From patchwork Thu May 7 18:51:45 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Gustavo A. R. Silva" X-Patchwork-Id: 11534687 X-Patchwork-Delegate: herbert@gondor.apana.org.au Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8F15614B4 for ; Thu, 7 May 2020 18:47:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 75CDD21BE5 for ; Thu, 7 May 2020 18:47:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588877241; bh=kmGDD3oC3EB4KQRIO7ZBSOzgTGdqiOKS8/Gs5OxyZzQ=; h=Date:From:To:Cc:Subject:List-ID:From; b=mlZ0Lx4qLyQTvKZdsW8+ZI31OPVH6zOwOsysffAwrKtk8NNPFNoYNHHa9159qFuHr 2FeXyMNoKBj99wy3uW5LC/n17DDVBs3dFIdLAKzZLPHWs/R0O5DSGDdOu3dSBasFZr lBLONOknTx2Abkm3Z5PzezXGRIr0tsSCTHuYBr+0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728465AbgEGSrU (ORCPT ); Thu, 7 May 2020 14:47:20 -0400 Received: from mail.kernel.org ([198.145.29.99]:47778 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728056AbgEGSrT (ORCPT ); Thu, 7 May 2020 14:47:19 -0400 Received: from embeddedor (unknown [189.207.59.248]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D8A782184D; Thu, 7 May 2020 18:47:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588877239; bh=kmGDD3oC3EB4KQRIO7ZBSOzgTGdqiOKS8/Gs5OxyZzQ=; h=Date:From:To:Cc:Subject:From; b=aQxNvVL4LnuUDIlx7X8iJ3ft1lNV6QVFUbl5bZMcJufApldo3SFTFMFJplJfTqMaa aQhG09ZmEJVF2CZLRxbvL8/rWJJi394/CcJOQZaO4qhDgaUmkMlfQd5uFA1pti9SQX jSuf6bWpyzrCCe3uuZ9amCXb2unSpP7HAZCZO5xo= Date: Thu, 7 May 2020 13:51:45 -0500 From: "Gustavo A. R. Silva" To: Ayush Sawal , Vinay Kumar Yadav , Rohit Maheshwari Cc: linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] crypto: Replace zero-length array with flexible-array Message-ID: <20200507185145.GA14096@embeddedor> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] sizeof(flexible-array-member) triggers a warning because flexible array members have incomplete type[1]. There are some instances of code in which the sizeof operator is being incorrectly/erroneously applied to zero-length arrays and the result is zero. Such instances may be hiding some bugs. So, this work (flexible-array member conversions) will also help to get completely rid of those sorts of issues. This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva --- drivers/crypto/chelsio/chcr_crypto.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/crypto/chelsio/chcr_crypto.h b/drivers/crypto/chelsio/chcr_crypto.h index 542bebae001f..1cc522a07aac 100644 --- a/drivers/crypto/chelsio/chcr_crypto.h +++ b/drivers/crypto/chelsio/chcr_crypto.h @@ -223,7 +223,7 @@ struct chcr_authenc_ctx { struct __aead_ctx { struct chcr_gcm_ctx gcm[0]; - struct chcr_authenc_ctx authenc[0]; + struct chcr_authenc_ctx authenc[]; }; struct chcr_aead_ctx { @@ -235,7 +235,7 @@ struct chcr_aead_ctx { u8 nonce[4]; u16 hmac_ctrl; u16 mayverify; - struct __aead_ctx ctx[0]; + struct __aead_ctx ctx[]; }; struct hmac_ctx { @@ -247,7 +247,7 @@ struct hmac_ctx { struct __crypto_ctx { struct hmac_ctx hmacctx[0]; struct ablk_ctx ablkctx[0]; - struct chcr_aead_ctx aeadctx[0]; + struct chcr_aead_ctx aeadctx[]; }; struct chcr_context { @@ -257,7 +257,7 @@ struct chcr_context { unsigned int ntxq; unsigned int nrxq; struct completion cbc_aes_aio_done; - struct __crypto_ctx crypto_ctx[0]; + struct __crypto_ctx crypto_ctx[]; }; struct chcr_hctx_per_wr {