Magisk/native/jni/magiskpolicy/sepolicy.c
topjohnwu 3b071116ac Update magiskpolicy
- Generalize avtab node extraction and insertion
- Add new supported rules: type_change, type_member
- Update help message with official policy language
2018-11-29 03:46:29 -05:00

627 lines
15 KiB
C

#include <dirent.h>
#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 <limits.h>
#include <string.h>
#include <cil/cil.h>
#include <sepol/debug.h>
#include <sepol/policydb/policydb.h>
#include <sepol/policydb/expand.h>
#include <sepol/policydb/link.h>
#include <sepol/policydb/services.h>
#include <sepol/policydb/avrule_block.h>
#include <sepol/policydb/conditional.h>
#include <sepol/policydb/constraint.h>
#include "utils.h"
#include "magiskpolicy.h"
#include "sepolicy.h"
#include "logging.h"
policydb_t *policydb = NULL;
extern int policydb_index_decls(sepol_handle_t * handle, policydb_t * p);
static int get_attr(const char *type, int value) {
type_datum_t *attr = hashtab_search(policydb->p_types.table, type);
if (!attr)
return 1;
if (attr->flavor != TYPE_ATTRIB)
return 1;
return ebitmap_get_bit(&policydb->attr_type_map[attr->s.value - 1], value - 1) != 0;
}
static int get_attr_id(const char *type) {
type_datum_t *attr = hashtab_search(policydb->p_types.table, type);
if (!attr)
return 1;
if (attr->flavor != TYPE_ATTRIB)
return 1;
return attr->s.value;
}
static int set_attr(const char *type, int value) {
type_datum_t *attr = hashtab_search(policydb->p_types.table, type);
if (!attr)
return 1;
if (attr->flavor != TYPE_ATTRIB)
return 1;
if(ebitmap_set_bit(&policydb->type_attr_map[value-1], attr->s.value-1, 1))
return 1;
if(ebitmap_set_bit(&policydb->attr_type_map[attr->s.value-1], value-1, 1))
return 1;
return 0;
}
static avtab_ptr_t get_avtab_node(avtab_key_t *key, avtab_extended_perms_t *xperms) {
avtab_ptr_t node;
avtab_datum_t avdatum;
int match = 0;
/* AVTAB_XPERMS entries are not necessarily unique */
if (key->specified & AVTAB_XPERMS) {
node = avtab_search_node(&policydb->te_avtab, key);
while (node) {
if ((node->datum.xperms->specified == xperms->specified) &&
(node->datum.xperms->driver == xperms->driver)) {
match = 1;
break;
}
node = avtab_search_node_next(node, key->specified);
}
if (!match)
node = NULL;
} else {
node = avtab_search_node(&policydb->te_avtab, key);
}
if (!node) {
memset(&avdatum, 0, sizeof avdatum);
/*
* AUDITDENY, aka DONTAUDIT, are &= assigned, versus |= for
* others. Initialize the data accordingly.
*/
avdatum.data = key->specified == AVTAB_AUDITDENY ? ~0U : 0U;
/* this is used to get the node - insertion is actually unique */
node = avtab_insert_nonunique(&policydb->te_avtab, key, &avdatum);
}
return node;
}
static int add_avrule(avtab_key_t *key, int p, int not) {
avtab_datum_t *datum = &get_avtab_node(key, NULL)->datum;
if(not) {
if (p < 0)
datum->data = 0U;
else
datum->data &= ~(1U << (p - 1));
} else {
if (p < 0)
datum->data = ~0U;
else
datum->data |= 1U << (p - 1);
}
return 0;
}
static int add_rule_auto(type_datum_t *src, type_datum_t *tgt, class_datum_t *cls,
perm_datum_t *perm, int effect, int not) {
avtab_key_t key;
hashtab_ptr_t cur;
int ret = 0;
if (src == NULL) {
hashtab_for_each(policydb->p_types.table, &cur) {
src = cur->datum;
ret |= add_rule_auto(src, tgt, cls, perm, effect, not);
}
} else if (tgt == NULL) {
hashtab_for_each(policydb->p_types.table, &cur) {
tgt = cur->datum;
ret |= add_rule_auto(src, tgt, cls, perm, effect, not);
}
} else if (cls == NULL) {
hashtab_for_each(policydb->p_classes.table, &cur) {
cls = cur->datum;
ret |= add_rule_auto(src, tgt, cls, perm, effect, not);
}
} else {
key.source_type = src->s.value;
key.target_type = tgt->s.value;
key.target_class = cls->s.value;
key.specified = effect;
return add_avrule(&key, perm ? perm->s.value : -1, not);
}
return ret;
}
#define ioctl_driver(x) (x>>8 & 0xFF)
#define ioctl_func(x) (x & 0xFF)
