From e7bf90e5afe3aa1d1282c1635a49e17a32c4ecec Mon Sep 17 00:00:00 2001
From: Wenwen Wang <wenwen@cs.uga.edu>
Date: Thu, 11 Jul 2019 14:22:02 -0500
Subject: [PATCH] block/bio-integrity: fix a memory leak bug
Git-commit: e7bf90e5afe3aa1d1282c1635a49e17a32c4ecec
Patch-mainline: v5.3-rc1
References: git-fixes

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@redhat.com>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Wenwen Wang <wenwen@cs.uga.edu>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Coly Li <colyli@suse.de>

---
 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 4db620849515..fb95dbb21dd8 100644
--- a/block/bio-integrity.c
+++ b/block/bio-integrity.c
@@ -276,8 +276,12 @@ 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;
-- 
2.35.3