hv_func.h

   1 /* hash a key
   2  *--------------------------------------------------------------------------------------
   3  * The "hash seed" feature was added in Perl 5.8.1 to perturb the results
   4  * to avoid "algorithmic complexity attacks".
   5  *
   6  * If USE_HASH_SEED is defined, hash randomisation is done by default
   7  * (see also perl.c:perl_parse() and S_init_tls_and_interp() and util.c:get_hash_seed())
   8  */
   9 #ifndef PERL_SEEN_HV_FUNC_H /* compile once */
  10 #define PERL_SEEN_HV_FUNC_H
  11 #include "hv_macro.h"
  12
  13 #if !( 0 \
  14         || defined(PERL_HASH_FUNC_SIPHASH) \
  15         || defined(PERL_HASH_FUNC_SIPHASH13) \
  16         || defined(PERL_HASH_FUNC_STADTX) \
  17         || defined(PERL_HASH_FUNC_ZAPHOD32) \
  18     )
  19 #   ifdef CAN64BITHASH
  20 #       define PERL_HASH_FUNC_STADTX
  21 #   else
  22 #       define PERL_HASH_FUNC_ZAPHOD32
  23 #   endif
  24 #endif
  25
  26 #ifndef PERL_HASH_USE_SBOX32_ALSO
  27 #define PERL_HASH_USE_SBOX32_ALSO 1
  28 #endif
  29
  30 #ifndef SBOX32_MAX_LEN
  31 #define SBOX32_MAX_LEN 24
  32 #endif
  33
  34 /* this must be after the SBOX32_MAX_LEN define */
  35 #include "sbox32_hash.h"
  36
  37 #if defined(PERL_HASH_FUNC_SIPHASH)
  38 # define __PERL_HASH_FUNC "SIPHASH_2_4"
  39 # define __PERL_HASH_SEED_BYTES 16
  40 # define __PERL_HASH_STATE_BYTES 32
  41 # define __PERL_HASH_SEED_STATE(seed,state) S_perl_siphash_seed_state(seed,state)
  42 # define __PERL_HASH_WITH_STATE(state,str,len) S_perl_hash_siphash_2_4_with_state((state),(U8*)(str),(len))
  43 #elif defined(PERL_HASH_FUNC_SIPHASH13)
  44 # define __PERL_HASH_FUNC "SIPHASH_1_3"
  45 # define __PERL_HASH_SEED_BYTES 16
  46 # define __PERL_HASH_STATE_BYTES 32
  47 # define __PERL_HASH_SEED_STATE(seed,state) S_perl_siphash_seed_state(seed,state)
  48 # define __PERL_HASH_WITH_STATE(state,str,len) S_perl_hash_siphash_1_3_with_state((state),(U8*)(str),(len))
  49 #elif defined(PERL_HASH_FUNC_STADTX)
  50 # define __PERL_HASH_FUNC "STADTX"
  51 # define __PERL_HASH_SEED_BYTES 16
  52 # define __PERL_HASH_STATE_BYTES 32
  53 # define __PERL_HASH_SEED_STATE(seed,state) stadtx_seed_state(seed,state)
  54 # define __PERL_HASH_WITH_STATE(state,str,len) (U32)stadtx_hash_with_state((state),(U8*)(str),(len))
  55 # include "stadtx_hash.h"
  56 #elif defined(PERL_HASH_FUNC_ZAPHOD32)
  57 # define __PERL_HASH_FUNC "ZAPHOD32"
  58 # define __PERL_HASH_SEED_BYTES 12
  59 # define __PERL_HASH_STATE_BYTES 12
  60 # define __PERL_HASH_SEED_STATE(seed,state) zaphod32_seed_state(seed,state)
  61 # define __PERL_HASH_WITH_STATE(state,str,len) (U32)zaphod32_hash_with_state((state),(U8*)(str),(len))
  62 # include "zaphod32_hash.h"
  63 #endif
  64
  65 #ifndef __PERL_HASH_WITH_STATE
  66 #error "No hash function defined!"