static int add_avxrule(avtab_key_t *key, uint16_t low, uint16_t high, int not) {
avtab_datum_t *datum;
avtab_extended_perms_t xperms;
memset(&xperms, 0, sizeof(xperms));
if (ioctl_driver(low) != ioctl_driver(high)) {
xperms.specified = AVTAB_XPERMS_IOCTLDRIVER;
xperms.driver = 0;
} else {
xperms.specified = AVTAB_XPERMS_IOCTLFUNCTION;
xperms.driver = ioctl_driver(low);
}
if (xperms.specified == AVTAB_XPERMS_IOCTLDRIVER) {
for (int i = ioctl_driver(low); i <= ioctl_driver(high); ++i) {
if (not)
xperm_clear(i, xperms.perms);
else
xperm_set(i, xperms.perms);
}
} else {
for (int i = ioctl_func(low); i <= ioctl_func(high); ++i) {
if (not)
xperm_clear(i, xperms.perms);
else
xperm_set(i, xperms.perms);
}
}
datum = &get_avtab_node(key, &xperms)->datum;
if (datum->xperms == NULL)
datum->xperms = xmalloc(sizeof(xperms));
memcpy(datum->xperms, &xperms, sizeof(xperms));
return 0;
}
static int add_xperm_rule_auto(type_datum_t *src, type_datum_t *tgt, class_datum_t *cls,
uint16_t low, uint16_t high, int effect, int not) {
avtab_key_t key;
hashtab_ptr_t cur;
int ret = 0;
if (src == NULL) {
hashtab_for_each(policydb->p_types.table, &cur) {
src = cur->datum;
ret |= add_xperm_rule_auto(src, tgt, cls, low, high, effect, not);
}
} else if (tgt == NULL) {
hashtab_for_each(policydb->p_types.table, &cur) {
tgt = cur->datum;
ret |= add_xperm_rule_auto(src, tgt, cls, low, high, effect, not);
}
} else if (cls == NULL) {
hashtab_for_each(policydb->p_classes.table, &cur) {
cls = cur->datum;
ret |= add_xperm_rule_auto(src, tgt, cls, low, high, effect, not);
}
} else {
key.source_type = src->s.value;
key.target_type = tgt->s.value;
key.target_class = cls->s.value;
key.specified = effect;
return add_avxrule(&key, low, high, not);
}
return ret;
}
int load_policydb(const char *filename) {
struct policy_file pf;
void *map;
size_t size;
int ret;
if (policydb)
destroy_policydb();
policydb = xcalloc(sizeof(*policydb), 1);
mmap_ro(filename, &map, &size);
policy_file_init(&pf);
pf.type = PF_USE_MEMORY;
pf.data = map;
pf.len = size;
if (policydb_init(policydb)) {
LOGE("policydb_init: Out of memory!\n");
return 1;
}
ret = policydb_read(policydb, &pf, 0);
if (ret) {
LOGE("error(s) encountered while parsing configuration\n");
return 1;
}
munmap(map, size);
return 0;
}
int compile_split_cil() {
DIR *dir;
struct dirent *entry;
char path[128];
struct cil_db *db = NULL;
sepol_policydb_t *pdb = NULL;
void *addr;
size_t size;
cil_db_init(&db);
cil_set_mls(db, 1);
cil_set_multiple_decls(db, 1);
cil_set_disable_neverallow(db, 1);
cil_set_target_platform(db, SEPOL_TARGET_SELINUX);
cil_set_policy_version(db, POLICYDB_VERSION_XPERMS_IOCTL);
cil_set_attrs_expand_generated(db, 0);
// plat
mmap_ro(SPLIT_PLAT_CIL, &addr, &size);
if (cil_add_file(db, SPLIT_PLAT_CIL, addr, size))
return 1;
LOGD("cil_add[%s]\n", SPLIT_PLAT_CIL);
munmap(addr, size);
// mapping
char plat[10];
int fd = open(SPLIT_NONPLAT_VER, O_RDONLY | O_CLOEXEC);
plat[read(fd, plat, sizeof(plat)) - 1] = '\0';
sprintf(path, SPLIT_PLAT_MAPPING, plat);
mmap_ro(path, &addr, &size);
if (cil_add_file(db, path, addr, size))
return 1;
LOGD("cil_add[%s]\n", path);
munmap(addr, size);
close(fd);
// nonplat
dir = opendir(NONPLAT_POLICY_DIR);
while ((entry = readdir(dir))) {
if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0)
continue;
if (strend(entry->d_name, ".cil") == 0) {
sprintf(path, NONPLAT_POLICY_DIR "%s", entry->d_name);
mmap_ro(path, &addr, &size);
if (cil_add_file(db, path, addr, size))
return 1;
LOGD("cil_add[%s]\n", path);
munmap(addr, size);
}
}
closedir(dir);
if (cil_compile(db))
return 1;
if (cil_build_policydb(db, &pdb))
return 1;
cil_db_destroy(&db);
policydb = &pdb->p;
return 0;
}
int dump_policydb(const char *filename) {
int fd, ret;
void *data = NULL;
size_t len;
policydb_to_image(NULL, policydb, &data, &len);
if (data == NULL) {
LOGE("Fail to dump policy image!");
return 1;
}
fd = creat(filename, 0644);
if (fd < 0) {
