[PATCH AUTOSEL 4.19 086/101] block/bio-integrity: fix a memory leak bug

[Sasha Levin]

From: Wenwen Wang <wenwen@xxxxxxxxxx>

[ Upstream commit e7bf90e5afe3aa1d1282c1635a49e17a32c4ecec ]

In bio_integrity_prep(), a kernel buffer is allocated through kmalloc() to
hold integrity metadata. Later on, the buffer will be attached to the bio
structure through bio_integrity_add_page(), which returns the number of
bytes of integrity metadata attached. Due to unexpected situations,
bio_integrity_add_page() may return 0. As a result, bio_integrity_prep()
needs to be terminated with 'false' returned to indicate this error.
However, the allocated kernel buffer is not freed on this execution path,
leading to a memory leak.

To fix this issue, free the allocated buffer before returning from
bio_integrity_prep().

Reviewed-by: Ming Lei <ming.lei@xxxxxxxxxx>
Acked-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Wenwen Wang <wenwen@xxxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 block/bio-integrity.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/block/bio-integrity.c b/block/bio-integrity.c
index 67b5fb861a51..5bd90cd4b51e 100644
--- a/block/bio-integrity.c
+++ b/block/bio-integrity.c
@@ -291,8 +291,12 @@ bool bio_integrity_prep(struct bio *bio)
 		ret = bio_integrity_add_page(bio, virt_to_page(buf),
 					     bytes, offset);
 
-		if (ret == 0)
-			return false;
+		if (ret == 0) {
+			printk(KERN_ERR "could not attach integrity payload\n");
+			kfree(buf);
+			status = BLK_STS_RESOURCE;
+			goto err_end_io;
+		}
 
 		if (ret < bytes)
 			break;
-- 
2.20.1