Auto merge of #33940 - seanmonstar:siphash-1-3, r=alexcrichton

hashmap: use siphash-1-3 as default hasher

Also exposes `SipHash13` and `SipHash24` in `core::hash::sip`, for those that want to differentiate.

For motivation, see this quote from the original issue:

> we proposed SipHash-2-4 as a (strong) PRF/MAC, and so far no attack whatsoever has been found,
although many competent people tried to break it. However, fewer rounds may be sufficient and I would
be very surprised if SipHash-1-3 introduced weaknesses for hash tables.

This keeps a type alias of `SipHasher` to `SipHash24`, and since the internal default hasher of HashMap is specified as "not specified", changing it should not be a breaking change.

Closes #29754

2 files changed, 111 insertions, 21 deletions

diff --git a/src/libcoretest/hash/sip.rs b/src/libcoretest/hash/sip.rs
index 9b6cedd25b7..a5e6005545b 100644
--- a/src/libcoretest/hash/sip.rs
+++ b/src/libcoretest/hash/sip.rs
@@ -10,7 +10,7 @@
 use test::{Bencher, black_box};
 
 use core::hash::{Hash, Hasher};
-use core::hash::SipHasher;
+use core::hash::{SipHasher, SipHasher13, SipHasher24};
 
 // Hash just the bytes of the slice, without length prefix
 struct Bytes<'a>(&'a [u8]);
@@ -45,27 +45,117 @@ macro_rules! u8to64_le {
     });
 }
 
-fn hash<T: Hash>(x: &T) -> u64 {
-    let mut st = SipHasher::new();
+fn hash_with<H: Hasher, T: Hash>(mut st: H, x: &T) -> u64 {
     x.hash(&mut st);
     st.finish()
 }
 
-fn hash_with_keys<T: Hash>(k1: u64, k2: u64, x: &T) -> u64 {
-    let mut st = SipHasher::new_with_keys(k1, k2);
-    x.hash(&mut st);
-    st.finish()
+fn hash<T: Hash>(x: &T) -> u64 {
+    hash_with(SipHasher::new(), x)
 }
 
-fn hash_bytes(x: &[u8]) -> u64 {
-    let mut s = SipHasher::default();
+fn hash_bytes<H: Hasher>(mut s: H, x: &[u8]) -> u64 {
     Hasher::write(&mut s, x);
     s.finish()
 }
 
