net/ipv6: Revert remove expired routes with a separated list of routes

[ Upstream commit dade3f6a1e4e35a5ae916d5e78b3229ec34c78ec ]

This reverts commit 3dec89b14d37ee635e772636dad3f09f78f1ab87.

The commit has some race conditions given how expires is managed on a
fib6_info in relation to gc start, adding the entry to the gc list and
setting the timer value leading to UAF. Revert the commit and try again
in a later release.

Fixes: 3dec89b14d37 ("net/ipv6: Remove expired routes with a separated list of routes")
Cc: Kui-Feng Lee <thinker.li@gmail.com>
Signed-off-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20231219030243.25687-1-dsahern@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h
index 1ba9f4d..9ba6413 100644 (file)
--- a/include/net/ip6_fib.h
+++ b/include/net/ip6_fib.h
@@ -179,9 +179,6 @@ struct fib6_info {
 
        refcount_t                      fib6_ref;
        unsigned long                   expires;
-
-       struct hlist_node               gc_link;
-
        struct dst_metrics              *fib6_metrics;
 #define fib6_pmtu              fib6_metrics->metrics[RTAX_MTU-1]
 
@@ -250,6 +247,19 @@ static inline bool fib6_requires_src(const struct fib6_info *rt)
        return rt->fib6_src.plen > 0;
 }
 
+static inline void fib6_clean_expires(struct fib6_info *f6i)
+{
+       f6i->fib6_flags &= ~RTF_EXPIRES;
+       f6i->expires = 0;
+}
+
+static inline void fib6_set_expires(struct fib6_info *f6i,
+                                   unsigned long expires)
+{
+       f6i->expires = expires;
+       f6i->fib6_flags |= RTF_EXPIRES;
+}
+
 static inline bool fib6_check_expired(const struct fib6_info *f6i)
 {
        if (f6i->fib6_flags & RTF_EXPIRES)
@@ -257,11 +267,6 @@ static inline bool fib6_check_expired(const struct fib6_info *f6i)
        return false;
 }
 
-static inline bool fib6_has_expires(const struct fib6_info *f6i)
-{
-       return f6i->fib6_flags & RTF_EXPIRES;
-}
-
 /* Function to safely get fn->fn_sernum for passed in rt
  * and store result in passed in cookie.
  * Return true if we can get cookie safely
@@ -383,7 +388,6 @@ struct fib6_table {
        struct inet_peer_base   tb6_peers;
        unsigned int            flags;
        unsigned int            fib_seq;
-       struct hlist_head       tb6_gc_hlist;   /* GC candidates */
 #define RT6_TABLE_HAS_DFLT_ROUTER      BIT(0)
 };
 
@@ -500,48 +504,6 @@ void fib6_gc_cleanup(void);
 
 int fib6_init(void);
 
-/* fib6_info must be locked by the caller, and fib6_info->fib6_table can be
- * NULL.
- */
-static inline void fib6_set_expires_locked(struct fib6_info *f6i,
-                                          unsigned long expires)
-{
-       struct fib6_table *tb6;
-
-       tb6 = f6i->fib6_table;
-       f6i->expires = expires;
-       if (tb6 && !fib6_has_expires(f6i))
-               hlist_add_head(&f6i->gc_link, &tb6->tb6_gc_hlist);
-       f6i->fib6_flags |= RTF_EXPIRES;
-}
-
-/* fib6_info must be locked by the caller, and fib6_info->fib6_table can be
- * NULL.  If fib6_table is NULL, the fib6_info will no be inserted into the
- * list of GC candidates until it is inserted into a table.
- */
-static inline void fib6_set_expires(struct fib6_info *f6i,
-                                   unsigned long expires)
-{
-       spin_lock_bh(&f6i->fib6_table->tb6_lock);
-       fib6_set_expires_locked(f6i, expires);
-       spin_unlock_bh(&f6i->fib6_table->tb6_lock);
-}
-
-static inline void fib6_clean_expires_locked(struct fib6_info *f6i)
-{
-       if (fib6_has_expires(f6i))
-               hlist_del_init(&f6i->gc_link);
-       f6i->fib6_flags &= ~RTF_EXPIRES;
-       f6i->expires = 0;
-}
-
-static inline void fib6_clean_expires(struct fib6_info *f6i)
-{
-       spin_lock_bh(&f6i->fib6_table->tb6_lock);
-       fib6_clean_expires_locked(f6i);
-       spin_unlock_bh(&f6i->fib6_table->tb6_lock);
-}
-
 struct ipv6_route_iter {
        struct seq_net_private p;
        struct fib6_walker w;

diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 7772f42..4fc2cae 100644 (file)
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -160,8 +160,6 @@ struct fib6_info *fib6_info_alloc(gfp_t gfp_flags, bool with_fib6_nh)
        INIT_LIST_HEAD(&f6i->fib6_siblings);
        refcount_set(&f6i->fib6_ref, 1);
 
