Commit 445a5827 authored Aug 16, 2017 by Stephan Mueller Committed by Herbert Xu Aug 22, 2017

crypto: algif_skcipher - only call put_page on referenced and used pages



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.

Cc: <stable@vger.kernel.org>
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

parent 549f6415

crypto/algif_skcipher.c

+7 −2

Original line number	Diff line number	Diff line
		@@ -87,8 +87,13 @@ 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);
		}

Admin message