[PATCH] block: check bio split for unaligned bvec

[Keith Busch <kbusch@meta.com>]

From: Keith Busch <kbusch@kernel.org>

Offsets and lengths need to be validated against the dma alignment. This
check was skipped for sufficiently a small bio with a single bvec, which
may allow an invalid request dispatched to the driver. Force the
validation for an unaligned bvec by forcing the bio split path that
handles this condition.

Fixes: 7eac33186957 ("iomap: simplify direct io validity check")
Fixes: 5ff3f74e145a ("block: simplify direct io validity check")
Reported-by: Carlos Maiolino <cem@kernel.org>
Signed-off-by: Keith Busch <kbusch@kernel.org>
---
 block/blk.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/block/blk.h b/block/blk.h
index 1a2d9101bba04..004048fa0c5a8 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -404,6 +404,8 @@ static inline bool bio_may_need_split(struct bio *bio,
 	bv = __bvec_iter_bvec(bio->bi_io_vec, bio->bi_iter);
 	if (bio->bi_iter.bi_size > bv->bv_len - bio->bi_iter.bi_bvec_done)
 		return true;
+	if ((bv->bv_offset | bv->bv_len) & lim->dma_alignment)
+		return true;
 	return bv->bv_len + bv->bv_offset > lim->max_fast_segment_size;
 }
 
-- 
2.52.0