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authorNeilBrown <neilb@suse.de>2007-07-17 04:06:12 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-07-17 10:23:15 -0700
commitf0d76d70bc77b9b11256a3a23e98e80878be1578 (patch)
treeabf9e37302ce587c8c62e430aaf9f004548e653c /drivers/md/bitmap.c
parent713f6ab18b0e7d39f14401362bfe8015b1aedde1 (diff)
downloadlinux-stericsson-f0d76d70bc77b9b11256a3a23e98e80878be1578.tar.gz
md: check that internal bitmap does not overlap other data
We current completely trust user-space to set up metadata describing an consistant array. In particlar, that the metadata, data, and bitmap do not overlap. But userspace can be buggy, and it is better to report an error than corrupt data. So put in some appropriate checks. Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/md/bitmap.c')
-rw-r--r--drivers/md/bitmap.c35
1 files changed, 33 insertions, 2 deletions
diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 9620d452d030..ae94f3beb5fc 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -268,6 +268,31 @@ static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
if (page->index == bitmap->file_pages-1)
size = roundup(bitmap->last_page_size,
bdev_hardsect_size(rdev->bdev));
+ /* Just make sure we aren't corrupting data or
+ * metadata
+ */
+ if (bitmap->offset < 0) {
+ /* DATA BITMAP METADATA */
+ if (bitmap->offset
+ + page->index * (PAGE_SIZE/512)
+ + size/512 > 0)
+ /* bitmap runs in to metadata */
+ return -EINVAL;
+ if (rdev->data_offset + mddev->size*2
+ > rdev->sb_offset*2 + bitmap->offset)
+ /* data runs in to bitmap */
+ return -EINVAL;
+ } else if (rdev->sb_offset*2 < rdev->data_offset) {
+ /* METADATA BITMAP DATA */
+ if (rdev->sb_offset*2
+ + bitmap->offset
+ + page->index*(PAGE_SIZE/512) + size/512
+ > rdev->data_offset)
+ /* bitmap runs in to data */
+ return -EINVAL;
+ } else {
+ /* DATA METADATA BITMAP - no problems */
+ }
md_super_write(mddev, rdev,
(rdev->sb_offset<<1) + bitmap->offset
+ page->index * (PAGE_SIZE/512),
@@ -287,8 +312,14 @@ static int write_page(struct bitmap *bitmap, struct page *page, int wait)
{
struct buffer_head *bh;
- if (bitmap->file == NULL)
- return write_sb_page(bitmap, page, wait);
+ if (bitmap->file == NULL) {
+ switch (write_sb_page(bitmap, page, wait)) {
+ case -EINVAL:
+ bitmap->flags |= BITMAP_WRITE_ERROR;
+ return -EIO;
+ }
+ return 0;
+ }
bh = page_buffers(page);