mode;
+               inode->i_mode   = S_IFDIR |  (status->mode & S_IALLUGO);
                inode->i_op     = &afs_dir_inode_operations;
                inode->i_fop    = &afs_dir_file_operations;
                inode->i_mapping->a_ops = &afs_dir_aops;
@@ -198,7 +198,7 @@ static void afs_apply_status(struct afs_operation *op,
        if (status->mode != vnode->status.mode) {
                mode = inode->i_mode;
                mode &= ~S_IALLUGO;
-               mode |= status->mode;
+               mode |= status->mode & S_IALLUGO;
                WRITE_ONCE(inode->i_mode, mode);
        }