[34-longterm 018/209] block: check for proper length of iov entries in blk_rq_map_user_iov()

[Paul Gortmaker]

From: Jens Axboe <jaxboe@xxxxxxxxxxxx>

  =====================================================================
  | This is a commit scheduled for the next v2.6.34 longterm release. |
  | If you see a problem with using this for longterm, please comment.|
  =====================================================================

commit 9284bcf4e335e5f18a8bc7b26461c33ab60d0689 upstream.

Ensure that we pass down properly validated iov segments before
calling into the mapping or copy functions.

Reported-by: Dan Rosenberg <drosenberg@xxxxxxxxxxxxx>
Signed-off-by: Jens Axboe <jaxboe@xxxxxxxxxxxx>
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
---
 block/blk-map.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/block/blk-map.c b/block/blk-map.c
index 9083cf0..30a7e51 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -205,6 +205,8 @@ int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
 			unaligned = 1;
 			break;
 		}
+		if (!iov[i].iov_len)
+			return -EINVAL;
 	}
 
 	if (unaligned || (q->dma_pad_mask & len) || map_data)
-- 
1.7.4.4

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