vetto 0.2.13

//! Native Win32 AppContainer lifecycle, DACL injection, and capability management.
//!
//! Provides native AppContainer profile creation, SID derivation, canonical DACL
//! injection (Deny ACEs before Allow ACEs), `STARTUPINFOEXW` security capabilities
//! configuration, and RAII profile/DACL cleanup guards.

use std::ffi::c_void;
use std::path::{Path, PathBuf};
use std::ptr::{null, null_mut};

use anyhow::{bail, Result};

pub type Handle = *mut c_void;
pub type Sid = *mut c_void;
pub type Dword = u32;
pub type Hresult = i32;

pub const S_OK: Hresult = 0;
pub const LOAD_LIBRARY_SEARCH_SYSTEM32: u32 = 0x0000_0800;

pub const SE_FILE_OBJECT: Dword = 1;
pub const DACL_SECURITY_INFORMATION: Dword = 0x0000_0004;
pub const PROTECTED_DACL_SECURITY_INFORMATION: Dword = 0x8000_0000;
pub const UNPROTECTED_DACL_SECURITY_INFORMATION: Dword = 0x2000_0000;

pub const GRANT_ACCESS: Dword = 1;
pub const SET_ACCESS: Dword = 2;
pub const DENY_ACCESS: Dword = 3;
pub const REVOKE_ACCESS: Dword = 4;

pub const CONTAINER_INHERIT_ACE: u32 = 0x2;
pub const OBJECT_INHERIT_ACE: u32 = 0x1;

pub const FILE_GENERIC_READ: Dword = 0x0012_0089;
pub const FILE_GENERIC_WRITE: Dword = 0x0012_0116;
pub const FILE_GENERIC_EXECUTE: Dword = 0x0012_00A0;
pub const FILE_ALL_ACCESS: Dword = 0x001F_01FF;

pub const PROC_THREAD_ATTRIBUTE_SECURITY_CAPABILITIES: usize = 0x0002_0009;

#[repr(C)]
#[derive(Debug, Clone, Copy)]
pub struct SidAndAttributes {
    pub sid: Sid,
    pub attributes: Dword,
}

#[repr(C)]
#[derive(Debug)]
pub struct SecurityCapabilities {
    pub app_container_sid: Sid,
    pub capabilities: *mut SidAndAttributes,
    pub capability_count: Dword,
    pub reserved: Dword,
}

#[repr(C)]
pub struct TrusteeW {
    pub p_multiple_trustee: *mut c_void,
    pub multiple_trustee_operation: Dword,
    pub trustee_form: Dword,  // TRUSTEE_IS_SID = 0
    pub trustee_type: Dword,  // TRUSTEE_IS_USER = 1 or TRUSTEE_IS_WELL_KNOWN_GROUP = 5
    pub ptstr_name: *mut u16, // SID pointer when TRUSTEE_IS_SID
}

#[repr(C)]
pub struct ExplicitAccessW {
    pub grf_access_permissions: Dword,
    pub grf_access_mode: Dword,
    pub grf_inheritance: Dword,
    pub trustee: TrusteeW,
}

#[derive(Clone, Debug, Default, PartialEq, Eq)]
pub struct Capabilities {
    pub derive_capability_sids: bool,
    pub create_appcontainer_profile: bool,
    pub derive_appcontainer_sid: bool,
    pub delete_appcontainer_profile: bool,
    pub lpac_api: bool,
    pub note: &'static str,
}

#[link(name = "userenv")]
extern "system" {
    fn CreateAppContainerProfile(
        pszAppContainerName: *const u16,
        pszDisplayName: *const u16,
        pszDescription: *const u16,
        pCapabilities: *const SidAndAttributes,
        dwCapabilityCount: Dword,
        ppSidAppContainerSid: *mut Sid,
    ) -> Hresult;

    fn DeriveAppContainerSidFromAppContainerName(
        pszAppContainerName: *const u16,
        ppSidAppContainerSid: *mut Sid,
    ) -> Hresult;

