From patchwork Wed Feb 2 23:53:00 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Casey Schaufler X-Patchwork-Id: 12733570 X-Patchwork-Delegate: paul@paul-moore.com Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8D1C3C433FE for ; Wed, 2 Feb 2022 23:59:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348234AbiBBX7x (ORCPT ); Wed, 2 Feb 2022 18:59:53 -0500 Received: from sonic314-27.consmr.mail.ne1.yahoo.com ([66.163.189.153]:42030 "EHLO sonic314-27.consmr.mail.ne1.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348224AbiBBX7w (ORCPT ); Wed, 2 Feb 2022 18:59:52 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s2048; t=1643846392; bh=HWPHx+c9mffkOYBlCL7PsaufKRO5fGg8oeT9SIKx648=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From:Subject:Reply-To; b=sh4LY0sEvEl11GPkF77rzyGDafdkgGVEr8voHWxyBWZ3F27roqk4EKiZqKwcPNuHO/nhR31B2ojz3V7/fzZWWx2VT2rcDvKc1kC+5ZQEnw1YxmjeiDu7b+l8bbv5EPWYxujIfRUwqO8rto+FGveaYxpwWQBfg1Hc9ac1/IZYjO3bydNdwoxqXE09m2Pcf3DWy0ShjiSqQXb8FwhXv+2nDyYdLX6E9fQO7nU+E4zeHndUiUHRiaf9zny23U+tBotUmCyqEZ6FR0l69Y0r6a+odzKHigVZQMCcD7fUYe79uB/cThFF/K1bIrCnIAw+8PiET9D8uBAZuB1bGiJE4IDeTA== X-SONIC-DKIM-SIGN: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s2048; t=1643846392; bh=P5g+uhbsJe0yjPTOrazpGBzz0dkof+C/uejbPynu7gY=; h=X-Sonic-MF:From:To:Subject:Date:From:Subject; b=fqgDPowV/F00A7s4BnSxjWLBdlQp7+MJfDq13ynvKoLqZPC6bKhDUbY5ju+xxWWgOfD5V8O1CaQRU9ZzzK+nYr6mbCk1z6DcfNVjUN9KqFYOCGtpI8rq3bPLxuCAV/qb4L6ZC8aPAAkbe9uIAdt6wEQKcj4j+X9j7yrOd9NaPakeu0ZrnNeC2c3pA/TcOVm3LohYr5AMeaFyr25d2UVhDKlj8MDQINNM4rfZ0/NH1rStNiPCfZQjSngoxpzqbNP5eONjvbEsFvP+wKJS9vuNIBz1rhtJQiaPtbEqbwBIN0MDA4Qz+gwpf7JVcCpZUFmEiLkv9g4U+asMI97yyLTkqg== X-YMail-OSG: bDrZt.AVM1lb8k_UtgaM6KZ6gIRSDhS4Ao7bl0a989WlofQRkeblB9UWm2NAyVZ DI4yq2NVEIfPdieN3_FkqEMRbbPLboxs8oq894exr.bDvn64J0TuJl8_do1F9V306MtCWQ51Z47. hUX_cs1CLUxOPCV_37wO3lq4C8e.S8n2dXP.PfuvDolf0z7v0vXQ2mDvZsFnCs3_x6_FS1YSmnJp m.a8sAZUvhzasfeEe_1ibuPHiWi965TRjcid._JZ2fdmb7WGiE0_WVRE0mqGEvIhPtxUEhEZy8Nc KmcDVdEDIvUHt176niU1Qa7spAis_ccx7ifL5NyC2oVMkvJQCHmg9a5u3bOucHhte_nWuZNOyekY Vk6JhnWuc8bjhp7dqsCFVNam6SQt9HcpAc3y1xevc.o9.SnSvZyRZhMUes6QNrko7BncTu7Y3hAt WAPEGOdSJLfA82uP00qOAK5oWvS2DyGHq2isndFdu4Ir1.bndD5NFapDqNkN1PLcsQvRYfB5WYK3 0_LrshTcJPPS0ETkG.iU5F5Owa6i58GnxxPadoJMKmNBTCM2TDyvsK_6ub2XWjtwrTh8cM3qIjxh DDbRy.sZmnHd_SYyeG31rGMEufjQc7L0ibyhNFYuoeIPs5b1h99sZzGcE6tH7Pucz9xbcNKs5LCJ klMLnkkzRhLLTITcI2A63q3FK3X33TmEGeKmCcjjvggBbqADWLE9IrTxG4oCwouu6BEzvRPhemQz LNu0mJPjHVPtJV0Cvmxus4uSC1ac9ipilCmcf2woWhDQrOKbTwKQmCEss1A57C9LhSU09kJHxHCR Cy0GRrSDGSI5iums6y2QK_moiRmULb3r0Xxf5vkNt4KLE6kAS7zYdbnJSxamPJelmt82zEoGJPsA YDV4TgbN3ySs0B6sPmEzzZBlRwoEXwLIWMmmiY7a9gvBOrEilJ78TpD2UixbisWQhXYd0UWhxRXt b3GrLZLq7daGYUwt8lSSzw2XWWHBHHTlNAFvZrJzYZphsAroJd9a3jP5R1wh9A.pLViL.JjkLPYl