LOGE("Can't open '%s': %s\n", filename, strerror(errno));
return 1;
}
ret = xwrite(fd, data, len);
close(fd);
if (ret < 0)
return 1;
return 0;
}
void destroy_policydb() {
policydb_destroy(policydb);
free(policydb);
policydb = NULL;
}
int create_domain(const char *d) {
symtab_datum_t *src = hashtab_search(policydb->p_types.table, d);
if(src) {
LOGW("Domain %s already exists\n", d);
return 0;
}
type_datum_t *typedatum = (type_datum_t *) malloc(sizeof(type_datum_t));
type_datum_init(typedatum);
typedatum->primary = 1;
typedatum->flavor = TYPE_TYPE;
uint32_t value = 0;
symtab_insert(policydb, SYM_TYPES, strdup(d), typedatum, SCOPE_DECL, 1, &value);
typedatum->s.value = value;
if (ebitmap_set_bit(&policydb->global->branch_list->declared.scope[SYM_TYPES], value - 1, 1)) {
return 1;
}
policydb->type_attr_map = realloc(policydb->type_attr_map, sizeof(ebitmap_t) * policydb->p_types.nprim);
policydb->attr_type_map = realloc(policydb->attr_type_map, sizeof(ebitmap_t) * policydb->p_types.nprim);
ebitmap_init(&policydb->type_attr_map[value-1]);
ebitmap_init(&policydb->attr_type_map[value-1]);
ebitmap_set_bit(&policydb->type_attr_map[value-1], value-1, 1);
src = hashtab_search(policydb->p_types.table, d);
if(!src)
return 1;
if(policydb_index_decls(NULL, policydb))
return 1;
if(policydb_index_classes(policydb))
return 1;
if(policydb_index_others(NULL, policydb, 0))
return 1;
//Add the domain to all roles
for(unsigned i=0; i<policydb->p_roles.nprim; ++i) {
//Not sure all those three calls are needed
ebitmap_set_bit(&policydb->role_val_to_struct[i]->types.negset, value-1, 0);
ebitmap_set_bit(&policydb->role_val_to_struct[i]->types.types, value-1, 1);
type_set_expand(&policydb->role_val_to_struct[i]->types, &policydb->role_val_to_struct[i]->cache, policydb, 0);
}
return set_attr("domain", value);
}
int set_domain_state(const char *s, int state) {
type_datum_t *type;
hashtab_ptr_t cur;
if (s == NULL) {
hashtab_for_each(policydb->p_types.table, &cur) {
type = cur->datum;
if (ebitmap_set_bit(&policydb->permissive_map, type->s.value, state)) {
LOGW("Could not set bit in permissive map\n");
return 1;
}
}
} else {
type = hashtab_search(policydb->p_types.table, s);
if (type == NULL) {
LOGW("type %s does not exist\n", s);
return 1;
}
if (ebitmap_set_bit(&policydb->permissive_map, type->s.value, state)) {
LOGW("Could not set bit in permissive map\n");
return 1;
}
}
return 0;
}
int sepol_nametrans(const char *s, const char *t, const char *c, const char *d, const char *o) {
type_datum_t *src, *tgt, *def;
class_datum_t *cls;
src = hashtab_search(policydb->p_types.table, s);
if (src == NULL) {
LOGW("source type %s does not exist\n", s);
return 1;
}
tgt = hashtab_search(policydb->p_types.table, t);
if (tgt == NULL) {
LOGW("target type %s does not exist\n", t);
return 1;
}
cls = hashtab_search(policydb->p_classes.table, c);
if (cls == NULL) {
LOGW("class %s does not exist\n", c);
return 1;
}
def = hashtab_search(policydb->p_types.table, d);
if (def == NULL) {
LOGW("default type %s does not exist\n", d);
return 1;
}
filename_trans_t trans_key;
trans_key.stype = src->s.value;
trans_key.ttype = tgt->s.value;
trans_key.tclass = cls->s.value;
trans_key.name = (char *) o;
filename_trans_datum_t *trans_datum;
trans_datum = hashtab_search(policydb->p_types.table, (hashtab_key_t) &trans_key);
if (trans_datum == NULL) {
trans_datum = xcalloc(sizeof(*trans_datum), 1);
hashtab_insert(policydb->filename_trans, (hashtab_key_t) &trans_key, trans_datum);
}
// Overwrite existing
trans_datum->otype = def->s.value;
return 0;
}
int add_typeattribute(const char *domainS, const char *attr) {
type_datum_t *domain;
domain = hashtab_search(policydb->p_types.table, domainS);
if (domain == NULL) {
LOGW("source type %s does not exist\n", domainS);
return 1;
}
set_attr(attr, domain->s.value);
int typeId = get_attr_id(attr);
//Now let's update all constraints!
