block: fix .bi_size overflow

commit 79d08f89bb1b5c2c1ff90d9bb95497ab9e8aa7e0 upstream

'bio->bi_iter.bi_size' is 'unsigned int', which at most hold 4G - 1
bytes.

Before 07173c3ec276 ("block: enable multipage bvecs"), one bio can
include very limited pages, and usually at most 256, so the fs bio
size won't be bigger than 1M bytes most of times.

Since we support multi-page bvec, in theory one fs bio really can
be added > 1M pages, especially in case of hugepage, or big writeback
with too many dirty pages. Then there is chance in which .bi_size
is overflowed.

Fixes this issue by using bio_full() to check if the added segment may
overflow .bi_size.
Signed-off-by: NHui Zhu <teawaterz@linux.alibaba.com>
Cc: Liu Yiding <liuyd.fnst@cn.fujitsu.com>
Cc: kernel test robot <rong.a.chen@intel.com>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: linux-xfs@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org
Cc: stable@vger.kernel.org
Fixes: 07173c3ec276 ("block: enable multipage bvecs")
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Reviewed-by: NJoseph Qi <joseph.qi@linux.alibaba.com>

block/bio.c

@@ -700,7 +700,7 @@ int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page
 			return 0;
 	}
 
-	if (bio_full(bio))
+	if (bio_full(bio, len))
 		return 0;
 
 	/*
@@ -795,7 +795,7 @@ void __bio_add_page(struct bio *bio, struct page *page,
 	struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt];
 
 	WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED));
-	WARN_ON_ONCE(bio_full(bio));
+	WARN_ON_ONCE(bio_full(bio, len));
 
 	bv->bv_page = page;
 	bv->bv_offset = off;
@@ -820,7 +820,7 @@ int bio_add_page(struct bio *bio, struct page *page,
 		 unsigned int len, unsigned int offset)
 {
 	if (!__bio_try_merge_page(bio, page, len, offset)) {
-		if (bio_full(bio))
+		if (bio_full(bio, len))
 			return 0;
 		__bio_add_page(bio, page, len, offset);
 	}
@@ -898,7 +898,7 @@ int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)
 		if (unlikely(ret))
 			return bio->bi_vcnt > orig_vcnt ? 0 : ret;
 
-	} while (iov_iter_count(iter) && !bio_full(bio));
+	} while (iov_iter_count(iter) && !bio_full(bio, 0));
 
 	return 0;
 }

fs/iomap.c

@@ -333,7 +333,7 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
 	if (iop)
 		atomic_inc(&iop->read_count);
 
-	if (!ctx->bio || !is_contig || bio_full(ctx->bio)) {
+	if (!ctx->bio || !is_contig || bio_full(ctx->bio, plen)) {
 		gfp_t gfp = mapping_gfp_constraint(page->mapping, GFP_KERNEL);
 		int nr_vecs = (length + PAGE_SIZE - 1) >> PAGE_SHIFT;
 

fs/xfs/xfs_aops.c

@@ -620,7 +620,7 @@ xfs_add_to_ioend(
 	if (!__bio_try_merge_page(wpc->ioend->io_bio, page, len, poff)) {
 		if (iop)
 			atomic_inc(&iop->write_count);
-		if (bio_full(wpc->ioend->io_bio))
+		if (bio_full(wpc->ioend->io_bio, len))
 			xfs_chain_bio(wpc->ioend, wbc, bdev, sector);
 		__bio_add_page(wpc->ioend->io_bio, page, len, poff);
 	}

include/linux/bio.h

@@ -127,9 +127,23 @@ static inline void *bio_data(struct bio *bio)
 	return NULL;
 }
 
-static inline bool bio_full(struct bio *bio)
+/**
+ * bio_full - check if the bio is full
+ * @bio:	bio to check
+ * @len:	length of one segment to be added
+ *
+ * Return true if @bio is full and one segment with @len bytes can't be
+ * added to the bio, otherwise return false
+ */
+static inline bool bio_full(struct bio *bio, unsigned len)
 {
-	return bio->bi_vcnt >= bio->bi_max_vecs;
+	if (bio->bi_vcnt >= bio->bi_max_vecs)
+		return true;
+
+	if (bio->bi_iter.bi_size > UINT_MAX - len)
+		return true;
+
+	return false;
 }
 
 /*