From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx4+R95ivWcVghB2q06drxv+4AQ8cIyNM4vFo8S4tZmiYZBjOgRMhBiL+Th2X8YHwDPcE8BKQ ARC-Seal: i=1; a=rsa-sha256; t=1523282153; cv=none; d=google.com; s=arc-20160816; b=X1pkiPLhKXHWWZlQ8eR77LclBOIAEzbsAgWVnnsRMi2aE6k3qmT6HsDtEs8G8mJuH+ usa2ABZL6uuvc878NPrmG3P3hojCpQ4Sb3tueMQ765hcp9b/WqjkVHilUZh5+oGRpjvN rIcrVuYnxRP6nTiG6OdZfC6MLgZzFUyw/pH6n9fxrb0dRxBaCf2CQU6E2SkMbjPqibF/ DIxPRhS6LCmravJXY3dZp9ySxJT5Q05vTrnbBiegbMcvnhM8Y/XqIAJ43vcOKiNT0+RM 1Cge13JWD9d6vaOK1bnPF+5yDq71XGOT83oYDM5CfPfsa2VwFJT4iTCGztsdoKYZWdU3 L+SQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature:delivered-to:list-id:list-subscribe:list-unsubscribe :list-help:list-post:precedence:mailing-list :arc-authentication-results; bh=6NB0vqSoUgWTZAcA6cfxu0y92CQriqdtNfdKQsTwrqs=; b=wiL1t//L26eCp8M9FiiA+wme0F1OBeSX3lW+cfdlSVAH04J+Sq10/nwE389xAGRzMJ 3dvhMixrxga/mNJFgj3D2qPYS4JfNsdmRam4o36LfB1klx8Yh5/HiA58fAW1iWYPHJuf sbDvGU9LZMxfhXSbYbQG1Mtt36rKIn80bJCG+s637+KwO5/t7tEB9+EWVmhRkbdpy+o4 +EP01WwnLdUw6i3lnodQJSjndmisfX2zp921jQsSTrA8GSogO6o2SPKSqXfUDxrU7+hz 3iF0pSykB4aUN8woJzJGrqamdBXT8vAk6ufRWUZTern0eI2jQQCl5rhv5PUGkB97uxzv mzCA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=Tbp/m8cH; spf=pass (google.com: domain of kernel-hardening-return-12924-gregkh=linuxfoundation.org@lists.openwall.com designates 195.42.179.200 as permitted sender) smtp.mailfrom=kernel-hardening-return-12924-gregkh=linuxfoundation.org@lists.openwall.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=Tbp/m8cH; spf=pass (google.com: domain of kernel-hardening-return-12924-gregkh=linuxfoundation.org@lists.openwall.com designates 195.42.179.200 as permitted sender) smtp.mailfrom=kernel-hardening-return-12924-gregkh=linuxfoundation.org@lists.openwall.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm List-Post: List-Help: List-Unsubscribe: List-Subscribe: From: Salvatore Mesoraca To: linux-kernel@vger.kernel.org Cc: kernel-hardening@lists.openwall.com, linux-crypto@vger.kernel.org, "David S. Miller" , Herbert Xu , Kees Cook , Salvatore Mesoraca , Eric Biggers , Laura Abbott Subject: [PATCH 6/6] crypto: cfb - avoid VLA use Date: Mon, 9 Apr 2018 15:54:04 +0200 Message-Id: <1523282044-22075-7-git-send-email-s.mesoraca16@gmail.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1523282044-22075-1-git-send-email-s.mesoraca16@gmail.com> References: <1523282044-22075-1-git-send-email-s.mesoraca16@gmail.com> X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1597277107754358358?= X-GMAIL-MSGID: =?utf-8?q?1597277107754358358?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: We avoid 3 VLAs[1] by always allocating MAX_BLOCKSIZE bytes or, when needed for alignement, MAX_BLOCKSIZE + MAX_ALIGNMASK bytes. We also check the selected cipher at instance creation time, if it doesn't comply with these limits, the creation will fail. [1] http://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com Signed-off-by: Salvatore Mesoraca --- crypto/cfb.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/crypto/cfb.c b/crypto/cfb.c index 94ee39b..f500816 100644 --- a/crypto/cfb.c +++ b/crypto/cfb.c @@ -28,6 +28,7 @@ #include #include #include +#include "internal.h" struct crypto_cfb_ctx { struct crypto_cipher *child; @@ -53,9 +54,8 @@ static void crypto_cfb_encrypt_one(struct crypto_skcipher *tfm, static void crypto_cfb_final(struct skcipher_walk *walk, struct crypto_skcipher *tfm) { - const unsigned int bsize = crypto_cfb_bsize(tfm); const unsigned long alignmask = crypto_skcipher_alignmask(tfm); - u8 tmp[bsize + alignmask]; + u8 tmp[MAX_BLOCKSIZE + MAX_ALIGNMASK]; u8 *stream = PTR_ALIGN(tmp + 0, alignmask + 1); u8 *src = walk->src.virt.addr; u8 *dst = walk->dst.virt.addr; @@ -94,7 +94,7 @@ static int crypto_cfb_encrypt_inplace(struct skcipher_walk *walk, unsigned int nbytes = walk->nbytes; u8 *src = walk->src.virt.addr; u8 *iv = walk->iv; - u8 tmp[bsize]; + u8 tmp[MAX_BLOCKSIZE]; do { crypto_cfb_encrypt_one(tfm, iv, tmp); @@ -164,7 +164,7 @@ static int crypto_cfb_decrypt_inplace(struct skcipher_walk *walk, unsigned int nbytes = walk->nbytes; u8 *src = walk->src.virt.addr; u8 *iv = walk->iv; - u8 tmp[bsize]; + u8 tmp[MAX_BLOCKSIZE]; do { crypto_cfb_encrypt_one(tfm, iv, tmp); @@ -295,6 +295,12 @@ static int crypto_cfb_create(struct crypto_template *tmpl, struct rtattr **tb) if (err) goto err_drop_spawn; + err = -EINVAL; + if (alg->cra_blocksize > MAX_BLOCKSIZE) + goto err_drop_spawn; + if (alg->cra_alignmask > MAX_ALIGNMASK) + goto err_drop_spawn; + inst->alg.base.cra_priority = alg->cra_priority; /* we're a stream cipher independend of the crypto cra_blocksize */ inst->alg.base.cra_blocksize = 1; -- 1.9.1