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siphash: Make siphash functions consistently return 64-bit results

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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 <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This commit is contained in:
David Gibson 2023-09-28 11:20:53 +10:00 committed by Stefano Brivio
parent c1d2a070f2
commit ca6e94702c
3 changed files with 14 additions and 16 deletions
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17
siphash.c
View file

@ -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;
}

6
siphash.h
View file

@ -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 */

7
tcp.c
View file

@ -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;
}
/**