Implement GetProcessFlags for KernelSU

zygiskd/src/constants.rs

@@ -38,7 +38,13 @@ pub enum DaemonSocketAction {
     PingHeartbeat,
     RequestLogcatFd,
     ReadNativeBridge,
+    GetProcessFlags,
     ReadModules,
     RequestCompanionSocket,
     GetModuleDir,
 }
+
+// Zygisk process flags
+pub const PROCESS_GRANTED_ROOT: u32 = 1 << 0;
+pub const PROCESS_ON_DENYLIST: u32 = 1 << 1;
+pub const PROCESS_IS_SYSUI: u32 = 1 << 31;

zygiskd/src/main.rs

@@ -3,6 +3,7 @@
 mod companion;
 mod constants;
 mod dl;
+mod root_impl;
 mod utils;
 mod watchdog;
 mod zygiskd;

zygiskd/src/root_impl/kernelsu.rs

@@ -0,0 +1,29 @@
+use nix::libc::prctl;
+
+const KERNEL_SU_OPTION: i32 = 0xdeadbeefu32 as i32;
+
+const CMD_GET_VERSION: u64 = 2;
+const CMD_GET_ALLOW_LIST: u64 = 5;
+const CMD_GET_DENY_LIST: u64 = 6;
+
+pub fn is_kernel_su() -> bool {
+    let mut version = 0;
+    unsafe { prctl(KERNEL_SU_OPTION, CMD_GET_VERSION, &mut version as *mut i32) };
+    version > 0
+}
+
+pub fn uid_on_allowlist(uid: i32) -> bool {
+    let mut size = 1024u32;
+    let mut uids = vec![0; size as usize];
+    unsafe { prctl(KERNEL_SU_OPTION, CMD_GET_ALLOW_LIST, uids.as_mut_ptr(), &mut size as *mut u32) };
+    uids.resize(size as usize, 0);
+    uids.contains(&uid)
+}
+
+pub fn uid_on_denylist(uid: i32) -> bool {
+    let mut size = 1024u32;
+    let mut uids = vec![0; size as usize];
+    unsafe { prctl(KERNEL_SU_OPTION, CMD_GET_DENY_LIST, uids.as_mut_ptr(), &mut size as *mut u32) };
+    uids.resize(size as usize, 0);
+    uids.contains(&uid)
+}

zygiskd/src/root_impl/magisk.rs

@@ -0,0 +1,13 @@
+
+
+pub fn is_magisk() -> bool {
+    todo!("is_magisk")
+}
+
+pub fn uid_on_allowlist(uid: i32) -> bool {
+    todo!("uid_on_allowlist")
+}
+
+pub fn uid_on_denylist(uid: i32) -> bool {
+    todo!("uid_on_denylist")
+}

zygiskd/src/root_impl/mod.rs

@@ -0,0 +1,24 @@
+mod kernelsu;
+mod magisk;
+
+pub fn uid_on_allowlist(uid: i32) -> bool {
+    if kernelsu::is_kernel_su() {
+        kernelsu::uid_on_allowlist(uid)
+    } else if magisk::is_magisk() {
+        magisk::uid_on_allowlist(uid)
+    } else {
+        log::warn!("Unknown root implementation");
+        false
+    }
+}
+
+pub fn uid_on_denylist(uid: i32) -> bool {
+    if kernelsu::is_kernel_su() {
+        kernelsu::uid_on_denylist(uid)
+    } else if magisk::is_magisk() {
+        magisk::uid_on_denylist(uid)
+    } else {
+        log::warn!("Unknown root implementation");
+        false
+    }
+}

zygiskd/src/utils.rs

@@ -40,6 +40,7 @@ pub trait UnixStreamExt {
     fn read_usize(&mut self) -> Result<usize>;
     fn read_string(&mut self) -> Result<String>;
     fn write_u8(&mut self, value: u8) -> Result<()>;
+    fn write_u32(&mut self, value: u32) -> Result<()>;
     fn write_usize(&mut self, value: usize) -> Result<()>;
     fn write_string(&mut self, value: &str) -> Result<()>;
 }
@@ -75,6 +76,11 @@ impl UnixStreamExt for UnixStream {
         Ok(())
     }
 
+    fn write_u32(&mut self, value: u32) -> Result<()> {
+        self.write_all(&value.to_ne_bytes())?;
+        Ok(())
+    }
+
     fn write_usize(&mut self, value: usize) -> Result<()> {
         self.write_all(&value.to_ne_bytes())?;
         Ok(())

zygiskd/src/zygiskd.rs

@@ -1,6 +1,6 @@
 use crate::constants::DaemonSocketAction;
 use crate::utils::UnixStreamExt;
-use crate::{constants, lp_select, utils};
+use crate::{constants, lp_select, root_impl, utils};
 use anyhow::{bail, Result};
 use memfd::Memfd;
 use nix::{
@@ -67,10 +67,10 @@ fn get_arch() -> Result<&'static str> {
     let output = Command::new("getprop").arg("ro.product.cpu.abi").output()?;
     let system_arch = String::from_utf8(output.stdout)?;
     if system_arch.contains("arm") {
-        return Ok(lp_select!("armeabi-v7a", "arm64-v8a"))
+        return Ok(lp_select!("armeabi-v7a", "arm64-v8a"));
     }
     if system_arch.contains("x86") {
-        return Ok(lp_select!("x86", "x86_64"))
+        return Ok(lp_select!("x86", "x86_64"));
     }
     bail!("Unsupported system architecture: {}", system_arch);
 }
@@ -193,6 +193,18 @@ fn handle_daemon_action(mut stream: UnixStream, context: &Context) -> Result<()>
         DaemonSocketAction::ReadNativeBridge => {
             stream.write_string(&context.native_bridge)?;
         }
+        DaemonSocketAction::GetProcessFlags => {
+            let uid = stream.read_u32()? as i32;
+            let mut flags = 0u32;
+            if root_impl::uid_on_allowlist(uid) {
+                flags |= constants::PROCESS_GRANTED_ROOT;
+            }
+            if root_impl::uid_on_denylist(uid) {
+                flags |= constants::PROCESS_ON_DENYLIST;
+            }
+            // TODO: PROCESS_IS_SYSUI?
+            stream.write_u32(flags)?;
+        }
         DaemonSocketAction::ReadModules => {
             stream.write_usize(context.modules.len())?;
             for module in context.modules.iter() {