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authorDavid Howells <dhowells@redhat.com>2021-09-01 19:22:50 +0100
committerDavid Howells <dhowells@redhat.com>2021-09-13 09:10:39 +0100
commit3978d816523991dd86cf9aae88c295230a5ea3b2 (patch)
treeb7f9045e2544d879129f26dee2b40e0e2cc517c7 /fs/afs/write.c
parent581b2027af0018944ba301d68e7af45c6d1128b5 (diff)
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/
Diffstat (limited to 'fs/afs/write.c')
-rw-r--r--fs/afs/write.c17
1 files changed, 15 insertions, 2 deletions
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