diff options
| author | Eric Dumazet <edumazet@google.com> | 2021-08-25 16:17:28 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2021-08-26 10:20:34 +0100 |
| commit | 4785305c05b25a242e5314cc821f54ade4c18810 (patch) | |
| tree | 97d15607963a33938c42b4bb5361aab12b34b38b | |
| parent | 92ea47fe09b531642e5b791d74645a6f08b23725 (diff) | |
ipv6: use siphash in rt6_exception_hash()
A group of security researchers brought to our attention
the weakness of hash function used in rt6_exception_hash()
Lets use siphash instead of Jenkins Hash, to considerably
reduce security risks.
Following patch deals with IPv4.
Fixes: 35732d01fe31 ("ipv6: introduce a hash table to store dst cache")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Keyu Man <kman001@ucr.edu>
Cc: Wei Wang <weiwan@google.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Acked-by: Wei Wang <weiwan@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/ipv6/route.c | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/net/ipv6/route.c b/net/ipv6/route.c index b6ddf23d3833..c5e8ecb96426 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -41,6 +41,7 @@ #include <linux/nsproxy.h> #include <linux/slab.h> #include <linux/jhash.h> +#include <linux/siphash.h> #include <net/net_namespace.h> #include <net/snmp.h> #include <net/ipv6.h> @@ -1484,17 +1485,24 @@ static void rt6_exception_remove_oldest(struct rt6_exception_bucket *bucket) static u32 rt6_exception_hash(const struct in6_addr *dst, const struct in6_addr *src) { - static u32 seed __read_mostly; - u32 val; + static siphash_key_t rt6_exception_key __read_mostly; + struct { + struct in6_addr dst; + struct in6_addr src; + } __aligned(SIPHASH_ALIGNMENT) combined = { + .dst = *dst, + }; + u64 val; - net_get_random_once(&seed, sizeof(seed)); - val = jhash2((const u32 *)dst, sizeof(*dst)/sizeof(u32), seed); + net_get_random_once(&rt6_exception_key, sizeof(rt6_exception_key)); #ifdef CONFIG_IPV6_SUBTREES if (src) - val = jhash2((const u32 *)src, sizeof(*src)/sizeof(u32), val); + combined.src = *src; #endif - return hash_32(val, FIB6_EXCEPTION_BUCKET_SIZE_SHIFT); + val = siphash(&combined, sizeof(combined), &rt6_exception_key); + + return hash_64(val, FIB6_EXCEPTION_BUCKET_SIZE_SHIFT); } /* Helper function to find the cached rt in the hash table |