Parse rule files with Rust

native/src/Android.mk

@@ -176,7 +176,8 @@ LOCAL_SRC_FILES := \
     sepolicy/sepolicy.cpp \
     sepolicy/rules.cpp \
     sepolicy/policydb.cpp \
-    sepolicy/statement.cpp
+    sepolicy/statement.cpp \
+    sepolicy/policy-rs.cpp
 include $(BUILD_STATIC_LIBRARY)
 
 include src/Android-rs.mk

native/src/Cargo.lock

@@ -83,7 +83,7 @@ dependencies = [
  "codespan-reporting",
  "proc-macro2",
  "quote",
- "syn 2.0.15",
+ "syn 2.0.16",
 ]
 
 [[package]]
@@ -96,7 +96,7 @@ version = "1.0.94"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.15",
+ "syn 2.0.16",
 ]
 
 [[package]]
@@ -168,9 +168,9 @@ dependencies = [
 
 [[package]]
 name = "io-lifetimes"
-version = "1.0.10"
+version = "1.0.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9c66c74d2ae7e79a5a8f7ac924adbe38ee42a859c6539ad869eb51f0b52dc220"
+checksum = "eae7b9aee968036d54dce06cebaefd919e4472e753296daccd6d344e3e2df0c2"
 dependencies = [
  "hermit-abi",
  "libc",
@@ -179,15 +179,15 @@ dependencies = [
 
 [[package]]
 name = "libc"
-version = "0.2.142"
+version = "0.2.144"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6a987beff54b60ffa6d51982e1aa1146bc42f19bd26be28b0586f252fccf5317"
+checksum = "2b00cc1c228a6782d0f076e7b232802e0c5689d41bb5df366f2a6b6621cfdfe1"
 
 [[package]]
 name = "linux-raw-sys"
-version = "0.3.6"
+version = "0.3.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b64f40e5e03e0d54f03845c8197d0291253cdbedfb1cb46b13c2c117554a9f4c"
+checksum = "ef53942eb7bf7ff43a617b3e2c1c4a5ecf5944a7c1bc12d7ee39bbb15e5c1519"
 
 [[package]]
 name = "log"
@@ -228,13 +228,17 @@ dependencies = [
  "base",
  "cxx",
  "cxx-gen",
+ "magiskpolicy",
 ]
 
 [[package]]
 name = "magiskpolicy"
 version = "0.0.0"
 dependencies = [
+ "anyhow",
  "base",
+ "cxx",
+ "cxx-gen",
 ]
 
 [[package]]
@@ -331,9 +335,9 @@ dependencies = [
 
 [[package]]
 name = "quote"
-version = "1.0.26"
+version = "1.0.27"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4424af4bf778aae2051a77b60283332f386554255d722233d09fbfc7e30da2fc"
+checksum = "8f4f29d145265ec1c483c7c654450edde0bfe043d3938d6972630663356d9500"
 dependencies = [
  "proc-macro2",
 ]
@@ -349,9 +353,9 @@ dependencies = [
 
 [[package]]
 name = "regex"
-version = "1.8.1"
+version = "1.8.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "af83e617f331cc6ae2da5443c602dfa5af81e517212d9d611a5b3ba1777b5370"
+checksum = "d1a59b5d8e97dee33696bf13c5ba8ab85341c002922fba050069326b9c498974"
 dependencies = [
  "aho-corasick",
  "memchr",
@@ -360,15 +364,15 @@ dependencies = [
 
 [[package]]
 name = "regex-syntax"
-version = "0.7.1"
+version = "0.7.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a5996294f19bd3aae0453a862ad728f60e6600695733dd5df01da90c54363a3c"
+checksum = "436b050e76ed2903236f032a59761c1eb99e1b0aead2c257922771dab1fc8c78"
 
 [[package]]
 name = "rustix"
-version = "0.37.18"
+version = "0.37.19"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8bbfc1d1c7c40c01715f47d71444744a81669ca84e8b63e25a55e169b1f86433"
+checksum = "acf8729d8542766f1b2cf77eb034d52f40d375bb8b615d0b147089946e16613d"
 dependencies = [
  "bitflags",
  "errno",
@@ -391,9 +395,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "2.0.15"
+version = "2.0.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a34fcf3e8b60f57e6a14301a2e916d323af98b0ea63c599441eec8558660c822"
+checksum = "a6f671d4b5ffdb8eadec19c0ae67fe2639df8684bd7bc4b83d986b8db549cf01"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -439,14 +443,14 @@ checksum = "f9456a42c5b0d803c8cd86e73dd7cc9edd429499f37a3550d286d5e86720569f"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 2.0.15",
+ "syn 2.0.16",
 ]
 
