- Generalize avtab node extraction and insertion - Add new supported rules: type_change, type_member - Update help message with official policy language
503 lines
12 KiB
C++
503 lines
12 KiB
C++
/* magiskpolicy.cpp - Main function for policy patching
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*
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* Includes all the parsing logic for the policy statements
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*/
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#include <stdio.h>
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#include <limits.h>
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#include "sepolicy.h"
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#include "magiskpolicy.h"
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#include "magisk.h"
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#include "utils.h"
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#include "flags.h"
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static const char *type_msg_1 =
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"Type 1:\n"
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"\"<rule_name> source_type target_type class perm_set\"\n"
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"Rules: allow, deny, auditallow, auditdeny\n";
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static const char *type_msg_2 =
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"Type 2:\n"
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"\"<rule_name> source_type target_type class operation xperm_set\"\n"
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"Rules: allowxperm, auditallowxperm, dontauditxperm\n"
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"* The only supported operation is ioctl\n"
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"* The only supported xperm_set format is range ([low-high])\n";
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static const char *type_msg_3 =
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"Type 3:\n"
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"\"<rule_name> class\"\n"
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"Rules: create, permissive, enforcing\n";
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static const char *type_msg_4 =
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"Type 4:\n"
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"\"attradd class attribute\"\n";
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static const char *type_msg_5 =
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"Type 5:\n"
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"\"<rule_name> source_type target_type class default_type\"\n"
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"Rules: type_transition, type_change, type_member\n";
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static const char *type_msg_6 =
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"Type 6:\n"
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"\"name_transition source_type target_type class default_type object_name\"\n";
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[[noreturn]] static void statements() {
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fprintf(stderr,
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"One policy statement should be treated as one parameter;\n"
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"this means a full policy statement should be enclosed in quotes;\n"
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"multiple policy statements can be provided in a single command\n"
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"\n"
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"The statements has a format of \"<rule_name> [args...]\"\n"
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"Multiple types and permissions can be grouped into collections\n"
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"wrapped in curly brackets.\n"
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"'*' represents a collection containing all valid matches.\n"
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"\n"
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"Supported policy statements:\n"
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"\n"
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"%s\n"
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"%s\n"
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"%s\n"
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"%s\n"
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"%s\n"
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"%s\n"
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"Notes:\n"
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"* Type 4 - 6 does not support collections\n"
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"* Object classes cannot be collections\n"
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"* source_type and target_type can also be attributes\n"
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"\n"
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"Example: allow { s1 s2 } { t1 t2 } class *\n"
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"Will be expanded to:\n"
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"\n"
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"allow s1 t1 class { all permissions }\n"
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"allow s1 t2 class { all permissions }\n"
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"allow s2 t1 class { all permissions }\n"
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"allow s2 t2 class { all permissions }\n"
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"\n",
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type_msg_1, type_msg_2, type_msg_3, type_msg_4, type_msg_5, type_msg_6);
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exit(0);
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}
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[[noreturn]] static void usage(char *arg0) {
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fprintf(stderr,
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"MagiskPolicy v" xstr(MAGISK_VERSION) "(" xstr(MAGISK_VER_CODE) ") (by topjohnwu)\n\n"
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"Usage: %s [--options...] [policy statements...]\n"
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"\n"
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"Options:\n"
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" --help show help message for policy statements\n"
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" --load FILE load policies from FILE\n"
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" --compile-split compile and load split cil policies\n"
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" from system and vendor just like init\n"
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" --save FILE save policies to FILE\n"
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" --live directly apply sepolicy live\n"
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" --magisk inject built-in rules for a minimal\n"
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" Magisk selinux environment\n"
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"\n"
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"If neither --load or --compile-split is specified, it will load\n"
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"from current live policies (" SELINUX_POLICY ")\n"
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"\n",
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arg0);
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exit(1);
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}
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static int parse_bracket(char *tok, char *&stmt, Vector<const char *> *vec) {
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if (tok == nullptr || tok[0] != '{') {
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// Not in a bracket
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vec->push_back(tok);
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} else {
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if (stmt)
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stmt[-1] = ' ';
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tok = strchr(tok, '{') + 1;
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char *end = strchr(tok, '}');
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if (end == nullptr) // Bracket not closed
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return 1;
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*end = '\0';
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char *cur;
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while ((cur = strtok_r(nullptr, " ", &tok)) != nullptr)
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vec->push_back(cur);
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stmt = end + 1;
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}
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return 0;
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}
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// Pattern 1: action { source } { target } class { permission }
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static int parse_pattern_1(int action, const char *action_str, char *stmt) {
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int (*action_func)(const char*, const char*, const char*, const char*);
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switch (action) {
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case 0:
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action_func = sepol_allow;
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break;
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case 1:
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action_func = sepol_deny;
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break;
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case 2:
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action_func = sepol_auditallow;
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break;
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case 3:
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action_func = sepol_auditdeny;
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break;
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default:
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return 1;
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}
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int state = 0;
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char *cur, *cls;
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Vector<const char*> source, target, permission;
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while ((cur = strtok_r(nullptr, " ", &stmt)) != nullptr) {
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if (cur[0] == '*') cur = ALL;
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Vector<const char *> *vec;
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switch (state) {
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case 0:
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vec = &source;
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break;
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case 1:
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vec = ⌖
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break;
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case 2:
