[PATCH] fix possible PAGE_CACHE_SHIFT overflows
We've had two instances recently of overflows when doing
64_bit_value = (32_bit_value << PAGE_CACHE_SHIFT)
I did a tree-wide grep of `<<.*PAGE_CACHE_SHIFT' and this is the result.
- afs_rxfs_fetch_descriptor.offset is of type off_t, which seems broken.
- jfs and jffs are limited to 4GB anyway.
- reiserfs map_block_for_writepage() takes an unsigned long for the block -
it should take sector_t. (It'll fail for huge filesystems with
blocksize<PAGE_CACHE_SIZE)
- cramfs_read() needs to use sector_t (I think cramsfs is busted on large
filesystems anyway)
- affs is limited in file size anyway.
- I generally didn't fix 32-bit overflows in directory operations.
- arm's __flush_dcache_page() is peculiar. What if the page lies beyond 4G?
- gss_wrap_req_priv() needs checking (snd_buf->page_base)
Cc: Oleg Drokin <green@linuxhacker.ru>
Cc: David Howells <dhowells@redhat.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: <reiserfs-dev@namesys.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Anton Altaparmakov <aia21@cantab.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: <linux-fsdevel@vger.kernel.org>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/romfs/inode.c b/fs/romfs/inode.c
index c74f382..0a13859 100644
--- a/fs/romfs/inode.c
+++ b/fs/romfs/inode.c
@@ -418,7 +418,7 @@
romfs_readpage(struct file *file, struct page * page)
{
struct inode *inode = page->mapping->host;
- unsigned long offset, avail, readlen;
+ loff_t offset, avail, readlen;
void *buf;
int result = -EIO;
@@ -429,8 +429,8 @@
goto err_out;
/* 32 bit warning -- but not for us :) */
- offset = page->index << PAGE_CACHE_SHIFT;
- if (offset < inode->i_size) {
+ offset = page_offset(page);
+ if (offset < i_size_read(inode)) {
avail = inode->i_size-offset;
readlen = min_t(unsigned long, avail, PAGE_SIZE);
if (romfs_copyfrom(inode, buf, ROMFS_I(inode)->i_dataoffset+offset, readlen) == readlen) {