[PATCH userspace 2/2] libsepol,checkpolicy: add support for self keyword in type transitions

[Ondrej Mosnacek <omosnace@redhat.com>]

With the addition of the anon_inode class in the kernel, 'self'
transition rules became useful, but haven't been implemented.

This patch implements the self keyword in all 'typetransition'
statements at the TE language level and adds the support to the module
policydb format. Note that changing the kernel policydb format is not
necessary at all, as type transitions are always expanded in the kernel
policydb.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
---
 checkpolicy/policy_define.c                | 42 ++++++++++++-
 libsepol/include/sepol/policydb/policydb.h |  4 +-
 libsepol/src/expand.c                      | 69 ++++++++++++++--------
 libsepol/src/link.c                        |  1 +
 libsepol/src/module_to_cil.c               | 30 ++++++----
 libsepol/src/policydb.c                    | 33 +++++++++--
 libsepol/src/write.c                       | 19 +++---
 7 files changed, 148 insertions(+), 50 deletions(-)

diff --git a/checkpolicy/policy_define.c b/checkpolicy/policy_define.c
index 16b78346..7e328edc 100644
--- a/checkpolicy/policy_define.c
+++ b/checkpolicy/policy_define.c
@@ -1634,6 +1634,15 @@ static int define_compute_type_helper(int which, avrule_t ** rule)
 	}
 	add = 1;
 	while ((id = queue_remove(id_queue))) {
+		if (strcmp(id, "self") == 0) {
+			free(id);
+			if (add == 0) {
+				yyerror("-self is not supported");
+				goto bad;
+			}
+			avrule->flags |= RULE_SELF;
+			continue;
+		}
 		if (set_types(&avrule->ttypes, id, &add, 0))
 			goto bad;
 	}
@@ -3300,7 +3309,7 @@ int define_filename_trans(void)
 	type_datum_t *typdatum;
 	uint32_t otype;
 	unsigned int c, s, t;
-	int add, rc;
+	int add, self, rc;
 
 	if (pass == 1) {
 		/* stype */
@@ -3333,8 +3342,18 @@ int define_filename_trans(void)
 			goto bad;
 	}
 
-	add =1;
+	self = 0;
+	add = 1;
 	while ((id = queue_remove(id_queue))) {
+		if (strcmp(id, "self") == 0) {
+			free(id);
+			if (add == 0) {
+				yyerror("-self is not supported");
+				goto bad;
+			}
+			self = 1;
+			continue;
+		}
 		if (set_types(&ttypes, id, &add, 0))
 			goto bad;
 	}
@@ -3396,6 +3415,24 @@ int define_filename_trans(void)
 					goto bad;
 				}
 			}
+			if (self) {
+				rc = policydb_filetrans_insert(
+					policydbp, s+1, s+1, c+1, name,
+					NULL, otype, NULL
+				);
+				if (rc != SEPOL_OK) {
+					if (rc == SEPOL_EEXIST) {
+						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[s],
+							policydbp->p_class_val_to_name[c]);
+						goto bad;
+					}
+					yyerror("out of memory");
+					goto bad;
+				}
+			}
 		}
 	
 		/* Now add the real rule since we didn't find any duplicates */
@@ -3418,6 +3455,7 @@ int define_filename_trans(void)
 		}
 		ftr->tclass = c + 1;
 		ftr->otype = otype;
+		ftr->flags = self ? RULE_SELF : 0;
 	}
 
 	free(name);
diff --git a/libsepol/include/sepol/policydb/policydb.h b/libsepol/include/sepol/policydb/policydb.h
index 4bf9f05d..de0068a6 100644
--- a/libsepol/include/sepol/policydb/policydb.h
+++ b/libsepol/include/sepol/policydb/policydb.h
@@ -314,6 +314,7 @@ typedef struct role_allow_rule {
 } role_allow_rule_t;
 
 typedef struct filename_trans_rule {
+	uint32_t flags; /* may have RULE_SELF set */
 	type_set_t stypes;
 	type_set_t ttypes;
 	uint32_t tclass;
@@ -781,9 +782,10 @@ extern int policydb_set_target_platform(policydb_t *p, int platform);
 #define MOD_POLICYDB_VERSION_XPERMS_IOCTL  18
 #define MOD_POLICYDB_VERSION_INFINIBAND		19
 #define MOD_POLICYDB_VERSION_GLBLUB		20
+#define MOD_POLICYDB_VERSION_SELF_TYPETRANS	21
 
