Magisk/native/jni/magiskpolicy/sepolicy.c
2020-05-21 06:48:02 -07:00

564 lines
14 KiB
C

#include <stdlib.h>
#include <sepol/policydb/expand.h>
#include <logging.hpp>
#include "sepolicy.h"
extern void *xmalloc(size_t size);
extern void *xcalloc(size_t nmemb, size_t size);
extern void *xrealloc(void *ptr, size_t size);
// Internal libsepol APIs
extern int policydb_index_decls(sepol_handle_t * handle, policydb_t * p);
extern int context_from_string(
sepol_handle_t * handle,
const policydb_t * policydb,
context_struct_t ** cptr,
const char *con_str, size_t con_str_len);
// Generic hash table traversal
#define hash_for_each(node_ptr, n_slots, table, block) \
for (int __i = 0; __i < (table)->n_slots; ++__i) { \
__typeof__(*(table)->node_ptr) node; \
__typeof__(node) __next; \
for (node = (table)->node_ptr[__i]; node; node = __next) { \
__next = node->next; \
block \
} \
}
// hashtab traversal
#define hashtab_for_each(hashtab, block) \
hash_for_each(htable, size, hashtab, block)
// avtab traversal
#define avtab_for_each(avtab, block) \
hash_for_each(htable, nslot, avtab, block)
static int set_attr(policydb_t *db, const char *type, int value) {
type_datum_t *attr = hashtab_search(db->p_types.table, type);
if (!attr || attr->flavor != TYPE_ATTRIB)
return -1;
if (ebitmap_set_bit(&db->type_attr_map[value - 1], attr->s.value - 1, 1))
return -1;
if (ebitmap_set_bit(&db->attr_type_map[attr->s.value - 1], value - 1, 1))
return -1;
return attr->s.value;
}
static void check_avtab_node(policydb_t *db, avtab_ptr_t node) {
int redundant = 0;
if (node->key.specified == AVTAB_AUDITDENY)
redundant = node->datum.data == ~0U;
else if (node->key.specified & AVTAB_XPERMS)
redundant = node->datum.xperms == NULL;
else
redundant = node->datum.data == 0U;
if (redundant)
avtab_remove_node(&db->te_avtab, node);
}
static avtab_ptr_t get_avtab_node(policydb_t *db, 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(&db->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(&db->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(&db->te_avtab, key, &avdatum);
}
return node;
}
static int add_avrule(policydb_t *db, avtab_key_t *key, int val, int not) {
avtab_ptr_t node = get_avtab_node(NULL, key, NULL);
if (not) {
if (val < 0)
node->datum.data = 0U;
else
node->datum.data &= ~(1U << (val - 1));
} else {
if (val < 0)
node->datum.data = ~0U;
else
node->datum.data |= 1U << (val - 1);
}
check_avtab_node(db, node);
return 0;
}
static int add_rule_auto(policydb_t *db, type_datum_t *src, type_datum_t *tgt, class_datum_t *cls,
perm_datum_t *perm, int effect, int not) {
avtab_key_t key;
int ret = 0;
if (src == NULL) {
hashtab_for_each(db->p_types.table, {
src = node->datum;
ret |= add_rule_auto(db, src, tgt, cls, perm, effect, not);
})
} else if (tgt == NULL) {
hashtab_for_each(db->p_types.table, {
tgt = node->datum;
ret |= add_rule_auto(db, src, tgt, cls, perm, effect, not);
})
} else if (cls == NULL) {
hashtab_for_each(db->p_classes.table, {
cls = node->datum;
ret |= add_rule_auto(db, 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(db, &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(policydb_t *db, 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(db, 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(policydb_t *db, 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;
int ret = 0;
if (src == NULL) {
hashtab_for_each(db->p_types.table, {
src = node->datum;
ret |= add_xperm_rule_auto(db, src, tgt, cls, low, high, effect, not);
})
} else if (tgt == NULL) {
