diff options
| -rw-r--r-- | erts/emulator/beam/utils.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/erts/emulator/beam/utils.c b/erts/emulator/beam/utils.c index 4dc724605b..85647b8500 100644 --- a/erts/emulator/beam/utils.c +++ b/erts/emulator/beam/utils.c @@ -1678,17 +1678,22 @@ make_internal_hash(Eterm term) * the order in which keys and values are encountered. * We therefore calculate context independent hashes for all . * key-value pairs and then xor them together. + * + * We *do* need to use an initial seed for each pair, i.e. the + * hash value, so the hash value is reset for each pair with 'hash'. + * If we don't, no additional entropy is given to the system and the + * hash collision resolution in maps:from_list/1 would fail. */ ESTACK_PUSH(s, hash_xor_pairs); ESTACK_PUSH(s, hash); ESTACK_PUSH(s, HASH_MAP_TAIL); - hash = 0; - hash_xor_pairs = 0; for (i = size - 1; i >= 0; i--) { + ESTACK_PUSH(s, hash); /* initial seed for all pairs */ ESTACK_PUSH(s, HASH_MAP_PAIR); ESTACK_PUSH(s, vs[i]); ESTACK_PUSH(s, ks[i]); } + hash_xor_pairs = 0; goto pop_next; } case HAMT_SUBTAG_HEAD_ARRAY: @@ -1700,7 +1705,6 @@ make_internal_hash(Eterm term) ESTACK_PUSH(s, hash_xor_pairs); ESTACK_PUSH(s, hash); ESTACK_PUSH(s, HASH_MAP_TAIL); - hash = 0; hash_xor_pairs = 0; } switch (hdr & _HEADER_MAP_SUBTAG_MASK) { @@ -1717,6 +1721,7 @@ make_internal_hash(Eterm term) while (i) { if (is_list(*ptr)) { Eterm* cons = list_val(*ptr); + ESTACK_PUSH(s, hash); /* initial seed for all pairs */ ESTACK_PUSH(s, HASH_MAP_PAIR); ESTACK_PUSH(s, CDR(cons)); ESTACK_PUSH(s, CAR(cons)); @@ -1921,7 +1926,7 @@ make_internal_hash(Eterm term) } case HASH_MAP_PAIR: hash_xor_pairs ^= hash; - hash = 0; + hash = (Uint32) ESTACK_POP(s); /* initial seed for all pairs */ goto pop_next; case HASH_CDR: |