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vec = nullptr;
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cls = cur;
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break;
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case 3:
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vec = &permission;
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break;
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default:
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return 1;
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}
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if (vec && parse_bracket(cur, stmt, vec))
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return 1;
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++state;
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}
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if (state != 4 || source.empty() || target.empty() || permission.empty())
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return 1;
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for (auto src : source)
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for (auto tgt : target)
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for (auto perm : permission)
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if (action_func(src, tgt, cls, perm))
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fprintf(stderr, "Error in: %s %s %s %s %s\n", action_str, src, tgt, cls, perm);
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return 0;
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}
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// Pattern 2: action { source } { target } { class } ioctl range
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static int parse_pattern_2(int action, const char *action_str, char *stmt) {
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int (*action_func)(const char*, const char*, const char*, const char*);
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switch (action) {
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case 0:
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action_func = sepol_allowxperm;
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break;
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case 1:
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action_func = sepol_auditallowxperm;
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break;
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case 2:
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action_func = sepol_dontauditxperm;
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break;
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default:
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return 1;
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}
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int state = 0;
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char *cur, *range;
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Vector<const char *> source, target, classes;
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while ((cur = strtok_r(nullptr, " ", &stmt)) != nullptr) {
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if (cur[0] == '*') cur = ALL;
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Vector<const char *> *vec;
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switch (state) {
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case 0:
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vec = &source;
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break;
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case 1:
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vec = ⌖
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break;
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case 2:
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vec = &classes;
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break;
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case 3:
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// Currently only support ioctl
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if (strcmp(cur, "ioctl"))
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return 1;
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vec = nullptr;
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break;
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case 4:
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vec = nullptr;
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range = cur;
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break;
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default:
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return 1;
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}
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if (vec && parse_bracket(cur, stmt, vec))
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return 1;
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++state;
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}
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if (state != 5 || source.empty() || target.empty() || classes.empty())
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return 1;
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for (auto src : source)
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for (auto tgt : target)
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for (auto cls : classes)
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if (action_func(src, tgt, cls, range))
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fprintf(stderr, "Error in: %s %s %s %s %s\n", action_str, src, tgt, cls, range);
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return 0;
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}
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// Pattern 3: action { type }
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static int parse_pattern_3(int action, const char *action_str, char* stmt) {
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int (*action_func)(const char*);
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switch (action) {
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case 0:
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action_func = sepol_create;
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break;
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case 1:
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action_func = sepol_permissive;
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break;
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case 2:
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action_func = sepol_enforce;
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break;
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default:
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return 1;
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}
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char *cur;
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Vector<const char *> domains;
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while ((cur = strtok_r(nullptr, " {}", &stmt)) != nullptr) {
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if (cur[0] == '*') cur = ALL;
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domains.push_back(cur);
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}
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if (domains.empty())
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return 1;
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for (auto dom : domains)
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if (action_func(dom))
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fprintf(stderr, "Error in: %s %s\n", action_str, dom);
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return 0;
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}
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// Pattern 4: action { class } { attribute }
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static int parse_pattern_4(int action, const char *action_str, char *stmt) {
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int (*action_func)(const char*, const char*);
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switch (action) {
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case 0:
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action_func = sepol_attradd;
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break;
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default:
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return 1;
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}
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int state = 0;
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char *cur;
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Vector<const char *> classes, attribute;
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while ((cur = strtok_r(nullptr, " ", &stmt)) != nullptr) {
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if (cur[0] == '*') cur = ALL;
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Vector<const char *> *vec;
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switch (state) {
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case 0:
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vec = &classes;
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break;
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case 1:
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vec = &attribute;
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break;
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default:
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return 1;
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}
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if (parse_bracket(cur, stmt, vec))
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return 1;
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++state;
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}
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if (state != 2 || classes.empty() || attribute.empty())
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return 1;
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for (auto cls : classes)
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for (auto attr : attribute)
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if (action_func(cls, attr))
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fprintf(stderr, "Error in: %s %s %s\n", action_str, cls, attr);
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return 0;
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}
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// Pattern 5: action source target class default
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static int parse_pattern_5(int action, const char *action_str, char *stmt) {
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int (*action_func)(const char*, const char*, const char*, const char*);
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switch (action) {
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case 0:
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action_func = sepol_typetrans;
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break;
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case 1:
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action_func = sepol_typechange;
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break;
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case 2:
