diff options
| author | Jiang Liu <liuj97@gmail.com> | 2013-06-07 00:07:26 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-08-11 18:35:24 -0700 |
| commit | 408fd687175ed6a1fea8cb901882c369ce1d4478 (patch) | |
| tree | d8ae07983e1c0b8c72a81b9e5b70d72e59e7d88a | |
| parent | f7b071d02492426c5b5c1086fe082ba7a0de6de8 (diff) | |
zram: avoid access beyond the zram device
commit 12a7ad3b810e77137d0caf97a6dd97591e075b30 upstream.
Function valid_io_request() should verify the entire request are within
the zram device address range. Otherwise it may cause invalid memory
access when accessing/modifying zram->meta->table[index] because the
'index' is out of range. Then it may access non-exist memory, randomly
modify memory belong to other subsystems, which is hard to track down.
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/staging/zram/zram_drv.c | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c index 27ab8241deb..1742ce55b4a 100644 --- a/drivers/staging/zram/zram_drv.c +++ b/drivers/staging/zram/zram_drv.c @@ -420,13 +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; |