linux-kernel - [PATCH 4.4 090/168] block: do not leak memory in bio_copy_user

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Message-Id: <20190424170929.084490771@linuxfoundation.org>
Date:   Wed, 24 Apr 2019 19:08:54 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, linux-block@...r.kernel.org,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Chaitanya Kulkarni <chaitanya.kulkarni@....com>,
        Jérôme Glisse <jglisse@...hat.com>,
        Jens Axboe <axboe@...nel.dk>
Subject: [PATCH 4.4 090/168] block: do not leak memory in bio_copy_user_iov()

From: Jérôme Glisse <jglisse@...hat.com>

commit a3761c3c91209b58b6f33bf69dd8bb8ec0c9d925 upstream.

When bio_add_pc_page() fails in bio_copy_user_iov() we should free
the page we just allocated otherwise we are leaking it.

Cc: linux-block@...r.kernel.org
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: stable@...r.kernel.org
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@....com>
Signed-off-by: Jérôme Glisse <jglisse@...hat.com>
Signed-off-by: Jens Axboe <axboe@...nel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 block/bio.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/block/bio.c
+++ b/block/bio.c
@@ -1216,8 +1216,11 @@ struct bio *bio_copy_user_iov(struct req
 			}
 		}
 
-		if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes)
+		if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes) {
+			if (!map_data)
+				__free_page(page);
 			break;
+		}
 
 		len -= bytes;
 		offset = 0;