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action_func = sepol_typemember;
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break;
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default:
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return 1;
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}
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int state = 0;
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char *cur;
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char *source, *target, *cls, *def;
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while ((cur = strtok_r(nullptr, " ", &stmt)) != nullptr) {
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switch(state) {
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case 0:
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source = cur;
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break;
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case 1:
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target = cur;
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break;
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case 2:
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cls = cur;
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break;
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case 3:
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def = cur;
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break;
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default:
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return 1;
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}
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++state;
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}
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if (state < 4) return 1;
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if (action_func(source, target, cls, def))
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fprintf(stderr, "Error in: %s %s %s %s %s\n", action_str, source, target, cls, def);
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return 0;
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}
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// Pattern 6: action source target class default filename
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static int parse_pattern_6(int action, const char *action_str, char *stmt) {
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int state = 0;
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char *cur;
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char *source, *target, *cls, *def, *filename;
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while ((cur = strtok_r(nullptr, " ", &stmt)) != nullptr) {
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switch(state) {
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case 0:
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source = cur;
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break;
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case 1:
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target = cur;
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break;
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case 2:
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cls = cur;
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break;
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case 3:
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def = cur;
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break;
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case 4:
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filename = cur;
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break;
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default:
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return 1;
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}
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++state;
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}
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if (state < 4) return 1;
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if (sepol_nametrans(source, target, cls, def, filename))
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fprintf(stderr, "Error in: %s %s %s %s %s %s\n",
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action_str, source, target, cls, def, filename);
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return 0;
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}
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#define add_action(name, type, num) \
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else if (strcmp(name, action) == 0) { \
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if (parse_pattern_##type(num, name, remain)) \
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fprintf(stderr, "Syntax error in '%s'\n\n%s\n", orig.c_str(), type_msg_##type); \
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}
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static void parse_statement(char *statement) {
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char *action, *remain;
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// strtok will modify the origin string, duplicate the statement for error messages
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CharArray orig(statement);
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action = strtok_r(statement, " ", &remain);
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if (remain == nullptr) remain = &action[strlen(action)];
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if (0) {}
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add_action("allow", 1, 0)
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add_action("deny", 1, 1)
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add_action("auditallow", 1, 2)
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add_action("auditdeny", 1, 3)
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add_action("allowxperm", 2, 0)
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add_action("auditallowxperm", 2, 1)
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add_action("dontauditxperm", 2, 2)
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add_action("create", 3, 0)
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add_action("permissive", 3, 1)
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add_action("enforce", 3, 2)
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add_action("attradd", 4, 0)
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add_action("type_transition", 5, 0)
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add_action("type_change", 5, 1)
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add_action("type_member", 5, 2)
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add_action("name_transition", 6, 0)
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else { fprintf(stderr, "Unknown statement: '%s'\n\n", orig.c_str()); }
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}
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int magiskpolicy_main(int argc, char *argv[]) {
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cmdline_logging();
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const char *outfile = nullptr;
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bool magisk = false, live = false;
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if (argc < 2) usage(argv[0]);
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int i = 1;
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for (; i < argc; ++i) {
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// Parse options
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if (argv[i][0] == '-' && argv[i][1] == '-') {
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if (strcmp(argv[i] + 2, "live") == 0)
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live = true;
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else if (strcmp(argv[i] + 2, "magisk") == 0)
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magisk = true;
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else if (strcmp(argv[i] + 2, "load") == 0) {
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if (argv[i + 1] == nullptr)
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usage(argv[0]);
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if (load_policydb(argv[i + 1])) {
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fprintf(stderr, "Cannot load policy from %s\n", argv[i + 1]);
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return 1;
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}
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++i;
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} else if (strcmp(argv[i] + 2, "compile-split") == 0) {
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if (compile_split_cil()) {
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fprintf(stderr, "Cannot compile split cil\n");
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return 1;
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}
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} else if (strcmp(argv[i] + 2, "save") == 0) {
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if (argv[i + 1] == nullptr)
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usage(argv[0]);
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outfile = argv[i + 1];
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++i;
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} else if (strcmp(argv[i] + 2, "help") == 0) {
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statements();
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} else {
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usage(argv[0]);
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}
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} else {
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break;
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}
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}
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// Use current policy if nothing is loaded
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if (policydb == nullptr && load_policydb(SELINUX_POLICY)) {
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fprintf(stderr, "Cannot load policy from " SELINUX_POLICY "\n");
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return 1;
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}
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for (; i < argc; ++i)
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parse_statement(argv[i]);
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if (magisk)
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sepol_magisk_rules();
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if (live && dump_policydb(SELINUX_LOAD)) {
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fprintf(stderr, "Cannot apply policy\n");
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return 1;
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}
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if (outfile && dump_policydb(outfile)) {
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fprintf(stderr, "Cannot dump policy to %s\n", outfile);
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return 1;
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}
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destroy_policydb();
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return 0;
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}
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