From ca6e94702cfbe29b279cf18f39a0fe492fae6f83 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Thu, 28 Sep 2023 11:20:53 +1000 Subject: siphash: Make siphash functions consistently return 64-bit results Some of the siphas_*b() functions return 64-bit results, others 32-bit results, with no obvious pattern. siphash_32b() also appears to do this incorrectly - taking the 64-bit hash value and simply returning it truncated, rather than folding the two halves together. Since SipHash proper is defined to give a 64-bit hash, make all of them return 64-bit results. In the one caller which needs a 32-bit value, tcp_seq_init() do the fold down to 32-bits ourselves. Signed-off-by: David Gibson Signed-off-by: Stefano Brivio --- siphash.c | 17 +++++++---------- siphash.h | 6 +++--- tcp.c | 7 ++++--- 3 files changed, 14 insertions(+), 16 deletions(-) diff --git a/siphash.c b/siphash.c index e266e15..20009fe 100644 --- a/siphash.c +++ b/siphash.c @@ -61,7 +61,6 @@ uint64_t v[4] = { 0x736f6d6570736575ULL, 0x646f72616e646f6dULL, \ 0x6c7967656e657261ULL, 0x7465646279746573ULL }; \ uint64_t b = (uint64_t)(len) << 56; \ - uint32_t ret; \ int __i; \ \ do { \ @@ -93,8 +92,6 @@ v[2] ^= 0xff; \ SIPROUND(4); \ b = (v[0] ^ v[1]) ^ (v[2] ^ v[3]); \ - ret = (uint32_t)(b >> 32) ^ (uint32_t)b; \ - (void)ret; \ } while (0) /** @@ -132,12 +129,12 @@ uint64_t siphash_8b(const uint8_t *in, const uint64_t *k) * @in: Input data (two addresses, two ports) * @k: Hash function key, 128 bits * - * Return: 32 bits obtained by XORing the two halves of the 64-bit hash output + * Return: the 64-bit hash output */ /* NOLINTNEXTLINE(clang-diagnostic-unknown-attributes) */ __attribute__((optimize("-fno-strict-aliasing"))) /* See siphash_8b() */ /* cppcheck-suppress unusedFunction */ -uint32_t siphash_12b(const uint8_t *in, const uint64_t *k) +uint64_t siphash_12b(const uint8_t *in, const uint64_t *k) { uint32_t *in32 = (uint32_t *)in; uint64_t combined; @@ -151,7 +148,7 @@ uint32_t siphash_12b(const uint8_t *in, const uint64_t *k) b |= *(in32 + 2); POSTAMBLE; - return ret; + return b; } /** @@ -194,7 +191,7 @@ uint64_t siphash_20b(const uint8_t *in, const uint64_t *k) /* NOLINTNEXTLINE(clang-diagnostic-unknown-attributes) */ __attribute__((optimize("-fno-strict-aliasing"))) /* See siphash_8b() */ /* cppcheck-suppress unusedFunction */ -uint32_t siphash_32b(const uint8_t *in, const uint64_t *k) +uint64_t siphash_32b(const uint8_t *in, const uint64_t *k) { uint64_t *in64 = (uint64_t *)in; int i; @@ -217,11 +214,11 @@ uint32_t siphash_32b(const uint8_t *in, const uint64_t *k) * @in: Input data (two addresses, two ports) * @k: Hash function key, 128 bits * - * Return: 32 bits obtained by XORing the two halves of the 64-bit hash output + * Return: the 64-bit hash output */ /* NOLINTNEXTLINE(clang-diagnostic-unknown-attributes) */ __attribute__((optimize("-fno-strict-aliasing"))) /* See siphash_8b() */ -uint32_t siphash_36b(const uint8_t *in, const uint64_t *k) +uint64_t siphash_36b(const uint8_t *in, const uint64_t *k) { uint32_t *in32 = (uint32_t *)in; int i; @@ -239,5 +236,5 @@ uint32_t siphash_36b(const uint8_t *in, const uint64_t *k) b |= *in32; POSTAMBLE; - return ret; + return b; } diff --git a/siphash.h b/siphash.h index 5b0d0c3..de04c56 100644 --- a/siphash.h +++ b/siphash.h @@ -7,9 +7,9 @@ #define SIPHASH_H uint64_t siphash_8b(const uint8_t *in, const uint64_t *k); -uint32_t siphash_12b(const uint8_t *in, const uint64_t *k); +uint64_t siphash_12b(const uint8_t *in, const uint64_t *k); uint64_t siphash_20b(const uint8_t *in, const uint64_t *k); -uint32_t siphash_32b(const uint8_t *in, const uint64_t *k); -uint32_t siphash_36b(const uint8_t *in, const uint64_t *k); +uint64_t siphash_32b(const uint8_t *in, const uint64_t *k); +uint64_t siphash_36b(const uint8_t *in, const uint64_t *k); #endif /* SIPHASH_H */ diff --git a/tcp.c b/tcp.c index 2933123..19baba5 100644 --- a/tcp.c +++ b/tcp.c @@ -1826,7 +1826,8 @@ static void tcp_seq_init(const struct ctx *c, struct tcp_tap_conn *conn, .srcport = conn->fport, .dstport = conn->eport, }; - uint32_t ns, seq = 0; + uint64_t hash; + uint32_t ns; if (CONN_V4(conn)) inany_from_af(&aany, AF_INET, &c->ip4.addr); @@ -1834,12 +1835,12 @@ static void tcp_seq_init(const struct ctx *c, struct tcp_tap_conn *conn, inany_from_af(&aany, AF_INET6, &c->ip6.addr); in.dst = aany; - seq = siphash_36b((uint8_t *)&in, c->tcp.hash_secret); + hash = siphash_36b((uint8_t *)&in, c->tcp.hash_secret); /* 32ns ticks, overflows 32 bits every 137s */ ns = (now->tv_sec * 1000000000 + now->tv_nsec) >> 5; - conn->seq_to_tap = seq + ns; + conn->seq_to_tap = ((uint32_t)(hash >> 32) ^ (uint32_t)hash) + ns; } /** -- cgit v1.2.3