Commit 887207ed authored Nov 28, 2017 by Eric Biggers Committed by Herbert Xu Nov 29, 2017

crypto: af_alg - fix NULL pointer dereference in



 af_alg_free_areq_sgls()

If allocating the ->tsgl member of 'struct af_alg_async_req' failed,
during cleanup we dereferenced the NULL ->tsgl pointer in
af_alg_free_areq_sgls(), because ->tsgl_entries was nonzero.

Fix it by only freeing the ->tsgl list if it is non-NULL.

This affected both algif_skcipher and algif_aead.

Fixes: e870456d ("crypto: algif_skcipher - overhaul memory management")
Fixes: d887c52d ("crypto: algif_aead - overhaul memory management")
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: <stable@vger.kernel.org> # v4.14+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

parent b32a7dc8

crypto/af_alg.c

+7 −6

Original line number	Diff line number	Diff line
		@@ -672,15 +672,16 @@ void af_alg_free_areq_sgls(struct af_alg_async_req *areq)
		}

		tsgl = areq->tsgl;
		if (tsgl) {
		for_each_sg(tsgl, sg, areq->tsgl_entries, i) {
		if (!sg_page(sg))
		continue;
		put_page(sg_page(sg));
		}

		if (areq->tsgl && areq->tsgl_entries)
		sock_kfree_s(sk, tsgl, areq->tsgl_entries * sizeof(*tsgl));
		}
		}
		EXPORT_SYMBOL_GPL(af_alg_free_areq_sgls);

		/**

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