From: Wenwen Wang <wen...@cs.uga.edu>

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().

Signed-off-by: Wenwen Wang <wen...@cs.uga.edu>
---
 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)
                        break;
-- 
2.7.4

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