[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>

8 files changed, 17 insertions, 17 deletions

diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index 6682d6d7f294..5c61c24dab2a 100644
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -137,7 +137,7 @@ static inline void afs_dir_check_page(struct inode *dir, struct page *page)
 #endif
 
         /* determine how many magic numbers there should be in this page */
-        latter = dir->i_size - (page->index << PAGE_CACHE_SHIFT);
+        latter = dir->i_size - page_offset(page);
         if (latter >= PAGE_SIZE)
                 qty = PAGE_SIZE;
         else
diff --git a/fs/buffer.c b/fs/buffer.c
index 263df0f192aa..55f0975a9b15 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1762,7 +1762,7 @@ static int __block_write_full_page(struct inode *inode, struct page *page,
          * handle that here by just cleaning them.
          */
 
-        block = page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
+        block = (sector_t)page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
         head = page_buffers(page);
         bh = head;
 
@@ -2635,7 +2635,7 @@ int block_truncate_page(struct address_space *mapping,
         pgoff_t index = from >> PAGE_CACHE_SHIFT;
         unsigned offset = from & (PAGE_CACHE_SIZE-1);
         unsigned blocksize;
-        pgoff_t iblock;
+        sector_t iblock;
         unsigned length, pos;
         struct inode *inode = mapping->host;
         struct page *page;
@@ -2651,7 +2651,7 @@ int block_truncate_page(struct address_space *mapping,
                 return 0;
 
         length = blocksize - length;
-        iblock = index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
+        iblock = (sector_t)index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
         
         page = grab_cache_page(mapping, index);
         err = -ENOMEM;
diff --git a/fs/freevxfs/vxfs_immed.c b/fs/freevxfs/vxfs_immed.c
index d0401dc68d41..6f5df1700e95 100644
--- a/fs/freevxfs/vxfs_immed.c
+++ b/fs/freevxfs/vxfs_immed.c
@@ -99,8 +99,8 @@ static int
 vxfs_immed_readpage(struct file *fp, struct page *pp)
 {
         struct vxfs_inode_info  *vip = VXFS_INO(pp->mapping->host);
-        u_int64_t               offset = pp->index << PAGE_CACHE_SHIFT;
-        caddr_t                 kaddr;
+        u_int64_t       offset = (u_int64_t)pp->index << PAGE_CACHE_SHIFT;
+        caddr_t         kaddr;
 
         kaddr = kmap(pp);
         memcpy(kaddr, vip->vii_immed.vi_immed + offset, PAGE_CACHE_SIZE);
diff --git a/fs/jffs/inode-v23.c b/fs/jffs/inode-v23.c
index 3dcc6d2162cb..2559ee10beda 100644
--- a/fs/jffs/inode-v23.c
+++ b/fs/jffs/inode-v23.c
@@ -757,7 +757,7 @@ jffs_do_readpage_nolock(struct file *file, struct page *page)
 
         read_len = 0;
         result = 0;
-        offset = page->index << PAGE_CACHE_SHIFT;
+        offset = page_offset(page);
 
         kmap(page);
         buf = page_address(page);
@@ -1545,7 +1545,7 @@ jffs_commit_write(struct file *filp, struct page *page,
 {
        void *addr = page_address(page) + from;
        /* XXX: PAGE_CACHE_SHIFT or PAGE_SHIFT */
-       loff_t pos = (page->index<<PAGE_CACHE_SHIFT) + from;
+       loff_t pos = page_offset(page) + from;
 
        return jffs_file_write(filp, addr, to-from, &pos);
 } /* jffs_commit_write() */
diff --git a/fs/mpage.c b/fs/mpage.c
index f1d2d02bd4c8..e431cb3878d6 100644
--- a/fs/mpage.c
+++ b/fs/mpage.c
@@ -184,7 +184,7 @@ do_mpage_readpage(struct bio *bio, struct page *page, unsigned nr_pages,
         if (page_has_buffers(page))
                 goto confused;
 
-        block_in_file = page->index << (PAGE_CACHE_SHIFT - blkbits);
+        block_in_file = (sector_t)page->index << (PAGE_CACHE_SHIFT - blkbits);
         last_block = (i_size_read(inode) + blocksize - 1) >> blkbits;
 
         bh.b_page = page;
@@ -466,7 +466,7 @@ __mpage_writepage(struct bio *bio, struct page *page, get_block_t get_block,
          * The page has no buffers: map it to disk
          */
         BUG_ON(!PageUptodate(page));
-        block_in_file = page->index << (PAGE_CACHE_SHIFT - blkbits);
+        block_in_file = (sector_t)page->index << (PAGE_CACHE_SHIFT - blkbits);
         last_block = (i_size - 1) >> blkbits;
         map_bh.b_page = page;
         for (page_block = 0; page_block < blocks_per_page; ) {
diff --git a/fs/romfs/inode.c b/fs/romfs/inode.c
index c74f382dabba..0a13859fd57b 100644
--- a/fs/romfs/inode.c
+++ b/fs/romfs/inode.c
@@ -418,7 +418,7 @@ static int
 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 @@ romfs_readpage(struct file *file, struct page * page)
                 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) {
diff --git a/fs/smbfs/file.c b/fs/smbfs/file.c
index 3c6eb3ba718e..7042e62726a4 100644
--- a/fs/smbfs/file.c
+++ b/fs/smbfs/file.c
@@ -209,8 +209,8 @@ smb_updatepage(struct file *file, struct page *page, unsigned long offset,
 {
         struct dentry *dentry = file->f_dentry;
 
-        DEBUG1("(%s/%s %d@%ld)\n", DENTRY_PATH(dentry), 
-               count, (page->index << PAGE_CACHE_SHIFT)+offset);
+        DEBUG1("(%s/%s %d@%lld)\n", DENTRY_PATH(dentry), count,
+                ((unsigned long long)page->index << PAGE_CACHE_SHIFT) + offset);
 
         return smb_writepage_sync(dentry->d_inode, page, offset, count);
 }
diff --git a/fs/sysv/dir.c b/fs/sysv/dir.c
index 69a085abad6f..cce8b05cba5a 100644
--- a/fs/sysv/dir.c
+++ b/fs/sysv/dir.c
@@ -103,7 +103,7 @@ static int sysv_readdir(struct file * filp, void * dirent, filldir_t filldir)
                         offset = (char *)de - kaddr;
 
                         over = filldir(dirent, name, strnlen(name,SYSV_NAMELEN),
-                                        (n<<PAGE_CACHE_SHIFT) | offset,
+                                        ((loff_t)n<<PAGE_CACHE_SHIFT) | offset,
                                         fs16_to_cpu(SYSV_SB(sb), de->inode),
                                         DT_UNKNOWN);
                         if (over) {
@@ -115,7 +115,7 @@ static int sysv_readdir(struct file * filp, void * dirent, filldir_t filldir)
         }
 
 done:
-        filp->f_pos = (n << PAGE_CACHE_SHIFT) | offset;
+        filp->f_pos = ((loff_t)n << PAGE_CACHE_SHIFT) | offset;
         unlock_kernel();
         return 0;
 }