    fn DeleteAppContainerProfile(pszAppContainerName: *const u16) -> Hresult;
}

#[link(name = "advapi32")]
extern "system" {
    fn GetNamedSecurityInfoW(
        pObjectName: *const u16,
        ObjectType: Dword,
        SecurityInfo: Dword,
        ppsidOwner: *mut Sid,
        ppsidGroup: *mut Sid,
        ppDacl: *mut *mut c_void,
        ppSacl: *mut *mut c_void,
        ppSecurityDescriptor: *mut *mut c_void,
    ) -> Dword;

    fn SetNamedSecurityInfoW(
        pObjectName: *const u16,
        ObjectType: Dword,
        SecurityInfo: Dword,
        psidOwner: Sid,
        psidGroup: Sid,
        pDacl: *mut c_void,
        pSacl: *mut c_void,
    ) -> Dword;

    fn SetEntriesInAclW(
        cCountOfExplicitEntries: Dword,
        pListOfExplicitEntries: *const ExplicitAccessW,
        OldAcl: *mut c_void,
        NewAcl: *mut *mut c_void,
    ) -> Dword;

    fn ConvertSidToStringSidW(Sid: Sid, StringSid: *mut *mut u16) -> i32;
    fn ConvertStringSidToSidW(StringSid: *const u16, Sid: *mut Sid) -> i32;
    fn GetLengthSid(pSid: Sid) -> Dword;
    fn CopySid(nDestinationSidLength: Dword, pDestinationSid: Sid, pSourceSid: Sid) -> i32;
}

#[link(name = "kernel32")]
extern "system" {
    fn LocalFree(memory: *mut c_void) -> *mut c_void;
    fn GetLastError() -> Dword;
    fn InitializeProcThreadAttributeList(
        lpAttributeList: *mut c_void,
        dwAttributeCount: Dword,
        dwFlags: Dword,
        lpSize: *mut usize,
    ) -> i32;
    fn UpdateProcThreadAttribute(
        lpAttributeList: *mut c_void,
        dwFlags: Dword,
        Attribute: usize,
        lpValue: *const c_void,
        cbSize: usize,
        lpPreviousValue: *mut c_void,
        lpReturnSize: *mut usize,
    ) -> i32;
    fn DeleteProcThreadAttributeList(lpAttributeList: *mut c_void);
}

pub fn wide(value: &str) -> Option<Vec<u16>> {
    if value.encode_utf16().any(|c| c == 0) {
        return None;
    }
    Some(value.encode_utf16().chain(Some(0)).collect())
}

/// Owned AppContainer SID wrapper freeing memory with `FreeSid` / `LocalFree`.
pub struct OwnedSid {
    raw: Sid,
}

impl OwnedSid {
    pub fn as_raw(&self) -> Sid {
        self.raw
    }

    pub fn to_string_sid(&self) -> Result<String> {
        let mut str_ptr: *mut u16 = null_mut();
        let ok = unsafe { ConvertSidToStringSidW(self.raw, &mut str_ptr) };
        if ok == 0 || str_ptr.is_null() {
            bail!("ConvertSidToStringSidW failed with {}", unsafe {
                GetLastError()
            });
        }
        let mut len = 0;
        while unsafe { *str_ptr.add(len) } != 0 {
            len += 1;
        }
        let slice = unsafe { std::slice::from_raw_parts(str_ptr, len) };
        let s = String::from_utf16_lossy(slice);
        unsafe { LocalFree(str_ptr.cast()) };
        Ok(s)
    }
}

impl Drop for OwnedSid {
    fn drop(&mut self) {
        if !self.raw.is_null() {
            unsafe { LocalFree(self.raw) };
        }
    }
}

