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 X-Spam-Level: X-Spam-Status: No, score=-20.5 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, UNWANTED_LANGUAGE_BODY,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0388FC4743E for ; Tue, 8 Jun 2021 16:06:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E4E8961042 for ; Tue, 8 Jun 2021 16:06:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230261AbhFHQHz (ORCPT ); Tue, 8 Jun 2021 12:07:55 -0400 Received: from linux.microsoft.com ([13.77.154.182]:47562 "EHLO linux.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230205AbhFHQHy (ORCPT ); Tue, 8 Jun 2021 12:07:54 -0400 Received: from nramas-ThinkStation-P520 (c-73-42-176-67.hsd1.wa.comcast.net [73.42.176.67]) by linux.microsoft.com (Postfix) with ESMTPSA id 84BD120B7188; Tue, 8 Jun 2021 09:06:01 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 84BD120B7188 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1623168361; bh=dtIyOy4Ilzq3XGMrQp8PfRC6MPvd5F+IjWQXdREdog4=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=PzsmbAg0cgBlIsRrfdHTj9feHMHTrfbFu24zLm8xGp33WHBylZkeg89rsQoWSP5u6 QAsXRiI69xBVqtKaze/ZOwXIbLqvbqvzGwTwpuuPxJw+KGj7XZqlbWpT1Kvj78v5eR bALfd3QTyfBVzmE+PZ16atVDeswAAYIbx8hr13SI= Message-ID: <6f42e07fb057efdc72dc292017f6dbf05c3adfe9.camel@linux.microsoft.com> Subject: Re: [PATCH 2/2] evm: output EVM digest calculation info From: nramas To: Mimi Zohar , linux-integrity@vger.kernel.org Cc: linux-security-module@vger.kernel.org, Stefan Berger , Russell Coker Date: Tue, 08 Jun 2021 09:06:00 -0700 In-Reply-To: <20210608132950.424148-3-zohar@linux.ibm.com> References: <20210608132950.424148-1-zohar@linux.ibm.com> <20210608132950.424148-3-zohar@linux.ibm.com> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.36.5-0ubuntu1 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: On Tue, 2021-06-08 at 09:29 -0400, Mimi Zohar wrote: > Output the data used in calculating the EVM digest and the resulting > digest as ascii hexadecimal strings. Reviewed-by: Lakshmi Ramasubramanian > > Suggested-by: Lakshmi Ramasubramanian > (CONFIG_DYNAMIC_DEBUG) > Signed-off-by: Mimi Zohar > --- > Changelog: > - Use pr_debug *phN format > - Define dump_security_xattr() for larger binary data > - Based on CONFIG_DYNAMIC_DEBUG > > security/integrity/evm/evm_crypto.c | 42 > +++++++++++++++++++++++++++++ > security/integrity/evm/evm_main.c | 4 +++ > 2 files changed, 46 insertions(+) > > diff --git a/security/integrity/evm/evm_crypto.c > b/security/integrity/evm/evm_crypto.c > index 1628e2ca9862..900cf8a157b6 100644 > --- a/security/integrity/evm/evm_crypto.c > +++ b/security/integrity/evm/evm_crypto.c > @@ -10,6 +10,8 @@ > * Using root's kernel master key (kmk), calculate the HMAC > */ > > +#define pr_fmt(fmt) "EVM: "fmt > + > #include > #include > #include > @@ -175,6 +177,29 @@ static void hmac_add_misc(struct shash_desc > *desc, struct inode *inode, > type != EVM_XATTR_PORTABLE_DIGSIG) > crypto_shash_update(desc, (u8 *)&inode->i_sb->s_uuid, > UUID_SIZE); > crypto_shash_final(desc, digest); > + > + pr_debug("hmac_misc: (%lu) [%*phN]\n", sizeof(struct h_misc), > + (int) sizeof(struct h_misc), &hmac_misc); > +} > + > +/* > + * Dump large security xattr values as a continuous ascii > hexademical string. > + * (pr_debug is limited to 64 bytes.) > + */ > +static void dump_security_xattr(const char *prefix, const void *src, > size_t count) > +{ > +#if defined(DEBUG) || defined(CONFIG_DYNAMIC_DEBUG) > + char *asciihex, *p; > + > + p = asciihex = kmalloc(count * 2 + 1, GFP_KERNEL); > + if (!asciihex) > + return; > + > + p = bin2hex(p, src, count); > + *p = 0; > + pr_debug("%s: (%lu) %.*s\n", prefix, count, (int) count * 2, > asciihex); > + kfree(asciihex); > +#endif > } > > /* > @@ -230,6 +255,16 @@ static int evm_calc_hmac_or_hash(struct dentry > *dentry, > req_xattr_value_len); > if (is_ima) > ima_present = true; > + > + if (req_xattr_value_len < 64) > + pr_debug("%s: (%lu) [%*phN]\n", > req_xattr_name, > + req_xattr_value_len, > + (int)req_xattr_value_len, > + req_xattr_value); > + else > + dump_security_xattr(req_xattr_name, > + req_xattr_value, > + req_xattr_value_len > ); > continue; > } > size = vfs_getxattr_alloc(&init_user_ns, dentry, xattr- > >name, > @@ -246,6 +281,13 @@ static int evm_calc_hmac_or_hash(struct dentry > *dentry, > crypto_shash_update(desc, (const u8 *)xattr_value, > xattr_size); > if (is_ima) > ima_present = true; > + > + if (xattr_size < 64) > + pr_debug("%s: (%lu) [%*phN]", xattr->name, > xattr_size, > + (int)xattr_size, xattr_value); > + else > + dump_security_xattr(xattr->name, xattr_value, > + xattr_size); > } > hmac_add_misc(desc, inode, type, data->digest); > > diff --git a/security/integrity/evm/evm_main.c > b/security/integrity/evm/evm_main.c > index 2c226e634ae9..059ac17a0041 100644 > --- a/security/integrity/evm/evm_main.c > +++ b/security/integrity/evm/evm_main.c > @@ -11,6 +11,8 @@ > * evm_inode_removexattr, and evm_verifyxattr > */ > > +#define pr_fmt(fmt) "EVM: "fmt > + > #include > #include > #include > @@ -272,6 +274,8 @@ static enum integrity_status > evm_verify_hmac(struct dentry *dentry, > else > evm_status = INTEGRITY_FAIL; > } > + pr_debug("digest: (%d) [%*phN]\n", digest.hdr.length, > digest.hdr.length, > + digest.digest); > out: > if (iint) > iint->evm_status = evm_status;