| Date | Thu, 23 Apr 2009 00:20:43 -0700 | From | Chris Wright <> | Subject | [patch 023/100] SCSI: sg: fix iovec bugs introduced by the block layer conversion |
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-stable review patch. If anyone has any objections, please let us know. ---------------------
From: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
upstream commit: 0fdf96b67ac2649cc1ddb29b316a0db11586c6a8
- needs to use copy_from_user for iovec before passing it to blk_rq_map_user_iov().
- before the block layer conversion, if ->dxfer_len and sum of iovec disagrees, the shorter one wins. However, currently sg returns -EINVAL. This restores the old behavior.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Acked-by: Douglas Gilbert <dgilbert@interlog.com> Cc: stable@kernel.org Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: Chris Wright <chrisw@sous-sol.org> --- drivers/scsi/sg.c | 28 ++++++++++++++++++++++++---- 1 file changed, 24 insertions(+), 4 deletions(-)
--- a/drivers/scsi/sg.c +++ b/drivers/scsi/sg.c @@ -1673,10 +1673,30 @@ static int sg_start_req(Sg_request *srp, md->null_mapped = hp->dxferp ? 0 : 1; } - if (iov_count) - res = blk_rq_map_user_iov(q, rq, md, hp->dxferp, iov_count, - hp->dxfer_len, GFP_ATOMIC); - else + if (iov_count) { + int len, size = sizeof(struct sg_iovec) * iov_count; + struct iovec *iov; + + iov = kmalloc(size, GFP_ATOMIC); + if (!iov) + return -ENOMEM; + + if (copy_from_user(iov, hp->dxferp, size)) { + kfree(iov); + return -EFAULT; + } + + len = iov_length(iov, iov_count); + if (hp->dxfer_len < len) { + iov_count = iov_shorten(iov, iov_count, hp->dxfer_len); + len = hp->dxfer_len; + } + + res = blk_rq_map_user_iov(q, rq, md, (struct sg_iovec *)iov, + iov_count, + len, GFP_ATOMIC); + kfree(iov); + } else res = blk_rq_map_user(q, rq, md, hp->dxferp, hp->dxfer_len, GFP_ATOMIC);
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