 #define MOD_POLICYDB_VERSION_MIN MOD_POLICYDB_VERSION_BASE
-#define MOD_POLICYDB_VERSION_MAX MOD_POLICYDB_VERSION_GLBLUB
+#define MOD_POLICYDB_VERSION_MAX MOD_POLICYDB_VERSION_SELF_TYPETRANS
 
 #define POLICYDB_CONFIG_MLS    1
 
diff --git a/libsepol/src/expand.c b/libsepol/src/expand.c
index 7316124f..8d19850e 100644
--- a/libsepol/src/expand.c
+++ b/libsepol/src/expand.c
@@ -1407,6 +1407,40 @@ static int copy_role_trans(expand_state_t * state, role_trans_rule_t * rules)
 	return 0;
 }
 
+static int expand_filename_trans_helper(expand_state_t *state,
+					filename_trans_rule_t *rule,
+					unsigned int s, unsigned int t)
+{
+	uint32_t mapped_otype, present_otype;
+	int rc;
+
+	mapped_otype = state->typemap[rule->otype - 1];
+
+	rc = policydb_filetrans_insert(
+		state->out, s + 1, t + 1,
+		rule->tclass, rule->name,
+		NULL, mapped_otype, &present_otype
+	);
+	if (rc == SEPOL_EEXIST) {
+		/* duplicate rule, ignore */
+		if (present_otype == mapped_otype)
+			return 0;
+
+		ERR(state->handle, "Conflicting name-based type_transition %s %s:%s \"%s\":  %s vs %s",
+		    state->out->p_type_val_to_name[s],
+		    state->out->p_type_val_to_name[t],
+		    state->out->p_class_val_to_name[rule->tclass - 1],
+		    rule->name,
+		    state->out->p_type_val_to_name[present_otype - 1],
+		    state->out->p_type_val_to_name[mapped_otype - 1]);
+		return -1;
+	} else if (rc < 0) {
+		ERR(state->handle, "Out of memory!");
+		return -1;
+	}
+	return 0;
+}
+
 static int expand_filename_trans(expand_state_t *state, filename_trans_rule_t *rules)
 {
 	unsigned int i, j;
@@ -1417,8 +1451,6 @@ static int expand_filename_trans(expand_state_t *state, filename_trans_rule_t *r
 
 	cur_rule = rules;
 	while (cur_rule) {
-		uint32_t mapped_otype, present_otype;
-
 		ebitmap_init(&stypes);
 		ebitmap_init(&ttypes);
 
@@ -1434,32 +1466,21 @@ static int expand_filename_trans(expand_state_t *state, filename_trans_rule_t *r
 			return -1;
 		}
 
-		mapped_otype = state->typemap[cur_rule->otype - 1];
 
 		ebitmap_for_each_positive_bit(&stypes, snode, i) {
 			ebitmap_for_each_positive_bit(&ttypes, tnode, j) {
-				rc = policydb_filetrans_insert(
-					state->out, i + 1, j + 1,
-					cur_rule->tclass, cur_rule->name,
-					NULL, mapped_otype, &present_otype
+				rc = expand_filename_trans_helper(
+					state, cur_rule, i, j
 				);
-				if (rc == SEPOL_EEXIST) {
-					/* duplicate rule, ignore */
-					if (present_otype == mapped_otype)
-						continue;
-
-					ERR(state->handle, "Conflicting name-based type_transition %s %s:%s \"%s\":  %s vs %s",
-					    state->out->p_type_val_to_name[i],
-					    state->out->p_type_val_to_name[j],
-					    state->out->p_class_val_to_name[cur_rule->tclass - 1],
-					    cur_rule->name,
-					    state->out->p_type_val_to_name[present_otype - 1],
-					    state->out->p_type_val_to_name[mapped_otype - 1]);
-					return -1;
-				} else if (rc < 0) {
-					ERR(state->handle, "Out of memory!");
-					return -1;
-				}
+				if (rc)
+					return rc;
+			}
+			if (cur_rule->flags & RULE_SELF) {
+				rc = expand_filename_trans_helper(
+					state, cur_rule, i, i
+				);
+				if (rc)
+					return rc;
 			}
 		}
 
