diff options
| author |   Jiang Liu <liuj97@gmail.com> | 2013-06-07 00:07:26 +0800 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-06-06 12:12:20 -0700 |
| commit | 12a7ad3b810e77137d0caf97a6dd97591e075b30 (patch) | |
| tree | 6eeed81f7990e9e78f4c98fb703a7a1cf022896f /drivers/staging/zram/zram_drv.c | |
| parent | zram: avoid double free in function zram_bvec_write() (diff) | |
| download | linux-dev-12a7ad3b810e77137d0caf97a6dd97591e075b30.tar.xz linux-dev-12a7ad3b810e77137d0caf97a6dd97591e075b30.zip | |
zram: avoid access beyond the zram device
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>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/staging/zram/zram_drv.c')
| -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 f7603617db75..9f097ce55b24 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; |