hashtab_for_each(db->p_types.table, {
tgt = node->datum;
ret |= add_xperm_rule_auto(db, src, tgt, cls, low, high, effect, not);
})
} else if (cls == NULL) {
hashtab_for_each(db->p_classes.table, {
cls = node->datum;
ret |= add_xperm_rule_auto(db, 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(db, &key, low, high, not);
}
return ret;
}
int create_domain(policydb_t *db, const char *d) {
symtab_datum_t *src = hashtab_search(db->p_types.table, d);
if (src) {
LOGW("Domain %s already exists\n", d);
return 0;
}
type_datum_t *typedatum = xmalloc(sizeof(type_datum_t));
type_datum_init(typedatum);
typedatum->primary = 1;
typedatum->flavor = TYPE_TYPE;
uint32_t value = 0;
symtab_insert(db, SYM_TYPES, strdup(d), typedatum, SCOPE_DECL, 1, &value);
typedatum->s.value = value;
if (ebitmap_set_bit(&db->global->branch_list->declared.scope[SYM_TYPES], value - 1, 1)) {
return 1;
}
db->type_attr_map = xrealloc(db->type_attr_map, sizeof(ebitmap_t) * db->p_types.nprim);
db->attr_type_map = xrealloc(db->attr_type_map, sizeof(ebitmap_t) * db->p_types.nprim);
ebitmap_init(&db->type_attr_map[value-1]);
ebitmap_init(&db->attr_type_map[value-1]);
ebitmap_set_bit(&db->type_attr_map[value-1], value-1, 1);
src = hashtab_search(db->p_types.table, d);
if (!src)
return 1;
if (policydb_index_decls(NULL, db))
return 1;
if (policydb_index_classes(db))
return 1;
if (policydb_index_others(NULL, db, 0))
return 1;
// Add the domain to all roles
for (unsigned i = 0; i < db->p_roles.nprim; ++i) {
// Not sure all those three calls are needed
ebitmap_set_bit(&db->role_val_to_struct[i]->types.negset, value - 1, 0);
ebitmap_set_bit(&db->role_val_to_struct[i]->types.types, value - 1, 1);
type_set_expand(&db->role_val_to_struct[i]->types, &db->role_val_to_struct[i]->cache, db, 0);
}
return set_attr(db, "domain", value);
}
int set_domain_state(policydb_t *db, const char *s, int state) {
type_datum_t *type;
if (s == NULL) {
hashtab_for_each(db->p_types.table, {
type = node->datum;
if (ebitmap_set_bit(&db->permissive_map, type->s.value, state)) {
LOGW("Could not set bit in permissive map\n");
return 1;
}
})
} else {
type = hashtab_search(db->p_types.table, s);
if (type == NULL) {
LOGW("type %s does not exist\n", s);
return 1;
}
if (ebitmap_set_bit(&db->permissive_map, type->s.value, state)) {
LOGW("Could not set bit in permissive map\n");
return 1;
}
}
return 0;
}
int add_filename_trans(policydb_t *db, 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(db->p_types.table, s);
if (src == NULL) {
LOGW("source type %s does not exist\n", s);
return 1;
}
tgt = hashtab_search(db->p_types.table, t);
if (tgt == NULL) {
LOGW("target type %s does not exist\n", t);
return 1;
}
cls = hashtab_search(db->p_classes.table, c);
if (cls == NULL) {
LOGW("class %s does not exist\n", c);
return 1;
}
def = hashtab_search(db->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(db->filename_trans, (hashtab_key_t) &trans_key);
if (trans_datum == NULL) {
trans_datum = xcalloc(sizeof(*trans_datum), 1);
hashtab_insert(db->filename_trans, (hashtab_key_t) &trans_key, trans_datum);
}
// Overwrite existing
trans_datum->otype = def->s.value;
return 0;
}
int add_typeattribute(policydb_t *db, const char *type, const char *attr) {
type_datum_t *domain = hashtab_search(db->p_types.table, type);
if (domain == NULL) {
LOGW("type %s does not exist\n", type);
return 1;
}
int attr_id = set_attr(db, attr, domain->s.value);
if (attr_id < 0)
return 1;
hashtab_for_each(db->p_classes.table, {
class_datum_t *cls = node->datum;
