]>
Commit | Line | Data |
---|---|---|
532ac7d7 XL |
1 | use crate::mem; |
2 | use crate::slice; | |
9e0c209e | 3 | |
abe05a73 XL |
4 | pub fn hashmap_random_keys() -> (u64, u64) { |
5 | let mut v = (0, 0); | |
6 | unsafe { | |
60c5eb7d | 7 | let view = slice::from_raw_parts_mut(&mut v as *mut _ as *mut u8, mem::size_of_val(&v)); |
abe05a73 XL |
8 | imp::fill_bytes(view); |
9 | } | |
e74abb32 | 10 | v |
9e0c209e SL |
11 | } |
12 | ||
60c5eb7d XL |
13 | #[cfg(all( |
14 | unix, | |
15 | not(target_os = "ios"), | |
16 | not(target_os = "openbsd"), | |
17 | not(target_os = "freebsd"), | |
18 | not(target_os = "netbsd"), | |
19 | not(target_os = "fuchsia"), | |
20 | not(target_os = "redox") | |
21 | ))] | |
1a4d82fc | 22 | mod imp { |
532ac7d7 XL |
23 | use crate::fs::File; |
24 | use crate::io::Read; | |
1a4d82fc | 25 | |
abe05a73 | 26 | #[cfg(any(target_os = "linux", target_os = "android"))] |
1a4d82fc | 27 | fn getrandom(buf: &mut [u8]) -> libc::c_long { |
1a4d82fc | 28 | unsafe { |
abe05a73 | 29 | libc::syscall(libc::SYS_getrandom, buf.as_mut_ptr(), buf.len(), libc::GRND_NONBLOCK) |
1a4d82fc JJ |
30 | } |
31 | } | |
32 | ||
abe05a73 | 33 | #[cfg(not(any(target_os = "linux", target_os = "android")))] |
60c5eb7d XL |
34 | fn getrandom_fill_bytes(_buf: &mut [u8]) -> bool { |
35 | false | |
36 | } | |
1a4d82fc | 37 | |
b7449926 | 38 | #[cfg(any(target_os = "linux", target_os = "android"))] |
abe05a73 | 39 | fn getrandom_fill_bytes(v: &mut [u8]) -> bool { |
532ac7d7 XL |
40 | use crate::sync::atomic::{AtomicBool, Ordering}; |
41 | use crate::sys::os::errno; | |
b7449926 XL |
42 | |
43 | static GETRANDOM_UNAVAILABLE: AtomicBool = AtomicBool::new(false); | |
44 | if GETRANDOM_UNAVAILABLE.load(Ordering::Relaxed) { | |
45 | return false; | |
46 | } | |
47 | ||
1a4d82fc | 48 | let mut read = 0; |
9cc50fc6 | 49 | while read < v.len() { |
85aaf69f | 50 | let result = getrandom(&mut v[read..]); |
1a4d82fc JJ |
51 | if result == -1 { |
52 | let err = errno() as libc::c_int; | |
53 | if err == libc::EINTR { | |
54 | continue; | |
48663c56 XL |
55 | } else if err == libc::ENOSYS || err == libc::EPERM { |
56 | // Fall back to reading /dev/urandom if `getrandom` is not | |
57 | // supported on the current kernel. | |
58 | // | |
59 | // Also fall back in case it is disabled by something like | |
60 | // seccomp or inside of virtual machines. | |
b7449926 XL |
61 | GETRANDOM_UNAVAILABLE.store(true, Ordering::Relaxed); |
62 | return false; | |
a7813a04 | 63 | } else if err == libc::EAGAIN { |
b7449926 | 64 | return false; |
1a4d82fc JJ |
65 | } else { |
66 | panic!("unexpected getrandom error: {}", err); | |
67 | } | |
68 | } else { | |
85aaf69f | 69 | read += result as usize; |
1a4d82fc JJ |
70 | } |
71 | } | |
b7449926 | 72 | true |
1a4d82fc JJ |
73 | } |
74 | ||
abe05a73 XL |
75 | pub fn fill_bytes(v: &mut [u8]) { |
76 | // getrandom_fill_bytes here can fail if getrandom() returns EAGAIN, | |
77 | // meaning it would have blocked because the non-blocking pool (urandom) | |
b7449926 | 78 | // has not initialized in the kernel yet due to a lack of entropy. The |
abe05a73 XL |
79 | // fallback we do here is to avoid blocking applications which could |
80 | // depend on this call without ever knowing they do and don't have a | |
b7449926 XL |
81 | // work around. The PRNG of /dev/urandom will still be used but over a |
82 | // possibly predictable entropy pool. | |
83 | if getrandom_fill_bytes(v) { | |
84 | return; | |
1a4d82fc | 85 | } |
1a4d82fc | 86 | |
b7449926 XL |
87 | // getrandom failed because it is permanently or temporarily (because |
88 | // of missing entropy) unavailable. Open /dev/urandom, read from it, | |
89 | // and close it again. | |
90 | let mut file = File::open("/dev/urandom").expect("failed to open /dev/urandom"); | |
91 | file.read_exact(v).expect("failed to read /dev/urandom") | |