Cx03MiMcC4zP2t0PwrfHp4PSHL7sEMHVngRe1yCpWFdv9VROh.SZfzAXBTDklJ9nQouyyr.dVXbn 25xQOu2jBXcERtDbFwVf7pd0pZnEAmzROXzKrUhvMtX2_FU8O1fWkiWeuY2EEsUoIHtMjt95cxOr 2g54t0nLhvOyqb.pYLPOJ4vCrwA_ppQ5DQtwWk6.X2eCaNIvHwqiDjgQmmkZv69Zm4I0yeU4OD5W QWi67xzYzW7jip9pxnaLl709MAPWm3QXEMuH8MoxoRWw8l_6V7aLJeFZ8WH5QNvCRppYVtjevabc If11HmwoJ8DXJQHngqzB_4CKmqhqN9YEhk2HCBaS8Ar7yVYO4ZrA2ftF.cGxC5H_eIx.esrYIoqZ aXTdILITVNKRnvwyHcxy6hD3qd5i1PbARMtE.MHniKsaGDgQ_EHrGBDMlIqlgcpRwTcZWLt3n9aZ 7KUShQxIqH61n63ajaCTzY24ZgWIOFqqhq_JKXRpwaLSv1Yqt14.tB.y8REXxadHB__3FddKpLez 5FXO4AL9npRuYqHFlUFy0lRUYYU9AlyHZxafW1YrWNMBNameehxQi41MiENefcO33fcbKaUou0He QiX5stpgbwAXClhoy6AsRmzdwtEoKsrpWNVPdvNRS8uWrg2vOvzJlOl30NOxfb8VMcV.ylX5q6IM 52l_j9KEzjSyDMKnurfHMaQ5wdhx2Ky8RZAVUGSqBUoOutDFnD2MYgAfN3BVgDqZGQhBKek0YtpF F78DiTZBmkqZzuhZ5.4rPd2QrQgypul0MuMcneV6_WVYMRyHSrGLtY1cXqDPJo0Ihg7d8nIpZ6fk Vg3L1D6MFs.RJTMUsOrCyZ4mlU4s8.qBuVPtXi66g_iggjXmRIeQFonZRKiuh4qbLqsHzjKWraVT M2E2QJnO6X5SFOx8tpeXOJVkp8OvgoNyS5RHApp05M7B0CsGjKEZ1.JwS7Miuvtrz5fhSE7ydg8O T7IruG5cVsg2RzihIv2VUuhbWNE1lVO6vpDVPmUGJbnHn6S2wicC4NEguDToSpC90Awe0Fo2T.L5 kkK1NXVIdo3RBujIzor0ETlsZxZh.k0YwK5kGif7N_TnXyiG7YI6q9uRyWS5tO8.gtO5_pAzKo4x A7kH5KXUUXJdWVZukXdhxQOKyNpBBNOfPVeByk_6afixcRzIRauBtRsrs.7ShNnIFI5kq124olvs 5jbLjMSLCnzUdm7d3e4z675LRcl6MpgCT0IjgwXoe6MaQpIzvspyL749L7.49SSssFkclvsw- X-Sonic-MF: Received: from sonic.gate.mail.ne1.yahoo.com by sonic314.consmr.mail.ne1.yahoo.com with HTTP; Wed, 2 Feb 2022 23:59:52 +0000 Received: by kubenode513.mail-prod1.omega.gq1.yahoo.com (VZM Hermes SMTP Server) with ESMTPA ID 246274658a7f9c615ce7598170f9f417; Wed, 02 Feb 2022 23:59:47 +0000 (UTC) From: Casey Schaufler To: casey.schaufler@intel.com, jmorris@namei.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org Cc: casey@schaufler-ca.com, linux-audit@redhat.com, keescook@chromium.org, john.johansen@canonical.com, penguin-kernel@i-love.sakura.ne.jp, paul@paul-moore.com, sds@tycho.nsa.gov, linux-kernel@vger.kernel.org Subject: [PATCH v32 05/28] IMA: avoid label collisions with stacked LSMs Date: Wed, 2 Feb 2022 15:53:00 -0800 Message-Id: <20220202235323.23929-6-casey@schaufler-ca.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20220202235323.23929-1-casey@schaufler-ca.com> References: <20220202235323.23929-1-casey@schaufler-ca.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: selinux@vger.kernel.org Integrity measurement may filter on security module information and needs to be clear in the case of multiple active security modules which applies. Provide a boot option ima_rules_lsm= to allow the user to specify an active security module to apply filters to. If not specified, use the first registered module that supports the audit_rule_match() LSM hook. Allow the user to specify in the IMA policy an lsm= option to specify the security module