mirror of
https://github.com/topjohnwu/Magisk.git
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353 lines
10 KiB
C++
353 lines
10 KiB
C++
#include <cstring>
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#include <vector>
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#include <string>
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#include <base.hpp>
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#include "policy.hpp"
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using namespace std;
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static const char *type_msg_1 =
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R"EOF("allow *source_type *target_type *class *perm_set"
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"deny *source_type *target_type *class *perm_set"
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"auditallow *source_type *target_type *class *perm_set"
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"dontaudit *source_type *target_type *class *perm_set"
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)EOF";
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static const char *type_msg_2 =
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R"EOF("allowxperm *source_type *target_type *class operation xperm_set"
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"auditallowxperm *source_type *target_type *class operation xperm_set"
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"dontauditxperm *source_type *target_type *class operation xperm_set"
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- The only supported operation is 'ioctl'
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- xperm_set format is either 'low-high', 'value', or '*'.
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'*' will be treated as '0x0000-0xFFFF'.
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All values should be written in hexadecimal.
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)EOF";
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static const char *type_msg_3 =
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R"EOF("permissive ^type"
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"enforce ^type"
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)EOF";
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static const char *type_msg_4 =
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R"EOF("typeattribute ^type ^attribute"
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)EOF";
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static const char *type_msg_5 =
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R"EOF("type type_name ^(attribute)"
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- Argument 'attribute' is optional, default to 'domain'
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)EOF";
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static const char *type_msg_6 =
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R"EOF("attribute attribute_name"
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)EOF";
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static const char *type_msg_7 =
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R"EOF("type_transition source_type target_type class default_type (object_name)"
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- Argument 'object_name' is optional
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)EOF";
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static const char *type_msg_8 =
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R"EOF("type_change source_type target_type class default_type"
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"type_member source_type target_type class default_type"
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)EOF";
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static const char *type_msg_9 =
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R"EOF("genfscon fs_name partial_path fs_context"
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)EOF";
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void statement_help() {
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fprintf(stderr,
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R"EOF(One policy statement should be treated as one parameter;
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this means each policy statement should be enclosed in quotes.
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Multiple policy statements can be provided in a single command.
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Statements has a format of "<rule_name> [args...]".
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Arguments labeled with (^) can accept one or more entries. Multiple
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entries consist of a space separated list enclosed in braces ({}).
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Arguments labeled with (*) are the same as (^), but additionally
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support the match-all operator (*).
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Example: "allow { s1 s2 } { t1 t2 } class *"
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Will be expanded to:
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allow s1 t1 class { all-permissions-of-class }
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allow s1 t2 class { all-permissions-of-class }
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allow s2 t1 class { all-permissions-of-class }
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allow s2 t2 class { all-permissions-of-class }
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Supported policy statements:
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%s
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%s
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%s
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%s
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%s
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%s
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%s
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%s
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%s
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)EOF", type_msg_1, type_msg_2, type_msg_3, type_msg_4,
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type_msg_5, type_msg_6, type_msg_7, type_msg_8, type_msg_9);
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exit(0);
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}
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using parsed_tokens = vector<vector<const char *>>;
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static bool tokenize_string(char *stmt, parsed_tokens &arr) {
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// cur is the pointer to where the top level is parsing
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char *cur = stmt;
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for (char *tok; (tok = strtok_r(nullptr, " ", &cur)) != nullptr;) {
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vector<const char *> token;
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if (tok[0] == '{') {
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// cur could point to somewhere in the braces, restore the string
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if (cur)
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cur[-1] = ' ';
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++tok;
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char *end = strchr(tok, '}');
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if (end == nullptr) {
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// Bracket not closed, syntax error
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return false;
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}
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*end = '\0';
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for (char *sub_tok; (sub_tok = strtok_r(nullptr, " ", &tok)) != nullptr;)
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token.push_back(sub_tok);
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cur = end + 1;
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} else if (tok[0] == '*') {
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token.push_back(nullptr);
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} else {
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token.push_back(tok);
