From 3978d816523991dd86cf9aae88c295230a5ea3b2 Mon Sep 17 00:00:00 2001 From: David Howells Date: Wed, 1 Sep 2021 19:22:50 +0100 Subject: 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 Tested-by: Markus Suvanto cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/163111667354.283156.12720698333342917516.stgit@warthog.procyon.org.uk/ --- fs/afs/dir.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'fs/afs/dir.c') diff --git a/fs/afs/dir.c b/fs/afs/dir.c index ac829e63c570..a8e3ae55f1f9 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; -- cgit v1.2.3