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/file.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) (limited to 'fs/afs/file.c') diff --git a/fs/afs/file.c b/fs/afs/file.c index 6688fff14b0b..4c8d786b53e0 100644 --- a/fs/afs/file.c +++ b/fs/afs/file.c @@ -24,12 +24,13 @@ static void afs_invalidatepage(struct page *page, unsigned int offset, static int afs_releasepage(struct page *page, gfp_t gfp_flags); static void afs_readahead(struct readahead_control *ractl); +static ssize_t afs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter); const struct file_operations afs_file_operations = { .open = afs_open, .release = afs_release, .llseek = generic_file_llseek, - .read_iter = generic_file_read_iter, + .read_iter = afs_file_read_iter, .write_iter = afs_file_write, .mmap = afs_file_mmap, .splice_read = generic_file_splice_read, @@ -503,3 +504,16 @@ static int afs_file_mmap(struct file *file, struct vm_area_struct *vma) vma->vm_ops = &afs_vm_ops; return ret; } + +static ssize_t afs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter) +{ + struct afs_vnode *vnode = AFS_FS_I(file_inode(iocb->ki_filp)); + struct afs_file *af = iocb->ki_filp->private_data; + int ret; + + ret = afs_validate(vnode, af->key); + if (ret < 0) + return ret; + + return generic_file_read_iter(iocb, iter); +} -- cgit v1.2.3