From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 77683C001B2 for ; Thu, 8 Dec 2022 23:18:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229712AbiLHXSF (ORCPT ); Thu, 8 Dec 2022 18:18:05 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58216 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229656AbiLHXSE (ORCPT ); Thu, 8 Dec 2022 18:18:04 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C9D6579C93; Thu, 8 Dec 2022 15:18:01 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 9CD65620B3; Thu, 8 Dec 2022 23:18:00 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 875B3C433EF; Thu, 8 Dec 2022 23:17:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1670541480; bh=rd79PBsqcgAsOpiLcHMxEP/sk2UK4Dh/a8VVAA6SQ/k=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Vp1HXQUb5QfqqnrUWIs78XUnzr8cBvRwQ5ycZ50tmQqCKltrtum4u7Oqrc6zGSbYq SPD4//EXmEFrt0mEuLUNh4mjFoEiSnuqReSIfjUsJ0u5h0nQi2L9/yohC2SCcHN2zF D9gP16Km5VXBDyI8NnNlzFIqWxRvvQPJlO0+Z6xgyt/aPZeC6Xw3Kmq1xHe1lomjn8 mTdx5szDs2CccXckuLKnsbO1Mj6RJo7xvAi3Qx92Kb1LCUqGmCkEwyGorBGQstq0Xo qegdmvVWVEfMFpbkeDPco4FZph5m2hahdb69Cbpy5vAzpvfnFoVGfTjitjOjGFu9jd lW/Ltxb8gp0fA== Date: Thu, 8 Dec 2022 15:17:57 -0800 From: Eric Biggers To: Roberto Sassu Cc: dhowells@redhat.com, herbert@gondor.apana.org.au, davem@davemloft.net, zohar@linux.ibm.com, dmitry.kasatkin@gmail.com, paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, keyrings@vger.kernel.org, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, Roberto Sassu , stable@vger.kernel.org Subject: Re: [PATCH] KEYS: asymmetric: Make a copy of sig and digest in vmalloced stack Message-ID: References: <20221208164610.867747-1-roberto.sassu@huaweicloud.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221208164610.867747-1-roberto.sassu@huaweicloud.com> Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org On Thu, Dec 08, 2022 at 05:46:10PM +0100, Roberto Sassu wrote: > diff --git a/crypto/asymmetric_keys/public_key.c b/crypto/asymmetric_keys/public_key.c > index 2f8352e88860..307799ffbc3e 100644 > --- a/crypto/asymmetric_keys/public_key.c > +++ b/crypto/asymmetric_keys/public_key.c > @@ -363,7 +363,8 @@ int public_key_verify_signature(const struct public_key *pkey, > struct scatterlist src_sg[2]; > char alg_name[CRYPTO_MAX_ALG_NAME]; > char *key, *ptr; > - int ret; > + char *sig_s, *digest; > + int ret, verif_bundle_len; > > pr_devel("==>%s()\n", __func__); > > @@ -400,8 +401,21 @@ int public_key_verify_signature(const struct public_key *pkey, > if (!req) > goto error_free_tfm; > > - key = kmalloc(pkey->keylen + sizeof(u32) * 2 + pkey->paramlen, > - GFP_KERNEL); > + verif_bundle_len = pkey->keylen + sizeof(u32) * 2 + pkey->paramlen; > + > + sig_s = sig->s; > + digest = sig->digest; > + > + if (IS_ENABLED(CONFIG_VMAP_STACK)) { > + if (!virt_addr_valid(sig_s)) > + verif_bundle_len += sig->s_size; > + > + if (!virt_addr_valid(digest)) > + verif_bundle_len += sig->digest_size; > + } > + > + /* key points to a buffer which could contain the sig and digest too. */ > + key = kmalloc(verif_bundle_len, GFP_KERNEL); > if (!key) > goto error_free_req; > > @@ -424,9 +438,24 @@ int public_key_verify_signature(const struct public_key *pkey, > goto error_free_key; > } > > + if (IS_ENABLED(CONFIG_VMAP_STACK)) { > + ptr += pkey->paramlen; > + > + if (!virt_addr_valid(sig_s)) { > + sig_s = ptr; > + memcpy(sig_s, sig->s, sig->s_size); > + ptr += sig->s_size; > + } > + > + if (!virt_addr_valid(digest)) { > + digest = ptr; > + memcpy(digest, sig->digest, sig->digest_size); > + } > + } > + > sg_init_table(src_sg, 2); > - sg_set_buf(&src_sg[0], sig->s, sig->s_size); > - sg_set_buf(&src_sg[1], sig->digest, sig->digest_size); > + sg_set_buf(&src_sg[0], sig_s, sig->s_size); > + sg_set_buf(&src_sg[1], digest, sig->digest_size); > akcipher_request_set_crypt(req, src_sg, NULL, sig->s_size, > sig->digest_size); > crypto_init_wait(&cwait); We should try to avoid adding error-prone special cases. How about just doing the copy of the signature and digest unconditionally? That would be much simpler. It would even mean that the scatterlist would only need one element. Also, the size of buffer needed is only max(pkey->keylen + sizeof(u32) * 2 + pkey->paramlen, sig->s_size + sig->digest_size) ... since the signature and digest aren't needed until the key was already used. - Eric