6.12-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet edumazet@google.com
[ Upstream commit cb827db50a88aebec516151681adb6db10b688ee ]
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 Signed-off-by: Sasha Levin sashal@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 154a2681f55cc..388ff1d6d86b7 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; @@ -260,12 +260,14 @@ 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) @@ -1038,14 +1040,14 @@ 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; }
@@ -1217,10 +1219,10 @@ 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); } }
@@ -1230,9 +1232,9 @@ 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); } }