diff options
| author | Eric Dumazet <edumazet@google.com> | 2021-08-26 02:17:28 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-09-03 11:09:24 +0300 |
| commit | dced8347a727528b388f04820f48166f1e651af6 (patch) | |
| tree | 9138785985ed4736fd072efaeef54f703b03d0e3 /net | |
| parent | f517335a61ff8037b18ba1b0a002c1f82926a934 (diff) | |
| download | linux-dced8347a727528b388f04820f48166f1e651af6.tar.xz | |
ipv6: use siphash in rt6_exception_hash()
[ Upstream commit 4785305c05b25a242e5314cc821f54ade4c18810 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to '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 62db3c98424b..bcf4fae83a9b 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> @@ -1482,17 +1483,24 @@ 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 |