From: Christoph Hellwig hch@lst.de
commit 3eb96946f0be6bf447cbdf219aba22bc42672f92 upstream.
This patch is a backport.
Since the dawn of time bio_check_eod has a check for a non-zero size of the device. This doesn't really make any sense as we never want to send I/O to a device that's been set to zero size, or never moved out of that.
I am a bit surprised we haven't caught this for a long time, but the removal of the extra validation inside of zram caused syzbot to trip over this issue recently. I've added a Fixes tag for that commit, but the issue really goes back way before git history.
Fixes: 9fe95babc742 ("zram: remove valid_io_request") Reported-by: syzbot+2aca91e1d3ae43aef10c@syzkaller.appspotmail.com Bug: https://syzkaller.appspot.com/bug?extid=2aca91e1d3ae43aef10c Signed-off-by: Christoph Hellwig hch@lst.de Link: https://lore.kernel.org/r/20230524060538.1593686-1-hch@lst.de Signed-off-by: Jens Axboe axboe@kernel.dk (cherry picked from commit 3eb96946f0be6bf447cbdf219aba22bc42672f92) Signed-off-by: Miguel García miguelgarciaroman8@gmail.com --- block/blk-core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/block/blk-core.c b/block/blk-core.c index 94941e3ce219..6a66f4f6912f 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -515,7 +515,7 @@ static inline int bio_check_eod(struct bio *bio) sector_t maxsector = bdev_nr_sectors(bio->bi_bdev); unsigned int nr_sectors = bio_sectors(bio);
- if (nr_sectors && maxsector && + if (nr_sectors && (nr_sectors > maxsector || bio->bi_iter.bi_sector > maxsector - nr_sectors)) { pr_info_ratelimited("%s: attempt to access beyond end of device\n"