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| author | Eric Dumazet <edumazet@google.com> | 2024-10-08 12:13:07 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2024-10-09 19:33:57 -0700 |
| commit | 4daf4dc275f1aa3b9629334c4185d62b7bdff1c4 (patch) | |
| tree | f3edd15150405eeb07221cc3e9b9682bee9a64aa /net/ipv6 | |
| parent | 4a0ec2aa0704c8271fde33a0f7bb92d09c066c17 (diff) | |
| download | lwn-4daf4dc275f1aa3b9629334c4185d62b7bdff1c4.tar.gz lwn-4daf4dc275f1aa3b9629334c4185d62b7bdff1c4.zip | |
ipv6: switch inet6_acaddr_hash() to less predictable hash
commit 2384d02520ff ("net/ipv6: Add anycast addresses to a global hashtable")
added inet6_acaddr_hash(), using ipv6_addr_hash() and net_hash_mix()
to get hash spreading for typical users.
However ipv6_addr_hash() is highly predictable and a malicious user
could abuse a specific hash bucket.
Switch to __ipv6_addr_jhash(). We could use a dedicated
secret, or reuse net_hash_mix() as I did in this patch.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20241008121307.800040-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/ipv6')
| -rw-r--r-- | net/ipv6/anycast.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/net/ipv6/anycast.c b/net/ipv6/anycast.c index 0627c4c18d1a..562cace50ca9 100644 --- a/net/ipv6/anycast.c +++ b/net/ipv6/anycast.c @@ -49,9 +49,10 @@ static DEFINE_SPINLOCK(acaddr_hash_lock); static int ipv6_dev_ac_dec(struct net_device *dev, const struct in6_addr *addr); -static u32 inet6_acaddr_hash(struct net *net, const struct in6_addr *addr) +static u32 inet6_acaddr_hash(const struct net *net, + const struct in6_addr *addr) { - u32 val = ipv6_addr_hash(addr) ^ net_hash_mix(net); + u32 val = __ipv6_addr_jhash(addr, net_hash_mix(net)); return hash_32(val, IN6_ADDR_HSIZE_SHIFT); } |