1a4d82fc JJ |
92 | } |
93 | } | |
94 | ||
9cc50fc6 | 95 | #[cfg(target_os = "openbsd")] |
1a4d82fc | 96 | mod imp { |
532ac7d7 | 97 | use crate::sys::os::errno; |
9cc50fc6 | 98 | |
abe05a73 XL |
99 | pub fn fill_bytes(v: &mut [u8]) { |
100 | // getentropy(2) permits a maximum buffer size of 256 bytes | |
101 | for s in v.chunks_mut(256) { | |
60c5eb7d | 102 | let ret = unsafe { libc::getentropy(s.as_mut_ptr() as *mut libc::c_void, s.len()) }; |
abe05a73 XL |
103 | if ret == -1 { |
104 | panic!("unexpected getentropy error: {}", errno()); | |
9cc50fc6 SL |
105 | } |
106 | } | |
107 | } | |
108 | } | |
1a4d82fc | 109 | |
48663c56 XL |
110 | // On iOS and MacOS `SecRandomCopyBytes` calls `CCRandomCopyBytes` with |
111 | // `kCCRandomDefault`. `CCRandomCopyBytes` manages a CSPRNG which is seeded | |
112 | // from `/dev/random` and which runs on its own thread accessed via GCD. | |
113 | // This seems needlessly heavyweight for the purposes of generating two u64s | |
114 | // once per thread in `hashmap_random_keys`. Therefore `SecRandomCopyBytes` is | |
115 | // only used on iOS where direct access to `/dev/urandom` is blocked by the | |
116 | // sandbox. | |
9cc50fc6 SL |
117 | #[cfg(target_os = "ios")] |
118 | mod imp { | |
532ac7d7 XL |
119 | use crate::io; |
120 | use crate::ptr; | |
e9174d1e | 121 | use libc::{c_int, size_t}; |
1a4d82fc | 122 | |
e9174d1e | 123 | enum SecRandom {} |
1a4d82fc | 124 | |
1a4d82fc | 125 | #[allow(non_upper_case_globals)] |
e9174d1e | 126 | const kSecRandomDefault: *const SecRandom = ptr::null(); |
1a4d82fc | 127 | |
60c5eb7d XL |
128 | extern "C" { |
129 | fn SecRandomCopyBytes(rnd: *const SecRandom, count: size_t, bytes: *mut u8) -> c_int; | |
1a4d82fc JJ |
130 | } |
131 | ||
abe05a73 | 132 | pub fn fill_bytes(v: &mut [u8]) { |
60c5eb7d | 133 | let ret = unsafe { SecRandomCopyBytes(kSecRandomDefault, v.len(), v.as_mut_ptr()) }; |
abe05a73 | 134 | if ret == -1 { |
60c5eb7d | 135 | panic!("couldn't generate random bytes: {}", io::Error::last_os_error()); |
1a4d82fc JJ |
136 | } |
137 | } | |
138 | } | |
9e0c209e | 139 | |
60c5eb7d | 140 | #[cfg(any(target_os = "freebsd", target_os = "netbsd"))] |
9e0c209e | 141 | mod imp { |
532ac7d7 | 142 | use crate::ptr; |
9e0c209e | 143 | |
abe05a73 XL |
144 | pub fn fill_bytes(v: &mut [u8]) { |
145 | let mib = [libc::CTL_KERN, libc::KERN_ARND]; | |
146 | // kern.arandom permits a maximum buffer size of 256 bytes | |
147 | for s in v.chunks_mut(256) { | |
148 | let mut s_len = s.len(); | |
149 | let ret = unsafe { | |
60c5eb7d XL |
150 | libc::sysctl( |
151 | mib.as_ptr(), | |
152 | mib.len() as libc::c_uint, | |
153 | s.as_mut_ptr() as *mut _, | |
154 | &mut s_len, | |
155 | ptr::null(), | |
156 | 0, | |
157 | ) | |
abe05a73 XL |
158 | }; |
159 | if ret == -1 || s_len != s.len() { | |
60c5eb7d XL |
160 | panic!( |
161 | "kern.arandom sysctl failed! (returned {}, s.len() {}, oldlenp {})", | |
162 | ret, | |
163 | s.len(), | |
164 | s_len | |
165 | ); | |
9e0c209e SL |
166 | } |
167 | } | |
168 | } | |
169 | } | |
c30ab7b3 SL |
170 | |
171 | #[cfg(target_os = "fuchsia")] | |
172 | mod imp { | |
ea8adc8c | 173 | #[link(name = "zircon")] |
60c5eb7d | 174 | extern "C" { |
8faf50e0 | 175 | fn zx_cprng_draw(buffer: *mut u8, len: usize); |
c30ab7b3 SL |
176 | } |
177 | ||
abe05a73 | 178 | pub fn fill_bytes(v: &mut [u8]) { |
8faf50e0 | 179 | unsafe { zx_cprng_draw(v.as_mut_ptr(), v.len()) } |
c30ab7b3 SL |
180 | } |
181 | } | |
416331ca XL |
182 | |
183 | #[cfg(target_os = "redox")] | |
184 | mod imp { | |
185 | use crate::fs::File; | |
186 | use crate::io::Read; | |
187 | ||
188 | pub fn fill_bytes(v: &mut [u8]) { | |
189 | // Open rand:, read from it, and close it again. | |
190 | let mut file = File::open("rand:").expect("failed to open rand:"); | |
191 | file.read_exact(v).expect("failed to read rand:") | |
192 | } | |
193 | } |