Magisk/sepolicy-inject.c
2013-06-27 21:42:09 -04:00

212 lines
4.9 KiB
C

#include <getopt.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <sepol/policydb/policydb.h>
#include <sepol/policydb/services.h>
void usage(char *arg0) {
fprintf(stderr, "%s -s <source type> -t <target type> -c <class> -p <perm> -P <policy file> -o <output file>\n", arg0);
exit(1);
}
void *cmalloc(size_t s) {
void *t = malloc(s);
if (t == NULL) {
fprintf(stderr, "Out of memory\n");
exit(1);
}
return t;
}
int add_rule(char *s, char *t, char *c, char *p, policydb_t *policy) {
type_datum_t *src, *tgt;
class_datum_t *cls;
perm_datum_t *perm;
avtab_datum_t *av;
avtab_key_t key;
src = hashtab_search(policy->p_types.table, s);
if (src == NULL) {
fprintf(stderr, "source type %s does not exist\n", s);
return 1;
}
tgt = hashtab_search(policy->p_types.table, t);
if (tgt == NULL) {
fprintf(stderr, "target type %s does not exist\n", t);
return 1;
}
cls = hashtab_search(policy->p_classes.table, c);
if (cls == NULL) {
fprintf(stderr, "class %s does not exist\n", c);
return 1;
}
perm = hashtab_search(cls->permissions.table, p);
if (perm == NULL) {
if (cls->comdatum == NULL) {
fprintf(stderr, "perm %s does not exist in class %s\n", p, c);
return 1;
}
perm = hashtab_search(cls->comdatum->permissions.table, p);
if (perm == NULL) {
fprintf(stderr, "perm %s does not exist in class %s\n", p, c);
return 1;
}
}
// See if there is already a rule
key.source_type = src->s.value;
key.target_type = tgt->s.value;
key.target_class = cls->s.value;
key.specified = AVTAB_ALLOWED;
av = avtab_search(&policy->te_avtab, &key);
if (av == NULL) {
av = cmalloc(sizeof av);
av->data |= 1U << (perm->s.value - 1);
int ret = avtab_insert(&policy->te_avtab, &key, av);
if (ret) {
fprintf(stderr, "Error inserting into avtab\n");
return 1;
}
}
av->data |= 1U << (perm->s.value - 1);
return 0;
}
int load_policy(char *filename, policydb_t *policydb, struct policy_file *pf) {
int fd;
struct stat sb;
void *map;
int ret;
fd = open(filename, O_RDONLY);
if (fd < 0) {
fprintf(stderr, "Can't open '%s': %s\n",
filename, strerror(errno));
return 1;
}
if (fstat(fd, &sb) < 0) {
fprintf(stderr, "Can't stat '%s': %s\n",
filename, strerror(errno));
return 1;
}
map = mmap(NULL, sb.st_size, PROT_READ | PROT_WRITE, MAP_PRIVATE,
fd, 0);
if (map == MAP_FAILED) {
fprintf(stderr, "Can't mmap '%s': %s\n",
filename, strerror(errno));
return 1;
}
policy_file_init(pf);
pf->type = PF_USE_MEMORY;
pf->data = map;
pf->len = sb.st_size;
if (policydb_init(policydb)) {
fprintf(stderr, "policydb_init: Out of memory!\n");
return 1;
}
ret = policydb_read(policydb, pf, 1);
if (ret) {
fprintf(stderr, "error(s) encountered while parsing configuration\n");
return 1;
}
return 0;
}
int main(int argc, char **argv)
{
char *policy = NULL, *source = NULL, *target = NULL, *class = NULL, *perm = NULL, *outfile = NULL;
policydb_t policydb;
struct policy_file pf, outpf;
sidtab_t sidtab;
char ch;
FILE *fp;
struct option long_options[] = {
{"source", required_argument, NULL, 's'},
{"target", required_argument, NULL, 't'},
{"class", required_argument, NULL, 'c'},
{"perm", required_argument, NULL, 'p'},
{"policy", required_argument, NULL, 'P'},
{"output", required_argument, NULL, 'o'},
{NULL, 0, NULL, 0}
};
while ((ch = getopt_long(argc, argv, "s:t:c:p:P:o:", long_options, NULL)) != -1) {
switch (ch) {
case 's':
source = optarg;
break;
case 't':
target = optarg;
break;
case 'c':
class = optarg;
break;
case 'p':
perm = optarg;
break;
case 'P':
policy = optarg;
break;
case 'o':
outfile = optarg;
break;
default:
usage(argv[0]);
}
}
if (!source || !target || !class || !perm || !policy)
usage(argv[0]);
sepol_set_policydb(&policydb);
sepol_set_sidtab(&sidtab);
if (load_policy(policy, &policydb, &pf)) {
fprintf(stderr, "Could not load policy\n");
return 1;
}
if (policydb_load_isids(&policydb, &sidtab))
return 1;
if (add_rule(source, target, class, perm, &policydb)) {
fprintf(stderr, "Could not add rule\n");
return 1;
}
fp = fopen(outfile, "w");
if (!fp) {
fprintf(stderr, "Could not open outfile\n");
return 1;
}
policy_file_init(&outpf);
outpf.type = PF_USE_STDIO;
outpf.fp = fp;
if (policydb_write(&policydb, &outpf)) {
fprintf(stderr, "Could not write policy\n");
return 1;
}
policydb_destroy(&policydb);
fclose(fp);
return 0;
}