[PATCH] checkpolicy: add support for using last path component in type transition rules

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This patch adds support for using the last path component as part of the
information in making labeling decisions for new objects.  A example
rule looks like so:

type_transition unconfined_t etc_t:file system_conf_t eric;

This rule says if unconfined_t creates a file in a directory labeled
etc_t and the last path component is "eric" (no globbing, no matching
magic, just exact strcmp) it should be labeled system_conf_t.

The kernel and policy representation does not have support for such
rules in conditionals, and thus policy explicitly notes that fact if
such a rule is added to a conditional.

Signed-off-by: Eric Paris <eparis@xxxxxxxxxx>
---

diff -up checkpolicy-2.0.23/module_compiler.c.eparis2 checkpolicy-2.0.23/module_compiler.c
--- checkpolicy-2.0.23/module_compiler.c.eparis2	2010-12-21 16:35:45.000000000 -0500
+++ checkpolicy-2.0.23/module_compiler.c	2011-03-23 14:19:51.152530839 -0400
@@ -1313,6 +1313,18 @@ void append_role_allow(role_allow_rule_t
 }
 
 /* this doesn't actually append, but really prepends it */
+void append_filename_trans(filename_trans_rule_t * filename_trans_rules)
+{
+	avrule_decl_t *decl = stack_top->decl;
+
+	/* filename transitions are not allowed within conditionals */
+	assert(stack_top->type == 1);
+
+	filename_trans_rules->next = decl->filename_trans_rules;
+	decl->filename_trans_rules = filename_trans_rules;
+}
+
+/* this doesn't actually append, but really prepends it */
 void append_range_trans(range_trans_rule_t * range_tr_rules)
 {
 	avrule_decl_t *decl = stack_top->decl;
diff -up checkpolicy-2.0.23/module_compiler.h.eparis2 checkpolicy-2.0.23/module_compiler.h
--- checkpolicy-2.0.23/module_compiler.h.eparis2	2010-12-21 16:35:45.000000000 -0500
+++ checkpolicy-2.0.23/module_compiler.h	2011-03-23 14:19:51.154531123 -0400
@@ -80,6 +80,7 @@ void append_avrule(avrule_t * avrule);
 void append_role_trans(role_trans_rule_t * role_tr_rules);
 void append_role_allow(role_allow_rule_t * role_allow_rules);
 void append_range_trans(range_trans_rule_t * range_tr_rules);
+void append_filename_trans(filename_trans_rule_t * filename_trans_rules);
 
 /* Create a new optional block and add it to the global policy.
  * During the second pass resolve the block's requirements.  Return 0
diff -up checkpolicy-2.0.23/policy_define.c.eparis2 checkpolicy-2.0.23/policy_define.c
--- checkpolicy-2.0.23/policy_define.c.eparis2	2010-12-21 16:35:45.000000000 -0500
+++ checkpolicy-2.0.23/policy_define.c	2011-03-28 13:50:57.667710915 -0400
@@ -2196,6 +2196,190 @@ int define_role_allow(void)
 	return 0;
 }
 
