zram: avoid access beyond the zram device

[pandora-kernel.git] / drivers / staging / zram / zram_drv.c

diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c
index 3335a6c..9f097ce 100644 (file)
--- a/drivers/staging/zram/zram_drv.c
+++ b/drivers/staging/zram/zram_drv.c
@@ -272,8 +272,6 @@ static int zram_bvec_write(struct zram *zram, struct bio_vec *bvec, u32 index,
 
        if (page_zero_filled(uncmem)) {
                kunmap_atomic(user_mem);
-               if (is_partial_io(bvec))
-                       kfree(uncmem);
                zram->stats.pages_zero++;
                zram_set_flag(meta, index, ZRAM_ZERO);
                ret = 0;
@@ -422,13 +420,20 @@ out:
  */
 static inline int valid_io_request(struct zram *zram, struct bio *bio)
 {
-       if (unlikely(
-               (bio->bi_sector >= (zram->disksize >> SECTOR_SHIFT)) ||
-               (bio->bi_sector & (ZRAM_SECTOR_PER_LOGICAL_BLOCK - 1)) ||
-               (bio->bi_size & (ZRAM_LOGICAL_BLOCK_SIZE - 1)))) {
+       u64 start, end, bound;
+       
+       /* unaligned request */
+       if (unlikely(bio->bi_sector & (ZRAM_SECTOR_PER_LOGICAL_BLOCK - 1)))
+               return 0;
+       if (unlikely(bio->bi_size & (ZRAM_LOGICAL_BLOCK_SIZE - 1)))
+               return 0;
 
+       start = bio->bi_sector;
+       end = start + (bio->bi_size >> SECTOR_SHIFT);
+       bound = zram->disksize >> SECTOR_SHIFT;
+       /* out of range range */
+       if (unlikely(start >= bound || end >= bound || start > end))
                return 0;
-       }
 
        /* I/O request is valid */
        return 1;