afs: Add missing vnode validation checks
afs_d_revalidate() should only be validating the directory entry it is
given and the directory to which that belongs; it shouldn't be validating
the inode/vnode to which that dentry points. Besides, validation need to
be done even if we don't call afs_d_revalidate() - which might be the case
if we're starting from a file descriptor.
In order for afs_d_revalidate() to be fixed, validation points must be
added in some other places. Certain directory operations, such as
afs_unlink(), already check this, but not all and not all file operations
either.
Note that the validation of a vnode not only checks to see if the
attributes we have are correct, but also gets a promise from the server to
notify us if that file gets changed by a third party.
Add the following checks:
- Check the vnode we're going to make a hard link to.
- Check the vnode we're going to move/rename.
- Check the vnode we're going to read from.
- Check the vnode we're going to write to.
- Check the vnode we're going to sync.
- Check the vnode we're going to make a mapped page writable for.
Some of these aren't strictly necessary as we're going to perform a server
operation that might get the attributes anyway from which we can determine
if something changed - though it might not get us a callback promise.
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Markus Suvanto <markus.suvanto@gmail.com>
cc: linux-afs@lists.infradead.org
Link: https://lore.kernel.org/r/163111667354.283156.12720698333342917516.stgit@warthog.procyon.org.uk/
diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index ac829e6..a8e3ae5 100644
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -1792,6 +1792,10 @@ static int afs_link(struct dentry *from, struct inode *dir,
goto error;
}
+ ret = afs_validate(vnode, op->key);
+ if (ret < 0)
+ goto error_op;
+
afs_op_set_vnode(op, 0, dvnode);
afs_op_set_vnode(op, 1, vnode);
op->file[0].dv_delta = 1;
@@ -1805,6 +1809,8 @@ static int afs_link(struct dentry *from, struct inode *dir,
op->create.reason = afs_edit_dir_for_link;
return afs_do_sync_operation(op);
+error_op:
+ afs_put_operation(op);
error:
d_drop(dentry);
_leave(" = %d", ret);
@@ -1989,6 +1995,11 @@ static int afs_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
if (IS_ERR(op))
return PTR_ERR(op);
+ ret = afs_validate(vnode, op->key);
+ op->error = ret;
+ if (ret < 0)
+ goto error;
+
afs_op_set_vnode(op, 0, orig_dvnode);
afs_op_set_vnode(op, 1, new_dvnode); /* May be same as orig_dvnode */
op->file[0].dv_delta = 1;