+avrule_t *define_cond_filename_trans(void)
+{
+	yyerror("type transitions with a filename not allowed inside "
+		"conditionals\n");
+	return COND_ERR;
+}
+
+int define_filename_trans(void)
+{
+	char *id, *name = NULL;
+	type_set_t stypes, ttypes;
+	ebitmap_t e_stypes, e_ttypes;
+	ebitmap_t e_tclasses;
+	ebitmap_node_t *snode, *tnode, *cnode;
+	filename_trans_t *ft;
+	filename_trans_rule_t *ftr;
+	class_datum_t *cladatum;
+	type_datum_t *typdatum;
+	uint32_t otype;
+	unsigned int c, s, t;
+	int add;
+
+	if (pass == 1) {
+		/* stype */
+		while ((id = queue_remove(id_queue)))
+			free(id);
+		/* ttype */
+		while ((id = queue_remove(id_queue)))
+			free(id);
+		/* tclass */
+		while ((id = queue_remove(id_queue)))
+			free(id);
+		/* otype */
+		id = queue_remove(id_queue);
+		free(id);
+		/* name */
+		id = queue_remove(id_queue);
+		free(id);
+		return 0;
+	}
+
+
+	add = 1;
+	type_set_init(&stypes);
+	while ((id = queue_remove(id_queue))) {
+		if (set_types(&stypes, id, &add, 0))
+			goto bad;
+	}
+
+	add =1;
+	type_set_init(&ttypes);
+	while ((id = queue_remove(id_queue))) {
+		if (set_types(&ttypes, id, &add, 0))
+			goto bad;
+	}
+
+	ebitmap_init(&e_tclasses);
+	while ((id = queue_remove(id_queue))) {
+		if (!is_id_in_scope(SYM_CLASSES, id)) {
+			yyerror2("class %s is not within scope", id);
+			free(id);
+			goto bad;
+		}
+		cladatum = hashtab_search(policydbp->p_classes.table, id);
+		if (!cladatum) {
+			yyerror2("unknown class %s", id);
+			goto bad;
+		}
+		if (ebitmap_set_bit(&e_tclasses, cladatum->s.value - 1, TRUE)) {
+			yyerror("Out of memory");
+			goto bad;
+		}
+		free(id);
+	}
+
+	id = (char *)queue_remove(id_queue);
+	if (!id) {
+		yyerror("no otype in transition definition?");
+		goto bad;
+	}
+	if (!is_id_in_scope(SYM_TYPES, id)) {
+		yyerror2("type %s is not within scope", id);
+		free(id);
+		goto bad;
+	}
+	typdatum = hashtab_search(policydbp->p_types.table, id);
+	if (!typdatum) {
+		yyerror2("unknown type %s used in transition definition", id);
+		goto bad;
+	}
+	free(id);
+	otype = typdatum->s.value;
+
+	name = queue_remove(id_queue);
+	if (!name) {
+		yyerror("no pathname specified in filename_trans definition?");
+		goto bad;
+	}
+
+	/* We expand the class set into seperate rules.  We expand the types
+	 * just to make sure there are not duplicates.  They will get turned
+	 * into seperate rules later */
+	ebitmap_init(&e_stypes);
+	if (type_set_expand(&stypes, &e_stypes, policydbp, 1))
+		goto bad;
+
+	ebitmap_init(&e_ttypes);
+	if (type_set_expand(&ttypes, &e_ttypes, policydbp, 1))
+		goto bad;
+
+	ebitmap_for_each_bit(&e_tclasses, cnode, c) {
+		if (!ebitmap_node_get_bit(cnode, c))
+			continue;
+		ebitmap_for_each_bit(&e_stypes, snode, s) {
+			if (!ebitmap_node_get_bit(snode, s))
+				continue;
+			ebitmap_for_each_bit(&e_ttypes, tnode, t) {
+				if (!ebitmap_node_get_bit(tnode, t))
+					continue;
+	
+				for (ft = policydbp->filename_trans; ft; ft = ft->next) {
+					if (ft->stype == (s + 1) &&
+					    ft->ttype == (t + 1) &&
+					    ft->tclass == (c + 1) &&
+					    !strcmp(ft->name, name)) {
+						yyerror2("duplicate filename transition for: filename_trans %s %s %s:%s",
+							 name, 
+							 policydbp->p_type_val_to_name[s],
+							 policydbp->p_type_val_to_name[t],
+							 policydbp->p_class_val_to_name[c]);
+						goto bad;
+					}
+				}
+	
+				ft = malloc(sizeof(*ft));
+				if (!ft) {
+					yyerror("out of memory");
+					goto bad;
+				}
+				memset(ft, 0, sizeof(*ft));
+	
+				ft->next = policydbp->filename_trans;
+				policydbp->filename_trans = ft;
+	
+				ft->name = strdup(name);
+				if (!ft->name) {
+					yyerror("out of memory");
+					goto bad;
