From 0598f8f3bb77893a13105d47bb7dfe42f1dc1f4e Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 27 Feb 2024 09:24:09 +0000 Subject: [PATCH 1/3] inet: annotate devconf data-races Add READ_ONCE() in ipv4_devconf_get() and corresponding WRITE_ONCE() in ipv4_devconf_set() Add IPV4_DEVCONF_RO() and IPV4_DEVCONF_ALL_RO() macros, and use them when reading devconf fields. Signed-off-by: Eric Dumazet Reviewed-by: Jiri Pirko Link: https://lore.kernel.org/r/20240227092411.2315725-2-edumazet@google.com Signed-off-by: Jakub Kicinski --- include/linux/inetdevice.h | 14 ++++++++------ net/ipv4/devinet.c | 21 +++++++++++---------- net/ipv4/igmp.c | 4 ++-- net/ipv4/proc.c | 2 +- net/ipv4/route.c | 4 ++-- 5 files changed, 24 insertions(+), 21 deletions(-) diff --git a/include/linux/inetdevice.h b/include/linux/inetdevice.h index ddb27fc0ee8c8..cb5280e6cc219 100644 --- a/include/linux/inetdevice.h +++ b/include/linux/inetdevice.h @@ -53,13 +53,15 @@ struct in_device { }; #define IPV4_DEVCONF(cnf, attr) ((cnf).data[IPV4_DEVCONF_ ## attr - 1]) +#define IPV4_DEVCONF_RO(cnf, attr) READ_ONCE(IPV4_DEVCONF(cnf, attr)) #define IPV4_DEVCONF_ALL(net, attr) \ IPV4_DEVCONF((*(net)->ipv4.devconf_all), attr) +#define IPV4_DEVCONF_ALL_RO(net, attr) READ_ONCE(IPV4_DEVCONF_ALL(net, attr)) -static inline int ipv4_devconf_get(struct in_device *in_dev, int index) +static inline int ipv4_devconf_get(const struct in_device *in_dev, int index) { index--; - return in_dev->cnf.data[index]; + return READ_ONCE(in_dev->cnf.data[index]); } static inline void ipv4_devconf_set(struct in_device *in_dev, int index, @@ -67,7 +69,7 @@ static inline void ipv4_devconf_set(struct in_device *in_dev, int index, { index--; set_bit(index, in_dev->cnf.state); - in_dev->cnf.data[index] = val; + WRITE_ONCE(in_dev->cnf.data[index], val); } static inline void ipv4_devconf_setall(struct in_device *in_dev) @@ -81,18 +83,18 @@ static inline void ipv4_devconf_setall(struct in_device *in_dev) ipv4_devconf_set((in_dev), IPV4_DEVCONF_ ## attr, (val)) #define IN_DEV_ANDCONF(in_dev, attr) \ - (IPV4_DEVCONF_ALL(dev_net(in_dev->dev), attr) && \ + (IPV4_DEVCONF_ALL_RO(dev_net(in_dev->dev), attr) && \ IN_DEV_CONF_GET((in_dev), attr)) #define IN_DEV_NET_ORCONF(in_dev, net, attr) \ - (IPV4_DEVCONF_ALL(net, attr) || \ + (IPV4_DEVCONF_ALL_RO(net, attr) || \ IN_DEV_CONF_GET((in_dev), attr)) #define IN_DEV_ORCONF(in_dev, attr) \ IN_DEV_NET_ORCONF(in_dev, dev_net(in_dev->dev), attr) #define IN_DEV_MAXCONF(in_dev, attr) \ - (max(IPV4_DEVCONF_ALL(dev_net(in_dev->dev), attr), \ + (max(IPV4_DEVCONF_ALL_RO(dev_net(in_dev->dev), attr), \ IN_DEV_CONF_GET((in_dev), attr))) #define IN_DEV_FORWARD(in_dev) IN_DEV_CONF_GET((in_dev), FORWARDING) diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c index bc74f131fe4df..ca75d0fff1d1e 100644 --- a/net/ipv4/devinet.c +++ b/net/ipv4/devinet.c @@ -1982,7 +1982,7 @@ static int inet_fill_link_af(struct sk_buff *skb, const struct net_device *dev, return -EMSGSIZE; for (i = 0; i < IPV4_DEVCONF_MAX; i++) - ((u32 *) nla_data(nla))[i] = in_dev->cnf.data[i]; + ((u32 *) nla_data(nla))[i] = READ_ONCE(in_dev->cnf.data[i]); return 0; } @@ -2068,9 +2068,9 @@ static int inet_netconf_msgsize_devconf(int type) } static int inet_netconf_fill_devconf(struct sk_buff *skb, int ifindex, - struct ipv4_devconf *devconf, u32 portid, - u32 seq, int event, unsigned