From cb827db50a88aebec516151681adb6db10b688ee Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Thu, 6 Feb 2025 08:30:51 +0000
Subject: [PATCH] net: fib_rules: annotate data-races around rule->[io]ifindex
rule->iifindex and rule->oifindex can be read without holding RTNL.
Add READ_ONCE()/WRITE_ONCE() annotations where needed.
Fixes: 32affa5578f0 ("fib: rules: no longer hold RTNL in fib_nl_dumprule()")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20250206083051.2494877-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
net/core/fib_rules.c | 24 +++++++++++++-----------
1 file changed, 13 insertions(+), 11 deletions(-)
diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c
index e684ba3ebb38..94a7872ab231 100644
--- a/net/core/fib_rules.c
+++ b/net/core/fib_rules.c
@@ -37,8 +37,8 @@ static const struct fib_kuid_range fib_kuid_range_unset = {
bool fib_rule_matchall(const struct fib_rule *rule)
{
- if (rule->iifindex || rule->oifindex || rule->mark || rule->tun_id ||
- rule->flags)
+ if (READ_ONCE(rule->iifindex) || READ_ONCE(rule->oifindex) ||
+ rule->mark || rule->tun_id || rule->flags)
return false;
if (rule->suppress_ifgroup != -1 || rule->suppress_prefixlen != -1)
return false;
@@ -261,12 +261,14 @@ static int fib_rule_match(struct fib_rule *rule, struct fib_rules_ops *ops,
struct flowi *fl, int flags,
struct fib_lookup_arg *arg)
{
- int ret = 0;
+ int iifindex, oifindex, ret = 0;
- if (rule->iifindex && (rule->iifindex != fl->flowi_iif))
+ iifindex = READ_ONCE(rule->iifindex);
+ if (iifindex && (iifindex != fl->flowi_iif))
goto out;
- if (rule->oifindex && (rule->oifindex != fl->flowi_oif))
+ oifindex = READ_ONCE(rule->oifindex);
+ if (oifindex && (oifindex != fl->flowi_oif))
goto out;
if ((rule->mark ^ fl->flowi_mark) & rule->mark_mask)
@@ -1041,14 +1043,14 @@ static int fib_nl_fill_rule(struct sk_buff *skb, struct fib_rule *rule,
if (rule->iifname[0]) {
if (nla_put_string(skb, FRA_IIFNAME, rule->iifname))
goto nla_put_failure;
- if (rule->iifindex == -1)
+ if (READ_ONCE(rule->iifindex) == -1)
frh->flags |= FIB_RULE_IIF_DETACHED;
}
if (rule->oifname[0]) {
if (nla_put_string(skb, FRA_OIFNAME, rule->oifname))
goto nla_put_failure;
- if (rule->oifindex == -1)
+ if (READ_ONCE(rule->oifindex) == -1)
frh->flags |= FIB_RULE_OIF_DETACHED;
}
@@ -1220,10 +1222,10 @@ static void attach_rules(struct list_head *rules, struct net_device *dev)
list_for_each_entry(rule, rules, list) {
if (rule->iifindex == -1 &&
strcmp(dev->name, rule->iifname) == 0)
- rule->iifindex = dev->ifindex;
+ WRITE_ONCE(rule->iifindex, dev->ifindex);
if (rule->oifindex == -1 &&
strcmp(dev->name, rule->oifname) == 0)
- rule->oifindex = dev->ifindex;
+ WRITE_ONCE(rule->oifindex, dev->ifindex);
}
}
@@ -1233,9 +1235,9 @@ static void detach_rules(struct list_head *rules, struct net_device *dev)
list_for_each_entry(rule, rules, list) {
if (rule->iifindex == dev->ifindex)
- rule->iifindex = -1;
+ WRITE_ONCE(rule->iifindex, -1);
if (rule->oifindex == dev->ifindex)
- rule->oifindex = -1;
+ WRITE_ONCE(rule->oifindex, -1);
}
}