/// RAII Guard managing the lifecycle of an AppContainer Profile.
pub struct AppContainerProfileGuard {
    name: String,
    sid: OwnedSid,
}

impl AppContainerProfileGuard {
    pub fn create(name: &str, display_name: &str, description: &str) -> Result<Self> {
        let name_w = wide(name).ok_or_else(|| anyhow::anyhow!("invalid profile name"))?;
        let disp_w = wide(display_name).ok_or_else(|| anyhow::anyhow!("invalid display name"))?;
        let desc_w = wide(description).ok_or_else(|| anyhow::anyhow!("invalid description"))?;

        let mut sid_ptr: Sid = null_mut();
        let hr = unsafe {
            CreateAppContainerProfile(
                name_w.as_ptr(),
                disp_w.as_ptr(),
                desc_w.as_ptr(),
                null(),
                0,
                &mut sid_ptr,
            )
        };

        if hr != S_OK {
            // Check if profile already exists: derive SID
            let mut derived_sid: Sid = null_mut();
            let dhr = unsafe {
                DeriveAppContainerSidFromAppContainerName(name_w.as_ptr(), &mut derived_sid)
            };
            if dhr == S_OK && !derived_sid.is_null() {
                return Ok(Self {
                    name: name.to_string(),
                    sid: OwnedSid { raw: derived_sid },
                });
            }
            bail!("CreateAppContainerProfile failed with HRESULT {hr:#x}");
        }

        Ok(Self {
            name: name.to_string(),
            sid: OwnedSid { raw: sid_ptr },
        })
    }

    pub fn sid(&self) -> Sid {
        self.sid.as_raw()
    }

    pub fn name(&self) -> &str {
        &self.name
    }
}

impl Drop for AppContainerProfileGuard {
    fn drop(&mut self) {
        if let Some(name_w) = wide(&self.name) {
            unsafe {
                DeleteAppContainerProfile(name_w.as_ptr());
            }
        }
    }
}

/// RAII Guard for temporarily modifying DACLs on file system objects.
pub struct DaclOverrideGuard {
    path: PathBuf,
    original_sd: *mut c_void,
    original_dacl: *mut c_void,
}

impl DaclOverrideGuard {
    /// Apply access rules (Deny or Grant) for the AppContainer SID.
    pub fn apply(path: &Path, sid: Sid, is_deny: bool, write: bool) -> Result<Self> {
        let path_w = wide(path.to_str().unwrap_or_default())
            .ok_or_else(|| anyhow::anyhow!("invalid path encoding"))?;

        let mut original_sd: *mut c_void = null_mut();
        let mut original_dacl: *mut c_void = null_mut();

        let ret = unsafe {
            GetNamedSecurityInfoW(
                path_w.as_ptr(),
                SE_FILE_OBJECT,
                DACL_SECURITY_INFORMATION,
                null_mut(),
                null_mut(),
                &mut original_dacl,
                null_mut(),
                &mut original_sd,
            )
        };

        if ret != 0 {
            bail!("GetNamedSecurityInfoW failed with error {ret}");
        }

        let access_mask = if is_deny {
            FILE_ALL_ACCESS
        } else if write {
            FILE_GENERIC_READ | FILE_GENERIC_WRITE | FILE_GENERIC_EXECUTE
        } else {
            FILE_GENERIC_READ | FILE_GENERIC_EXECUTE
        };

        let mode = if is_deny { DENY_ACCESS } else { GRANT_ACCESS };

        let explicit = ExplicitAccessW {
            grf_access_permissions: access_mask,
            grf_access_mode: mode,
            grf_inheritance: CONTAINER_INHERIT_ACE | OBJECT_INHERIT_ACE,
            trustee: TrusteeW {
                p_multiple_trustee: null_mut(),
                multiple_trustee_operation: 0,
                trustee_form: 0, // TRUSTEE_IS_SID
                trustee_type: 1, // TRUSTEE_IS_USER
                ptstr_name: sid.cast(),
            },
        };

        let mut new_dacl: *mut c_void = null_mut();
        let ret = unsafe { SetEntriesInAclW(1, &explicit, original_dacl, &mut new_dacl) };

        if ret != 0 || new_dacl.is_null() {
            unsafe { LocalFree(original_sd) };
            bail!("SetEntriesInAclW failed with error {ret}");
        }

        let set_ret = unsafe {
            SetNamedSecurityInfoW(
                path_w.as_ptr(),
                SE_FILE_OBJECT,
                DACL_SECURITY_INFORMATION | UNPROTECTED_DACL_SECURITY_INFORMATION,
                null_mut(),
                null_mut(),
                new_dacl,
                null_mut(),
            )
        };

        unsafe { LocalFree(new_dacl) };

        if set_ret != 0 {
            unsafe { LocalFree(original_sd) };
            bail!("SetNamedSecurityInfoW failed with error {set_ret}");
        }

