From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:37028 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751824AbeCOADq (ORCPT ); Wed, 14 Mar 2018 20:03:46 -0400 Received: from pps.filterd (m0098421.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w2ENx51a137532 for ; Wed, 14 Mar 2018 20:03:46 -0400 Received: from e32.co.us.ibm.com (e32.co.us.ibm.com [32.97.110.150]) by mx0a-001b2d01.pphosted.com with ESMTP id 2gqcn3agad-1 (version=TLSv1.2 cipher=AES256-SHA256 bits=256 verify=NOT) for ; Wed, 14 Mar 2018 20:03:45 -0400 Received: from localhost by e32.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 14 Mar 2018 18:03:45 -0600 References: <20180314202020.3794-1-bauerman@linux.vnet.ibm.com> <20180314202020.3794-4-bauerman@linux.vnet.ibm.com> <20180314214045.GC14289@mail.hallyn.com> From: Thiago Jung Bauermann To: "Serge E. Hallyn" Cc: linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, James Morris , Mimi Zohar , Dmitry Kasatkin Subject: Re: [PATCH 3/4] ima: Improvements in ima_appraise_measurement() In-reply-to: <20180314214045.GC14289@mail.hallyn.com> Date: Wed, 14 Mar 2018 21:03:36 -0300 MIME-Version: 1.0 Content-Type: text/plain Message-Id: <87efkmjjc7.fsf@morokweng.localdomain> Sender: linux-integrity-owner@vger.kernel.org List-ID: Hello Serge, Thanks for quickly reviewing these patches! Serge E. Hallyn writes: > Quoting Thiago Jung Bauermann (bauerman@linux.vnet.ibm.com): >> From: Mimi Zohar >> @@ -241,16 +241,20 @@ int ima_appraise_measurement(enum ima_hooks func, >> } >> >> status = evm_verifyxattr(dentry, XATTR_NAME_IMA, xattr_value, rc, iint); >> - if ((status != INTEGRITY_PASS) && >> - (status != INTEGRITY_PASS_IMMUTABLE) && >> - (status != INTEGRITY_UNKNOWN)) { >> - if ((status == INTEGRITY_NOLABEL) >> - || (status == INTEGRITY_NOXATTRS)) >> - cause = "missing-HMAC"; >> - else if (status == INTEGRITY_FAIL) >> - cause = "invalid-HMAC"; >> + switch (status) { >> + case INTEGRITY_PASS: >> + case INTEGRITY_PASS_IMMUTABLE: >> + case INTEGRITY_UNKNOWN: > > Wouldn't it be more future-proof to replace this with a 'default', or > to at least add a "default: BUG()" to catch new status values? I agree. I like the "default: BUG()" option. >> + break; >> + case INTEGRITY_NOXATTRS: /* No EVM protected xattrs. */ >> + case INTEGRITY_NOLABEL: /* No security.evm xattr. */ >> + cause = "missing-HMAC"; >> + goto out; >> + case INTEGRITY_FAIL: /* Invalid HMAC/signature. */ >> + cause = "invalid-HMAC"; >> goto out; >> } >> + >> switch (xattr_value->type) { >> case IMA_XATTR_DIGEST_NG: >> /* first byte contains algorithm id */ >> @@ -316,17 +320,20 @@ int ima_appraise_measurement(enum ima_hooks func, >> integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, filename, >> op, cause, rc, 0); >> } else if (status != INTEGRITY_PASS) { >> + /* Fix mode, but don't replace file signatures. */ >> if ((ima_appraise & IMA_APPRAISE_FIX) && >> (!xattr_value || >> xattr_value->type != EVM_IMA_XATTR_DIGSIG)) { >> if (!ima_fix_xattr(dentry, iint)) >> status = INTEGRITY_PASS; >> - } else if ((inode->i_size == 0) && >> - (iint->flags & IMA_NEW_FILE) && >> - (xattr_value && >> - xattr_value->type == EVM_IMA_XATTR_DIGSIG)) { >> + } >> + >> + /* Permit new files with file signatures, but without data. */ >> + if (inode->i_size == 0 && iint->flags & IMA_NEW_FILE && > > This may be correct, but it's not identical to what you're replacing. > Since in either case you're setting status to INTEGRITY_PASS the final > result is the same, but with a few extra possible steps. Not sure > whether that matters. Good point. I'll have to defer this one to Mimi though. > >> + xattr_value && xattr_value->type == EVM_IMA_XATTR_DIGSIG) { >> status = INTEGRITY_PASS; >> } >> + >> integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, filename, >> op, cause, rc, 0); >> } else { -- Thiago Jung Bauermann IBM Linux Technology Center