From add66fcbd3fbe5aa0dd4dddfa23e119c12989a27 Mon Sep 17 00:00:00 2001 From: Andreas Gruenbacher Date: Thu, 7 Nov 2019 07:28:18 -0800 Subject: [PATCH] iomap: Fix overflow in iomap_page_mkwrite On architectures where loff_t is wider than pgoff_t, the expression ((page->index + 1) << PAGE_SHIFT) can overflow. Rewrite to use the page offset, which we already compute here anyway. Signed-off-by: Andreas Gruenbacher Reviewed-by: Christoph Hellwig Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong --- fs/iomap/buffered-io.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index c62e807956b6..d33c7bc5ee92 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -1067,20 +1067,19 @@ vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops) lock_page(page); size = i_size_read(inode); - if ((page->mapping != inode->i_mapping) || - (page_offset(page) > size)) { + offset = page_offset(page); + if (page->mapping != inode->i_mapping || offset > size) { /* We overload EFAULT to mean page got truncated */ ret = -EFAULT; goto out_unlock; } /* page is wholly or partially inside EOF */ - if (((page->index + 1) << PAGE_SHIFT) > size) + if (offset > size - PAGE_SIZE) length = offset_in_page(size); else length = PAGE_SIZE; - offset = page_offset(page); while (length > 0) { ret = iomap_apply(inode, offset, length, IOMAP_WRITE | IOMAP_FAULT, ops, page,