Patch "afs: Fix the maths in afs_fs_store_data()" has been added to the 3.18-stable tree

This is a note to let you know that I've just added the patch titled

afs: Fix the maths in afs_fs_store_data()

to the 3.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
afs-fix-the-maths-in-afs_fs_store_data.patch
and it can be found in the queue-3.18 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: David Howells <[email protected]>
Date: Thu, 16 Mar 2017 16:27:47 +0000
Subject: afs: Fix the maths in afs_fs_store_data()

From: David Howells <[email protected]>

[ Upstream commit 146a1192783697810b63a1e41c4d59fc93387340 ]

afs_fs_store_data() works out of the size of the write it's going to make, but it uses 32-bit unsigned subtraction in one place that gets automatically cast to loff_t.

However, if to < offset, then the number goes negative, but as the result isn't signed, this doesn't get sign-extended to 64-bits when placed in a loff_t.

Fix by casting the operands to loff_t.

---
 fs/afs/fsclient.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -1225,7 +1225,7 @@ int afs_fs_store_data(struct afs_server
 	_enter(",%x,{%x:%u},,",
 	       key_serial(wb->key), vnode->fid.vid, vnode->fid.vnode);
 
-	size = to - offset;
+	size = (loff_t)to - (loff_t)offset;
 	if (first != last)
 		size += (loff_t)(last - first) << PAGE_SHIFT;
 	pos = (loff_t)first << PAGE_SHIFT;

Patches currently in stable-queue which might be from [email protected] are

queue-3.18/afs-flush-outstanding-writes-when-an-fd-is-closed.patch queue-3.18/afs-fix-the-maths-in-afs_fs_store_data.patch queue-3.18/keys-don-t-permit-request_key-to-construct-a-new-keyring.patch queue-3.18/afs-populate-group-id-from-vnode-status.patch queue-3.18/afs-adjust-mode-bits-processing.patch queue-3.18/afs-fix-page-leak-in-afs_write_begin.patch queue-3.18/afs-fix-missing-put_page.patch queue-3.18/afs-populate-and-use-client-modification-time.patch queue-3.18/afs-fix-afs_kill_pages.patch queue-3.18/don-t-leak-a-key-reference-if-request_key-tries-to-use-a-revoked-keyring.patch