+				}
+				ft->stype = s + 1;
+				ft->ttype = t + 1;
+				ft->tclass = c + 1;
+				ft->otype = otype;
+			}
+		}
+	
+		/* Now add the real rule since we didn't find any duplicates */
+		ftr = malloc(sizeof(*ftr));
+		if (!ftr) {
+			yyerror("out of memory");
+			goto bad;
+		}
+		filename_trans_rule_init(ftr);
+		append_filename_trans(ftr);
+
+		ftr->name = strdup(name);
+		ftr->stypes = stypes;
+		ftr->ttypes = ttypes;
+		ftr->tclass = c + 1;
+		ftr->otype = otype;
+	}
+
+	free(name);
+	ebitmap_destroy(&e_stypes);
+	ebitmap_destroy(&e_ttypes);
+	ebitmap_destroy(&e_tclasses);
+
+	return 0;
+
+bad:
+	free(name);
+	return -1;
+}
+
 static constraint_expr_t *constraint_expr_clone(constraint_expr_t * expr)
 {
 	constraint_expr_t *h = NULL, *l = NULL, *e, *newe;
diff -up checkpolicy-2.0.23/policy_define.h.eparis2 checkpolicy-2.0.23/policy_define.h
--- checkpolicy-2.0.23/policy_define.h.eparis2	2010-12-21 16:35:45.000000000 -0500
+++ checkpolicy-2.0.23/policy_define.h	2011-03-28 13:50:05.489297128 -0400
@@ -16,6 +16,7 @@
 avrule_t *define_cond_compute_type(int which);
 avrule_t *define_cond_pol_list(avrule_t *avlist, avrule_t *stmt);
 avrule_t *define_cond_te_avtab(int which);
+avrule_t *define_cond_filename_trans(void);
 cond_expr_t *define_cond_expr(uint32_t expr_type, void *arg1, void* arg2);
 int define_attrib(void);
 int define_av_perms(int inherits);
@@ -47,6 +48,7 @@ int define_range_trans(int class_specifi
 int define_role_allow(void);
 int define_role_trans(void);
 int define_role_types(void);
+int define_filename_trans(void);
 int define_sens(void);
 int define_te_avtab(int which);
 int define_typealias(void);
diff -up checkpolicy-2.0.23/policy_parse.y.eparis2 checkpolicy-2.0.23/policy_parse.y
--- checkpolicy-2.0.23/policy_parse.y.eparis2	2011-03-23 14:19:51.133528148 -0400
+++ checkpolicy-2.0.23/policy_parse.y	2011-03-28 13:49:03.489482156 -0400
@@ -342,7 +342,10 @@ cond_rule_def           : cond_transitio
 			| require_block
 			{ $$ = NULL; }
                         ;
-cond_transition_def	: TYPE_TRANSITION names names ':' names identifier ';'
+cond_transition_def	: TYPE_TRANSITION names names ':' names identifier identifier ';'
+                        { $$ = define_cond_filename_trans() ;
+                          if ($$ == COND_ERR) return -1;}
+			| TYPE_TRANSITION names names ':' names identifier ';'
                         { $$ = define_cond_compute_type(AVRULE_TRANSITION) ;
                           if ($$ == COND_ERR) return -1;}
                         | TYPE_MEMBER names names ':' names identifier ';'
@@ -377,7 +380,10 @@ cond_dontaudit_def	: DONTAUDIT names nam
 			{ $$ = define_cond_te_avtab(AVRULE_DONTAUDIT);
                           if ($$ == COND_ERR) return -1; }
 		        ;
-transition_def		: TYPE_TRANSITION names names ':' names identifier ';'
+			;
+transition_def		: TYPE_TRANSITION  names names ':' names identifier identifier ';'
+			{if (define_filename_trans()) return -1; }
+			| TYPE_TRANSITION names names ':' names identifier ';'
                         {if (define_compute_type(AVRULE_TRANSITION)) return -1;}
                         | TYPE_MEMBER names names ':' names identifier ';'
                         {if (define_compute_type(AVRULE_MEMBER)) return -1;}
diff -up checkpolicy-2.0.23/test/dismod.c.eparis2 checkpolicy-2.0.23/test/dismod.c
--- checkpolicy-2.0.23/test/dismod.c.eparis2	2011-03-23 14:19:51.142529423 -0400
+++ checkpolicy-2.0.23/test/dismod.c	2011-03-23 14:19:51.160531973 -0400
@@ -52,6 +52,7 @@
 #define DISPLAY_AVBLOCK_ROLE_ALLOW	4
 #define DISPLAY_AVBLOCK_REQUIRES	5
 #define DISPLAY_AVBLOCK_DECLARES	6
+#define DISPLAY_AVBLOCK_FILENAME_TRANS	7
 