 #[test]
 #[allow(unused_must_use)]
-fn test_siphash() {
+fn test_siphash_1_3() {
+    let vecs : [[u8; 8]; 64] = [
+        [ 0xdc, 0xc4, 0x0f, 0x05, 0x58, 0x01, 0xac, 0xab ],
+        [ 0x93, 0xca, 0x57, 0x7d, 0xf3, 0x9b, 0xf4, 0xc9 ],
+        [ 0x4d, 0xd4, 0xc7, 0x4d, 0x02, 0x9b, 0xcb, 0x82 ],
+        [ 0xfb, 0xf7, 0xdd, 0xe7, 0xb8, 0x0a, 0xf8, 0x8b ],
+        [ 0x28, 0x83, 0xd3, 0x88, 0x60, 0x57, 0x75, 0xcf ],
+        [ 0x67, 0x3b, 0x53, 0x49, 0x2f, 0xd5, 0xf9, 0xde ],
+        [ 0xa7, 0x22, 0x9f, 0xc5, 0x50, 0x2b, 0x0d, 0xc5 ],
+        [ 0x40, 0x11, 0xb1, 0x9b, 0x98, 0x7d, 0x92, 0xd3 ],
+        [ 0x8e, 0x9a, 0x29, 0x8d, 0x11, 0x95, 0x90, 0x36 ],
+        [ 0xe4, 0x3d, 0x06, 0x6c, 0xb3, 0x8e, 0xa4, 0x25 ],
+        [ 0x7f, 0x09, 0xff, 0x92, 0xee, 0x85, 0xde, 0x79 ],
+        [ 0x52, 0xc3, 0x4d, 0xf9, 0xc1, 0x18, 0xc1, 0x70 ],
+        [ 0xa2, 0xd9, 0xb4, 0x57, 0xb1, 0x84, 0xa3, 0x78 ],
+        [ 0xa7, 0xff, 0x29, 0x12, 0x0c, 0x76, 0x6f, 0x30 ],
+        [ 0x34, 0x5d, 0xf9, 0xc0, 0x11, 0xa1, 0x5a, 0x60 ],
+        [ 0x56, 0x99, 0x51, 0x2a, 0x6d, 0xd8, 0x20, 0xd3 ],
+        [ 0x66, 0x8b, 0x90, 0x7d, 0x1a, 0xdd, 0x4f, 0xcc ],
+        [ 0x0c, 0xd8, 0xdb, 0x63, 0x90, 0x68, 0xf2, 0x9c ],
+        [ 0x3e, 0xe6, 0x73, 0xb4, 0x9c, 0x38, 0xfc, 0x8f ],
+        [ 0x1c, 0x7d, 0x29, 0x8d, 0xe5, 0x9d, 0x1f, 0xf2 ],
+        [ 0x40, 0xe0, 0xcc, 0xa6, 0x46, 0x2f, 0xdc, 0xc0 ],
+        [ 0x44, 0xf8, 0x45, 0x2b, 0xfe, 0xab, 0x92, 0xb9 ],
+        [ 0x2e, 0x87, 0x20, 0xa3, 0x9b, 0x7b, 0xfe, 0x7f ],
+        [ 0x23, 0xc1, 0xe6, 0xda, 0x7f, 0x0e, 0x5a, 0x52 ],
+        [ 0x8c, 0x9c, 0x34, 0x67, 0xb2, 0xae, 0x64, 0xf4 ],
+        [ 0x79, 0x09, 0x5b, 0x70, 0x28, 0x59, 0xcd, 0x45 ],
+        [ 0xa5, 0x13, 0x99, 0xca, 0xe3, 0x35, 0x3e, 0x3a ],
+        [ 0x35, 0x3b, 0xde, 0x4a, 0x4e, 0xc7, 0x1d, 0xa9 ],
+        [ 0x0d, 0xd0, 0x6c, 0xef, 0x02, 0xed, 0x0b, 0xfb ],
+        [ 0xf4, 0xe1, 0xb1, 0x4a, 0xb4, 0x3c, 0xd9, 0x88 ],
+        [ 0x63, 0xe6, 0xc5, 0x43, 0xd6, 0x11, 0x0f, 0x54 ],
+        [ 0xbc, 0xd1, 0x21, 0x8c, 0x1f, 0xdd, 0x70, 0x23 ],
+        [ 0x0d, 0xb6, 0xa7, 0x16, 0x6c, 0x7b, 0x15, 0x81 ],
+        [ 0xbf, 0xf9, 0x8f, 0x7a, 0xe5, 0xb9, 0x54, 0x4d ],
+        [ 0x3e, 0x75, 0x2a, 0x1f, 0x78, 0x12, 0x9f, 0x75 ],
+        [ 0x91, 0x6b, 0x18, 0xbf, 0xbe, 0xa3, 0xa1, 0xce ],
+        [ 0x06, 0x62, 0xa2, 0xad, 0xd3, 0x08, 0xf5, 0x2c ],
+        [ 0x57, 0x30, 0xc3, 0xa3, 0x2d, 0x1c, 0x10, 0xb6 ],
+        [ 0xa1, 0x36, 0x3a, 0xae, 0x96, 0x74, 0xf4, 0xb3 ],
+        [ 0x92, 0x83, 0x10, 0x7b, 0x54, 0x57, 0x6b, 0x62 ],
+        [ 0x31, 0x15, 0xe4, 0x99, 0x32, 0x36, 0xd2, 0xc1 ],
