[PATCH] md: check bio address after mapping through partitions.

Partitions are not limited to live within a device.  So we should range
check after partition mapping.

Note that 'maxsector' was being used for two different things.  I have
split off the second usage into 'old_sector' so that maxsector can be still
be used for it's primary usage later in the function.

Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Neil Brown <neilb@suse.de>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index 1360665..c7b1dac 100644 (file)
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -2999,6 +2999,7 @@ void generic_make_request(struct bio *bio)
 {
        request_queue_t *q;
        sector_t maxsector;
+       sector_t old_sector;
        int ret, nr_sectors = bio_sectors(bio);
        dev_t old_dev;
 
@@ -3027,7 +3028,7 @@ void generic_make_request(struct bio *bio)
         * NOTE: we don't repeat the blk_size check for each new device.
         * Stacking drivers are expected to know what they are doing.
         */
-       maxsector = -1;
+       old_sector = -1;
        old_dev = 0;
        do {
                char b[BDEVNAME_SIZE];
@@ -3061,15 +3062,30 @@ end_io:
                 */
                blk_partition_remap(bio);
 
-               if (maxsector != -1)
+               if (old_sector != -1)
                        blk_add_trace_remap(q, bio, old_dev, bio->bi_sector, 
-                                           maxsector);
+                                           old_sector);
 
                blk_add_trace_bio(q, bio, BLK_TA_QUEUE);
 
-               maxsector = bio->bi_sector;
+               old_sector = bio->bi_sector;
                old_dev = bio->bi_bdev->bd_dev;
 
+               maxsector = bio->bi_bdev->bd_inode->i_size >> 9;
+               if (maxsector) {
+                       sector_t sector = bio->bi_sector;
+
+                       if (maxsector < nr_sectors || maxsector - nr_sectors < sector) {
+                               /*
+                                * This may well happen - partitions are not checked
+                                * to make sure they are within the size of the
+                                * whole device.
+                                */
+                               handle_bad_sector(bio);
+                               goto end_io;
+                       }
+               }
+
                ret = q->make_request_fn(q, bio);
        } while (ret);
 }