diff --git a/libsepol/src/link.c b/libsepol/src/link.c
index ecfb5786..7e8313cb 100644
--- a/libsepol/src/link.c
+++ b/libsepol/src/link.c
@@ -1482,6 +1482,7 @@ static int copy_filename_trans_list(filename_trans_rule_t * list,
 
 		new_rule->tclass = module->map[SYM_CLASSES][cur->tclass - 1];
 		new_rule->otype = module->map[SYM_TYPES][cur->otype - 1];
+		new_rule->flags = cur->flags;
 
 		cur = cur->next;
 	}
diff --git a/libsepol/src/module_to_cil.c b/libsepol/src/module_to_cil.c
index 156a74a2..0e211c93 100644
--- a/libsepol/src/module_to_cil.c
+++ b/libsepol/src/module_to_cil.c
@@ -1608,20 +1608,30 @@ static int filename_trans_to_cil(int indent, struct policydb *pdb, struct filena
 			goto exit;
 		}
 
-		ts = &rule->ttypes;
-		rc = process_typeset(pdb, ts, attr_list, &ttypes, &num_ttypes);
-		if (rc != 0) {
-			goto exit;
-		}
-
-		for (stype = 0; stype < num_stypes; stype++) {
-			for (ttype = 0; ttype < num_ttypes; ttype++) {
-				cil_println(indent, "(typetransition %s %s %s \"%s\" %s)",
-					    stypes[stype], ttypes[ttype],
+		if (rule->flags & RULE_SELF) {
+			for (stype = 0; stype < num_stypes; stype++) {
+				cil_println(indent, "(typetransition %s self %s \"%s\" %s)",
+					    stypes[stype],
 					    pdb->p_class_val_to_name[rule->tclass - 1],
 					    rule->name,
 					    pdb->p_type_val_to_name[rule->otype - 1]);
 			}
+		} else {
+			ts = &rule->ttypes;
+			rc = process_typeset(pdb, ts, attr_list, &ttypes, &num_ttypes);
+			if (rc != 0) {
+				goto exit;
+			}
+
+			for (stype = 0; stype < num_stypes; stype++) {
+				for (ttype = 0; ttype < num_ttypes; ttype++) {
+					cil_println(indent, "(typetransition %s %s %s \"%s\" %s)",
+						    stypes[stype], ttypes[ttype],
+						    pdb->p_class_val_to_name[rule->tclass - 1],
+						    rule->name,
+						    pdb->p_type_val_to_name[rule->otype - 1]);
+				}
+			}
 		}
 
 		names_destroy(&stypes, &num_stypes);
diff --git a/libsepol/src/policydb.c b/libsepol/src/policydb.c
index 7c99571f..fc260eb6 100644
--- a/libsepol/src/policydb.c
+++ b/libsepol/src/policydb.c
@@ -327,6 +327,13 @@ static const struct policydb_compat_info policydb_compat[] = {
 	 .ocon_num = OCON_IBENDPORT + 1,
 	 .target_platform = SEPOL_TARGET_SELINUX,
 	},
+	{
+	 .type = POLICY_BASE,
+	 .version = MOD_POLICYDB_VERSION_SELF_TYPETRANS,
+	 .sym_num = SYM_NUM,
+	 .ocon_num = OCON_IBENDPORT + 1,
+	 .target_platform = SEPOL_TARGET_SELINUX,
+	},
 	{
 	 .type = POLICY_MOD,
 	 .version = MOD_POLICYDB_VERSION_BASE,
@@ -446,7 +453,13 @@ static const struct policydb_compat_info policydb_compat[] = {
 	 .ocon_num = 0,
 	 .target_platform = SEPOL_TARGET_SELINUX,
 	},
-
+	{
+	 .type = POLICY_MOD,
+	 .version = MOD_POLICYDB_VERSION_SELF_TYPETRANS,
+	 .sym_num = SYM_NUM,
+	 .ocon_num = 0,
+	 .target_platform = SEPOL_TARGET_SELINUX,
+	},
 };
 
