From: Li Nan <linan122@xxxxxxxxxx>
If we write a large number to md/bitmap_set_bits, md_bitmap_checkpage()
will return -EINVAL because 'page >= bitmap->pages', but the return value
was not checked immediately in md_bitmap_get_counter() in order to set
*blocks value and slab-out-of-bounds occurs.
Move check of 'page >= bitmap->pages' to md_bitmap_get_counter() and
return directly if true.
Fixes: ef4256733506 ("md/bitmap: optimise scanning of empty bitmaps.")
Signed-off-by: Li Nan <linan122@xxxxxxxxxx>
Reviewed-by: Yu Kuai <yukuai3@xxxxxxxxxx>
---
drivers/md/md-bitmap.c | 17 +++++++++--------
1 file changed, 9 insertions(+), 8 deletions(-)
diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
index 920bb68156d2..e122b19c124d 100644
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c
@@ -46,6 +46,7 @@ static inline char *bmname(struct bitmap *bitmap)
*
* if we find our page, we increment the page's refcount so that it stays
* allocated while we're using it
+ * the caller must make sure 'page < bimap->pages'
*/
static int md_bitmap_checkpage(struct bitmap_counts *bitmap,
unsigned long page, int create, int no_hijack)
@@ -54,14 +55,6 @@ __acquires(bitmap->lock)
{
unsigned char *mappage;
- if (page >= bitmap->pages) {
- /* This can happen if bitmap_start_sync goes beyond
- * End-of-device while looking for a whole page.
- * It is harmless.
- */
- return -EINVAL;
- }
-
if (bitmap->bp[page].hijacked) /* it's hijacked, don't try to alloc */
return 0;
@@ -1387,6 +1380,14 @@ __acquires(bitmap->lock)
sector_t csize;
int err;
+ if (page >= bitmap->pages) {
+ /*
+ * This can happen if bitmap_start_sync goes beyond
+ * End-of-device while looking for a whole page or
+ * user set a huge number to sysfs bitmap_set_bits.
+ */
+ return NULL;
+ }
err = md_bitmap_checkpage(bitmap, page, create, 0);
if (bitmap->bp[page].hijacked ||
--
2.31.1
