From: Nikolay Aleksandrov nikolay@nvidia.com

mainline inclusion from mainline-v5.16-rc8 commit f83a112bd91a494cdee671aec74e777470fb4a07 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I6DKZJ CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...

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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.co...

Fixes: d902eee43f19 ("bridge: Add multicast count/interval sysfs entries") Reported-by: Eric Dumazet eric.dumazet@gmail.com Signed-off-by: Nikolay Aleksandrov nikolay@nvidia.com Signed-off-by: Jakub Kicinski kuba@kernel.org

Conflicts: net/bridge/br_multicast.c net/bridge/br_netlink.c net/bridge/br_private.h net/bridge/br_sysfs_br.c

Signed-off-by: Zhengchao Shao shaozhengchao@huawei.com Reviewed-by: Yue Haibing yuehaibing@huawei.com Signed-off-by: Yongqiang Liu liuyongqiang13@huawei.com --- net/bridge/br_multicast.c | 16 ++++++++++++++++ net/bridge/br_netlink.c | 2 +- net/bridge/br_private.h | 5 +++++ net/bridge/br_sysfs_br.c | 2 +- 4 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c index 3504c3acd38f..ed67a43efdef 100644 --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -2351,6 +2351,22 @@ int br_multicast_set_mld_version(struct net_bridge *br, unsigned long val) } #endif

+void br_multicast_set_startup_query_intvl(struct net_bridge *br, + unsigned long val) +{ + unsigned long intvl_jiffies = clock_t_to_jiffies(val); + + if (intvl_jiffies < BR_MULTICAST_STARTUP_QUERY_INTVL_MIN) { + br_info(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; + } + + br->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 c00cb376263a..b3bcfb77077a 100644 --- a/net/bridge/br_netlink.c +++ b/net/bridge/br_netlink.c @@ -1237,7 +1237,7 @@ 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_startup_query_interval = clock_t_to_jiffies(val); + br_multicast_set_startup_query_intvl(br, val); }

if (data[IFLA_BR_MCAST_STATS_ENABLED]) { diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h index 23fed55942fa..877fbc65a2fe 100644 --- a/net/bridge/br_private.h +++ b/net/bridge/br_private.h @@ -31,6 +31,9 @@ #define BR_PORT_BITS 10 #define BR_MAX_PORTS (1<<BR_PORT_BITS)

+#define BR_MULTICAST_QUERY_INTVL_MIN msecs_to_jiffies(1000) +#define BR_MULTICAST_STARTUP_QUERY_INTVL_MIN BR_MULTICAST_QUERY_INTVL_MIN + #define BR_VERSION "2.3"

/* Control of forwarding link local multicast */ @@ -1200,4 +1203,6 @@ void br_do_proxy_suppress_arp(struct sk_buff *skb, struct net_bridge *br, void br_do_suppress_nd(struct sk_buff *skb, struct net_bridge *br, u16 vid, struct net_bridge_port *p, struct nd_msg *msg); struct nd_msg *br_is_nd_neigh_msg(struct sk_buff *skb, struct nd_msg *m); +void br_multicast_set_startup_query_intvl(struct net_bridge *br, + unsigned long val); #endif diff --git a/net/bridge/br_sysfs_br.c b/net/bridge/br_sysfs_br.c index 0318a69888d4..bfbffc5088ac 100644 --- a/net/bridge/br_sysfs_br.c +++ b/net/bridge/br_sysfs_br.c @@ -618,7 +618,7 @@ static ssize_t multicast_startup_query_interval_show(

static int set_startup_query_interval(struct net_bridge *br, unsigned long val) { - br->multicast_startup_query_interval = clock_t_to_jiffies(val); + br_multicast_set_startup_query_intvl(br, val); return 0; }