Magisk/sepolicy-inject.c
2016-10-02 22:48:49 +08:00

772 lines
20 KiB
C

/*
* This was derived from public domain works with updates to
* work with more modern SELinux libraries.
*
* It is released into the public domain.
*
*/
#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/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>
extern void phh_rules(policydb_t *policydb);
extern void magisk_rules(policydb_t *policydb);
void usage(char *arg0) {
fprintf(stderr, "%s -s <source type> -t <target type> -c <class> -p <perm_list> -P <policy file>\n", arg0);
fprintf(stderr, "\tInject a rule\n\n");
fprintf(stderr, "%s -s <source type> -a <type_attribute> -P <policy file>\n", arg0);
fprintf(stderr, "\tAdd a type_attribute to a domain\n\n");
fprintf(stderr, "%s -Z <source type> -P <policy file>\n", arg0);
fprintf(stderr, "\tInject a permissive domain\n\n");
fprintf(stderr, "%s -z <source type> -P <policy file>\n", arg0);
fprintf(stderr, "\tInject a non-permissive domain\n\n");
fprintf(stderr, "%s -e -s <source type> -P <policy file>\n", arg0);
fprintf(stderr, "\tCheck if a SELinux type exists\n\n");
fprintf(stderr, "%s -e -c <class> -P <policy file>\n", arg0);
fprintf(stderr, "\tCheck if a SELinux class exists\n\n");
fprintf(stderr, "All options can add -o <output file> to output to another file\n");
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 get_attr(char *type, int value, policydb_t *policy) {
type_datum_t *attr = hashtab_search(policy->p_types.table, type);
if (!attr)
exit(1);
if (attr->flavor != TYPE_ATTRIB)
exit(1);
return !! ebitmap_get_bit(&policy->attr_type_map[attr->s.value-1], value-1);
//return !! ebitmap_get_bit(&policy->type_attr_map[value-1], attr->s.value-1);
}
int get_attr_id(char *type, policydb_t *policy) {
type_datum_t *attr = hashtab_search(policy->p_types.table, type);
if (!attr)
exit(1);
if (attr->flavor != TYPE_ATTRIB)
exit(1);
return attr->s.value;
}
int set_attr(char *type, int value, policydb_t *policy) {
type_datum_t *attr = hashtab_search(policy->p_types.table, type);
if (!attr)
exit(1);
if (attr->flavor != TYPE_ATTRIB)
exit(1);
if(ebitmap_set_bit(&policy->type_attr_map[value-1], attr->s.value-1, 1))
exit(1);
if(ebitmap_set_bit(&policy->attr_type_map[attr->s.value-1], value-1, 1))
exit(1);
return 0;
}
void create_domain(char *d, policydb_t *policy) {
symtab_datum_t *src = hashtab_search(policy->p_types.table, d);
if(src)
return;
type_datum_t *typdatum = (type_datum_t *) malloc(sizeof(type_datum_t));
type_datum_init(typdatum);
typdatum->primary = 1;
typdatum->flavor = TYPE_TYPE;
uint32_t value = 0;
int r = symtab_insert(policy, SYM_TYPES, strdup(d), typdatum, SCOPE_DECL, 1, &value);
typdatum->s.value = value;
fprintf(stderr, "source type %s does not exist: %d,%d\n", d, r, value);
if (ebitmap_set_bit(&policy->global->branch_list->declared.scope[SYM_TYPES], value - 1, 1)) {
exit(1);
}
policy->type_attr_map = realloc(policy->type_attr_map, sizeof(ebitmap_t)*policy->p_types.nprim);
policy->attr_type_map = realloc(policy->attr_type_map, sizeof(ebitmap_t)*policy->p_types.nprim);
ebitmap_init(&policy->type_attr_map[value-1]);
ebitmap_init(&policy->attr_type_map[value-1]);
ebitmap_set_bit(&policy->type_attr_map[value-1], value-1, 1);
