diff options
| author | Kuniyuki Iwashima <kuniyu@google.com> | 2026-09-20 19:14:32 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-09-21 18:12:42 -0700 |
| commit | be31fe6333f534155e6b408f1ef6d77974bb41aa (patch) | |
| tree | 80b1e8520ecb0c8b0c77a99748f3c4cfe566f3c4 /include/net | |
| parent | 10de7ed8ef4840da9ca21de4c29578657ac367db (diff) | |
| download | linux-be31fe6333f534155e6b408f1ef6d77974bb41aa.tar.gz linux-be31fe6333f534155e6b408f1ef6d77974bb41aa.zip | |
ipv6: Fix dst leak for uncached routes.
ip6_route_output_flags(), ip6_rt_put_flags(), and ip6_dst_check()
detect an uncached route by list_empty(&rt->dst.rt_uncached),
which replaced the static DST_NOCACHE flag check in commit
a4c2fd7f7891 ("net: remove DST_NOCACHE flag").
When a device is unregistered, rt6_uncached_list_flush_dev()
unlinks uncached routes tied to the device from rt6_uncached_list.
Previously, they were moved to another list with list_move()
(__list_del_entry() + list_add()), and since commit 98aa546af5e4
("inet: remove (struct uncached_list)->quarantine"), the routes
are just unlinked with list_del_init().
If list_del_init() runs concurrently, list_empty() evaluates to
true; ip6_route_output_flags() calls dst_hold_safe() incorrectly
and ip6_rt_put_flags() skips ip6_rt_put(), leaking dst, and thus
dev tied via rt->from as well.
The same race is partially fixed by commit 9a6f0c4d5796 ("dst:
fix races in rt6_uncached_list_del() and rt_del_uncached_list()").
Let's check rt6->dst.rt_uncached_list instead.
Note that IPv4 does not have the same issue.
Fixes: 98aa546af5e4 ("inet: remove (struct uncached_list)->quarantine")
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Hangbin Liu <liuhangbin@kylinos.cn>
Reviewed-by: Xuanqiang Luo <luoxuanqiang@kylinos.cn>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260920191558.2990636-1-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'include/net')
| -rw-r--r-- | include/net/ip6_route.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h index b9e8d2b759e9..0f9b7a260d25 100644 --- a/include/net/ip6_route.h +++ b/include/net/ip6_route.h @@ -101,12 +101,12 @@ static inline struct dst_entry *ip6_route_output(struct net *net, } /* Only conditionally release dst if flags indicates - * !RT6_LOOKUP_F_DST_NOREF or dst is in uncached_list. + * !RT6_LOOKUP_F_DST_NOREF or dst is uncached. */ static inline void ip6_rt_put_flags(struct rt6_info *rt, int flags) { if (!(flags & RT6_LOOKUP_F_DST_NOREF) || - !list_empty(&rt->dst.rt_uncached)) + rt->dst.rt_uncached_list) ip6_rt_put(rt); } |