 #if 0
@@ -3822,10 +3835,11 @@ static int role_allow_rule_read(role_allow_rule_t ** r, struct policy_file *fp)
 	return 0;
 }
 
-static int filename_trans_rule_read(filename_trans_rule_t ** r, struct policy_file *fp)
+static int filename_trans_rule_read(policydb_t *p, filename_trans_rule_t **r,
+				    struct policy_file *fp)
 {
-	uint32_t buf[2], nel;
-	unsigned int i, len;
+	uint32_t buf[3], nel, i, len;
+	unsigned int entries;
 	filename_trans_rule_t *ftr, *lftr;
 	int rc;
 
@@ -3870,11 +3884,18 @@ static int filename_trans_rule_read(filename_trans_rule_t ** r, struct policy_fi
 		if (type_set_read(&ftr->ttypes, fp))
 			return -1;
 
-		rc = next_entry(buf, fp, sizeof(uint32_t) * 2);
+		if (p->policyvers >= MOD_POLICYDB_VERSION_SELF_TYPETRANS)
+			entries = 3;
+		else
+			entries = 2;
+
+		rc = next_entry(buf, fp, sizeof(uint32_t) * entries);
 		if (rc < 0)
 			return -1;
 		ftr->tclass = le32_to_cpu(buf[0]);
 		ftr->otype = le32_to_cpu(buf[1]);
+		if (p->policyvers >= MOD_POLICYDB_VERSION_SELF_TYPETRANS)
+			ftr->flags = le32_to_cpu(buf[2]);
 	}
 
 	return 0;
@@ -3977,7 +3998,7 @@ static int avrule_decl_read(policydb_t * p, avrule_decl_t * decl,
 	}
 
 	if (p->policyvers >= MOD_POLICYDB_VERSION_FILENAME_TRANS &&
-	    filename_trans_rule_read(&decl->filename_trans_rules, fp))
+	    filename_trans_rule_read(p, &decl->filename_trans_rules, fp))
 		return -1;
 
 	if (p->policyvers >= MOD_POLICYDB_VERSION_RANGETRANS &&
diff --git a/libsepol/src/write.c b/libsepol/src/write.c
index d7ac2b25..0b4f5d9a 100644
--- a/libsepol/src/write.c
+++ b/libsepol/src/write.c
@@ -1929,11 +1929,12 @@ static int role_allow_rule_write(role_allow_rule_t * r, struct policy_file *fp)
 	return POLICYDB_SUCCESS;
 }
 
-static int filename_trans_rule_write(filename_trans_rule_t * t, struct policy_file *fp)
+static int filename_trans_rule_write(policydb_t *p, filename_trans_rule_t *t,
+				     struct policy_file *fp)
 {
 	int nel = 0;
-	size_t items;
-	uint32_t buf[2], len;
+	size_t items, entries;
+	uint32_t buf[3], len;
 	filename_trans_rule_t *ftr;
 
 	for (ftr = t; ftr; ftr = ftr->next)
@@ -1962,10 +1963,14 @@ static int filename_trans_rule_write(filename_trans_rule_t * t, struct policy_fi
 
 		buf[0] = cpu_to_le32(ftr->tclass);
 		buf[1] = cpu_to_le32(ftr->otype);
+		buf[2] = cpu_to_le32(ftr->flags);
 
-		items = put_entry(buf, sizeof(uint32_t), 2, fp);
-		if (items != 2)
-			return POLICYDB_ERROR;
+		if (p->policyvers >= MOD_POLICYDB_VERSION_SELF_TYPETRANS)
+			entries = 3;
+		else
+			entries = 2;
+
+		items = put_entry(buf, sizeof(uint32_t), entries, fp);
 	}
 	return POLICYDB_SUCCESS;
 }
@@ -2039,7 +2044,7 @@ static int avrule_decl_write(avrule_decl_t * decl, int num_scope_syms,
 	}
 
 	if (p->policyvers >= MOD_POLICYDB_VERSION_FILENAME_TRANS &&
-	    filename_trans_rule_write(decl->filename_trans_rules, fp))
+	    filename_trans_rule_write(p, decl->filename_trans_rules, fp))
 		return POLICYDB_ERROR;
 
 	if (p->policyvers >= MOD_POLICYDB_VERSION_RANGETRANS &&
-- 
2.35.1