//Add the domain to all roles
for(unsigned i=0; i<policy->p_roles.nprim; ++i) {
//Not sure all those three calls are needed
ebitmap_set_bit(&policy->role_val_to_struct[i]->types.negset, value-1, 0);
ebitmap_set_bit(&policy->role_val_to_struct[i]->types.types, value-1, 1);
type_set_expand(&policy->role_val_to_struct[i]->types, &policy->role_val_to_struct[i]->cache, policy, 0);
}
src = hashtab_search(policy->p_types.table, d);
if(!src)
exit(1);
extern int policydb_index_decls(policydb_t * p);
if(policydb_index_decls(policy))
exit(1);
if(policydb_index_classes(policy))
exit(1);
if(policydb_index_others(NULL, policy, 1))
exit(1);
set_attr("domain", value, policy);
}
int add_irule(int s, int t, int c, int p, int effect, int not, policydb_t* policy) {
avtab_datum_t *av;
avtab_key_t key;
key.source_type = s;
key.target_type = t;
key.target_class = c;
key.specified = effect;
av = avtab_search(&policy->te_avtab, &key);
if (av == NULL) {
av = cmalloc(sizeof(*av));
av->data |= 1U << (p - 1);
int ret = avtab_insert(&policy->te_avtab, &key, av);
if (ret) {
fprintf(stderr, "Error inserting into avtab\n");
return 1;
}
}
if(not)
av->data &= ~(1U << (p - 1));
else
av->data |= 1U << (p - 1);
return 0;
}
int add_typerule(char *s, char *targetAttribute, char **minusses, char *c, char *p, int effect, int not, policydb_t *policy) {
type_datum_t *src, *tgt;
class_datum_t *cls;
perm_datum_t *perm;
//64(0kB) should be enough for everyone, right?
int m[64] = { -1 };
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, targetAttribute);
if (tgt == NULL) {
fprintf(stderr, "target type %s does not exist\n", targetAttribute);
return 1;
}
if(tgt->flavor != TYPE_ATTRIB)
exit(1);
for(int i=0; minusses && minusses[i]; ++i) {
type_datum_t *obj;
obj = hashtab_search(policy->p_types.table, minusses[i]);
if (obj == NULL) {
fprintf(stderr, "minus type %s does not exist\n", minusses[i]);
return 1;
}
m[i] = obj->s.value-1;
m[i+1] = -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;
}
}
ebitmap_node_t *node;
int i;
int ret = 0;
ebitmap_for_each_bit(&policy->attr_type_map[tgt->s.value-1], node, i) {
if(ebitmap_node_get_bit(node, i)) {
int found = 0;
for(int j=0; m[j] != -1; ++j) {
if(i == m[j])
found = 1;
}
if(!found)
ret |= add_irule(src->s.value, i+1, cls->s.value, perm->s.value, effect, not, policy);
}
}
return ret;
}
int add_transition(char *srcS, char *origS, char *tgtS, char *c, policydb_t *policy) {
type_datum_t *src, *tgt, *orig;
class_datum_t *cls;
avtab_datum_t *av;
avtab_key_t key;
src = hashtab_search(policy->p_types.table, srcS);
if (src == NULL) {
fprintf(stderr, "source type %s does not exist\n", srcS);
return 1;
}
tgt = hashtab_search(policy->p_types.table, tgtS);
if (tgt == NULL) {
fprintf(stderr, "target type %s does not exist\n", tgtS);
return 1;
}
cls = hashtab_search(policy->p_classes.table, c);
if (cls == NULL) {
fprintf(stderr, "class %s does not exist\n", c);
return 1;
}
orig = hashtab_search(policy->p_types.table, origS);
if (cls == NULL) {
fprintf(stderr, "class %s does not exist\n", origS);
return 1;
}
key.source_type = src->s.value;
key.target_type = orig->s.value;
key.target_class = cls->s.value;
key.specified = AVTAB_TRANSITION;
av = avtab_search(&policy->te_avtab, &key);
