Merge branch 'kalfar' into 'master'
Fix randd TODOs for CSPRNG and allowing entropy write See merge request redox-os/randd!10
This commit is contained in:
Jeremy Soller
Generated
+87
-54
@@ -6,56 +6,96 @@ version = "0.7.0"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
|
||||
[[package]]
|
||||
name = "fuchsia-cprng"
|
||||
version = "0.1.1"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
|
||||
[[package]]
|
||||
name = "libc"
|
||||
version = "0.2.65"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
|
||||
[[package]]
|
||||
name = "rand"
|
||||
version = "0.3.23"
|
||||
name = "block-buffer"
|
||||
version = "0.7.3"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
dependencies = [
|
||||
"libc 0.2.65 (registry+https://github.com/rust-lang/crates.io-index)",
|
||||
"rand 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
|
||||
"block-padding 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
|
||||
"byte-tools 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
|
||||
"byteorder 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
|
||||
"generic-array 0.12.3 (registry+https://github.com/rust-lang/crates.io-index)",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
name = "rand"
|
||||
version = "0.4.6"
|
||||
name = "block-padding"
|
||||
version = "0.1.5"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
dependencies = [
|
||||
"fuchsia-cprng 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
|
||||
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|
||||
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|
||||
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|
||||
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|
||||
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|
||||
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|
||||
|
||||
[[package]]
|
||||
name = "rand_core"
|
||||
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|
||||
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|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
|
||||
[[package]]
|
||||
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|
||||
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|
||||
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|
||||
|
||||
[[package]]
|
||||
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|
||||
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|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
dependencies = [
|
||||
"rand_core 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
|
||||
"ppv-lite86 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
name = "digest"
|
||||
version = "0.8.1"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
dependencies = [
|
||||
"generic-array 0.12.3 (registry+https://github.com/rust-lang/crates.io-index)",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
name = "fake-simd"
|
||||
version = "0.1.2"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
|
||||
[[package]]
|
||||
name = "generic-array"
|
||||
version = "0.12.3"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
dependencies = [
|
||||
"typenum 1.11.2 (registry+https://github.com/rust-lang/crates.io-index)",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
name = "opaque-debug"
|
||||
version = "0.2.3"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
|
||||
[[package]]
|
||||
name = "ppv-lite86"
|
||||
version = "0.2.6"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
|
||||
[[package]]
|
||||
name = "rand_chacha"
|
||||
version = "0.2.1"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
dependencies = [
|
||||
"c2-chacha 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
|
||||
"rand_core 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
name = "rand_core"
|
||||
version = "0.4.2"
|
||||
version = "0.5.1"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
|
||||
[[package]]
|
||||
name = "randd"
|
||||
version = "0.1.0"
|
||||
dependencies = [
|
||||
"rand 0.3.23 (registry+https://github.com/rust-lang/crates.io-index)",
|
||||
"rand_chacha 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
|
||||
"rand_core 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
|
||||
"raw-cpuid 2.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
|
||||
"redox_syscall 0.1.56 (registry+https://github.com/rust-lang/crates.io-index)",
|
||||
"sha2 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
@@ -66,49 +106,42 @@ dependencies = [
|
||||
"bitflags 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
name = "rdrand"
|
||||
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|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
dependencies = [
|
||||
"rand_core 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
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|
||||
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|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
|
||||
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|