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}
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arr.push_back(std::move(token));
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}
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return true;
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}
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// Check array size and all args listed in 'ones' have size = 1 (no multiple entries)
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template <int size, int ...ones>
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static bool check_tokens(parsed_tokens &arr) {
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if (arr.size() != size)
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return false;
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initializer_list<int> list{ones...};
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for (int i : list)
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if (arr[i].size() != 1)
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return false;
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return true;
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}
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template <int size, int ...ones>
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static bool tokenize_and_check(char *stmt, parsed_tokens &arr) {
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return tokenize_string(stmt, arr) && check_tokens<size, ones...>(arr);
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}
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template <typename Func, typename ...Args>
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static void run_and_check(const Func &fn, const char *action, Args ...args) {
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if (!fn(args...)) {
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string s = "Error in: %s";
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for (int i = 0; i < sizeof...(args); ++i) s += " %s";
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s += "\n";
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LOGW(s.data(), action, (args ? args : "*")...);
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}
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}
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#define run_fn(...) run_and_check(fn, action, __VA_ARGS__)
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// Pattern 1: allow { source } { target } { class } { permission }
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template <typename Func>
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static bool parse_pattern_1(const Func &fn, const char *action, char *stmt) {
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parsed_tokens arr;
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if (!tokenize_and_check<4>(stmt, arr))
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return false;
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for (auto src : arr[0])
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for (auto tgt : arr[1])
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for (auto cls : arr[2])
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for (auto perm : arr[3])
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run_fn(src, tgt, cls, perm);
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return true;
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}
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// Pattern 2: allowxperm { source } { target } { class } ioctl range
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template <typename Func>
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static bool parse_pattern_2(const Func &fn, const char *action, char *stmt) {
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parsed_tokens arr;
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if (!tokenize_and_check<5, 3, 4>(stmt, arr) || arr[3][0] != "ioctl"sv)
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return false;
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auto range = arr[4][0];
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for (auto src : arr[0])
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for (auto tgt : arr[1])
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for (auto cls : arr[2])
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run_fn(src, tgt, cls, range);
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return true;
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}
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// Pattern 3: permissive { type }
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template <typename Func>
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static bool parse_pattern_3(const Func &fn, const char *action, char *stmt) {
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parsed_tokens arr;
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if (!tokenize_and_check<1>(stmt, arr))
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return false;
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for (auto type : arr[0])
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run_fn(type);
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return true;
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}
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// Pattern 4: typeattribute { type } { attribute }
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template <typename Func>
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static bool parse_pattern_4(const Func &fn, const char *action, char *stmt) {
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parsed_tokens arr;
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if (!tokenize_and_check<2>(stmt, arr))
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return false;
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for (auto type : arr[0])
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for (auto attr : arr[1])
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run_fn(type, attr);
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return true;
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}
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// Pattern 5: type name { attribute }
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template <typename Func>
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static bool parse_pattern_5(const Func &fn, const char *action, char *stmt) {
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parsed_tokens arr;
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string tmp_str;
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if (!tokenize_string(stmt, arr))
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return false;
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if (arr.size() == 1) {
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arr.emplace_back(initializer_list<const char*>{ "domain" });
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}
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if (!check_tokens<2, 0>(arr))
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return false;
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for (auto attr : arr[1])
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run_fn(arr[0][0], attr);
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return true;
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}
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// Pattern 6: attribute name
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template <typename Func>
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static bool parse_pattern_6(const Func &fn, const char *action, char *stmt) {
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parsed_tokens arr;
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if (!tokenize_and_check<1, 0>(stmt, arr))
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return false;
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run_fn(arr[0][1]);
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return true;
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}
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// Pattern 7: type_transition source target class default (filename)
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template <typename Func>
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static bool parse_pattern_7(const Func &fn, const char *action, char *stmt) {