if (av == NULL) {
av = cmalloc(sizeof(*av));
av->data = tgt->s.value;
int ret = avtab_insert(&policy->te_avtab, &key, av);
if (ret) {
fprintf(stderr, "Error inserting into avtab\n");
return 1;
}
} else {
fprintf(stderr, "Warning, rule already defined! Won't override.\n");
fprintf(stderr, "Previous value = %d, wanted value = %d\n", av->data, tgt->s.value);
}
return 0;
}
int add_file_transition(char *srcS, char *origS, char *tgtS, char *c, char* filename, policydb_t *policy) {
type_datum_t *src, *tgt, *orig;
class_datum_t *cls;
src = hashtab_search(policy->p_types.table, srcS);
if (src == NULL) {
fprintf(stderr, "source type %s does not exist\n", srcS);
return 1;
}
tgt = hashtab_search(policy->p_types.table, tgtS);
if (tgt == NULL) {
fprintf(stderr, "target type %s does not exist\n", tgtS);
return 1;
}
cls = hashtab_search(policy->p_classes.table, c);
if (cls == NULL) {
fprintf(stderr, "class %s does not exist\n", c);
return 1;
}
orig = hashtab_search(policy->p_types.table, origS);
if (cls == NULL) {
fprintf(stderr, "class %s does not exist\n", origS);
return 1;
}
filename_trans_t *new_transition = cmalloc(sizeof(*new_transition));
new_transition->stype = src->s.value;
new_transition->ttype = orig->s.value;
new_transition->tclass = cls->s.value;
new_transition->otype = tgt->s.value;
new_transition->name = strdup(filename);
new_transition->next = policy->filename_trans;
policy->filename_trans = new_transition;
return 0;
}
int add_type(char *domainS, char *typeS, policydb_t *policy) {
type_datum_t *domain;
domain = hashtab_search(policy->p_types.table, domainS);
if (domain == NULL) {
fprintf(stderr, "source type %s does not exist\n", domainS);
return 1;
}
set_attr(typeS, domain->s.value, policy);
int typeId = get_attr_id(typeS, policy);
//Now let's update all constraints!
//(kernel doesn't support (yet?) type_names rules)
for(int i=0; i<policy->p_classes.nprim; ++i) {
class_datum_t *cl = policy->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 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 add_rule_auto(type_datum_t *src, type_datum_t *tgt, class_datum_t *cls, perm_datum_t *perm, int effect, int not, policydb_t *policy) {
hashtab_t type_table, class_table, perm_table;
hashtab_ptr_t cur;
type_table = policy->p_types.table;
class_table = policy->p_classes.table;
if (src == NULL) {
for (int i = 0; i < type_table->size; ++i) {
cur = type_table->htable[i];
while (cur != NULL) {
src = cur->datum;
if(add_rule_auto(src, tgt, cls, perm, effect, not, policy))
return 1;
cur = cur->next;
}
}
} else if (tgt == NULL) {
for (int i = 0; i < type_table->size; ++i) {
cur = type_table->htable[i];
while (cur != NULL) {
tgt = cur->datum;
if(add_rule_auto(src, tgt, cls, perm, effect, not, policy))
return 1;
cur = cur->next;
}
}
} else if (cls == NULL) {
for (int i = 0; i < class_table->size; ++i) {
cur = class_table->htable[i];
while (cur != NULL) {
cls = cur->datum;
if(add_rule_auto(src, tgt, cls, perm, effect, not, policy))
return 1;
cur = cur->next;
}
}
} else if (perm == NULL) {
perm_table = cls->permissions.table;
for (int i = 0; i < perm_table->size; ++i) {
cur = perm_table->htable[i];
while (cur != NULL) {
perm = cur->datum;