int flags, - int type) + const struct ipv4_devconf *devconf, + u32 portid, u32 seq, int event, + unsigned int flags, int type) { struct nlmsghdr *nlh; struct netconfmsg *ncm; @@ -2095,27 +2095,28 @@ static int inet_netconf_fill_devconf(struct sk_buff *skb, int ifindex, if ((all || type == NETCONFA_FORWARDING) && nla_put_s32(skb, NETCONFA_FORWARDING, - IPV4_DEVCONF(*devconf, FORWARDING)) < 0) + IPV4_DEVCONF_RO(*devconf, FORWARDING)) < 0) goto nla_put_failure; if ((all || type == NETCONFA_RP_FILTER) && nla_put_s32(skb, NETCONFA_RP_FILTER, - IPV4_DEVCONF(*devconf, RP_FILTER)) < 0) + IPV4_DEVCONF_RO(*devconf, RP_FILTER)) < 0) goto nla_put_failure; if ((all || type == NETCONFA_MC_FORWARDING) && nla_put_s32(skb, NETCONFA_MC_FORWARDING, - IPV4_DEVCONF(*devconf, MC_FORWARDING)) < 0) + IPV4_DEVCONF_RO(*devconf, MC_FORWARDING)) < 0) goto nla_put_failure; if ((all || type == NETCONFA_BC_FORWARDING) && nla_put_s32(skb, NETCONFA_BC_FORWARDING, - IPV4_DEVCONF(*devconf, BC_FORWARDING)) < 0) + IPV4_DEVCONF_RO(*devconf, BC_FORWARDING)) < 0) goto nla_put_failure; if ((all || type == NETCONFA_PROXY_NEIGH) && nla_put_s32(skb, NETCONFA_PROXY_NEIGH, - IPV4_DEVCONF(*devconf, PROXY_ARP)) < 0) + IPV4_DEVCONF_RO(*devconf, PROXY_ARP)) < 0) goto nla_put_failure; if ((all || type == NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN) && nla_put_s32(skb, NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN, - IPV4_DEVCONF(*devconf, IGNORE_ROUTES_WITH_LINKDOWN)) < 0) + IPV4_DEVCONF_RO(*devconf, + IGNORE_ROUTES_WITH_LINKDOWN)) < 0) goto nla_put_failure; out: diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c index efeeca2b13285..717e97a389a8a 100644 --- a/net/ipv4/igmp.c +++ b/net/ipv4/igmp.c @@ -120,12 +120,12 @@ */ #define IGMP_V1_SEEN(in_dev) \ - (IPV4_DEVCONF_ALL(dev_net(in_dev->dev), FORCE_IGMP_VERSION) == 1 || \ + (IPV4_DEVCONF_ALL_RO(dev_net(in_dev->dev), FORCE_IGMP_VERSION) == 1 || \ IN_DEV_CONF_GET((in_dev), FORCE_IGMP_VERSION) == 1 || \ ((in_dev)->mr_v1_seen && \ time_before(jiffies, (in_dev)->mr_v1_seen))) #define IGMP_V2_SEEN(in_dev) \ - (IPV4_DEVCONF_ALL(dev_net(in_dev->dev), FORCE_IGMP_VERSION) == 2 || \ + (IPV4_DEVCONF_ALL_RO(dev_net(in_dev->dev), FORCE_IGMP_VERSION) == 2 || \ IN_DEV_CONF_GET((in_dev), FORCE_IGMP_VERSION) == 2 || \ ((in_dev)->mr_v2_seen && \ time_before(jiffies, (in_dev)->mr_v2_seen))) diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c index 5f4654ebff487..914bc9c35cc70 100644 --- a/net/ipv4/proc.c +++ b/net/ipv4/proc.c @@ -395,7 +395,7 @@ static int snmp_seq_show_ipstats(struct seq_file *seq, void *v) seq_printf(seq, " %s", snmp4_ipstats_list[i].name); seq_printf(seq, "\nIp: %d %d", - IPV4_DEVCONF_ALL(net, FORWARDING) ? 1 : 2, + IPV4_DEVCONF_ALL_RO(net, FORWARDING) ? 1 : 2, READ_ONCE(net->ipv4.sysctl_ip_default_ttl)); BUILD_BUG_ON(offsetof(struct ipstats_mib, mibs) != 0); diff --git a/net/ipv4/route.c b/net/ipv4/route.c index b512288d6fcc6..c8f76f56dc165 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -2313,7 +2313,7 @@ static int ip_route_input_slow(struct sk_buff *skb, __be32 daddr, __be32 saddr, if (IN_DEV_BFORWARD(in_dev)) goto make_route; /* not do cache if bc_forwarding is enabled */ - if (IPV4_DEVCONF_ALL(net, BC_FORWARDING)) + if (IPV4_DEVCONF_ALL_RO(net, BC_FORWARDING)) do_cache = false; goto brd_input; } @@ -2993,7 +2993,7 @@ static int rt_fill_info(struct