 [[package]]
 name = "unicode-ident"
-version = "1.0.8"
+version = "1.0.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e5464a87b239f13a63a501f2701565754bae92d243d4bb7eb12f6d57d2269bf4"
+checksum = "b15811caf2415fb889178633e7724bad2509101cde276048e013b9def5e51fa0"
 
 [[package]]
 name = "unicode-width"

native/src/Cargo.toml

@@ -2,19 +2,23 @@
 exclude = ["external"]
 members = ["base", "boot", "core", "init", "sepolicy"]
 
+[workspace.dependencies]
+cxx = { path = "external/cxx-rs" }
+cxx-gen = { path = "external/cxx-rs/gen/lib" }
+libc = "0.2"
+cfg-if = "1.0"
+anyhow = "1.0"
+num-traits = "0.2"
+num-derive = "0.3"
+
 [profile.dev]
 opt-level = "z"
 lto = true
 codegen-units = 1
 panic = "abort"
-strip = true
 
 [profile.release]
 opt-level = "z"
 lto = true
 codegen-units = 1
 panic = "abort"
-strip = true
-
-[patch.crates-io]
-cxx = { path = "external/cxx-rs" }

native/src/base/Cargo.toml

@@ -7,9 +7,9 @@ edition = "2021"
 path = "lib.rs"
 
 [build-dependencies]
-cxx-gen = { path = "../external/cxx-rs/gen/lib" }
+cxx-gen = { workspace = true }
 
 [dependencies]
-cxx = { path = "../external/cxx-rs" }
+cxx = { workspace = true }
-libc = "0.2"
+libc = { workspace = true }
-cfg-if = "1.0"
+cfg-if = { workspace = true }

native/src/base/files.rs

@@ -1,14 +1,12 @@
 use std::cmp::min;
 use std::ffi::CStr;
-use std::fs::File;
 use std::io;
 use std::io::{BufRead, Write};
 use std::os::unix::io::{AsRawFd, FromRawFd, OwnedFd, RawFd};
-use std::path::Path;
 
 use libc::{c_char, c_uint, mode_t, EEXIST, ENOENT, O_CLOEXEC, O_PATH};
 
-use crate::{bfmt_cstr, errno, xopen};
+use crate::{bfmt_cstr, errno, error, xopen};
 
 pub mod unsafe_impl {
     use std::ffi::CStr;
@@ -137,9 +135,43 @@ pub extern "C" fn mkdirs(path: *const c_char, mode: mode_t) -> i32 {
     }
 }
 
-pub fn read_lines<P: AsRef<Path>>(path: P) -> io::Result<io::Lines<io::BufReader<File>>> {
+pub trait BufReadExt {
-    let file = File::open(path)?;
+    fn foreach_lines<F: FnMut(&mut String) -> bool>(&mut self, f: F);
-    Ok(io::BufReader::new(file).lines())
+    fn foreach_props<F: FnMut(&str, &str) -> bool>(&mut self, f: F);
+}
+
+impl<T: BufRead> BufReadExt for T {
+    fn foreach_lines<F: FnMut(&mut String) -> bool>(&mut self, mut f: F) {
+        let mut buf = String::new();
+        loop {
+            match self.read_line(&mut buf) {
+                Ok(0) => break,
+                Ok(_) => {
+                    if !f(&mut buf) {
+                        break;
+                    }
+                }
+                Err(e) => {
+                    error!("{}", e);
+                    break;
+                }
+            };
+            buf.clear();
+        }
+    }
+
+    fn foreach_props<F: FnMut(&str, &str) -> bool>(&mut self, mut f: F) {
+        self.foreach_lines(|line| {
+            let line = line.trim();
+            if line.starts_with('#') {
+                return true;
+            }
+            if let Some((key, value)) = line.split_once('=') {
+                return f(key, value);
+            }
+            return true;
+        });
+    }
 }
 
 pub trait WriteExt {

native/src/boot/Cargo.toml

@@ -9,7 +9,7 @@ path = "lib.rs"
 
