Subject: [PATCH 09/36] ipv4: Initialize flowi4_multipath_hash in data path

From: David Ahern <[email-masked]>
Date: Sun, 13 Sep 2020 12:43:39 -0600

[ Upstream commit 1869e226a7b3ef75b4f70ede2f1b7229f7157fa4 ]

flowi4_multipath_hash was added by the commit referenced below for
tunnels. Unfortunately, the patch did not initialize the new field
for several fast path lookups that do not initialize the entire flow
struct to 0. Fix those locations. Currently, flowi4_multipath_hash
is random garbage and affects the hash value computed by
fib_multipath_hash for multipath selection.

Fixes: 24ba14406c5c ("route: Add multipath_hash in flowi_common to make user-define hash")
Signed-off-by: David Ahern <[email-masked]>
Cc: wenxu <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
---
 include/net/flow.h      | 1 +
 net/core/filter.c       | 1 +
 net/ipv4/fib_frontend.c | 1 +
 net/ipv4/route.c        | 1 +
 4 files changed, 4 insertions(+)

diff --git a/include/net/flow.h b/include/net/flow.h
index a50fb77a0b27..d058e63fb59a 100644
--- a/include/net/flow.h
+++ b/include/net/flow.h
@@ -116,6 +116,7 @@ static inline void flowi4_init_output(struct flowi4 *fl4, int oif,
 	fl4->saddr = saddr;
 	fl4->fl4_dport = dport;
 	fl4->fl4_sport = sport;
+	fl4->flowi4_multipath_hash = 0;
 }
 
 /* Reset some input parameters after previous lookup */
diff --git a/net/core/filter.c b/net/core/filter.c
index 5c490d473df1..cf2a68513bfd 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -4650,6 +4650,7 @@ static int bpf_ipv4_fib_lookup(struct net *net, struct bpf_fib_lookup *params,
 	fl4.saddr = params->ipv4_src;
 	fl4.fl4_sport = params->sport;
 	fl4.fl4_dport = params->dport;
+	fl4.flowi4_multipath_hash = 0;
 
 	if (flags & BPF_FIB_LOOKUP_DIRECT) {
 		u32 tbid = l3mdev_fib_table_rcu(dev) ? : RT_TABLE_MAIN;
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 2b0521feadaa..0a8220d30c99 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -372,6 +372,7 @@ static int __fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
 	fl4.flowi4_tun_key.tun_id = 0;
 	fl4.flowi4_flags = 0;
 	fl4.flowi4_uid = sock_net_uid(net, NULL);
+	fl4.flowi4_multipath_hash = 0;
 
 	no_addr = idev->ifa_list == NULL;
 
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index b3a8d32f7d8d..be004d59f3de 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -2104,6 +2104,7 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr,
 	fl4.daddr = daddr;
 	fl4.saddr = saddr;
 	fl4.flowi4_uid = sock_net_uid(net, NULL);
+	fl4.flowi4_multipath_hash = 0;
 
 	if (fib4_rules_early_flow_dissect(net, skb, &fl4, &_flkeys)) {
 		flkeys = &_flkeys;
-- 
2.26.2