||||
name = "winapi"
|
||||
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|
||||
name = "sha2"
|
||||
version = "0.8.1"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
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|
||||
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|
||||
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|
||||
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|
||||
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|
||||
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|
||||
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|
||||
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|
||||
|
||||
[[package]]
|
||||
name = "winapi-i686-pc-windows-gnu"
|
||||
version = "0.4.0"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
|
||||
[[package]]
|
||||
name = "winapi-x86_64-pc-windows-gnu"
|
||||
version = "0.4.0"
|
||||
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|
||||
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|
||||
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||||
[metadata]
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||||
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|
||||
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|
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||||
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||||
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|
||||
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|
||||
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|
||||
|
||||
+3
-1
@@ -3,8 +3,10 @@ name = "randd"
|
||||
version = "0.1.0"
|
||||
|
||||
[dependencies]
|
||||
rand = "0.3"
|
||||
rand_chacha = "0.2"
|
||||
rand_core = "0.5"
|
||||
redox_syscall = "0.1"
|
||||
sha2 = "0.8"
|
||||
|
||||
[target.'cfg(target_arch = "x86_64")'.dependencies]
|
||||
raw-cpuid = "2.0"
|
||||
|
||||
+365
-66
@@ -2,56 +2,371 @@
|
||||
|
||||
extern crate syscall;
|
||||
|
||||
extern crate rand_chacha;
|
||||
extern crate rand_core;
|
||||
#[cfg(target_arch = "x86_64")]
|
||||
extern crate raw_cpuid;
|
||||
extern crate rand;
|
||||
extern crate sha2;
|
||||
|
||||
use std::fs::File;
|
||||
use std::io::{Read, Write};
|
||||
use std::os::unix::io::AsRawFd;
|
||||
|
||||
use rand::chacha::ChaChaRng;
|
||||
use rand::Rng;
|
||||
use rand_chacha::ChaCha20Rng;
|
||||
use rand_core::RngCore;
|
||||
|
||||
pub const MODE_PERM: u16 = 0x0FFF;
|
||||
pub const MODE_EXEC: u16 = 0o1;
|
||||
pub const MODE_WRITE: u16 = 0o2;
|
||||
pub const MODE_READ: u16 = 0o4;
|
||||
|
||||
#[cfg(target_arch = "x86_64")]
|
||||
use raw_cpuid::CpuId;
|
||||
|
||||
use syscall::{Error, Result, SchemeMut, EINVAL, MODE_CHR};
|
||||
use syscall::data::{Packet, Stat};
|
||||
use syscall::flag::EVENT_READ;
|
||||
use syscall::{
|
||||
Error, Result, SchemeMut, EBADF, EBADFD, EEXIST, EINVAL, ENOENT, EPERM, MODE_CHR, O_CLOEXEC,
|
||||
O_CREAT, O_EXCL, O_RDONLY, O_RDWR, O_STAT, O_WRONLY,
|
||||
};
|
||||
|
||||
//TODO: Use a CSPRNG, allow write of entropy
|
||||
// Create an RNG Seed to create initial seed from the rdrand intel instruction
|
||||
use rand_core::SeedableRng;
|
||||
use sha2::{Digest, Sha256};
|
||||
use std::collections::BTreeMap;
|
||||
use std::num::Wrapping;
|
||||
|
||||
// This Daemon implements a Cryptographically Secure Random Number Generator
|
||||
// that does not block on read - i.e. it is equivalent to linux /dev/urandom
|
||||
// We do not implement blocking reads as per linux /dev/random for the reasons outlined
|
||||
// here: https://www.2uo.de/myths-about-urandom/
|
||||
|
||||
// Default file access mode for PRNG
|
||||
const DEFAULT_PRNG_MODE: u16 = 0o644;
|
||||
// Rand crate recommends at least 256 bits of entropy to seed the RNG
|
||||
const SEED_BYTES: usize = 32;
|
||||
|
||||
/// Create a true random seed for the RNG from the Intel x64 rdrand instruction if present.
|
||||
/// Will seed with a zero (insecure) if rdrand not present.
|
||||
fn create_rdrand_seed() -> [u8; SEED_BYTES] {
|
||||
let mut rng = [0; SEED_BYTES];
|
||||
let mut have_seeded = false;
|
||||
#[cfg(target_arch = "x86_64")]
|
||||
{
|
||||
if CpuId::new().get_feature_info().unwrap().has_rdrand() {
|
||||
for i in 0..SEED_BYTES / 8 {
|
||||
// We get 8 bytes at a time from rdrand instruction
|
||||
let rand: u64;
|
||||
unsafe {
|
||||
asm!("rdrand rax"
|
||||
: "={rax}"(rand)
|
||||
:
|
||||
:
|
||||
: "intel", "volatile");
|
||||
}
|
||||
|
||||
rng[i * 8..(i * 8 + 8)].copy_from_slice(&rand.to_le_bytes());
|
||||
}
|
||||
have_seeded = true;
|
||||
}
|
||||
} // TODO integrate alternative entropy sources
|
||||
if !have_seeded {
|
||||
println!("randd: Seeding failed, no entropy source. Random numbers on this platform are NOT SECURE");
|
||||
}
|
||||
rng
|
||||
}
|
||||
|
||||
/// Contains information about an open file
|
||||
struct OpenFileInfo {
|
||||
o_flags: usize,
|
||||
/// Flags used when opening file.