to use for a particular rule. Signed-off-by: Casey Schaufler To: Mimi Zohar To: linux-integrity@vger.kernel.org --- Documentation/ABI/testing/ima_policy | 8 ++++- include/linux/security.h | 14 ++++---- security/integrity/ima/ima_policy.c | 51 ++++++++++++++++++++++++---- security/security.c | 35 +++++++++++++++---- 4 files changed, 89 insertions(+), 19 deletions(-) diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy index 839fab811b18..64863e9d87ea 100644 --- a/Documentation/ABI/testing/ima_policy +++ b/Documentation/ABI/testing/ima_policy @@ -26,7 +26,7 @@ Description: [uid=] [euid=] [gid=] [egid=] [fowner=] [fgroup=]] lsm: [[subj_user=] [subj_role=] [subj_type=] - [obj_user=] [obj_role=] [obj_type=]] + [obj_user=] [obj_role=] [obj_type=]] [lsm=] option: [[appraise_type=]] [template=] [permit_directio] [appraise_flag=] [appraise_algos=] [keyrings=] base: @@ -126,6 +126,12 @@ Description: measure subj_user=_ func=FILE_CHECK mask=MAY_READ + It is possible to explicitly specify which security + module a rule applies to using lsm=. If the security + module specified is not active on the system the rule + will be rejected. If lsm= is not specified the first + security module registered on the system will be assumed. + Example of measure rules using alternate PCRs:: measure func=KEXEC_KERNEL_CHECK pcr=4 diff --git a/include/linux/security.h b/include/linux/security.h index 6da0c12c9170..1edbb362ee72 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -1977,25 +1977,27 @@ static inline void security_audit_rule_free(struct audit_lsm_rules *lsmrules) #ifdef CONFIG_IMA_LSM_RULES #ifdef CONFIG_SECURITY -int ima_filter_rule_init(u32 field, u32 op, char *rulestr, void **lsmrule); -int ima_filter_rule_match(u32 secid, u32 field, u32 op, void *lsmrule); -void ima_filter_rule_free(void *lsmrule); +int ima_filter_rule_init(u32 field, u32 op, char *rulestr, void **lsmrule, + int lsmslot); +int ima_filter_rule_match(u32 secid, u32 field, u32 op, void *lsmrule, + int lsmslot); +void ima_filter_rule_free(void *lsmrule, int lsmslot); #else static inline int ima_filter_rule_init(u32 field, u32 op, char *rulestr, - void **lsmrule) + void **lsmrule, int lsmslot) { return 0; } static inline int ima_filter_rule_match(u32 secid, u32 field, u32 op, - void *lsmrule) + void *lsmrule, int lsmslot) { return 0; } -static inline void ima_filter_rule_free(void *lsmrule) +static inline void ima_filter_rule_free(void *lsmrule, int lsmslot) { } #endif /* CONFIG_SECURITY */ diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c index 320ca80aacab..22952efcc0b0 100644 --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -90,6 +90,7 @@ struct ima_rule_entry { bool (*fgroup_op)(kgid_t cred_gid, kgid_t rule_gid); /* gid_eq(), gid_gt(), gid_lt() */ int