//(kernel doesn't support (yet?) type_names rules)
for(int i=0; i<policydb->p_classes.nprim; ++i) {
class_datum_t *cl = policydb->class_val_to_struct[i];
for(constraint_node_t *n = cl->constraints; n ; n=n->next) {
for(constraint_expr_t *e = n->expr; e; e=e->next) {
if(e->expr_type == CEXPR_NAMES) {
if(ebitmap_get_bit(&e->type_names->types, typeId-1)) {
ebitmap_set_bit(&e->names, domain->s.value-1, 1);
}
}
}
}
}
return 0;
}
int add_rule(const char *s, const char *t, const char *c, const char *p, int effect, int n) {
type_datum_t *src = NULL, *tgt = NULL;
class_datum_t *cls = NULL;
perm_datum_t *perm = NULL;
if (s) {
src = hashtab_search(policydb->p_types.table, s);
if (src == NULL) {
LOGW("source type %s does not exist\n", s);
return 1;
}
}
if (t) {
tgt = hashtab_search(policydb->p_types.table, t);
if (tgt == NULL) {
LOGW("target type %s does not exist\n", t);
return 1;
}
}
if (c) {
cls = hashtab_search(policydb->p_classes.table, c);
if (cls == NULL) {
LOGW("class %s does not exist\n", c);
return 1;
}
}
if (p) {
if (c == NULL) {
LOGW("No class is specified, cannot add perm [%s] \n", p);
return 1;
}
perm = hashtab_search(cls->permissions.table, p);
if (perm == NULL && cls->comdatum != NULL) {
perm = hashtab_search(cls->comdatum->permissions.table, p);
}
if (perm == NULL) {
LOGW("perm %s does not exist in class %s\n", p, c);
return 1;
}
}
return add_rule_auto(src, tgt, cls, perm, effect, n);
}
int add_xperm_rule(const char *s, const char *t, const char *c, const char *range, int effect,
int n) {
type_datum_t *src = NULL, *tgt = NULL;
class_datum_t *cls = NULL;
if (s) {
src = hashtab_search(policydb->p_types.table, s);
if (src == NULL) {
LOGW("source type %s does not exist\n", s);
return 1;
}
}
if (t) {
tgt = hashtab_search(policydb->p_types.table, t);
if (tgt == NULL) {
LOGW("target type %s does not exist\n", t);
return 1;
}
}
if (c) {
cls = hashtab_search(policydb->p_classes.table, c);
if (cls == NULL) {
LOGW("class %s does not exist\n", c);
return 1;
}
}
uint16_t low, high;
if (range) {
if (strchr(range, '-')){
sscanf(range, "%hx-%hx", &low, &high);
} else {
sscanf(range, "%hx", &low);
high = low;
}
} else {
low = 0;
high = 0xFFFF;
}
return add_xperm_rule_auto(src, tgt, cls, low, high, effect, n);
}
int add_type_rule(const char *s, const char *t, const char *c, const char *d, int effect) {
type_datum_t *src, *tgt, *def;
class_datum_t *cls;
avtab_key_t key;
avtab_datum_t *av;
src = hashtab_search(policydb->p_types.table, s);
if (src == NULL) {
LOGW("source type %s does not exist\n", s);
return 1;
}
tgt = hashtab_search(policydb->p_types.table, t);
if (tgt == NULL) {
LOGW("target type %s does not exist\n", t);
return 1;
}
cls = hashtab_search(policydb->p_classes.table, c);
if (cls == NULL) {
LOGW("class %s does not exist\n", c);
return 1;
}
def = hashtab_search(policydb->p_types.table, d);
if (def == NULL) {
LOGW("default type %s does not exist\n", d);
return 1;
}
key.source_type = src->s.value;
key.target_type = tgt->s.value;
key.target_class = cls->s.value;
key.specified = effect;
av = &get_avtab_node(&key, NULL)->datum;
av->data = def->s.value;
return 0;
}