net *net, __be32 dst, __be32 src, #ifdef CONFIG_IP_MROUTE if (ipv4_is_multicast(dst) && !ipv4_is_local_multicast(dst) && - IPV4_DEVCONF_ALL(net, MC_FORWARDING)) { + IPV4_DEVCONF_ALL_RO(net, MC_FORWARDING)) { int err = ipmr_get_route(net, skb, fl4->saddr, fl4->daddr, r, portid); From bbcf91053bb622c4c26a9bfc998d3b0c59227f10 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 27 Feb 2024 09:24:10 +0000 Subject: [PATCH 2/3] inet: do not use RTNL in inet_netconf_get_devconf() "ip -4 netconf show dev XXXX" no longer acquires RTNL. Return -ENODEV instead of -EINVAL if no netdev or idev can be found. Signed-off-by: Eric Dumazet Reviewed-by: Jiri Pirko Link: https://lore.kernel.org/r/20240227092411.2315725-3-edumazet@google.com Signed-off-by: Jakub Kicinski --- net/ipv4/devinet.c | 27 +++++++++++++++------------ 1 file changed, 15 insertions(+), 12 deletions(-) diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c index ca75d0fff1d1e..f045a34e90b97 100644 --- a/net/ipv4/devinet.c +++ b/net/ipv4/devinet.c @@ -2205,21 +2205,20 @@ static int inet_netconf_get_devconf(struct sk_buff *in_skb, struct netlink_ext_ack *extack) { struct net *net = sock_net(in_skb->sk); - struct nlattr *tb[NETCONFA_MAX+1]; + struct nlattr *tb[NETCONFA_MAX + 1]; + const struct ipv4_devconf *devconf; + struct in_device *in_dev = NULL; + struct net_device *dev = NULL; struct sk_buff *skb; - struct ipv4_devconf *devconf; - struct in_device *in_dev; - struct net_device *dev; int ifindex; int err; err = inet_netconf_valid_get_req(in_skb, nlh, tb, extack); if (err) - goto errout; + return err; - err = -EINVAL; if (!tb[NETCONFA_IFINDEX]) - goto errout; + return -EINVAL; ifindex = nla_get_s32(tb[NETCONFA_IFINDEX]); switch (ifindex) { @@ -2230,10 +2229,10 @@ static int inet_netconf_get_devconf(struct sk_buff *in_skb, devconf = net->ipv4.devconf_dflt; break; default: - dev = __dev_get_by_index(net, ifindex); - if (!dev) - goto errout; - in_dev = __in_dev_get_rtnl(dev); + err = -ENODEV; + dev = dev_get_by_index(net, ifindex); + if (dev) + in_dev = in_dev_get(dev); if (!in_dev) goto errout; devconf = &in_dev->cnf; @@ -2257,6 +2256,9 @@ static int inet_netconf_get_devconf(struct sk_buff *in_skb, } err = rtnl_unicast(skb, net, NETLINK_CB(in_skb).portid); errout: + if (in_dev) + in_dev_put(in_dev); + dev_put(dev); return err; } @@ -2826,5 +2828,6 @@ void __init devinet_init(void) rtnl_register(PF_INET, RTM_DELADDR, inet_rtm_deladdr, NULL, 0); rtnl_register(PF_INET, RTM_GETADDR, NULL, inet_dump_ifaddr, 0); rtnl_register(PF_INET, RTM_GETNETCONF, inet_netconf_get_devconf, - inet_netconf_dump_devconf, 0); + inet_netconf_dump_devconf, + RTNL_FLAG_DOIT_UNLOCKED); } From 167487070d644a285ed863516c80b3c35ec929d6 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 27 Feb 2024 09:24:11 +0000 Subject: [PATCH 3/3] inet: use xa_array iterator to implement inet_netconf_dump_devconf() 1) inet_netconf_dump_devconf() can run under RCU protection instead of RTNL. 2) properly return 0 at the end of a dump, avoiding an an extra recvmsg() system call. 3) Do not use inet_base_seq() anymore, for_each_netdev_dump() has nice properties. Restarting a GETDEVCONF dump if a device has been added/removed or if net->ipv4.dev_addr_genid has changed is moot. Signed-off-by: Eric Dumazet Reviewed-by: Jiri Pirko Link: https://lore.kernel.org/r/20240227092411.2315725-4-edumazet@google.com