lib/iov_iter.c: initialize bi.bi_idx before iterating over bvec

Initialize bi.bi_idx as 0 before iterating over bvec, otherwise
garbage data can be used as ->bi_idx.

Cc: Christoph Hellwig <hch@lst.de>
Reported-and-tested-by: Klara Modin <klarasmodin@gmail.com>
Fixes: e4e535bff2bc ("iov_iter: don't require contiguous pages in iov_iter_extract_bvec_pages")
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 9fc06f5fb7489fd812fe0f7db84cdbe3cbbcdabe..c761f6db3cb482dd613c93720417dab568535652 100644 (file)
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -1699,6 +1699,7 @@ static ssize_t iov_iter_extract_bvec_pages(struct iov_iter *i,
                i->bvec++;
                skip = 0;
        }
+       bi.bi_idx = 0;
        bi.bi_size = maxsize + skip;
        bi.bi_bvec_done = skip;