From 99b40610956a8a8755653a67392e2a8b772453be Mon Sep 17 00:00:00 2001 From: Nikolay Aleksandrov Date: Mon, 27 Dec 2021 19:21:15 +0200 Subject: net: bridge: mcast: add and enforce query interval minimum As reported[1] if query interval is set too low and we have multiple bridges or even a single bridge with multiple querier vlans configured we can crash the machine. Add a 1 second minimum which must be enforced by overwriting the value if set lower (i.e. without returning an error) to avoid breaking user-space. If that happens a log message is emitted to let the administrator know that the interval has been set to the minimum. The issue has been present since these intervals could be user-controlled. [1] https://lore.kernel.org/netdev/e8b9ce41-57b9-b6e2-a46a-ff9c791cf0ba@gmail.com/ Fixes: d902eee43f19 ("bridge: Add multicast count/interval sysfs entries") Reported-by: Eric Dumazet Signed-off-by: Nikolay Aleksandrov Signed-off-by: Jakub Kicinski --- net/bridge/br_private.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'net/bridge/br_private.h') diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h index c0efd697865a..4ed7f11042e8 100644 --- a/net/bridge/br_private.h +++ b/net/bridge/br_private.h @@ -28,6 +28,7 @@ #define BR_MAX_PORTS (1< Date: Mon, 27 Dec 2021 19:21:16 +0200 Subject: net: bridge: mcast: add and enforce startup query interval minimum As reported[1] if startup query interval is set too low in combination with large number of startup queries and we have multiple bridges or even a single bridge with multiple querier vlans configured we can crash the machine. Add a 1 second minimum which must be enforced by overwriting the value if set lower (i.e. without returning an error) to avoid breaking user-space. If that happens a log message is emitted to let the admin know that the startup interval has been set to the minimum. It doesn't make sense to make the startup interval lower than the normal query interval so use the same value of 1 second. The issue has been present since these intervals could be user-controlled. [1] https://lore.kernel.org/netdev/e8b9ce41-57b9-b6e2-a46a-ff9c791cf0ba@gmail.com/ Fixes: d902eee43f19 ("bridge: Add multicast count/interval sysfs entries") Reported-by: Eric Dumazet Signed-off-by: Nikolay Aleksandrov Signed-off-by: Jakub Kicinski --- net/bridge/br_multicast.c | 16 ++++++++++++++++ net/bridge/br_netlink.c | 2 +- net/bridge/br_private.h | 3 +++ net/bridge/br_sysfs_br.c | 2 +- net/bridge/br_vlan_options.c | 2 +- 5 files changed, 22 insertions(+), 3 deletions(-) (limited to 'net/bridge/br_private.h') diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c index 998da4a2d209..de2409889489 100644 --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -4538,6 +4538,22 @@ void br_multicast_set_query_intvl(struct net_bridge_mcast *brmctx, brmctx->multicast_query_interval = intvl_jiffies; } +void br_multicast_set_startup_query_intvl(struct net_bridge_mcast *brmctx, + unsigned long val) +{ + unsigned long intvl_jiffies = clock_t_to_jiffies(val); + + if (intvl_jiffies < BR_MULTICAST_STARTUP_QUERY_INTVL_MIN) { + br_info(brmctx->br, + "trying to set multicast startup query interval below minimum, setting to %lu (%ums)\n", + jiffies_to_clock_t(BR_MULTICAST_STARTUP_QUERY_INTVL_MIN), + jiffies_to_msecs(BR_MULTICAST_STARTUP_QUERY_INTVL_MIN)); + intvl_jiffies = BR_MULTICAST_STARTUP_QUERY_INTVL_MIN; + } + + brmctx->multicast_startup_query_interval = intvl_jiffies; +} + /** * br_multicast_list_adjacent - Returns snooped multicast addresses * @dev: The bridge port adjacent to which to retrieve addresses diff --git a/net/bridge/br_netlink.c b/net/bridge/br_netlink.c index 701dd8b8455e..2ff83d84230d 100644 --- a/net/bridge/br_netlink.c +++ b/net/bridge/br_netlink.c @@ -1369,7 +1369,7 @@ static int br_changelink(struct net_device *brdev, struct nlattr *tb[], if (data[IFLA_BR_MCAST_STARTUP_QUERY_INTVL]) { u64 val = nla_get_u64(data[IFLA_BR_MCAST_STARTUP_QUERY_INTVL]); - br->multicast_ctx.multicast_startup_query_interval = clock_t_to_jiffies(val); + br_multicast_set_startup_query_intvl(&br->multicast_ctx, val); } if (data[IFLA_BR_MCAST_STATS_ENABLED]) { diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h index 4ed7f11042e8..2187a0c3fd22 100644 --- a/net/bridge/br_private.h +++ b/net/bridge/br_private.h @@ -29,6 +29,7 @@ #define BR_MULTICAST_DEFAULT_HASH_MAX 4096 #define BR_MULTICAST_QUERY_INTVL_MIN msecs_to_jiffies(1000) +#define BR_MULTICAST_STARTUP_QUERY_INTVL_MIN BR_MULTICAST_QUERY_INTVL_MIN #define BR_HWDOM_MAX BITS_PER_LONG @@ -966,6 +967,8 @@ size_t br_multicast_querier_state_size(void); size_t br_rports_size(const struct net_bridge_mcast *brmctx); void br_multicast_set_query_intvl(struct net_bridge_mcast *brmctx, unsigned long val); +void br_multicast_set_startup_query_intvl(struct net_bridge_mcast *brmctx, + unsigned long val); static inline bool br_group_is_l2(const struct br_ip *group) { diff --git a/net/bridge/br_sysfs_br.c b/net/bridge/br_sysfs_br.c index f5bd1114a434..7b0c19772111 100644 --- a/net/bridge/br_sysfs_br.c +++ b/net/bridge/br_sysfs_br.c @@ -706,7 +706,7 @@ static ssize_t multicast_startup_query_interval_show( static int set_startup_query_interval(struct net_bridge *br, unsigned long val, struct netlink_ext_ack *extack) { - br->multicast_ctx.multicast_startup_query_interval = clock_t_to_jiffies(val); + br_multicast_set_startup_query_intvl(&br->multicast_ctx, val); return 0; } diff --git a/net/bridge/br_vlan_options.c b/net/bridge/br_vlan_options.c index bf1ac0874279..a6382973b3e7 100644 --- a/net/bridge/br_vlan_options.c +++ b/net/bridge/br_vlan_options.c @@ -535,7 +535,7 @@ static int br_vlan_process_global_one_opts(const struct net_bridge *br, u64 val; val = nla_get_u64(tb[BRIDGE_VLANDB_GOPTS_MCAST_STARTUP_QUERY_INTVL]); - v->br_mcast_ctx.multicast_startup_query_interval = clock_t_to_jiffies(val); + br_multicast_set_startup_query_intvl(&v->br_mcast_ctx, val); *changed = true; } if (tb[BRIDGE_VLANDB_GOPTS_MCAST_QUERIER]) { -- cgit v1.2.3 From 168fed986b3a7ec7b98cab1fe84e2f282b9e6a8f Mon Sep 17 00:00:00 2001 From: Nikolay Aleksandrov Date: Tue, 28 Dec 2021 17:31:42 +0200 Subject: net: bridge: mcast: fix br_multicast_ctx_vlan_global_disabled helper We need to first check if the context is a vlan one, then we need to check the global bridge multicast vlan snooping flag, and finally the vlan's multicast flag, otherwise we will unnecessarily enable vlan mcast processing (e.g. querier timers). Fixes: 7b54aaaf53cb ("net: bridge: multicast: add vlan state initialization and control") Signed-off-by: Nikolay Aleksandrov Link: https://lore.kernel.org/r/20211228153142.536969-1-nikolay@nvidia.com Signed-off-by: Jakub Kicinski --- net/bridge/br_private.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'net/bridge/br_private.h') diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h index 2187a0c3fd22..e8c6ee322c71 100644 --- a/net/bridge/br_private.h +++ b/net/bridge/br_private.h @@ -1153,9 +1153,9 @@ br_multicast_port_ctx_get_global(const struct net_bridge_mcast_port *pmctx) static inline bool br_multicast_ctx_vlan_global_disabled(const struct net_bridge_mcast *brmctx) { - return br_opt_get(brmctx->br, BROPT_MCAST_VLAN_SNOOPING_ENABLED) && - br_multicast_ctx_is_vlan(brmctx) && - !(brmctx->vlan->priv_flags & BR_VLFLAG_GLOBAL_MCAST_ENABLED); + return br_multicast_ctx_is_vlan(brmctx) && + (!br_opt_get(brmctx->br, BROPT_MCAST_VLAN_SNOOPING_ENABLED) || + !(brmctx->vlan->priv_flags & BR_VLFLAG_GLOBAL_MCAST_ENABLED)); } static inline bool -- cgit v1.2.3