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parsed_tokens arr;
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if (!tokenize_string(stmt, arr))
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return false;
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if (arr.size() == 4)
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arr.emplace_back(initializer_list<const char*>{nullptr});
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if (!check_tokens<5, 0, 1, 2, 3, 4>(arr))
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return false;
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run_fn(arr[0][0], arr[1][0], arr[2][0], arr[3][0], arr[4][0]);
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return true;
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}
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// Pattern 8: type_change source target class default
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template <typename Func>
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static bool parse_pattern_8(const Func &fn, const char *action, char *stmt) {
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parsed_tokens arr;
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if (!tokenize_and_check<4, 0, 1, 2, 3>(stmt, arr))
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return false;
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run_fn(arr[0][0], arr[1][0], arr[2][0], arr[3][0]);
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return true;
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}
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// Pattern 9: genfscon name path context
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template <typename Func>
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static bool parse_pattern_9(const Func &fn, const char *action, char *stmt) {
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parsed_tokens arr;
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if (!tokenize_and_check<3, 0, 1, 2>(stmt, arr))
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return false;
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run_fn(arr[0][0], arr[1][0], arr[2][0]);
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return true;
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}
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#define add_action_func(name, type, fn) \
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else if (strcmp(name, action) == 0) { \
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auto __fn = [=](auto && ...args){ return (fn)(args...); };\
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if (!parse_pattern_##type(__fn, name, remain)) \
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LOGW("Syntax error in '%s'\n\n%s\n", stmt, type_msg_##type); \
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}
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#define add_action(act, type) add_action_func(#act, type, act)
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void sepolicy::parse_statement(const char *stmt) {
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// strtok modify strings, create a copy
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string cpy(stmt);
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char *remain;
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char *action = strtok_r(cpy.data(), " ", &remain);
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if (remain == nullptr) {
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LOGW("Syntax error in '%s'\n\n", stmt);
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return;
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}
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if (0) {}
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add_action(allow, 1)
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add_action(deny, 1)
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add_action(auditallow, 1)
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add_action(dontaudit, 1)
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add_action(allowxperm, 2)
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add_action(auditallowxperm, 2)
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add_action(dontauditxperm, 2)
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add_action(permissive, 3)
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add_action(enforce, 3)
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add_action(typeattribute, 4)
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add_action(type, 5)
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add_action(attribute, 6)
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add_action(type_transition, 7)
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add_action(type_change, 8)
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add_action(type_member, 8)
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add_action(genfscon, 9)
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// Backwards compatible syntax
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add_action(create, 3)
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add_action_func("attradd", 4, typeattribute)
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add_action_func("name_transition", 7, type_transition)
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else { LOGW("Unknown action: '%s'\n\n", action); }
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}
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void sepolicy::load_rule_file(const char *file) {
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file_readline(true, file, [&](string_view line) -> bool {
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if (line.empty() || line[0] == '#')
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return true;
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parse_statement(line.data());
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return true;
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});
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}
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void sepolicy::load_rules(const string &rules) {
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struct cookie {
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const string &s;
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size_t pos;
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};
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cookie c{rules, 0};
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FILE *fp = funopen(&c, /* read */ [](void *v, char *buf, int sz) -> int {
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auto c = reinterpret_cast<cookie*>(v);
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if (c->pos == c->s.length())
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return 0;
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size_t end = std::min(c->pos + sz, c->s.length());
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int len = end - c->pos;
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memcpy(buf, c->s.data() + c->pos, len);
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c->pos = end;
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return len;
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}, /* write */ [](auto, auto, auto) -> int {
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return 0;
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}, /* seek */ [](auto, auto, auto) -> fpos_t {
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return 0;
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}, /* close */ [](auto) -> int {
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return 0;
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});
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file_readline(true, fp, [&](string_view line) -> bool {
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if (line.empty() || line[0] == '#')
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return true;
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parse_statement(line.data());
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return true;
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});
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}
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