pcr; unsigned int allowed_algos; /* bitfield of allowed hash algorithms */ + int which; /* which LSM rule applies to */ struct { void *rule; /* LSM file metadata specific */ char *args_p; /* audit value */ @@ -286,6 +287,20 @@ static int __init default_appraise_policy_setup(char *str) } __setup("ima_appraise_tcb", default_appraise_policy_setup); +static int ima_rules_lsm __ro_after_init; + +static int __init ima_rules_lsm_init(char *str) +{ + ima_rules_lsm = lsm_name_to_slot(str); + if (ima_rules_lsm < 0) { + ima_rules_lsm = 0; + pr_err("rule lsm \"%s\" not registered", str); + } + + return 1; +} +__setup("ima_rules_lsm=", ima_rules_lsm_init); + static struct ima_rule_opt_list *ima_alloc_rule_opt_list(const substring_t *src) { struct ima_rule_opt_list *opt_list; @@ -357,7 +372,7 @@ static void ima_lsm_free_rule(struct ima_rule_entry *entry) int i; for (i = 0; i < MAX_LSM_RULES; i++) { - ima_filter_rule_free(entry->lsm[i].rule); + ima_filter_rule_free(entry->lsm[i].rule, entry->which); kfree(entry->lsm[i].args_p); } } @@ -408,7 +423,8 @@ static struct ima_rule_entry *ima_lsm_copy_rule(struct ima_rule_entry *entry) ima_filter_rule_init(nentry->lsm[i].type, Audit_equal, nentry->lsm[i].args_p, - &nentry->lsm[i].rule); + &nentry->lsm[i].rule, + entry->which); if (!nentry->lsm[i].rule) pr_warn("rule for LSM \'%s\' is undefined\n", nentry->lsm[i].args_p); @@ -624,14 +640,16 @@ static bool ima_match_rules(struct ima_rule_entry *rule, security_inode_getsecid(inode, &osid); rc = ima_filter_rule_match(osid, rule->lsm[i].type, Audit_equal, - rule->lsm[i].rule); + rule->lsm[i].rule, + rule->which); break; case LSM_SUBJ_USER: case LSM_SUBJ_ROLE: case LSM_SUBJ_TYPE: rc = ima_filter_rule_match(secid, rule->lsm[i].type, Audit_equal, - rule->lsm[i].rule); + rule->lsm[i].rule, + rule->which); break; default: break; @@ -1026,7 +1044,7 @@ enum policy_opt { Opt_fowner_lt, Opt_fgroup_lt, Opt_appraise_type, Opt_appraise_flag, Opt_appraise_algos, Opt_permit_directio, Opt_pcr, Opt_template, Opt_keyrings, - Opt_label, Opt_err + Opt_lsm, Opt_label, Opt_err }; static const match_table_t policy_tokens = { @@ -1074,6 +1092,7 @@ static const match_table_t policy_tokens = { {Opt_template, "template=%s"}, {Opt_keyrings, "keyrings=%s"}, {Opt_label, "label=%s"}, + {Opt_lsm, "lsm=%s"}, {Opt_err, NULL} }; @@ -1092,7 +1111,8 @@ static int ima_lsm_rule_init(struct ima_rule_entry *entry, entry->lsm[lsm_rule].type = audit_type; result = ima_filter_rule_init(entry->lsm[lsm_rule].type, Audit_equal, entry->lsm[lsm_rule].args_p, - &entry->lsm[lsm_rule].rule); + &entry->lsm[lsm_rule].rule, + entry->which); if (!entry->lsm[lsm_rule].rule) { pr_warn("rule for LSM \'%s\' is undefined\n", entry->lsm[lsm_rule].args_p); @@ -1781,6 +1801,19 