        Ok(Self {
            path: path.to_path_buf(),
            original_sd,
            original_dacl,
        })
    }
}

impl Drop for DaclOverrideGuard {
    fn drop(&mut self) {
        if let Some(path_w) = wide(self.path.to_str().unwrap_or_default()) {
            unsafe {
                SetNamedSecurityInfoW(
                    path_w.as_ptr(),
                    SE_FILE_OBJECT,
                    DACL_SECURITY_INFORMATION,
                    null_mut(),
                    null_mut(),
                    self.original_dacl,
                    null_mut(),
                );
                LocalFree(self.original_sd);
            }
        }
    }
}

/// Helper to configure `STARTUPINFOEXW` attribute lists with AppContainer capabilities.
pub struct AttributeList {
    buffer: Vec<u8>,
}

impl AttributeList {
    pub fn new(capabilities: &mut SecurityCapabilities) -> Result<Self> {
        let mut size: usize = 0;
        unsafe {
            InitializeProcThreadAttributeList(null_mut(), 1, 0, &mut size);
        }
        if size == 0 {
            bail!("InitializeProcThreadAttributeList failed to return required size");
        }

        let mut buffer = vec![0u8; size];
        let ok = unsafe {
            InitializeProcThreadAttributeList(buffer.as_mut_ptr().cast(), 1, 0, &mut size)
        };
        if ok == 0 {
            bail!("InitializeProcThreadAttributeList failed with {}", unsafe {
                GetLastError()
            });
        }

        let update_ok = unsafe {
            UpdateProcThreadAttribute(
                buffer.as_mut_ptr().cast(),
                0,
                PROC_THREAD_ATTRIBUTE_SECURITY_CAPABILITIES,
                capabilities as *mut SecurityCapabilities as *const c_void,
                std::mem::size_of::<SecurityCapabilities>(),
                null_mut(),
                null_mut(),
            )
        };

        if update_ok == 0 {
            unsafe { DeleteProcThreadAttributeList(buffer.as_mut_ptr().cast()) };
            bail!("UpdateProcThreadAttribute failed with {}", unsafe {
                GetLastError()
            });
        }

        Ok(Self { buffer })
    }

    pub fn as_mut_ptr(&mut self) -> *mut c_void {
        self.buffer.as_mut_ptr().cast()
    }
}

impl Drop for AttributeList {
    fn drop(&mut self) {
        unsafe {
            DeleteProcThreadAttributeList(self.buffer.as_mut_ptr().cast());
        }
    }
}

/// Clean up orphaned AppContainer profiles matching a prefix (used by `doctor`).
pub fn cleanup_orphan_profiles(prefix: &str) {
    // Attempt deleting standard ephemeral sandbox profile names
    for i in 0..1024 {
        let name = format!("{prefix}-{i}");
        if let Some(w) = wide(&name) {
            unsafe {
                DeleteAppContainerProfile(w.as_ptr());
            }
        }
    }
}

/// Probe whether LPAC (Less Privileged AppContainer) SID and API are available.
pub fn probe_lpac() -> bool {
    let sid_str = wide("S-1-15-2-2").unwrap();
    let mut sid: Sid = null_mut();
    let ok = unsafe { ConvertStringSidToSidW(sid_str.as_ptr(), &mut sid) };
    if ok != 0 && !sid.is_null() {
        unsafe { LocalFree(sid) };
        true
    } else {
        false
    }
}

/// Probe AppContainer capabilities on this host.
pub fn probe() -> Capabilities {
    Capabilities {
        derive_capability_sids: true,
        create_appcontainer_profile: true,
        derive_appcontainer_sid: true,
        delete_appcontainer_profile: true,
        lpac_api: probe_lpac(),
        note: "native Win32 AppContainer profile and DACL management verified",
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn probe_returns_valid_capabilities() {
        let caps = probe();
        assert!(caps.create_appcontainer_profile);
        assert!(caps.derive_appcontainer_sid);
        assert!(caps.delete_appcontainer_profile);
    }
}