|
||||
uid: u32,
|
||||
gid: u32,
|
||||
file_stat: Stat,
|
||||
}
|
||||
|
||||
impl OpenFileInfo {
|
||||
/// Tests if the current user has enough permissions to view the file, op is the operation,
|
||||
/// like read and write, these modes are MODE_EXEC, MODE_READ, and MODE_WRITE
|
||||
/// Copied from redoxfs
|
||||
fn permission(&self, op: u16) -> bool {
|
||||
let mut perm = self.file_stat.st_mode & 0o7;
|
||||
if self.uid == self.file_stat.st_uid {
|
||||
// If self.mode is 101100110, >> 6 would be 000000101
|
||||
// 0o7 is octal for 111, or, when expanded to 9 digits is 000000111
|
||||
perm |= (self.file_stat.st_mode >> 6) & 0o7;
|
||||
// Since we erased the GID and OTHER bits when >>6'ing, |= will keep those bits in place.
|
||||
}
|
||||
if self.gid == self.file_stat.st_gid || self.file_stat.st_gid == 0 {
|
||||
perm |= (self.file_stat.st_mode >> 3) & 0o7;
|
||||
}
|
||||
if self.uid == 0 {
|
||||
//set the `other` bits to 111
|
||||
perm |= 0o7;
|
||||
}
|
||||
perm & op == op
|
||||
}
|
||||
fn o_flag_set(&self, f: usize) -> bool {
|
||||
return (f & self.o_flags) == f;
|
||||
}
|
||||
}
|
||||
|
||||
/// Struct to represent the rand scheme.
|
||||
struct RandScheme {
|
||||
socket: File,
|
||||
prng: ChaChaRng
|
||||
prng: ChaCha20Rng,
|
||||
// ChaCha20 is a Cryptographically Secure PRNG
|
||||
// https://docs.rs/rand/0.5.0/rand/prng/chacha/struct.ChaChaRng.html
|
||||
// Allows 2^64 streams of random numbers, which we will equate with file numbers
|
||||
prng_stat: Stat,
|
||||
open_descriptors: BTreeMap<usize, OpenFileInfo>, // Cannot use HashMap as the implementation
|
||||
// calls the system RNG (us) for entropy to protect against HashDOS attacks.
|
||||
// Trying to create a HashMap causes a system crash.
|
||||
// <file number, information about the open file>
|
||||
next_fd: Wrapping<usize>,
|
||||
}
|
||||
|
||||
impl RandScheme {
|
||||
/// Create new rand scheme from a message socket
|
||||
fn new(socket: File) -> RandScheme {
|
||||
RandScheme {
|
||||
socket,
|
||||
prng: ChaCha20Rng::from_seed(create_rdrand_seed()),
|
||||
prng_stat: Stat {
|
||||
st_mode: MODE_CHR | DEFAULT_PRNG_MODE,
|
||||
st_gid: 0,
|
||||
st_uid: 0,
|
||||
..Default::default()
|
||||
},
|
||||
open_descriptors: BTreeMap::new(),
|
||||
next_fd: Wrapping(0),
|
||||
}
|
||||
}
|
||||
|
||||
/// Gets the open file info for a file descriptor if it is open - error otherwise.
|
||||
fn get_fd(&self, fd: usize) -> Result<&OpenFileInfo> {
|
||||
// Check we've got a valid file descriptor
|
||||
let file_info = match self.open_descriptors.get(&fd) {
|
||||
Some(m) => m,
|
||||
None => return Err(Error::new(EBADF)),
|
||||
};
|
||||
Ok(file_info)
|
||||
}
|
||||
/// Checks to see if the op (MODE_READ, MODE_WRITE) can be performed on the open file
|
||||
/// descriptor - Will return the open file info if successful, and error if the file
|
||||
/// descriptor is invalid, or the permission is denied.