  67 #endif
  68 #ifndef __PERL_HASH_SEED_BYTES
  69 #error "__PERL_HASH_SEED_BYTES not defined"
  70 #endif
  71 #ifndef __PERL_HASH_FUNC
  72 #error "__PERL_HASH_FUNC not defined"
  73 #endif
  74
  75
  76 #if PERL_HASH_USE_SBOX32_ALSO != 1
  77 # define _PERL_HASH_FUNC                        __PERL_HASH_FUNC
  78 # define _PERL_HASH_SEED_BYTES                  __PERL_HASH_SEED_BYTES
  79 # define _PERL_HASH_STATE_BYTES                 __PERL_HASH_STATE_BYTES
  80 # define _PERL_HASH_SEED_STATE(seed,state)      __PERL_HASH_SEED_STATE(seed,state)
  81 # define _PERL_HASH_WITH_STATE(state,str,len)   __PERL_HASH_WITH_STATE(state,str,len)
  82 #else
  83
  84 #define _PERL_HASH_FUNC         "SBOX32_WITH_" __PERL_HASH_FUNC
  85
  86 #define _PERL_HASH_SEED_BYTES   ( __PERL_HASH_SEED_BYTES + (int)( 3 * sizeof(U32) ) )
  87
  88 #define _PERL_HASH_STATE_BYTES  \
  89     ( __PERL_HASH_STATE_BYTES + ( ( 1 + ( 256 * SBOX32_MAX_LEN ) ) * sizeof(U32) ) )
  90
  91 #define _PERL_HASH_SEED_STATE(seed,state) STMT_START {                                      \
  92     __PERL_HASH_SEED_STATE(seed,state);                                                     \
  93     sbox32_seed_state96(seed + __PERL_HASH_SEED_BYTES, state + __PERL_HASH_STATE_BYTES);    \
  94 } STMT_END
  95
  96 #define _PERL_HASH_WITH_STATE(state,str,len)                                            \
  97     (LIKELY(len <= SBOX32_MAX_LEN)                                                      \
  98         ? sbox32_hash_with_state((state + __PERL_HASH_STATE_BYTES),(U8*)(str),(len))    \
  99         : __PERL_HASH_WITH_STATE((state),(str),(len)))
 100
 101 #endif
 102
 103 PERL_STATIC_INLINE
 104 U32 S_perl_hash_with_seed(const U8 * const seed, const U8 * const str, const STRLEN len)
 105 {
 106     U8 state[_PERL_HASH_STATE_BYTES];
 107     _PERL_HASH_SEED_STATE(seed,state);
 108     return _PERL_HASH_WITH_STATE(state,str,len);
 109 }
 110
 111 #define PERL_HASH_WITH_SEED(seed,hash,str,len) \
 112     (hash) = S_perl_hash_with_seed((const U8 *) seed, (const U8 *) str,len)
 113 #define PERL_HASH_WITH_STATE(state,hash,str,len) \
 114     (hash) = _PERL_HASH_WITH_STATE((state),(U8*)(str),(len))
 115 #define PERL_HASH_SEED_STATE(seed,state) _PERL_HASH_SEED_STATE(seed,state)
 116 #define PERL_HASH_SEED_BYTES _PERL_HASH_SEED_BYTES
 117 #define PERL_HASH_STATE_BYTES _PERL_HASH_STATE_BYTES
 118 #define PERL_HASH_FUNC        _PERL_HASH_FUNC
 119
 120 #ifdef PERL_USE_SINGLE_CHAR_HASH_CACHE
 121 #define PERL_HASH(state,str,len) \
 122     (hash) = ((len) < 2 ? ( (len) == 0 ? PL_hash_chars[256] : PL_hash_chars[(U8)(str)[0]] ) \
 123                        : _PERL_HASH_WITH_STATE(PL_hash_state,(U8*)(str),(len)))
 124 #else
 125 #define PERL_HASH(hash,str,len) \
 126     PERL_HASH_WITH_STATE(PL_hash_state,hash,(U8*)(str),(len))
 127 #endif
 128
 129 /* Setup the hash seed, either we do things dynamically at start up,
 130  * including reading from the environment, or we randomly setup the
 131  * seed. The seed will be passed into the PERL_HASH_SEED_STATE() function
 132  * defined for the configuration defined for this perl, which will then
 133  * initialze whatever state it might need later in hashing. */
 134
 135 #ifndef PERL_HASH_SEED
 136 #   if defined(USE_HASH_SEED)
 137 #       define PERL_HASH_SEED PL_hash_seed
 138 #   else
 139        /* this is a 512 bit seed, which should be more than enough for the
 140         * configuration of any of our hash functions (with or without sbox).
 141         * If you actually use a hard coded seed, you are strongly encouraged
 142         * to replace this with something else of the correct length
 143         * for the hash function you are using (24-32 bytes depending on build
 144         * options). Repeat, you are *STRONGLY* encouraged not to use the value
 145         * provided here.
 146         */
 147 #       define PERL_HASH_SEED \
 148            ((const U8 *)"A long string of pseudorandomly "  \
 149                         "chosen bytes for hashing in Perl")
 150 #   endif
 151 #endif
 152
 153 /* legacy - only mod_perl should be doing this.  */
 154 #ifdef PERL_HASH_INTERNAL_ACCESS
 155 #define PERL_HASH_INTERNAL(hash,str,len) PERL_HASH(hash,str,len)
 156 #endif
 157
 158 /* This is SipHash by Jean-Philippe Aumasson and Daniel J. Bernstein.
 159  * The authors claim it is relatively secure compared to the alternatives
 160  * and that performance wise it is a suitable hash for languages like Perl.
 161  * See:
 162  *
 163  * https://www.131002.net/siphash/
 164  *
 165  * This implementation seems to perform slightly slower than one-at-a-time for
 166  * short keys, but degrades slower for longer keys. Murmur Hash outperforms it
 167  * regardless of keys size.
 168  *
 169  * It is 64 bit only.
