6.6-stable review patch. If anyone has any objections, please let me know.
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From: David Ahern dsahern@kernel.org
[ 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 --- include/net/ip6_fib.h | 64 +++++++++---------------------------------- net/ipv6/ip6_fib.c | 55 ++++--------------------------------- net/ipv6/route.c | 6 ++-- 3 files changed, 22 insertions(+), 103 deletions(-)
diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h index 1ba9f4ddf2f6d..9ba6413fd2e3e 100644 --- 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 7772f42ff2b94..4fc2cae0d116c 100644 --- 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 9c687b357e6a4..56525b5b95a2b 100644 --- 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;