Signed-off-by: Jakub Kicinski --- net/ipv4/devinet.c | 101 +++++++++++++++++++-------------------------- 1 file changed, 43 insertions(+), 58 deletions(-) diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c index f045a34e90b97..af741af61830a 100644 --- a/net/ipv4/devinet.c +++ b/net/ipv4/devinet.c @@ -2267,11 +2267,13 @@ static int inet_netconf_dump_devconf(struct sk_buff *skb, { const struct nlmsghdr *nlh = cb->nlh; struct net *net = sock_net(skb->sk); - int h, s_h; - int idx, s_idx; + struct { + unsigned long ifindex; + unsigned int all_default; + } *ctx = (void *)cb->ctx; + const struct in_device *in_dev; struct net_device *dev; - struct in_device *in_dev; - struct hlist_head *head; + int err = 0; if (cb->strict_check) { struct netlink_ext_ack *extack = cb->extack; @@ -2288,64 +2290,47 @@ static int inet_netconf_dump_devconf(struct sk_buff *skb, } } - s_h = cb->args[0]; - s_idx = idx = cb->args[1]; - - for (h = s_h; h < NETDEV_HASHENTRIES; h++, s_idx = 0) { - idx = 0; - head = &net->dev_index_head[h]; - rcu_read_lock(); - cb->seq = inet_base_seq(net); - hlist_for_each_entry_rcu(dev, head, index_hlist) { - if (idx < s_idx) - goto cont; - in_dev = __in_dev_get_rcu(dev); - if (!in_dev) - goto cont; - - if (inet_netconf_fill_devconf(skb, dev->ifindex, - &in_dev->cnf, - NETLINK_CB(cb->skb).portid, - nlh->nlmsg_seq, - RTM_NEWNETCONF, - NLM_F_MULTI, - NETCONFA_ALL) < 0) { - rcu_read_unlock(); - goto done; - } - nl_dump_check_consistent(cb, nlmsg_hdr(skb)); -cont: - idx++; - } - rcu_read_unlock(); + rcu_read_lock(); + for_each_netdev_dump(net, dev, ctx->ifindex) { + in_dev = __in_dev_get_rcu(dev); + if (!in_dev) + continue; + err = inet_netconf_fill_devconf(skb, dev->ifindex, + &in_dev->cnf, + NETLINK_CB(cb->skb).portid, + nlh->nlmsg_seq, + RTM_NEWNETCONF, NLM_F_MULTI, + NETCONFA_ALL); + if (err < 0) + goto done; } - if (h == NETDEV_HASHENTRIES) { - if (inet_netconf_fill_devconf(skb, NETCONFA_IFINDEX_ALL, - net->ipv4.devconf_all, - NETLINK_CB(cb->skb).portid, - nlh->nlmsg_seq, - RTM_NEWNETCONF, NLM_F_MULTI, - NETCONFA_ALL) < 0) + if (ctx->all_default == 0) { + err = inet_netconf_fill_devconf(skb, NETCONFA_IFINDEX_ALL, + net->ipv4.devconf_all, + NETLINK_CB(cb->skb).portid, + nlh->nlmsg_seq, + RTM_NEWNETCONF, NLM_F_MULTI, + NETCONFA_ALL); + if (err < 0) goto done; - else - h++; - } - if (h == NETDEV_HASHENTRIES + 1) { - if (inet_netconf_fill_devconf(skb, NETCONFA_IFINDEX_DEFAULT, - net->ipv4.devconf_dflt, - NETLINK_CB(cb->skb).portid, - nlh->nlmsg_seq, - RTM_NEWNETCONF, NLM_F_MULTI, - NETCONFA_ALL) < 0) + ctx->all_default++; + } + if (ctx->all_default == 1) { + err = inet_netconf_fill_devconf(skb, NETCONFA_IFINDEX_DEFAULT, + net->ipv4.devconf_dflt, + NETLINK_CB(cb->skb).portid, + nlh->nlmsg_seq, + RTM_NEWNETCONF, NLM_F_MULTI, + NETCONFA_ALL); + if (err < 0) goto done; - else - h++; + ctx->all_default++; } done: - cb->args[0] = h; - cb->args[1] = idx; - - return skb->len; + if (err < 0 && likely(skb->len)) + err = skb->len; + rcu_read_unlock(); + return err; } #ifdef CONFIG_SYSCTL @@ -2829,5 +2814,5 @@ void __init devinet_init(void) rtnl_register(PF_INET, RTM_GETADDR, NULL, inet_dump_ifaddr, 0); rtnl_register(PF_INET, RTM_GETNETCONF, inet_netconf_get_devconf, inet_netconf_dump_devconf, - RTNL_FLAG_DOIT_UNLOCKED); + RTNL_FLAG_DOIT_UNLOCKED | RTNL_FLAG_DUMP_UNLOCKED); }