for (constraint_node_t *n = cls->constraints; n ; n = n->next) {
for (constraint_expr_t *e = n->expr; e; e = e->next) {
if (e->expr_type == CEXPR_NAMES &&
ebitmap_get_bit(&e->type_names->types, attr_id - 1)) {
ebitmap_set_bit(&e->names, domain->s.value - 1, 1);
}
}
}
})
return 0;
}
int add_rule(policydb_t *db,
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(db->p_types.table, s);
if (src == NULL) {
LOGW("source type %s does not exist\n", s);
return 1;
}
}
if (t) {
tgt = hashtab_search(db->p_types.table, t);
if (tgt == NULL) {
LOGW("target type %s does not exist\n", t);
return 1;
}
}
if (c) {
cls = hashtab_search(db->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(db, src, tgt, cls, perm, effect, n);
}
int add_xperm_rule(policydb_t *db, 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(db->p_types.table, s);
if (src == NULL) {
LOGW("source type %s does not exist\n", s);
return 1;
}
}
if (t) {
tgt = hashtab_search(db->p_types.table, t);
if (tgt == NULL) {
LOGW("target type %s does not exist\n", t);
return 1;
}
}
if (c) {
cls = hashtab_search(db->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(db, src, tgt, cls, low, high, effect, n);
}
int add_type_rule(policydb_t *db,
const char *s, const char *t, const char *c, const char *d, int effect) {
type_datum_t *src, *tgt, *def;
class_datum_t *cls;
src = hashtab_search(db->p_types.table, s);
if (src == NULL) {
LOGW("source type %s does not exist\n", s);
return 1;
}
tgt = hashtab_search(db->p_types.table, t);
if (tgt == NULL) {
LOGW("target type %s does not exist\n", t);
return 1;
}
cls = hashtab_search(db->p_classes.table, c);
if (cls == NULL) {
LOGW("class %s does not exist\n", c);
return 1;
}
def = hashtab_search(db->p_types.table, d);
if (def == NULL) {
LOGW("default type %s does not exist\n", d);
return 1;
}
avtab_key_t key;
key.source_type = src->s.value;
key.target_type = tgt->s.value;
key.target_class = cls->s.value;
key.specified = effect;
avtab_ptr_t node = get_avtab_node(db, &key, NULL);
node->datum.data = def->s.value;
return 0;
}
int add_genfscon(policydb_t *db, const char *name, const char *path, const char *context) {
// First try to create context
context_struct_t *ctx;
if (context_from_string(NULL, db, &ctx, context, strlen(context))) {
LOGW("Failed to create context from string [%s]\n", context);
return 1;
}
// Allocate genfs context
ocontext_t *newc = xcalloc(sizeof(*newc), 1);
newc->u.name = strdup(path);
memcpy(&newc->context[0], ctx, sizeof(*ctx));
free(ctx);
// Find or allocate genfs
genfs_t *last_gen = NULL;
genfs_t *newfs = NULL;
for (genfs_t *node = db->genfs; node; node = node->next) {
if (strcmp(node->fstype, name) == 0) {
newfs = node;
break;
}
last_gen = node;
}
if (newfs == NULL) {
newfs = xcalloc(sizeof(*newfs), 1);
newfs->fstype = strdup(name);
// Insert
if (last_gen)
last_gen->next = newfs;
else
db->genfs = newfs;
}
// Insert or replace genfs context
ocontext_t *last_ctx = NULL;
for (ocontext_t *node = newfs->head; node; node = node->next) {
if (strcmp(node->u.name, path) == 0) {
// Unlink
if (last_ctx)
last_ctx->next = node->next;
else
newfs->head = NULL;
// Destroy old node
free(node->u.name);
context_destroy(&node->context[0]);
free(node);
break;
}
last_ctx = node;
}
// Insert
if (last_ctx)
last_ctx->next = newc;
else
newfs->head = newc;
return 0;
}
void strip_dontaudit(policydb_t *db) {
avtab_for_each(&db->te_avtab, {
if (node->key.specified == AVTAB_AUDITDENY || node->key.specified == AVTAB_XPERMS_DONTAUDIT)
avtab_remove_node(&db->te_avtab, node);
})
}