From 51c1639884b409a98a4581a7b661ef65b94e9d86 Mon Sep 17 00:00:00 2001 From: Etienne Dechamps Date: Sat, 20 Jul 2013 14:50:28 +0100 Subject: [PATCH] Fix hash_function(). The hashing function that tinc uses is currently broken as it only looks at the first 4 bytes of data. This leads to interesting bugs, like the node UDP address cache being subtly broken because two addresses with the same protocol and port (but not the same IP address) will override each other. This is because the first four bytes of sockaddr_in contains the IP protocol and port, while the IP address itself is contained in the four remaining bytes that are never used when the hash is computed. --- src/hash.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/hash.c b/src/hash.c index 36b510c..a40e799 100644 --- a/src/hash.c +++ b/src/hash.c @@ -29,7 +29,7 @@ static uint32_t hash_function(const void *p, size_t len) { uint32_t hash = 0; while(true) { for(int i = len > 4 ? 4 : len; --i;) - hash += q[i] << (8 * i); + hash += q[len - i] << (8 * i); hash *= 0x9e370001UL; // Golden ratio prime. if(len <= 4) break; -- 2.25.1