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/write.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) (limited to 'fs/afs/write.c') diff --git a/fs/afs/write.c b/fs/afs/write.c index 66b235266893..32a764c24284 100644 --- a/fs/afs/write.c +++ b/fs/afs/write.c @@ -807,6 +807,7 @@ int afs_writepages(struct address_space *mapping, ssize_t afs_file_write(struct kiocb *iocb, struct iov_iter *from) { struct afs_vnode *vnode = AFS_FS_I(file_inode(iocb->ki_filp)); + struct afs_file *af = iocb->ki_filp->private_data; ssize_t result; size_t count = iov_iter_count(from); @@ -822,6 +823,10 @@ ssize_t afs_file_write(struct kiocb *iocb, struct iov_iter *from) if (!count) return 0; + result = afs_validate(vnode, af->key); + if (result < 0) + return result; + result = generic_file_write_iter(iocb, from); _leave(" = %zd", result); @@ -835,13 +840,18 @@ ssize_t afs_file_write(struct kiocb *iocb, struct iov_iter *from) */ int afs_fsync(struct file *file, loff_t start, loff_t end, int datasync) { - struct inode *inode = file_inode(file); - struct afs_vnode *vnode = AFS_FS_I(inode); + struct afs_vnode *vnode = AFS_FS_I(file_inode(file)); + struct afs_file *af = file->private_data; + int ret; _enter("{%llx:%llu},{n=%pD},%d", vnode->fid.vid, vnode->fid.vnode, file, datasync); + ret = afs_validate(vnode, af->key); + if (ret < 0) + return ret; + return file_write_and_wait_range(file, start, end); } @@ -855,11 +865,14 @@ vm_fault_t afs_page_mkwrite(struct vm_fault *vmf) struct file *file = vmf->vma->vm_file; struct inode *inode = file_inode(file); struct afs_vnode *vnode = AFS_FS_I(inode); + struct afs_file *af = file->private_data; unsigned long priv; vm_fault_t ret = VM_FAULT_RETRY; _enter("{{%llx:%llu}},{%lx}", vnode->fid.vid, vnode->fid.vnode, page->index); + afs_validate(vnode, af->key); + sb_start_pagefault(inode->i_sb); /* Wait for the page to be written to the cache before we allow it to -- cgit v1.2.3