Re: [PATCH] block: Clear kernel memory before copying to user

From
Laurence Oberman <loberman@redhat.com>
Date
2018-11-07 14:46:12
Reply to
Keith Busch, 2018-11-07
On Wed, 2018-11-07 at 07:37 -0700, Keith Busch wrote:
quoted hunk ↗ jump to hunk
If the kernel allocates a bounce buffer for user read data, this
memory
needs to be cleared before copying it to the user, otherwise it may
leak
kernel memory to user space.

Signed-off-by: Keith Busch <redacted>
---
 block/bio.c | 1 +
 1 file changed, 1 insertion(+)
diff --git a/block/bio.c b/block/bio.c
index d5368a445561..a50d59236b19 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1260,6 +1260,7 @@ struct bio *bio_copy_user_iov(struct
request_queue *q,
 		if (ret)
 			goto cleanup;
 	} else {
+		zero_fill_bio(bio);
 		iov_iter_advance(iter, bio->bi_iter.bi_size);
 	}
 
Straightforward, looks good from my view.

Reviewed-by:
Laurence Oberman [off-list ref]
Thread (15 messages) 15 messages, 5 authors, last reply 2018-11-08
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