 170  */
 171
 172 #ifdef CAN64BITHASH
 173
 174 #define SIPROUND            \
 175   STMT_START {              \
 176     v0 += v1; v1=ROTL64(v1,13); v1 ^= v0; v0=ROTL64(v0,32); \
 177     v2 += v3; v3=ROTL64(v3,16); v3 ^= v2;     \
 178     v0 += v3; v3=ROTL64(v3,21); v3 ^= v0;     \
 179     v2 += v1; v1=ROTL64(v1,17); v1 ^= v2; v2=ROTL64(v2,32); \
 180   } STMT_END
 181
 182 #define SIPHASH_SEED_STATE(key,v0,v1,v2,v3) \
 183 do {                                    \
 184     v0 = v2 = U8TO64_LE(key + 0);       \
 185     v1 = v3 = U8TO64_LE(key + 8);       \
 186   /* "somepseudorandomlygeneratedbytes" */  \
 187     v0 ^= UINT64_C(0x736f6d6570736575);  \
 188     v1 ^= UINT64_C(0x646f72616e646f6d);      \
 189     v2 ^= UINT64_C(0x6c7967656e657261);      \
 190     v3 ^= UINT64_C(0x7465646279746573);      \
 191 } while (0)
 192
 193 PERL_STATIC_INLINE
 194 void S_perl_siphash_seed_state(const unsigned char * const seed_buf, unsigned char * state_buf) {
 195     U64 *v= (U64*) state_buf;
 196     SIPHASH_SEED_STATE(seed_buf, v[0],v[1],v[2],v[3]);
 197 }
 198
 199 #define PERL_SIPHASH_FNC(FNC,SIP_ROUNDS,SIP_FINAL_ROUNDS) \
 200 PERL_STATIC_INLINE U32 \
 201 FNC ## _with_state \
 202   (const unsigned char * const state, const unsigned char *in, const STRLEN inlen) \
 203 {                                           \
 204   const int left = inlen & 7;               \
 205   const U8 *end = in + inlen - left;        \
 206                                             \
 207   U64 b = ( ( U64 )(inlen) ) << 56;         \
 208   U64 m;                                    \
 209   U64 v0 = U8TO64_LE(state);                \
 210   U64 v1 = U8TO64_LE(state+8);              \
 211   U64 v2 = U8TO64_LE(state+16);             \
 212   U64 v3 = U8TO64_LE(state+24);             \
 213                                             \
 214   for ( ; in != end; in += 8 )              \
 215   {                                         \
 216     m = U8TO64_LE( in );                    \
 217     v3 ^= m;                                \
 218                                             \
 219     SIP_ROUNDS;                             \
 220                                             \
 221     v0 ^= m;                                \
 222   }                                         \
 223                                             \
 224   switch( left )                            \
 225   {                                         \
 226   case 7: b |= ( ( U64 )in[ 6] )  << 48;    \
 227   case 6: b |= ( ( U64 )in[ 5] )  << 40;    \
 228   case 5: b |= ( ( U64 )in[ 4] )  << 32;    \
 229   case 4: b |= ( ( U64 )in[ 3] )  << 24;    \
 230   case 3: b |= ( ( U64 )in[ 2] )  << 16;    \
 231   case 2: b |= ( ( U64 )in[ 1] )  <<  8;    \
 232   case 1: b |= ( ( U64 )in[ 0] ); break;    \
 233   case 0: break;                            \
 234   }                                         \
 235                                             \
 236   v3 ^= b;                                  \
 237                                             \
 238   SIP_ROUNDS;                               \
 239                                             \
 240   v0 ^= b;                                  \
 241                                             \
 242   v2 ^= 0xff;                               \
 243                                             \
 244   SIP_FINAL_ROUNDS                          \
 245                                             \
 246   b = v0 ^ v1 ^ v2  ^ v3;                   \
 247   return (U32)(b & U32_MAX);                \
 248 }                                           \
 249                                             \
 250 PERL_STATIC_INLINE U32                      \
 251 FNC (const unsigned char * const seed, const unsigned char *in, const STRLEN inlen) \
 252 {                                                                   \
 253     U64 state[4];                                                   \
 254     SIPHASH_SEED_STATE(seed,state[0],state[1],state[2],state[3]);   \
 255     return FNC ## _with_state((U8*)state,in,inlen);                 \
 256 }
 257
 258
 259 PERL_SIPHASH_FNC(
 260     S_perl_hash_siphash_1_3
 261     ,SIPROUND;
 262     ,SIPROUND;SIPROUND;SIPROUND;
 263 )
 264
 265 PERL_SIPHASH_FNC(
 266     S_perl_hash_siphash_2_4
 267     ,SIPROUND;SIPROUND;
 268     ,SIPROUND;SIPROUND;SIPROUND;SIPROUND;
 269 )
 270 #endif /* defined(CAN64BITHASH) */
 271
 272
 273 #endif /*compile once*/
 274
 275 /*
 276  * ex: set ts=8 sts=4 sw=4 et:
 277  */