Merge pull request #159 from GuildMasterInfinite/fix-crypt-windows
Use `RtlGenRandom` on Windows
diff --git a/src/os.rs b/src/os.rs
index 970cfd7..7f24119 100644
--- a/src/os.rs
+++ b/src/os.rs
@@ -21,8 +21,8 @@
/// `/dev/urandom`, or from `getrandom(2)` system call if available.
/// - OpenBSD: calls `getentropy(2)`
/// - FreeBSD: uses the `kern.arandom` `sysctl(2)` mib
-/// - Windows: calls `CryptGenRandom`, using the default cryptographic
-/// service provider with the `PROV_RSA_FULL` type.
+/// - Windows: calls `RtlGenRandom`, exported from `advapi32.dll` as
+/// `SystemFunction036`.
/// - iOS: calls SecRandomCopyBytes as /dev/(u)random is sandboxed.
/// - PNaCl: calls into the `nacl-irt-random-0.1` IRT interface.
///
@@ -383,53 +383,25 @@
#[cfg(windows)]
mod imp {
use std::io;
- use std::ptr;
use Rng;
use super::{next_u32, next_u64};
- type BOOL = i32;
- type LPCSTR = *const i8;
- type DWORD = u32;
- type HCRYPTPROV = usize;
- type BYTE = u8;
-
- const PROV_RSA_FULL: DWORD = 1;
- const CRYPT_SILENT: DWORD = 0x00000040;
- const CRYPT_VERIFYCONTEXT: DWORD = 0xF0000000;
+ type BOOLEAN = u8;
+ type ULONG = u32;
#[link(name = "advapi32")]
extern "system" {
- fn CryptAcquireContextA(phProv: *mut HCRYPTPROV,
- szContainer: LPCSTR,
- szProvider: LPCSTR,
- dwProvType: DWORD,
- dwFlags: DWORD) -> BOOL;
- fn CryptGenRandom(hProv: HCRYPTPROV,
- dwLen: DWORD,
- pbBuffer: *mut BYTE) -> BOOL;
- fn CryptReleaseContext(hProv: HCRYPTPROV, dwFlags: DWORD) -> BOOL;
+ // This function's real name is `RtlGenRandom`.
+ fn SystemFunction036(RandomBuffer: *mut u8, RandomBufferLength: ULONG) -> BOOLEAN;
}
#[derive(Debug)]
- pub struct OsRng {
- hcryptprov: HCRYPTPROV
- }
+ pub struct OsRng;
impl OsRng {
pub fn new() -> io::Result<OsRng> {
- let mut hcp = 0;
- let ret = unsafe {
- CryptAcquireContextA(&mut hcp, ptr::null(), ptr::null(),
- PROV_RSA_FULL,
- CRYPT_VERIFYCONTEXT | CRYPT_SILENT)
- };
-
- if ret == 0 {
- Err(io::Error::last_os_error())
- } else {
- Ok(OsRng { hcryptprov: hcp })
- }
+ Ok(OsRng)
}
}
@@ -441,12 +413,11 @@
next_u64(&mut |v| self.fill_bytes(v))
}
fn fill_bytes(&mut self, v: &mut [u8]) {
- // CryptGenRandom takes a DWORD (u32) for the length so we need to
+ // RtlGenRandom takes an ULONG (u32) for the length so we need to
// split up the buffer.
- for slice in v.chunks_mut(<DWORD>::max_value() as usize) {
+ for slice in v.chunks_mut(<ULONG>::max_value() as usize) {
let ret = unsafe {
- CryptGenRandom(self.hcryptprov, slice.len() as DWORD,
- slice.as_mut_ptr())
+ SystemFunction036(slice.as_mut_ptr(), slice.len() as ULONG)
};
if ret == 0 {
panic!("couldn't generate random bytes: {}",
@@ -455,18 +426,6 @@
}
}
}
-
- impl Drop for OsRng {
- fn drop(&mut self) {
- let ret = unsafe {
- CryptReleaseContext(self.hcryptprov, 0)
- };
- if ret == 0 {
- panic!("couldn't release context: {}",
- io::Error::last_os_error());
- }
- }
- }
}
#[cfg(target_os = "nacl")]