+        [ 0x44, 0xd9, 0x1a, 0x3f, 0x92, 0xc1, 0x7c, 0x66 ],
+        [ 0x25, 0x88, 0x13, 0xc8, 0xfe, 0x4f, 0x70, 0x65 ],
+        [ 0xa6, 0x49, 0x89, 0xc2, 0xd1, 0x80, 0xf2, 0x24 ],
+        [ 0x6b, 0x87, 0xf8, 0xfa, 0xed, 0x1c, 0xca, 0xc2 ],
+        [ 0x96, 0x21, 0x04, 0x9f, 0xfc, 0x4b, 0x16, 0xc2 ],
+        [ 0x23, 0xd6, 0xb1, 0x68, 0x93, 0x9c, 0x6e, 0xa1 ],
+        [ 0xfd, 0x14, 0x51, 0x8b, 0x9c, 0x16, 0xfb, 0x49 ],
+        [ 0x46, 0x4c, 0x07, 0xdf, 0xf8, 0x43, 0x31, 0x9f ],
+        [ 0xb3, 0x86, 0xcc, 0x12, 0x24, 0xaf, 0xfd, 0xc6 ],
+        [ 0x8f, 0x09, 0x52, 0x0a, 0xd1, 0x49, 0xaf, 0x7e ],
+        [ 0x9a, 0x2f, 0x29, 0x9d, 0x55, 0x13, 0xf3, 0x1c ],
+        [ 0x12, 0x1f, 0xf4, 0xa2, 0xdd, 0x30, 0x4a, 0xc4 ],
+        [ 0xd0, 0x1e, 0xa7, 0x43, 0x89, 0xe9, 0xfa, 0x36 ],
+        [ 0xe6, 0xbc, 0xf0, 0x73, 0x4c, 0xb3, 0x8f, 0x31 ],
+        [ 0x80, 0xe9, 0xa7, 0x70, 0x36, 0xbf, 0x7a, 0xa2 ],
+        [ 0x75, 0x6d, 0x3c, 0x24, 0xdb, 0xc0, 0xbc, 0xb4 ],
+        [ 0x13, 0x15, 0xb7, 0xfd, 0x52, 0xd8, 0xf8, 0x23 ],
+        [ 0x08, 0x8a, 0x7d, 0xa6, 0x4d, 0x5f, 0x03, 0x8f ],
+        [ 0x48, 0xf1, 0xe8, 0xb7, 0xe5, 0xd0, 0x9c, 0xd8 ],
+        [ 0xee, 0x44, 0xa6, 0xf7, 0xbc, 0xe6, 0xf4, 0xf6 ],
+        [ 0xf2, 0x37, 0x18, 0x0f, 0xd8, 0x9a, 0xc5, 0xae ],
+        [ 0xe0, 0x94, 0x66, 0x4b, 0x15, 0xf6, 0xb2, 0xc3 ],
+        [ 0xa8, 0xb3, 0xbb, 0xb7, 0x62, 0x90, 0x19, 0x9d ]
+    ];
+
+    let k0 = 0x_07_06_05_04_03_02_01_00;
+    let k1 = 0x_0f_0e_0d_0c_0b_0a_09_08;
+    let mut buf = Vec::new();
+    let mut t = 0;
+    let mut state_inc = SipHasher13::new_with_keys(k0, k1);
+
+    while t < 64 {
+        let vec = u8to64_le!(vecs[t], 0);
+        let out = hash_with(SipHasher13::new_with_keys(k0, k1), &Bytes(&buf));
+        assert_eq!(vec, out);
+
+        let full = hash_with(SipHasher13::new_with_keys(k0, k1), &Bytes(&buf));
+        let i = state_inc.finish();
+
+        assert_eq!(full, i);
+        assert_eq!(full, vec);
+
+        buf.push(t as u8);
+        Hasher::write(&mut state_inc, &[t as u8]);
+
+        t += 1;
+    }
+}
+
+#[test]
+#[allow(unused_must_use)]
+fn test_siphash_2_4() {
     let vecs : [[u8; 8]; 64] = [
         [ 0x31, 0x0e, 0x0e, 0xdd, 0x47, 0xdb, 0x6f, 0x72, ],
         [ 0xfd, 0x67, 0xdc, 0x93, 0xc5, 0x39, 0xf8, 0x74, ],
@@ -137,14 +227,14 @@ fn test_siphash() {
     let k1 = 0x_0f_0e_0d_0c_0b_0a_09_08;
     let mut buf = Vec::new();
     let mut t = 0;
-    let mut state_inc = SipHasher::new_with_keys(k0, k1);
+    let mut state_inc = SipHasher24::new_with_keys(k0, k1);
 