-       INIT_HLIST_NODE(&f6i->gc_link);
-
        return f6i;
 }
 
@@ -248,7 +246,6 @@ static struct fib6_table *fib6_alloc_table(struct net *net, u32 id)
                                   net->ipv6.fib6_null_entry);
                table->tb6_root.fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;
                inet_peer_base_init(&table->tb6_peers);
-               INIT_HLIST_HEAD(&table->tb6_gc_hlist);
        }
 
        return table;
@@ -1060,8 +1057,6 @@ static void fib6_purge_rt(struct fib6_info *rt, struct fib6_node *fn,
                                    lockdep_is_held(&table->tb6_lock));
                }
        }
-
-       fib6_clean_expires_locked(rt);
 }
 
 /*
@@ -1123,10 +1118,9 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt,
                                if (!(iter->fib6_flags & RTF_EXPIRES))
                                        return -EEXIST;
                                if (!(rt->fib6_flags & RTF_EXPIRES))
-                                       fib6_clean_expires_locked(iter);
+                                       fib6_clean_expires(iter);
                                else
-                                       fib6_set_expires_locked(iter,
-                                                               rt->expires);
+                                       fib6_set_expires(iter, rt->expires);
 
                                if (rt->fib6_pmtu)
                                        fib6_metric_set(iter, RTAX_MTU,
@@ -1485,10 +1479,6 @@ int fib6_add(struct fib6_node *root, struct fib6_info *rt,
                if (rt->nh)
                        list_add(&rt->nh_list, &rt->nh->f6i_list);
                __fib6_update_sernum_upto_root(rt, fib6_new_sernum(info->nl_net));
-
-               if (fib6_has_expires(rt))
-                       hlist_add_head(&rt->gc_link, &table->tb6_gc_hlist);
-
                fib6_start_gc(info->nl_net, rt);
        }
 
@@ -2291,8 +2281,9 @@ static void fib6_flush_trees(struct net *net)
  *     Garbage collection
  */
 
-static int fib6_age(struct fib6_info *rt, struct fib6_gc_args *gc_args)
+static int fib6_age(struct fib6_info *rt, void *arg)
 {
+       struct fib6_gc_args *gc_args = arg;
        unsigned long now = jiffies;
 
        /*
@@ -2300,7 +2291,7 @@ static int fib6_age(struct fib6_info *rt, struct fib6_gc_args *gc_args)
         *      Routes are expired even if they are in use.
         */
 
-       if (fib6_has_expires(rt) && rt->expires) {
+       if (rt->fib6_flags & RTF_EXPIRES && rt->expires) {
                if (time_after(now, rt->expires)) {
                        RT6_TRACE("expiring %p\n", rt);
                        return -1;
@@ -2317,40 +2308,6 @@ static int fib6_age(struct fib6_info *rt, struct fib6_gc_args *gc_args)
        return 0;
 }
 
-static void fib6_gc_table(struct net *net,
-                         struct fib6_table *tb6,
-                         struct fib6_gc_args *gc_args)
-{
-       struct fib6_info *rt;
-       struct hlist_node *n;
-       struct nl_info info = {
-               .nl_net = net,
-               .skip_notify = false,
-       };
-
-       hlist_for_each_entry_safe(rt, n, &tb6->tb6_gc_hlist, gc_link)
-               if (fib6_age(rt, gc_args) == -1)
-                       fib6_del(rt, &info);
-}
-
-static void fib6_gc_all(struct net *net, struct fib6_gc_args *gc_args)
-{
-       struct fib6_table *table;
-       struct hlist_head *head;
-       unsigned int h;
-
-       rcu_read_lock();
-       for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {
-               head = &net->ipv6.fib_table_hash[h];
-               hlist_for_each_entry_rcu(table, head, tb6_hlist) {
-                       spin_lock_bh(&table->tb6_lock);
-                       fib6_gc_table(net, table, gc_args);
-                       spin_unlock_bh(&table->tb6_lock);
-               }
-       }
-       rcu_read_unlock();
-}
-
 void fib6_run_gc(unsigned long expires, struct net *net, bool force)
 {
        struct fib6_gc_args gc_args;
@@ -2366,7 +2323,7 @@ void fib6_run_gc(unsigned long expires, struct net *net, bool force)
                          net->ipv6.sysctl.ip6_rt_gc_interval;
        gc_args.more = 0;
 
-       fib6_gc_all(net, &gc_args);
+       fib6_clean_all(net, fib6_age, &gc_args);
        now = jiffies;
        net->ipv6.ip6_rt_last_gc = now;
 

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 9c687b3..56525b5 100644 (file)
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -3763,10 +3763,10 @@ static struct fib6_info *ip6_route_info_create(struct fib6_config *cfg,
                rt->dst_nocount = true;
 
        if (cfg->fc_flags & RTF_EXPIRES)
-               fib6_set_expires_locked(rt, jiffies +
-                                       clock_t_to_jiffies(cfg->fc_expires));
+               fib6_set_expires(rt, jiffies +
+                               clock_t_to_jiffies(cfg->fc_expires));
        else
-               fib6_clean_expires_locked(rt);
+               fib6_clean_expires(rt);
 
        if (cfg->fc_protocol == RTPROT_UNSPEC)
                cfg->fc_protocol = RTPROT_BOOT;