 [build-dependencies]
 protobuf-codegen = "3.2.0"
-cxx-gen = { path = "../external/cxx-rs/gen/lib" }
+cxx-gen = { workspace = true }
 
 [dependencies]
 base = { path = "../base" }

native/src/core/Cargo.toml

@@ -8,10 +8,10 @@ crate-type = ["staticlib"]
 path = "lib.rs"
 
 [build-dependencies]
-cxx-gen = { path = "../external/cxx-rs/gen/lib" }
+cxx-gen = { workspace = true }
 
 [dependencies]
 base = { path = "../base" }
-cxx = { path = "../external/cxx-rs" }
+cxx = { workspace = true }
-num-traits = "0.2"
+num-traits = { workspace = true }
-num-derive = "0.3"
+num-derive = { workspace = true }

native/src/init/Cargo.toml

@@ -8,8 +8,9 @@ crate-type = ["staticlib"]
 path = "lib.rs"
 
 [build-dependencies]
-cxx-gen = { path = "../external/cxx-rs/gen/lib" }
+cxx-gen = { workspace = true }
 
 [dependencies]
 base = { path = "../base" }
-cxx = { path = "../external/cxx-rs" }
+magiskpolicy = { path = "../sepolicy" }
+cxx = { workspace = true }

native/src/init/lib.rs

@@ -1,4 +1,6 @@
 pub use logging::*;
+// Has to be pub so all symbols in that crate is included
+pub use magiskpolicy;
 
 mod logging;
 

native/src/sepolicy/Cargo.toml

@@ -7,5 +7,10 @@ edition = "2021"
 crate-type = ["staticlib", "rlib"]
 path = "lib.rs"
 
+[build-dependencies]
+cxx-gen = { workspace = true }
+
 [dependencies]
 base = { path = "../base" }
+cxx = { workspace = true }
+anyhow = { workspace = true }

native/src/sepolicy/api.cpp

@@ -103,3 +103,13 @@ bool sepolicy::genfscon(const char *fs_name, const char *path, const char *ctx)
 bool sepolicy::exists(const char *type) {
     return hashtab_search(impl->db->p_types.table, type) != nullptr;
 }
+
+void sepolicy::load_rule_file(const char *file) {
+    rust::load_rule_file(*this, rust::Slice(
+            reinterpret_cast<const uint8_t *>(file), strlen(file)));
+}
+
+void sepolicy::load_rules(const std::string &rules) {
+    rust::load_rules(*this, rust::Slice(
+            reinterpret_cast<const uint8_t *>(rules.data()), rules.length()));
+}

native/src/sepolicy/build.rs

@@ -0,0 +1,8 @@
+use crate::gen::gen_cxx_binding;
+
+#[path = "../include/gen.rs"]
+mod gen;
+
+fn main() {
+    gen_cxx_binding("policy-rs");
+}

native/src/sepolicy/include/sepolicy.hpp

@@ -1,9 +1,10 @@
 #pragma once
 
 #include <stdlib.h>
-#include <selinux.hpp>
 #include <string>
 
+#include <selinux.hpp>
+
 #define ALL nullptr
 
 struct sepolicy {
@@ -17,7 +18,8 @@ struct sepolicy {
 
     // External APIs
     bool to_file(c_str file);
-    void parse_statement(c_str stmt);
+    void parse_statement(c_str stmt, int len);
+    void parse_statement(c_str stmt) { parse_statement(stmt, strlen(stmt)); }
     void load_rules(const std::string &rules);
     void load_rule_file(c_str file);
 

