libsepol: validate types

Check all types are valid values, especially important for aliases.

    ==9702==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x602000000af8 at pc 0x000000560698 bp 0x7ffcca93b9f0 sp 0x7ffcca93b9e8
    READ of size 8 at 0x602000000af8 thread T0
        #0 0x560697 in write_type_alias_rules_to_conf ./libsepol/src/kernel_to_conf.c:1424:10
        SELinuxProject#1 0x55af16 in sepol_kernel_policydb_to_conf ./libsepol/src/kernel_to_conf.c:3131:7
        SELinuxProject#2 0x55a34f in LLVMFuzzerTestOneInput ./libsepol/fuzz/binpolicy-fuzzer.c:38:9
        SELinuxProject#3 0x45aed3 in fuzzer::Fuzzer::ExecuteCallback(unsigned char const*, unsigned long) fuzzer.o
        SELinuxProject#4 0x446a12 in fuzzer::RunOneTest(fuzzer::Fuzzer*, char const*, unsigned long) fuzzer.o
        SELinuxProject#5 0x44c93b in fuzzer::FuzzerDriver(int*, char***, int (*)(unsigned char const*, unsigned long)) fuzzer.o
        SELinuxProject#6 0x475dd2 in main (./out/binpolicy-fuzzer+0x475dd2)
        SELinuxProject#7 0x7f518b1d57ec in __libc_start_main csu/../csu/libc-start.c:332:16
        SELinuxProject#8 0x423689 in _start (./out/binpolicy-fuzzer+0x423689)

Signed-off-by: Christian Göttsche <[email protected]>

libsepol/src/policydb_validate.c

@@ -348,6 +348,14 @@ static int validate_level(__attribute__ ((unused))hashtab_key_t k, hashtab_datum
 	return validate_mls_level(level->level, &flavors[SYM_LEVELS], &flavors[SYM_CATS]);
 }
 
+static int validate_datum(__attribute__ ((unused))hashtab_key_t k, hashtab_datum_t d, void *args)
+{
+	symtab_datum_t *s = d;
+	uint32_t *nprim = (uint32_t *)args;
+
+	return !value_isvalid(s->value, *nprim);
+}
+
 static int validate_datum_arrays(sepol_handle_t *handle, policydb_t *p, validate_t flavors[])
 {
 	unsigned int i;
@@ -406,6 +414,9 @@ static int validate_datum_arrays(sepol_handle_t *handle, policydb_t *p, validate
 		}
 	}
 
+	if (hashtab_map(p->p_types.table, validate_datum, &flavors[SYM_TYPES]))
+		goto bad;
+
 	if (hashtab_map(p->p_levels.table, validate_level, flavors))
 		goto bad;
 
@@ -707,14 +718,6 @@ static int validate_filename_trans_rules(sepol_handle_t *handle, filename_trans_
 	return -1;
 }
 
-static int validate_datum(__attribute__ ((unused))hashtab_key_t k, hashtab_datum_t d, void *args)
-{
-	symtab_datum_t *s = d;
-	uint32_t *nprim = (uint32_t *)args;
-
-	return !value_isvalid(s->value, *nprim);
-}
-
 static int validate_symtabs(sepol_handle_t *handle, symtab_t symtabs[], validate_t flavors[])
 {
 	unsigned int i;