     while t < 64 {
         let vec = u8to64_le!(vecs[t], 0);
-        let out = hash_with_keys(k0, k1, &Bytes(&buf));
+        let out = hash_with(SipHasher24::new_with_keys(k0, k1), &Bytes(&buf));
         assert_eq!(vec, out);
 
-        let full = hash_with_keys(k0, k1, &Bytes(&buf));
+        let full = hash_with(SipHasher24::new_with_keys(k0, k1), &Bytes(&buf));
         let i = state_inc.finish();
 
         assert_eq!(full, i);
@@ -156,7 +246,6 @@ fn test_siphash() {
         t += 1;
     }
 }
-
 #[test] #[cfg(target_arch = "arm")]
 fn test_hash_usize() {
     let val = 0xdeadbeef_deadbeef_u64;
@@ -289,7 +378,7 @@ fn bench_u32_keyed(b: &mut Bencher) {
     let k1 = black_box(0x1);
     let k2 = black_box(0x2);
     b.iter(|| {
-        hash_with_keys(k1, k2, &u)
+        hash_with(SipHasher::new_with_keys(k1, k2), &u)
     });
     b.bytes = 8;
 }
@@ -308,7 +397,7 @@ fn bench_u64(b: &mut Bencher) {
 fn bench_bytes_4(b: &mut Bencher) {
     let data = black_box([b' '; 4]);
     b.iter(|| {
-        hash_bytes(&data)
+        hash_bytes(SipHasher::default(), &data)
     });
     b.bytes = 4;
 }
@@ -317,7 +406,7 @@ fn bench_bytes_4(b: &mut Bencher) {
 fn bench_bytes_7(b: &mut Bencher) {
     let data = black_box([b' '; 7]);
     b.iter(|| {
-        hash_bytes(&data)
+        hash_bytes(SipHasher::default(), &data)
     });
     b.bytes = 7;
 }
@@ -326,7 +415,7 @@ fn bench_bytes_7(b: &mut Bencher) {
 fn bench_bytes_8(b: &mut Bencher) {
     let data = black_box([b' '; 8]);
     b.iter(|| {
-        hash_bytes(&data)
+        hash_bytes(SipHasher::default(), &data)
     });
     b.bytes = 8;
 }
@@ -335,7 +424,7 @@ fn bench_bytes_8(b: &mut Bencher) {
 fn bench_bytes_a_16(b: &mut Bencher) {
     let data = black_box([b' '; 16]);
     b.iter(|| {
-        hash_bytes(&data)
+        hash_bytes(SipHasher::default(), &data)
     });
     b.bytes = 16;
 }
@@ -344,7 +433,7 @@ fn bench_bytes_a_16(b: &mut Bencher) {
 fn bench_bytes_b_32(b: &mut Bencher) {
     let data = black_box([b' '; 32]);
     b.iter(|| {
-        hash_bytes(&data)
+        hash_bytes(SipHasher::default(), &data)
     });
     b.bytes = 32;
 }
@@ -353,7 +442,7 @@ fn bench_bytes_b_32(b: &mut Bencher) {
 fn bench_bytes_c_128(b: &mut Bencher) {
     let data = black_box([b' '; 128]);
     b.iter(|| {
-        hash_bytes(&data)
+        hash_bytes(SipHasher::default(), &data)
     });
     b.bytes = 128;
 }
diff --git a/src/libcoretest/lib.rs b/src/libcoretest/lib.rs
index 88d73df937f..0c4385725ed 100644
--- a/src/libcoretest/lib.rs
+++ b/src/libcoretest/lib.rs
@@ -26,6 +26,7 @@
 #![feature(nonzero)]
 #![feature(rand)]
 #![feature(raw)]
+#![feature(sip_hash_13)]
 #![feature(slice_patterns)]
 #![feature(step_by)]
 #![feature(test)]