[patch 25/58] bio: fix memcpy corruption in bio_copy_user_iov()

Greg KH
2009-05-06T22:04:49Z

[-- Attachment #1: bio-fix-memcpy-corruption-in-bio_copy_user_iov.patch --]
[-- Type: text/plain, Size: 921 bytes --]

2.6.29-stable review patch. If anyone has any objections, please let us know.

------------------

From: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>

commit 69838727bcd819a8fd73a88447801221788b0c6d upstream.

st driver uses blk_rq_map_user() in order to just build a request out
of page frames. In this case, map_data->offset is a non zero value and
iov[0].iov_base is NULL. We need to increase nr_pages for that.

Cc: stable@kernel.org
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
fs/bio.c | 3 +++
1 file changed, 3 insertions(+)

--- a/fs/bio.c
+++ b/fs/bio.c
@@ -806,6 +806,9 @@ struct bio *bio_copy_user_iov(struct req
len += iov[i].iov_len;
}

+ if (offset)
+ nr_pages++;
+
bmd = bio_alloc_map_data(nr_pages, iov_count, gfp_mask);
if (!bmd)
return ERR_PTR(-ENOMEM);