if(add_irule(src->s.value, tgt->s.value, cls->s.value, perm->s.value, effect, not, policy))
return 1;
cur = cur->next;
}
}
if (cls->comdatum != NULL) {
perm_table = cls->comdatum->permissions.table;
for (int i = 0; i < perm_table->size; ++i) {
cur = perm_table->htable[i];
while (cur != NULL) {
perm = cur->datum;
if(add_irule(src->s.value, tgt->s.value, cls->s.value, perm->s.value, effect, not, policy))
return 1;
cur = cur->next;
}
}
}
} else {
return add_irule(src->s.value, tgt->s.value, cls->s.value, perm->s.value, effect, not, policy);
}
return 0;
}
int add_rule(char *s, char *t, char *c, char *p, int effect, int not, policydb_t *policy) {
type_datum_t *src = NULL, *tgt = NULL;
class_datum_t *cls = NULL;
perm_datum_t *perm = NULL;
if (s) {
src = hashtab_search(policy->p_types.table, s);
if (src == NULL) {
fprintf(stderr, "source type %s does not exist\n", s);
return 1;
}
}
if (t) {
tgt = hashtab_search(policy->p_types.table, t);
if (tgt == NULL) {
fprintf(stderr, "target type %s does not exist\n", t);
return 1;
}
}
if (c) {
cls = hashtab_search(policy->p_classes.table, c);
if (cls == NULL) {
fprintf(stderr, "class %s does not exist\n", c);
return 1;
}
}
if (p) {
if (c == NULL) {
fprintf(stderr, "No class is specified, cannot add perm [%s] \n", p);
return 1;
}
if (cls != NULL) {
perm = hashtab_search(cls->permissions.table, p);
if (perm == NULL && cls->comdatum != NULL) {
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;
}
}
}
return add_rule_auto(src, tgt, cls, perm, effect, not, policy);
}
int live_patch(policydb_t *policydb) {
char *filename = "/sys/fs/selinux/load";
int fd, ret;
void *data = NULL;
size_t len;
policydb_to_image(NULL, policydb, &data, &len);
if (data == NULL) fprintf(stderr, "Error!");
// based on libselinux security_load_policy()
fd = open(filename, O_RDWR);
if (fd < 0) {
fprintf(stderr, "Can't open '%s': %s\n",
filename, strerror(errno));
return 1;
}
ret = write(fd, data, len);
close(fd);
if (ret < 0) {
fprintf(stderr, "Could not write policy to %s\n",
filename);
return 1;
}
return 0;
}
int main(int argc, char **argv)
{
char *policy = NULL, *source = NULL, *target = NULL, *class = NULL, *perm = NULL;
char *fcon = NULL, *outfile = NULL, *permissive = NULL, *attr = NULL, *filetrans = NULL;
int exists = 0, not = 0, live = 0, builtin = 0, magisk = 0;
policydb_t policydb;
struct policy_file pf, outpf;
sidtab_t sidtab;
int ch;
FILE *fp;
int permissive_value = 0, noaudit = 0;
struct option long_options[] = {
{"attr", required_argument, NULL, 'a'},
{"exists", no_argument, NULL, 'e'},
{"source", required_argument, NULL, 's'},
{"target", required_argument, NULL, 't'},
{"class", required_argument, NULL, 'c'},
{"perm", required_argument, NULL, 'p'},
{"fcon", required_argument, NULL, 'f'},
{"filetransition", required_argument, NULL, 'g'},
{"noaudit", no_argument, NULL, 'n'},
{"file", required_argument, NULL, 'P'},
{"output", required_argument, NULL, 'o'},
{"permissive", required_argument, NULL, 'Z'},
{"not-permissive", required_argument, NULL, 'z'},
{"not", no_argument, NULL, 0},
{"live", no_argument, NULL, 0},
{"magisk", no_argument, NULL, 0},
{NULL, 0, NULL, 0}
};
int option_index = -1;
while ((ch = getopt_long(argc, argv, "a:c:ef:g:s:t:p:P:o:Z:z:n", long_options, &option_index)) != -1) {