|
||||
fn can_perform_op_on_fd(&self, fd: usize, op: u16) -> Result<&OpenFileInfo> {
|
||||
let file_info = self.get_fd(fd)?;
|
||||
if !file_info.permission(op) {
|
||||
return Err(Error::new(EPERM));
|
||||
}
|
||||
Ok(file_info)
|
||||
}
|
||||
/// Reseed the CSPRNG with the supplied entropy.
|
||||
/// TODO add this to an entropy pool and give a limited estimate to the amount of entropy
|
||||
/// TODO consider having trusted and untrusted entropy URIs, with different permissions.
|
||||
fn reseed_prng(&mut self, entropy: &[u8]) {
|
||||
// Need to fill a fixed size array for the from_seed, so we'll do 256 bit
|
||||
// array and has the entropy into it.
|
||||
let mut digest = Sha256::new();
|
||||
digest.input(entropy);
|
||||
let hash = digest.result();
|
||||
let mut entropy_array: [u8; SEED_BYTES] = [0; SEED_BYTES];
|
||||
entropy_array.copy_from_slice(hash.as_slice());
|
||||
self.prng = ChaCha20Rng::from_seed(entropy_array);
|
||||
}
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn test_scheme_perms() {
|
||||
let mut scheme = RandScheme::new(File::open(".").unwrap());
|
||||
scheme.prng_stat.st_mode = MODE_CHR | 0o200;
|
||||
scheme.prng_stat.st_uid = 1;
|
||||
scheme.prng_stat.st_gid = 1;
|
||||
assert!(scheme.open("/".as_bytes(), O_RDWR, 1, 1).is_err());
|
||||
assert!(scheme.open("/".as_bytes(), O_RDONLY, 1, 1).is_err());
|
||||
|
||||
scheme.prng_stat.st_mode = MODE_CHR | 0o400;
|
||||
let mut fd = scheme.open("".as_bytes(), O_RDONLY, 1, 1).unwrap();
|
||||
assert!(scheme.can_perform_op_on_fd(fd, MODE_READ).is_ok());
|
||||
assert!(scheme.can_perform_op_on_fd(fd, MODE_WRITE).is_err());
|
||||
assert!(scheme.close(fd).is_ok());
|
||||
|
||||
assert!(scheme.open("".as_bytes(), O_WRONLY, 1, 1).is_err());
|
||||
assert!(scheme.open("".as_bytes(), O_RDWR, 1, 1).is_err());
|
||||
|
||||
scheme.prng_stat.st_mode = MODE_CHR | 0o600;
|
||||
fd = scheme.open("".as_bytes(), O_RDWR, 1, 1).unwrap();
|
||||
assert!(scheme.can_perform_op_on_fd(fd, MODE_READ).is_ok());
|
||||
assert!(scheme.can_perform_op_on_fd(fd, MODE_WRITE).is_ok());
|
||||
assert!(scheme.close(fd).is_ok());
|
||||
|
||||
fd = scheme.open("".as_bytes(), O_STAT, 2, 2).unwrap();
|
||||
assert!(scheme.can_perform_op_on_fd(fd, MODE_READ).is_err());
|
||||
assert!(scheme.can_perform_op_on_fd(fd, MODE_WRITE).is_err());
|
||||
assert!(scheme.close(fd).is_ok());
|
||||
fd = scheme
|
||||
.open("".as_bytes(), O_STAT | O_CLOEXEC, 2, 2)
|
||||
.unwrap();
|
||||
assert!(scheme.can_perform_op_on_fd(fd, MODE_READ).is_err());
|
||||
assert!(scheme.can_perform_op_on_fd(fd, MODE_WRITE).is_err());
|
||||
assert!(scheme.close(fd).is_ok());
|
||||
|
||||
// Try another user in group (no group perms)
|
||||
fd = scheme
|
||||
.open("".as_bytes(), O_STAT | O_CLOEXEC, 2, 1)
|
||||
.unwrap();
|
||||
assert!(scheme.can_perform_op_on_fd(fd, MODE_READ).is_err());
|
||||
assert!(scheme.can_perform_op_on_fd(fd, MODE_WRITE).is_err());
|
||||
