Re: [PATCH 2/2] libsepol: with pp to CIL, always write auditadm_r and secadm_r roles to the base module

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On 05/22/2015 01:34 PM, Steve Lawrence wrote:
In fedora and refpolicy, the auditadm_r and secadm_r roles can be in
either the base module or a non-base module, or they could be in both.
This means that it is possible for duplicate role declarations to exist.
CIL does not allow duplicate declarations of anything, but there is no
way for the pp compiler to know if the roles are declared in which
module, or if they are in both when compiling a single module. This
means we cannot use the same hack that we use for user_r, staff_r, etc.,
to generate CIL role declarations (i.e. only create role declarations
for these when defined in base).

So only for these two roles, always declare them as part of base,
regardless of where or if they are defined. This means that turning off
the auditadm module will never remove the auditamd_r role (likewise for
secadm), whereas right now, in some cases it would. This also means that
role allow rules will still exist for these roles even with the modules
removed. However, this is okay because the roles would not have any
types associated with them so no access would be allowed.

Signed-off-by: Steve Lawrence <slawrence@xxxxxxxxxx>
Reported-by: Miroslav Grepl <mgrepl@xxxxxxxxxx>

Thanks, applied.

---
  libsepol/src/module_to_cil.c | 28 +++++++++++++++++++++++++++-
  1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/libsepol/src/module_to_cil.c b/libsepol/src/module_to_cil.c
index 1ded21d..2d8046c 100644
--- a/libsepol/src/module_to_cil.c
+++ b/libsepol/src/module_to_cil.c
@@ -2035,12 +2035,22 @@ static int role_to_cil(int indent, struct policydb *pdb, struct avrule_block *UN
  			// one of these roles in base, the declaration will not appeaer in
  			// the resulting policy, likely resulting in a compilation error in
  			// CIL.
+			//
+			// To make things more complicated, the auditadm_r and secadm_r
+			// roles could actually be in either the base module or a non-base
+			// module, or both. So we can't rely on this same behavior. So for
+			// these roles, don't declare them here, even if they are in a base
+			// or non-base module. Instead we will just declare them in the
+			// base module elsewhere.
  			int is_base_role = (!strcmp(key, "user_r") ||
  			                    !strcmp(key, "staff_r") ||
  			                    !strcmp(key, "sysadm_r") ||
  			                    !strcmp(key, "system_r") ||
  			                    !strcmp(key, "unconfined_r"));
-			if ((is_base_role && pdb->policy_type == SEPOL_POLICY_BASE) || !is_base_role) {
+			int is_builtin_role = (!strcmp(key, "auditadm_r") ||
+			                       !strcmp(key, "secadm_r"));
+			if ((is_base_role && pdb->policy_type == SEPOL_POLICY_BASE) ||
+			    (!is_base_role && !is_builtin_role)) {
  				cil_println(indent, "(role %s)", key);
  			}
  		}
@@ -3717,6 +3727,17 @@ static int generate_default_object(void)
  	return 0;
  }

+static int generate_builtin_roles(void)
+{
+	// due to inconsistentencies between policies and CIL not allowing
+	// duplicate roles, some roles are always created, regardless of if they
+	// are declared in modules or not
+	cil_println(0, "(role auditadm_r)");
+	cil_println(0, "(role secadm_r)");
+
+	return 0;
+}
+
  static int generate_gen_require_attribute(void)
  {
  	cil_println(0, "(typeattribute " GEN_REQUIRE_ATTR ")");
@@ -3801,6 +3822,11 @@ int sepol_module_policydb_to_cil(FILE *fp, struct policydb *pdb, int linked)
  			goto exit;
  		}

+		rc = generate_builtin_roles();
+		if (rc != 0) {
+			goto exit;
+		}
+
  		// default attribute to be used to mimic gen_require in CIL
  		rc = generate_gen_require_attribute();
  		if (rc != 0) {



--
James Carter <jwcart2@xxxxxxxxxxxxx>
National Security Agency
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