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[77.8.186.56]) by smtp.gmail.com with ESMTPSA id p3sm339256ejy.94.2021.11.24.11.08.22 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 24 Nov 2021 11:08:22 -0800 (PST) From: =?utf-8?q?Christian_G=C3=B6ttsche?= To: selinux@vger.kernel.org Subject: [RFC PATCH v2 3/4] checkpolicy: add not-self neverallow support Date: Wed, 24 Nov 2021 20:08:14 +0100 Message-Id: <20211124190815.12757-3-cgzones@googlemail.com> X-Mailer: git-send-email 2.34.0 In-Reply-To: <20211124190815.12757-1-cgzones@googlemail.com> References: <20211123190704.14341-1-cgzones@googlemail.com> <20211124190815.12757-1-cgzones@googlemail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: selinux@vger.kernel.org Add support for using negated or complemented self in the target type of neverallow rules. Some refpolicy examples: neverallow * ~self:{ capability cap_userns capability2 cap2_userns } *; # no violations neverallow domain domain:file ~{ append read_file_perms write }; libsepol.report_failure: neverallow on line 565 of policy/modules/kernel/kernel.te (or line 30300 of policy.conf) violated by allow sysadm_t httpd_bugzilla_script_t:file { create setattr relabelfrom relabelto unlink link rename }; libsepol.report_failure: neverallow on line 565 of policy/modules/kernel/kernel.te (or line 30300 of policy.conf) violated by allow chromium_t chromium_t:file { create }; libsepol.report_failure: neverallow on line 564 of policy/modules/kernel/kernel.te (or line 30299 of policy.conf) violated by allow sysadm_t httpd_bugzilla_script_t:dir { create }; neverallow domain { domain -self }:file ~{ append read_file_perms write }; libsepol.report_failure: neverallow on line 565 of policy/modules/kernel/kernel.te (or line 30300 of policy.conf) violated by allow sysadm_t httpd_bugzilla_script_t:file { create setattr relabelfrom relabelto unlink link rename }; libsepol.report_failure: neverallow on line 564 of policy/modules/kernel/kernel.te (or line 30299 of policy.conf) violated by allow sysadm_t httpd_bugzilla_script_t:dir { create }; Using negated self in a complement `~{ domain -self }` is not supported. Signed-off-by: Christian Göttsche --- v2: - fix neverallowxperm usage --- checkpolicy/policy_define.c | 46 ++++++++++++++++++++++++++++++++----- checkpolicy/test/dismod.c | 6 ++++- 2 files changed, 45 insertions(+), 7 deletions(-) diff --git a/checkpolicy/policy_define.c b/checkpolicy/policy_define.c index d3eb6111..f27a6f33 100644 --- a/checkpolicy/policy_define.c +++ b/checkpolicy/policy_define.c @@ -2067,12 +2067,17 @@ static int define_te_avtab_xperms_helper(int which, avrule_t ** rule) while ((id = queue_remove(id_queue))) { if (strcmp(id, "self") == 0) { free(id); - if (add == 0) { - yyerror("-self is not supported"); + if (add == 0 && which != AVRULE_XPERMS_NEVERALLOW) { + yyerror("-self is only supported in neverallowxperm rules"); + ret = -1; + goto out; + } + avrule->flags |= (add ? RULE_SELF : RULE_NOTSELF); + if ((avrule->flags & RULE_SELF) && (avrule->flags & RULE_NOTSELF)) { + yyerror("self and -self is not supported"); ret = -1; goto out; } - avrule->flags |= RULE_SELF; continue; } if (set_types @@ -2083,6 +2088,18 @@ static int define_te_avtab_xperms_helper(int which, avrule_t ** rule) } } + if ((avrule->ttypes.flags & TYPE_COMP)) { + if (avrule->flags & RULE_NOTSELF) { + yyerror("-self is not supported in complements"); + ret = -1; + goto out; + } + if (avrule->flags & RULE_SELF) { + avrule->flags &= ~RULE_SELF; + avrule->flags |= RULE_NOTSELF; + } + } + ebitmap_init(&tclasses); ret = read_classes(&tclasses); if (ret) @@ -2528,12 +2545,17 @@ static int define_te_avtab_helper(int which, avrule_t ** rule) while ((id = queue_remove(id_queue))) { if (strcmp(id, "self") == 0) { free(id); - if (add == 0) { - yyerror("-self is not supported"); + if (add == 0 && which != AVRULE_NEVERALLOW) { + yyerror("-self is only supported in neverallow rules"); + ret = -1; + goto out; + } + avrule->flags |= (add ? RULE_SELF : RULE_NOTSELF); + if ((avrule->flags & RULE_SELF) && (avrule->flags & RULE_NOTSELF)) { + yyerror("self and -self is not supported"); ret = -1; goto out; } - avrule->flags |= RULE_SELF; continue; } if (set_types @@ -2544,6 +2566,18 @@ static int define_te_avtab_helper(int which, avrule_t ** rule) } } + if ((avrule->ttypes.flags & TYPE_COMP)) { + if (avrule->flags & RULE_NOTSELF) { + yyerror("-self is not supported in complements"); + ret = -1; + goto out; + } + if (avrule->flags & RULE_SELF) { + avrule->flags &= ~RULE_SELF; + avrule->flags |= RULE_NOTSELF; + } + } + ebitmap_init(&tclasses); ret = read_classes(&tclasses); if (ret) diff --git a/checkpolicy/test/dismod.c b/checkpolicy/test/dismod.c index ec2a3e9a..a2d74d42 100644 --- a/checkpolicy/test/dismod.c +++ b/checkpolicy/test/dismod.c @@ -124,7 +124,7 @@ static int display_type_set(type_set_t * set, uint32_t flags, policydb_t * polic } num_types = 0; - if (flags & RULE_SELF) { + if (flags & (RULE_SELF | RULE_NOTSELF)) { num_types++; } @@ -169,6 +169,10 @@ static int display_type_set(type_set_t * set, uint32_t flags, policydb_t * polic fprintf(fp, " self"); } + if (flags & RULE_NOTSELF) { + fprintf(fp, " -self"); + } + if (num_types > 1) fprintf(fp, " }");