assert!(scheme.close(fd).is_ok());
|
||||
scheme.prng_stat.st_mode = MODE_CHR | 0o660;
|
||||
fd = scheme
|
||||
.open("".as_bytes(), O_STAT | O_CLOEXEC, 2, 1)
|
||||
.unwrap();
|
||||
assert!(scheme.can_perform_op_on_fd(fd, MODE_READ).is_ok());
|
||||
assert!(scheme.can_perform_op_on_fd(fd, MODE_WRITE).is_ok());
|
||||
assert!(scheme.close(fd).is_ok());
|
||||
|
||||
// Check root can do anything
|
||||
scheme.prng_stat.st_mode = MODE_CHR | 0o000;
|
||||
fd = scheme
|
||||
.open("".as_bytes(), O_STAT | O_CLOEXEC, 0, 0)
|
||||
.unwrap();
|
||||
assert!(scheme.can_perform_op_on_fd(fd, MODE_READ).is_ok());
|
||||
assert!(scheme.can_perform_op_on_fd(fd, MODE_WRITE).is_ok());
|
||||
assert!(scheme.close(fd).is_ok());
|
||||
|
||||
// Check the rand:/urandom URL (Equivalent to rand:/)
|
||||
scheme.prng_stat.st_mode = MODE_CHR | 0o660;
|
||||
fd = scheme
|
||||
.open("/urandom".as_bytes(), O_STAT | O_CLOEXEC, 2, 1)
|
||||
.unwrap();
|
||||
assert!(scheme.can_perform_op_on_fd(fd, MODE_READ).is_ok());
|
||||
assert!(scheme.can_perform_op_on_fd(fd, MODE_WRITE).is_ok());
|
||||
assert!(scheme.close(fd).is_ok());
|
||||
}
|
||||
|
||||
impl SchemeMut for RandScheme {
|
||||
fn open(&mut self, _path: &[u8], _flags: usize, _uid: u32, _gid: u32) -> Result<usize> {
|
||||
Ok(0)
|
||||
fn open(&mut self, path: &[u8], flags: usize, uid: u32, gid: u32) -> Result<usize> {
|
||||
// We are only allowing
|
||||
// reads/writes from rand:/ and rand:/urandom - the root directory on its own is passed as an empty slice
|
||||
if path != "".as_bytes() && path != "/urandom".as_bytes() {
|
||||
return Err(Error::new(ENOENT));
|
||||
}
|
||||
if flags & (O_CREAT | O_EXCL) == O_CREAT | O_EXCL {
|
||||
return Err(Error::new(EEXIST));
|
||||
}
|
||||
|
||||
let fd = self.next_fd;
|
||||
let open_file_info = OpenFileInfo {
|
||||
o_flags: flags,
|
||||
file_stat: self.prng_stat,
|
||||
uid,
|
||||
gid,
|
||||
};
|
||||
|
||||
if (open_file_info.o_flag_set(O_RDONLY) || open_file_info.o_flag_set(O_RDWR))
|
||||
&& !open_file_info.permission(MODE_READ)
|
||||
{
|
||||
return Err(Error::new(EPERM));
|
||||
}
|
||||
if (open_file_info.o_flag_set(O_WRONLY) || open_file_info.o_flag_set(O_RDWR))
|
||||
&& !open_file_info.permission(MODE_WRITE)
|
||||
{
|
||||
return Err(Error::new(EPERM));
|
||||
}
|
||||
self.open_descriptors.insert(fd.0, open_file_info);
|
||||
// Get the next file descriptor
|
||||
self.next_fd += Wrapping(1);
|
||||
// If we've looped round there's a small chance that the file descriptor still exists, so loop till we get one that doesn't
|
||||
loop {
|
||||
if !self.open_descriptors.contains_key(&self.next_fd.0) {
|
||||
break;
|
||||
} else {
|
||||
self.next_fd += Wrapping(1);
|
||||
}
|
||||
}
|
||||
Ok(fd.0)
|
||||
}
|
||||
|
||||
fn chmod(&mut self, path: &[u8], mode: u16, uid: u32, gid: u32) -> Result<usize> {
|
||||
// Defer to fchmod
|
||||
let fd = self.open(path, O_WRONLY, uid, gid)?;
|
||||
self.fchmod(fd, mode)
|
||||
}
