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Commit 9e0a6433 authored by Stephan Mueller's avatar Stephan Mueller Committed by Greg Kroah-Hartman
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crypto: algif_skcipher - only call put_page on referenced and used pages 



commit 445a582738de6802669aeed9c33ca406c23c3b1f upstream.

For asynchronous operation, SGs are allocated without a page mapped to
them or with a page that is not used (ref-counted). If the SGL is freed,
the code must only call put_page for an SG if there was a page assigned
and ref-counted in the first place.

This fixes a kernel crash when using io_submit with more than one iocb
using the sendmsg and sendpage (vmsplice/splice) interface.

Signed-off-by: default avatarStephan Mueller <smueller@chronox.de>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 91a0e1ed

crypto/algif_skcipher.c

+7 −2
Original line number Diff line number Diff line
@@ -86,8 +86,13 @@ static void skcipher_free_async_sgls(struct skcipher_async_req *sreq) 
	}

	sgl = sreq->tsg;

	n = sg_nents(sgl);

	for_each_sg(sgl, sg, n, i)

		put_page(sg_page(sg));

	for_each_sg(sgl, sg, n, i) {

		struct page *page = sg_page(sg);



		/* some SGs may not have a page mapped */

		if (page && page_ref_count(page))

			put_page(page);

	}



	kfree(sreq->tsg);

}