 static policydb_t policydb;
 extern unsigned int ss_initialized;
@@ -480,6 +481,18 @@ void display_role_allow(role_allow_rule_
 	}
 }
 
+void display_filename_trans(filename_trans_rule_t * tr, policydb_t * p, FILE * fp)
+{
+	for (; tr; tr = tr->next) {
+		fprintf(fp, "filename transition %s", tr->name);
+		display_type_set(&tr->stypes, 0, p, fp);
+		display_type_set(&tr->ttypes, 0, p, fp);
+		display_id(p, fp, SYM_CLASSES, tr->tclass - 1, ":");
+		display_id(p, fp, SYM_TYPES, tr->otype - 1, "");
+		fprintf(fp, "\n");
+	}
+}
+
 int role_display_callback(hashtab_key_t key, hashtab_datum_t datum, void *data)
 {
 	role_datum_t *role;
@@ -647,6 +660,11 @@ int display_avdecl(avrule_decl_t * decl,
 			}
 			break;
 		}
+	case DISPLAY_AVBLOCK_FILENAME_TRANS:
+		display_filename_trans(decl->filename_trans_rules, policy,
+				       out_fp);
+			return -1;
+		break;
 	default:{
 			assert(0);
 		}
@@ -812,6 +830,7 @@ int menu()
 	printf("c)  Display policy capabilities\n");
 	printf("l)  Link in a module\n");
 	printf("u)  Display the unknown handling setting\n");
+	printf("F)  Display filename_trans rules\n");
 	printf("\n");
 	printf("f)  set output file\n");
 	printf("m)  display menu\n");
@@ -947,6 +966,11 @@ int main(int argc, char **argv)
 			if (out_fp != stdout)
 				printf("\nOutput to file: %s\n", OutfileName);
 			break;
+		case 'F':
+			fprintf(out_fp, "filename_trans rules:\n");
+			display_avblock(DISPLAY_AVBLOCK_FILENAME_TRANS,
+					0, &policydb, out_fp);
+			break;
 		case 'l':
 			link_module(&policydb, out_fp);
 			break;
diff -up checkpolicy-2.0.23/test/dispol.c.eparis2 checkpolicy-2.0.23/test/dispol.c
--- checkpolicy-2.0.23/test/dispol.c.eparis2	2010-12-21 16:35:45.000000000 -0500
+++ checkpolicy-2.0.23/test/dispol.c	2011-03-23 14:19:51.162532256 -0400
@@ -341,6 +341,21 @@ static void display_permissive(policydb_
 	}
 }
 
+static void display_filename_trans(policydb_t *p, FILE *fp)
+{
+	filename_trans_t *ft;
+
+	fprintf(fp, "filename_trans rules:\n");
+	for (ft = p->filename_trans; ft; ft = ft->next) {
+		fprintf(fp, "%s\n", ft->name);
+		display_id(p, fp, SYM_TYPES, ft->stype - 1, "");
+		display_id(p, fp, SYM_TYPES, ft->ttype - 1, "");
+		display_id(p, fp, SYM_CLASSES, ft->tclass - 1, ":");
+		display_id(p, fp, SYM_TYPES, ft->otype - 1, "");
+		fprintf(fp, "\n");
+	}
+}
+
 int menu()
 {
 	printf("\nSelect a command:\n");
@@ -355,6 +370,8 @@ int menu()
 	printf("c)  display policy capabilities\n");
 	printf("p)  display the list of permissive types\n");
 	printf("u)  display unknown handling setting\n");
+	printf("F)  display filename_trans rules\n");
+	printf("\n");
 	printf("f)  set output file\n");
 	printf("m)  display menu\n");
 	printf("q)  quit\n");
@@ -492,6 +509,9 @@ int main(int argc, char **argv)
 			if (out_fp != stdout)
 				printf("\nOutput to file: %s\n", OutfileName);
 			break;
+		case 'F':
+			display_filename_trans(&policydb, out_fp);
+			break;
 		case 'q':
 			policydb_destroy(&policydb);
 			exit(0);



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