switch (ch) {
case 0:
if(strcmp(long_options[option_index].name, "not") == 0)
not = 1;
else if(strcmp(long_options[option_index].name, "live") == 0)
live = 1;
else if(strcmp(long_options[option_index].name, "magisk") == 0)
magisk = 1;
else
usage(argv[0]);
break;
case 'a':
attr = optarg;
break;
case 'e':
exists = 1;
break;
case 'f':
fcon = optarg;
break;
case 'g':
filetrans = optarg;
break;
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;
case 'Z':
permissive = optarg;
permissive_value = 1;
break;
case 'z':
permissive = optarg;
permissive_value = 0;
break;
case 'n':
noaudit = 1;
break;
default:
usage(argv[0]);
}
}
// Use builtin rules if nothing specified
if (!magisk && !source && !target && !class && !perm && !permissive && !fcon && !attr &&!filetrans && !exists)
builtin = 1;
// Overwrite original if not specified
if(!outfile)
outfile = policy;
// Use current policy if not specified
if(!policy)
policy = "/sys/fs/selinux/policy";
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 (builtin) {
phh_rules(&policydb);
}
else if (magisk) {
magisk_rules(&policydb);
}
else if (permissive) {
type_datum_t *type;
create_domain(permissive, &policydb);
type = hashtab_search(policydb.p_types.table, permissive);
if (type == NULL) {
fprintf(stderr, "type %s does not exist\n", permissive);
return 1;
}
if (ebitmap_set_bit(&policydb.permissive_map, type->s.value, permissive_value)) {
fprintf(stderr, "Could not set bit in permissive map\n");
return 1;
}
} else if(exists) {
if(source) {
type_datum_t *tmp = hashtab_search(policydb.p_types.table, source);
if (!tmp)
exit(1);
else
exit(0);
} else if(class) {
class_datum_t *tmp = hashtab_search(policydb.p_classes.table, class);
if(!tmp)
exit(1);
else
exit(0);
} else {
usage(argv[0]);
}
} else if(filetrans) {
if(add_file_transition(source, fcon, target, class, filetrans, &policydb))
return 1;
} else if(fcon) {
if(add_transition(source, fcon, target, class, &policydb))
return 1;
} else if(attr) {
if(add_type(source, attr, &policydb))
return 1;
} else if(noaudit) {
if(add_rule(source, target, class, perm, AVTAB_AUDITDENY, not, &policydb))
return 1;
} else {
//Add a rule to a whole set of typeattribute, not just a type
if (target != NULL) {
if(*target == '=') {
char *saveptr = NULL;
char *targetAttribute = strtok_r(target, "-", &saveptr);
char *vals[64];
int i = 0;
char *m = NULL;
while( (m = strtok_r(NULL, "-", &saveptr)) != NULL) {
vals[i++] = m;
}
vals[i] = NULL;
if(add_typerule(source, targetAttribute+1, vals, class, perm, AVTAB_ALLOWED, not, &policydb))
return 1;
}
}
if (perm != NULL) {
char *saveptr = NULL;
char *p = strtok_r(perm, ",", &saveptr);
do {
if (add_rule(source, target, class, p, AVTAB_ALLOWED, not, &policydb)) {
fprintf(stderr, "Could not add rule\n");
return 1;
}
} while( (p = strtok_r(NULL, ",", &saveptr)) != NULL);
} else {
if (add_rule(source, target, class, perm, AVTAB_ALLOWED, not, &policydb)) {
fprintf(stderr, "Could not add rule\n");
return 1;
}
}
}
if (live) {
if (live_patch(&policydb)) {
fprintf(stderr, "Could not load new policy into kernel\n");
return 1;
}
}
if (outfile) {
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;
}
fclose(fp);
}
policydb_destroy(&policydb);
return 0;
}