[PATCH v2] block/bio-integrity: fix a memory leak bug

From: Wenwen Wang
Date: Thu Jul 11 2019 - 15:22:44 EST

From: Wenwen Wang <wenwen@xxxxxxxxxx>

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

Signed-off-by: Wenwen Wang <wenwen@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 4db6208..fb95dbb 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)