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) &(template_desc->num_fields)); entry->template = template_desc; break; + case Opt_lsm: + result = lsm_name_to_slot(args[0].from); + if (result == LSMBLOB_INVALID) { + int i; + + for (i = 0; i < MAX_LSM_RULES; i++) + entry->lsm[i].args_p = NULL; + result = -EINVAL; + break; + } + entry->which = result; + result = 0; + break; case Opt_err: ima_log_string(ab, "UNKNOWN", p); result = -EINVAL; @@ -1817,6 +1850,7 @@ ssize_t ima_parse_add_rule(char *rule) struct ima_rule_entry *entry; ssize_t result, len; int audit_info = 0; + int i; p = strsep(&rule, "\n"); len = strlen(p) + 1; @@ -1834,6 +1868,9 @@ ssize_t ima_parse_add_rule(char *rule) INIT_LIST_HEAD(&entry->list); + for (i = 0; i < MAX_LSM_RULES; i++) + entry->which = ima_rules_lsm; + result = ima_parse_rule(p, entry); if (result) { ima_free_rule(entry); @@ -2151,6 +2188,8 @@ int ima_policy_show(struct seq_file *m, void *v) seq_puts(m, "appraise_flag=check_blacklist "); if (entry->flags & IMA_PERMIT_DIRECTIO) seq_puts(m, "permit_directio "); + if (entry->which >= 0) + seq_printf(m, pt(Opt_lsm), lsm_slot_to_name(entry->which)); rcu_read_unlock(); seq_puts(m, "\n"); return 0; diff --git a/security/security.c b/security/security.c index 03a0af7e9e81..29fc50322b1f 100644 --- a/security/security.c +++ b/security/security.c @@ -2708,19 +2708,42 @@ int security_audit_rule_match(u32 secid, u32 field, u32 op, * The integrity subsystem uses the same hooks as * the audit subsystem. */ -int ima_filter_rule_init(u32 field, u32 op, char *rulestr, void **lsmrule) +int ima_filter_rule_init(u32 field, u32 op, char *rulestr, void **lsmrule, + int lsmslot) { - return call_int_hook(audit_rule_init, 0, field, op, rulestr, lsmrule); + struct security_hook_list *hp; + + hlist_for_each_entry(hp, &security_hook_heads.audit_rule_init, list) + if (hp->lsmid->slot == lsmslot) + return hp->hook.audit_rule_init(field, op, rulestr, + lsmrule); + + return 0; } -void ima_filter_rule_free(void *lsmrule) +void ima_filter_rule_free(void *lsmrule, int lsmslot) { - call_void_hook(audit_rule_free, lsmrule); + struct security_hook_list *hp; + + hlist_for_each_entry(hp, &security_hook_heads.audit_rule_free, list) { + if (hp->lsmid->slot == lsmslot) { + hp->hook.audit_rule_free(lsmrule); + return; + } + } } -int ima_filter_rule_match(u32 secid, u32 field, u32 op, void *lsmrule) +int ima_filter_rule_match(u32 secid, u32 field, u32 op, void *lsmrule, + int lsmslot) { - return call_int_hook(audit_rule_match, 0, secid, field, op, lsmrule); + struct security_hook_list *hp; + + hlist_for_each_entry(hp, &security_hook_heads.audit_rule_match, list) + if (hp->lsmid->slot == lsmslot) + return hp->hook.audit_rule_match(secid, field, op, + lsmrule); + + return 0; } #endif /* CONFIG_IMA_LSM_RULES */