native/src/sepolicy/lib.rs

@@ -1 +1,53 @@
+use io::Cursor;
+use std::fs::File;
+use std::io::{BufRead, BufReader};
+use std::pin::Pin;
+use std::{io, str};
+
 pub use base;
+use base::*;
+
+use crate::ffi::sepolicy;
+
+#[cxx::bridge]
+mod ffi {
+    unsafe extern "C++" {
+        include!("include/sepolicy.hpp");
+
+        type sepolicy;
+        unsafe fn parse_statement(self: Pin<&mut sepolicy>, stmt: *const c_char, len: i32);
+    }
+
+    #[namespace = "rust"]
+    extern "Rust" {
+        fn load_rules(sepol: Pin<&mut sepolicy>, rules: &[u8]);
+        fn load_rule_file(sepol: Pin<&mut sepolicy>, filename: &[u8]);
+    }
+}
+
+fn load_rules_from_reader<T: BufRead>(mut sepol: Pin<&mut sepolicy>, reader: &mut T) {
+    reader.foreach_lines(|line| {
+        let bytes = line.trim().as_bytes();
+        unsafe {
+            sepol
+                .as_mut()
+                .parse_statement(bytes.as_ptr().cast(), bytes.len() as i32);
+        }
+        true
+    });
+}
+
+pub fn load_rule_file(sepol: Pin<&mut sepolicy>, filename: &[u8]) {
+    fn inner(sepol: Pin<&mut sepolicy>, filename: &[u8]) -> anyhow::Result<()> {
+        let filename = str::from_utf8(filename)?;
+        let mut reader = BufReader::new(File::open(filename)?);
+        load_rules_from_reader(sepol, &mut reader);
+        Ok(())
+    }
+    inner(sepol, filename).ok_or_log();
+}
+
+pub fn load_rules(sepol: Pin<&mut sepolicy>, rules: &[u8]) {
+    let mut cursor = Cursor::new(rules);
+    load_rules_from_reader(sepol, &mut cursor);
+}

native/src/sepolicy/policy.hpp

@@ -5,6 +5,8 @@
 #include <sepol/policydb/policydb.h>
 #include <sepolicy.hpp>
 
+#include "policy-rs.hpp"
+
 struct sepol_impl : public sepolicy {
     avtab_ptr_t get_avtab_node(avtab_key_t *key, avtab_extended_perms_t *xperms);
     bool add_rule(const char *s, const char *t, const char *c, const char *p, int effect, bool invert);

native/src/sepolicy/statement.cpp

@@ -267,21 +267,21 @@ static bool parse_pattern_9(const Func &fn, const char *action, char *stmt) {
 
 #define add_action_func(name, type, fn) \
 else if (strcmp(name, action) == 0) {   \
-    auto __fn = [=](auto && ...args){ return (fn)(args...); };\
+    auto __fn = [&](auto && ...args){ return (fn)(args...); }; \
     if (!parse_pattern_##type(__fn, name, remain))             \
-        LOGW("Syntax error in '%s'\n\n%s\n", stmt, type_msg_##type); \
+        LOGW("Syntax error in '%.*s'\n\n%s\n", len, stmt, type_msg_##type); \
 }
 
 #define add_action(act, type) add_action_func(#act, type, act)
 
-void sepolicy::parse_statement(const char *stmt) {
+void sepolicy::parse_statement(const char *stmt, int len) {
     // strtok modify strings, create a copy
-    string cpy(stmt);
+    string cpy(stmt, len);
 
     char *remain;
     char *action = strtok_r(cpy.data(), " ", &remain);
     if (remain == nullptr) {
-        LOGW("Syntax error in '%s'\n\n", stmt);
+        LOGW("Syntax error in '%.*s'\n\n", len, stmt);
         return;
     }
 
@@ -310,43 +310,3 @@ void sepolicy::parse_statement(const char *stmt) {
 
     else { LOGW("Unknown action: '%s'\n\n", action); }
 }
-
-void sepolicy::load_rule_file(const char *file) {
-    file_readline(true, file, [&](string_view line) -> bool {
-        if (line.empty() || line[0] == '#')
-            return true;
-        parse_statement(line.data());
-        return true;
-    });
-}
-
-void sepolicy::load_rules(const string &rules) {
-    struct cookie {
-        const string &s;
-        size_t pos;
-    };
-    cookie c{rules, 0};
-    FILE *fp = funopen(&c, /* read */ [](void *v, char *buf, int sz) -> int {
-        auto c = reinterpret_cast<cookie*>(v);
-        if (c->pos == c->s.length())
-            return 0;
-        size_t end = std::min(c->pos + sz, c->s.length());
-        int len = end - c->pos;
-        memcpy(buf, c->s.data() + c->pos, len);
-        c->pos = end;
-        return len;
-    }, /* write */ [](auto, auto, auto) -> int {
-        return 0;
-    }, /* seek */ [](auto, auto, auto) -> fpos_t {
-        return 0;
-    }, /* close */ [](auto) -> int {
-        return 0;
-    });
-
-    file_readline(true, fp, [&](string_view line) -> bool {
-        if (line.empty() || line[0] == '#')
-            return true;
-        parse_statement(line.data());
-        return true;
-    });
-}