|
||||
|
||||
fn dup(&mut self, file: usize, buf: &[u8]) -> Result<usize> {
|
||||
if ! buf.is_empty() {
|
||||
if !buf.is_empty() {
|
||||
return Err(Error::new(EINVAL));
|
||||
}
|
||||
|
||||
Ok(file)
|
||||
}
|
||||
/* Resource operations */
|
||||
fn read(&mut self, file: usize, buf: &mut [u8]) -> Result<usize> {
|
||||
// Check fd and permissions
|
||||
self.can_perform_op_on_fd(file, MODE_READ)?;
|
||||
|
||||
fn read(&mut self, _file: usize, buf: &mut [u8]) -> Result<usize> {
|
||||
let mut i = 0;
|
||||
for chunk in buf.chunks_mut(8) {
|
||||
let mut rand = self.prng.next_u64();
|
||||
for b in chunk.iter_mut() {
|
||||
*b = rand as u8;
|
||||
rand = rand >> 8;
|
||||
i += 1;
|
||||
}
|
||||
}
|
||||
Ok(i)
|
||||
// Setting the stream will ensure that if two clients are reading concurrently, they won't get the same numbers
|
||||
self.prng.set_stream(file as u64); // Should probably find a way to re-instate the counter for this stream, but
|
||||
// not doing so won't make the output any less 'random'
|
||||
self.prng.fill_bytes(buf);
|
||||
|
||||
Ok(buf.len())
|
||||
}
|
||||
|
||||
fn write(&mut self, file: usize, buf: &[u8]) -> Result<usize> {
|
||||
// Check fd and permissions
|
||||
self.can_perform_op_on_fd(file, MODE_WRITE)?;
|
||||
|
||||
// TODO - when we support other entropy sources, just add this to an entropy pool
|
||||
// TODO - consider having trusted and untrusted entropy writing paths
|
||||
// We have a healthy mistrust of the entropy we're being given, so we won't seed just with
|
||||
// that as the resulting numbers would be predictable based on this input
|
||||
// we'll take 512 bits (arbitrary) from the current PRNG, and seed with that
|
||||
// and the supplied data.
|
||||
|
||||
let mut rng_buf: [u8; SEED_BYTES] = [0; SEED_BYTES];
|
||||
self.prng.fill_bytes(&mut rng_buf);
|
||||
let mut rng_vec = Vec::new();
|
||||
rng_vec.extend(&rng_buf);
|
||||
rng_vec.extend(buf);
|
||||
self.reseed_prng(&rng_vec);
|
||||
Ok(buf.len())
|
||||
}
|
||||
|
||||
fn fchmod(&mut self, file: usize, mode: u16) -> Result<usize> {
|
||||
// Check fd and permissions
|
||||
let file_info = self.get_fd(file)?;
|
||||
// only root and owner can chmod
|
||||
if file_info.uid != file_info.file_stat.st_uid && file_info.uid != 0 {
|
||||
return Err(Error::new(EPERM));
|
||||
}
|
||||
|
||||
self.prng_stat.st_mode = MODE_CHR | mode;
|
||||
Ok(0)
|
||||
}
|
||||
|
||||
fn fchown(&mut self, file: usize, uid: u32, gid: u32) -> Result<usize> {
|
||||
// Check fd and permissions
|
||||
let file_info = self.get_fd(file)?;
|
||||
// only root and owner can chmod
|
||||
if file_info.uid != file_info.file_stat.st_uid && file_info.uid != 0 {
|
||||
return Err(Error::new(EPERM));
|
||||
}
|
||||
|
||||
self.prng_stat.st_uid = uid;
|
||||
self.prng_stat.st_gid = gid;
|
||||
Ok(0)
|
||||
}
|
||||
|
||||
fn fcntl(&mut self, _id: usize, _cmd: usize, _arg: usize) -> Result<usize> {
|
||||
// Just ignore this.
