From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELuPx/RAPm1bzgjXR15OSYhM45CIxMzkKYoi4wVWLif1AYBcTBEbsV7tj+AOnSCdIo0TYB+1 ARC-Seal: i=1; a=rsa-sha256; t=1520915400; cv=none; d=google.com; s=arc-20160816; b=J9plCRB/WYofMYrIQLUBo5PWy1O9foTb/J2vStxnmt9w1JoYDZ31ApKW0yPwGGDxe+ heS0PrDhJVeod0JKWtVxjUNaTittSxVZKdrjjJNj2WRFlPsulfKtpoVJG4s8sdWYwALN 1fSin82MMravpt02XKq84C1+fym/14B2z1LTRLzx6OPh7Hk6kSuP0WHPmC/a9rkkbz6G vWIGLDDB6fbS8h4MWmNUVW2VyWM2AvtXSJamISHUMG7YiYF0aG4H6/JlLI0vgbx4cdP6 UeoSyW0vlik/7lRQKnHx+HD+/PclMU5Cuu8nwzckOG4E6PFEU185jksDllcsQUuuLAVZ 7WAg== 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=7elmkvTp7D2Y1qk9MSRAVsX+pNnrR9P0PXvPX04BVgc=; b=exdIA/yeITvOQyMv6odBOnRMZNhTCEJEjlISsBR4yP1Kvqr70XEFT2vL3z5xFcN5k8 z/tJ+tgtoFcJQ9NBM/yC0UvzDcMKxr1oG2ghgdJzGyqV2rT2BZ8L/mY41FlCduyeNx+0 8GtgQnzpli5i5MXRq406hYs/6v8xu43FUFlXD+5MMPcwmjX4ldFPAiplgpE1NBfIYWNc OAkc3GfauYj7lp9k3DHI52nXzCUrBCXmMBOWxccmfbNo0NrMCXkE0EO2Z08GxPixA4GO Tm+hgMpmduk0xuQLZXwcN4xgxSuSeg1varn2LaC2vyrLtOrrRyc6dgpHbdWz1XUbZ6IG rEog== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@tycho-ws.20150623.gappssmtp.com header.s=20150623 header.b=EHR72MOv; spf=pass (google.com: domain of kernel-hardening-return-12493-gregkh=linuxfoundation.org@lists.openwall.com designates 195.42.179.200 as permitted sender) smtp.mailfrom=kernel-hardening-return-12493-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=EHR72MOv; spf=pass (google.com: domain of kernel-hardening-return-12493-gregkh=linuxfoundation.org@lists.openwall.com designates 195.42.179.200 as permitted sender) smtp.mailfrom=kernel-hardening-return-12493-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: From: Tycho Andersen To: David Howells Cc: keyrings@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com, Tycho Andersen , James Morris , "Serge E. Hallyn" Subject: [PATCH 2/2] dh key: get rid of stack array allocation Date: Mon, 12 Mar 2018 22:29:07 -0600 Message-Id: <20180313042907.29598-2-tycho@tycho.ws> X-Mailer: git-send-email 2.15.1 In-Reply-To: <20180313042907.29598-1-tycho@tycho.ws> References: <20180313042907.29598-1-tycho@tycho.ws> X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1594795386978188484?= X-GMAIL-MSGID: =?utf-8?q?1594795386978188484?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: Similarly to the previous patch, we would like to get rid of stack allocated arrays: https://lkml.org/lkml/2018/3/7/621 In this case, we can also use a malloc style approach to free the temporary buffer, being careful to also use kzfree to free them (indeed, at least one of these has a memzero_explicit, but it seems like maybe they both should?). Signed-off-by: Tycho Andersen CC: David Howells CC: James Morris CC: "Serge E. Hallyn" --- security/keys/dh.c | 27 +++++++++++++++++++++------ 1 file changed, 21 insertions(+), 6 deletions(-) diff --git a/security/keys/dh.c b/security/keys/dh.c index d1ea9f325f94..f02261b24759 100644 --- a/security/keys/dh.c +++ b/security/keys/dh.c @@ -162,19 +162,27 @@ static int kdf_ctr(struct kdf_sdesc *sdesc, const u8 *src, unsigned int slen, goto err; if (zlen && h) { - u8 tmpbuffer[h]; + u8 *tmpbuffer; size_t chunk = min_t(size_t, zlen, h); - memset(tmpbuffer, 0, chunk); + + err = -ENOMEM; + tmpbuffer = kzalloc(chunk, GFP_KERNEL); + if (!tmpbuffer) + goto err; do { err = crypto_shash_update(desc, tmpbuffer, chunk); - if (err) + if (err) { + kzfree(tmpbuffer); goto err; + } zlen -= chunk; chunk = min_t(size_t, zlen, h); } while (zlen); + + kzfree(tmpbuffer); } if (src && slen) { @@ -184,13 +192,20 @@ static int kdf_ctr(struct kdf_sdesc *sdesc, const u8 *src, unsigned int slen, } if (dlen < h) { - u8 tmpbuffer[h]; + u8 *tmpbuffer; + + err = -ENOMEM; + tmpbuffer = kzalloc(h, GFP_KERNEL); + if (!tmpbuffer) + goto err; err = crypto_shash_final(desc, tmpbuffer); - if (err) + if (err) { + kzfree(tmpbuffer); goto err; + } memcpy(dst, tmpbuffer, dlen); - memzero_explicit(tmpbuffer, h); + kzfree(tmpbuffer); return 0; } else { err = crypto_shash_final(desc, dst); -- 2.15.1