From 6f7b0ee6c4ab067a2f7f8522647ec8e434c67c45 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Christian=20G=C3=B6ttsche?= Date: Fri, 25 Nov 2022 16:49:49 +0100 Subject: [PATCH] checkpolicy: add not-self neverallow support MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 } *; neverallow domain { domain -self -dockerc_t }:dir create; # no violations neverallow domain { domain -dockerc_t }:file ~{ append read_file_perms write }; libsepol.report_failure: neverallow on line 584 of policy/modules/kernel/kernel.te (or line 31357 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 584 of policy/modules/kernel/kernel.te (or line 31357 of policy.conf) violated by allow spc_t spc_t:file { create }; libsepol.report_failure: neverallow on line 584 of policy/modules/kernel/kernel.te (or line 31357 of policy.conf) violated by allow container_t container_t:file { create }; libsepol.report_failure: neverallow on line 584 of policy/modules/kernel/kernel.te (or line 31357 of policy.conf) violated by allow chromium_t chromium_t:file { create }; libsepol.report_failure: neverallow on line 584 of policy/modules/kernel/kernel.te (or line 31357 of policy.conf) violated by allow spc_user_t spc_user_t:file { create }; libsepol.report_failure: neverallow on line 582 of policy/modules/kernel/kernel.te (or line 31355 of policy.conf) violated by allow sysadm_t httpd_bugzilla_script_t:dir { create }; neverallow domain { domain -self -dockerc_t }:file ~{ append read_file_perms write }; libsepol.report_failure: neverallow on line 583 of policy/modules/kernel/kernel.te (or line 31356 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 582 of policy/modules/kernel/kernel.te (or line 31355 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 --- 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 c2ae7fe5..f277e600 100644 --- a/checkpolicy/policy_define.c +++ b/checkpolicy/policy_define.c @@ -2075,12 +2075,17 @@ 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 neverallow and 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 are mutual exclusive"); ret = -1; goto out; } - avrule->flags |= RULE_SELF; continue; } if (set_types @@ -2091,6 +2096,18 @@ 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) @@ -2537,12 +2554,17 @@ 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 and 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 are mutual exclusive"); ret = -1; goto out; } - avrule->flags |= RULE_SELF; continue; } if (set_types @@ -2553,6 +2575,18 @@ 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, " }");