From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx48WzeBa7blgQrt0kvNcmPuzQk26Z59lHfw93fQ1b/SEIwOd+E+SNlmbXgXZfwYeefg+/geb ARC-Seal: i=1; a=rsa-sha256; t=1524580563; cv=none; d=google.com; s=arc-20160816; b=Fm88w/fSE9CjJFAZfvtFyiu9ogikuvgSWJeLI2WbZSW9dhcTCS0C1L1NSan2BbSqbA WY5/grbUYB3t17pDO8fXp4tfWpAuLWje99VGsEktHJlZn0iZd4PeuQ3oi4eAVAfg9bap cfQRTTe65hOt7SDcbfZtGdhQe/GRYXdt/6ILQ3XE/jmU1/XwJkaCazBaR5EGk1eMf8un mpBzRLhNmgx8sPup8Ee5LQxHVBN+MXYGGQRIeEJbJSkEnYOkUcM9kJoSI86Djhr8a/L4 HN2rEZZyzIaBiPYh9VGD/UthZrnOIfdPtiqAZVAmLdmFlxOZraj5BS7MY7oS24vK7+y5 BmSw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date:dkim-signature:delivered-to :list-id:list-subscribe:list-unsubscribe:list-help:list-post :precedence:mailing-list:arc-authentication-results; bh=ap6CK/kvAFtmtUjG6ztmzVrqrS3F/RVS0naL0bKVRc0=; b=YjJYXGtHdKK8xYlEfnGUHkcxfxMW40MIkLt2bcHLIVah1wdscdBZsbOklY3V4NABgP k7zjN8BYIdwwl7Jo0qbljRThih3bm6fSnqhuechAtXvJgkE1NQiskw2br/C5v2aDU5bH rGMXCrPxw2GcI7ELyHiW6pBmui/AhbvOEntApDJzw/Tz0eXpkZftT9/peTa6JrdJUfL3 OJ476AIXd4CSJkIPYGARCFoxEdpvu6pqWnvONG2p6GhEiyE3kqvUyErdB3I1Y4ZRZzB/ PKYclVDZDFo0uQ36yypJKLX/NxuMP4bUU/HTCihs3ovL1jV25uVmvAPyhLwaZoudrO2+ pO8w== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@tycho-ws.20150623.gappssmtp.com header.s=20150623 header.b=Y99z8qD1; spf=pass (google.com: domain of kernel-hardening-return-13111-gregkh=linuxfoundation.org@lists.openwall.com designates 195.42.179.200 as permitted sender) smtp.mailfrom=kernel-hardening-return-13111-gregkh=linuxfoundation.org@lists.openwall.com Authentication-Results: mx.google.com; dkim=pass header.i=@tycho-ws.20150623.gappssmtp.com header.s=20150623 header.b=Y99z8qD1; spf=pass (google.com: domain of kernel-hardening-return-13111-gregkh=linuxfoundation.org@lists.openwall.com designates 195.42.179.200 as permitted sender) smtp.mailfrom=kernel-hardening-return-13111-gregkh=linuxfoundation.org@lists.openwall.com Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm List-Post: List-Help: List-Unsubscribe: List-Subscribe: Date: Tue, 24 Apr 2018 08:35:39 -0600 From: Tycho Andersen To: Eric Biggers Cc: David Howells , keyrings@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com, James Morris , "Serge E. Hallyn" , "Jason A . Donenfeld" Subject: Re: [PATCH 1/3] big key: get rid of stack array allocation Message-ID: <20180424143539.GB3125@cisco> References: <20180424010321.14739-1-tycho@tycho.ws> <20180424045015.GA4281@sol.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180424045015.GA4281@sol.localdomain> User-Agent: Mutt/1.9.4 (2018-02-28) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1598589451187807410?= X-GMAIL-MSGID: =?utf-8?q?1598638589298586096?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: Hi Eric, On Mon, Apr 23, 2018 at 09:50:15PM -0700, Eric Biggers wrote: > Hi Tycho, > > On Mon, Apr 23, 2018 at 07:03:19PM -0600, Tycho Andersen wrote: > > We're interested in getting rid of all of the stack allocated arrays in the > > kernel [1]. This patch simply hardcodes the iv length to match that of the > > hardcoded cipher. > > > > [1]: https://lkml.org/lkml/2018/3/7/621 > > > > v2: hardcode the length of the nonce to be the GCM AES IV length, and do a > > sanity check in init(), Eric Biggers > > > > Signed-off-by: Tycho Andersen > > CC: David Howells > > CC: James Morris > > CC: "Serge E. Hallyn" > > CC: Jason A. Donenfeld > > CC: Eric Biggers > > --- > > security/keys/big_key.c | 9 ++++++++- > > 1 file changed, 8 insertions(+), 1 deletion(-) > > > > diff --git a/security/keys/big_key.c b/security/keys/big_key.c > > index 933623784ccd..75c46786a166 100644 > > --- a/security/keys/big_key.c > > +++ b/security/keys/big_key.c > > @@ -22,6 +22,7 @@ > > #include > > #include > > #include > > +#include > > > > struct big_key_buf { > > unsigned int nr_pages; > > @@ -109,7 +110,7 @@ static int big_key_crypt(enum big_key_op op, struct big_key_buf *buf, size_t dat > > * an .update function, so there's no chance we'll wind up reusing the > > * key to encrypt updated data. Simply put: one key, one encryption. > > */ > > - u8 zero_nonce[crypto_aead_ivsize(big_key_aead)]; > > + u8 zero_nonce[GCM_AES_IV_SIZE]; > > > > aead_req = aead_request_alloc(big_key_aead, GFP_KERNEL); > > if (!aead_req) > > @@ -425,6 +426,12 @@ static int __init big_key_init(void) > > pr_err("Can't alloc crypto: %d\n", ret); > > return ret; > > } > > + > > + if (unlikely(crypto_aead_ivsize(big_key_aead) != GCM_AES_IV_SIZE)) { > > + WARN(1, "big key algorithm changed?"); > > + return -EINVAL; > > + } > > + > > 'big_key_aead' needs to be freed on error. > > err = -EINVAL; > goto free_aead; oof, yes, thanks. > Also how about defining the IV size next to the algorithm name? > Then all the algorithm details would be on adjacent lines: > > static const char big_key_alg_name[] = "gcm(aes)"; > #define BIG_KEY_IV_SIZE GCM_AES_IV_SIZE Sounds good, I'll fix both of these for v3. Cheers, Tycho