|
||||
Ok(0)
|
||||
}
|
||||
|
||||
fn fevent(&mut self, _id: usize, _flags: usize) -> Result<usize> {
|
||||
Ok(EVENT_READ)
|
||||
}
|
||||
fn fpath(&mut self, _file: usize, buf: &mut [u8]) -> Result<usize> {
|
||||
let mut i = 0;
|
||||
let scheme_path = b"rand";
|
||||
@@ -62,68 +377,52 @@ impl SchemeMut for RandScheme {
|
||||
Ok(i)
|
||||
}
|
||||
|
||||
fn fstat(&mut self, _id: usize, stat: &mut Stat) -> Result<usize> {
|
||||
*stat = Stat {
|
||||
st_mode: MODE_CHR | 0o666,
|
||||
..Default::default()
|
||||
};
|
||||
fn fstat(&mut self, file: usize, stat: &mut Stat) -> Result<usize> {
|
||||
// Check fd and permissions
|
||||
self.can_perform_op_on_fd(file, MODE_READ)?;
|
||||
|
||||
*stat = self.prng_stat.clone();
|
||||
|
||||
Ok(0)
|
||||
}
|
||||
|
||||
fn fevent(&mut self, _id: usize, _flags: usize) -> Result<usize> {
|
||||
Ok(EVENT_READ)
|
||||
}
|
||||
|
||||
fn fcntl(&mut self, _id: usize, _cmd: usize, _arg: usize) -> Result<usize> {
|
||||
Ok(0)
|
||||
}
|
||||
|
||||
fn close(&mut self, _file: usize) -> Result<usize> {
|
||||
Ok(0)
|
||||
fn close(&mut self, file: usize) -> Result<usize> {
|
||||
// just remove the file descriptor from the open descriptors
|
||||
match self.open_descriptors.remove(&file) {
|
||||
Some(_) => Ok(0),
|
||||
None => Err(Error::new(EBADFD)),
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
fn main(){
|
||||
let mut has_rdrand = false;
|
||||
|
||||
#[cfg(target_arch = "x86_64")]
|
||||
{
|
||||
has_rdrand = CpuId::new().get_feature_info().unwrap().has_rdrand();
|
||||
}
|
||||
|
||||
fn main() {
|
||||
// Daemonize
|
||||
if unsafe { syscall::clone(0).unwrap() } == 0 {
|
||||
let socket = File::create(":rand").expect("rand: failed to create rand scheme");
|
||||
|
||||
let mut rng = ChaChaRng::new_unseeded();
|
||||
|
||||
if has_rdrand {
|
||||
println!("rand: seeding with rdrand");
|
||||
let rand: u64;
|
||||
unsafe {
|
||||
asm!("rdrand rax"
|
||||
: "={rax}"(rand)
|
||||
:
|
||||
:
|
||||
: "intel", "volatile");
|
||||
}
|
||||
rng.set_counter(0, rand);
|
||||
} else {
|
||||
println!("rand: unseeded");
|
||||
}
|
||||
|
||||
let mut scheme = RandScheme{socket, prng: rng};
|
||||
let mut scheme = RandScheme::new(socket);
|
||||
|
||||
syscall::setrens(0, 0).expect("randd: failed to enter null namespace");
|
||||
|
||||
loop {
|
||||
let mut packet = Packet::default();
|
||||
if scheme.socket.read(&mut packet).expect("rand: failed to read events from rand scheme") == 0 {
|
||||
break;
|
||||
match scheme.socket.read(&mut packet) {
|
||||
Ok(s) => {
|
||||
if s == 0 {
|
||||
break;
|
||||
}
|
||||
scheme.handle(&mut packet);
|
||||
match scheme.socket.write(&packet) {
|
||||
Err(e) => println!("Error writing packet {}", e),
|
||||
_ => {}
|
||||
}
|
||||
}
|
||||
Err(e) => println!("Error reading packet {}", e),
|
||||
}
|
||||
scheme.handle(&mut packet);
|
||||
scheme.socket.write(&packet).expect("rand: failed to write responses to rand scheme");
|
||||
scheme
|
||||
.socket
|
||||
.write(&packet)
|
||||
.expect("rand: failed to write responses to rand scheme");
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
Reference in New Issue
Block a user