From 584eab291c67894cb17cc87544b9d086228ea70f Mon Sep 17 00:00:00 2001 From: Taehee Yoo Date: Thu, 22 Nov 2018 19:59:46 +0900 Subject: netfilter: add missing error handling code for register functions register_{netdevice/inetaddr/inet6addr}_notifier may return an error value, this patch adds the code to handle these error paths. Signed-off-by: Taehee Yoo Signed-off-by: Pablo Neira Ayuso --- net/ipv4/netfilter/ipt_MASQUERADE.c | 7 +++++-- net/ipv4/netfilter/nf_nat_masquerade_ipv4.c | 21 +++++++++++++++++---- net/ipv4/netfilter/nft_masq_ipv4.c | 4 +++- 3 files changed, 25 insertions(+), 7 deletions(-) (limited to 'net/ipv4') diff --git a/net/ipv4/netfilter/ipt_MASQUERADE.c b/net/ipv4/netfilter/ipt_MASQUERADE.c index ce1512b02cb2..fd3f9e8a74da 100644 --- a/net/ipv4/netfilter/ipt_MASQUERADE.c +++ b/net/ipv4/netfilter/ipt_MASQUERADE.c @@ -81,9 +81,12 @@ static int __init masquerade_tg_init(void) int ret; ret = xt_register_target(&masquerade_tg_reg); + if (ret) + return ret; - if (ret == 0) - nf_nat_masquerade_ipv4_register_notifier(); + ret = nf_nat_masquerade_ipv4_register_notifier(); + if (ret) + xt_unregister_target(&masquerade_tg_reg); return ret; } diff --git a/net/ipv4/netfilter/nf_nat_masquerade_ipv4.c b/net/ipv4/netfilter/nf_nat_masquerade_ipv4.c index a9d5e013e555..c7d7fa4fc369 100644 --- a/net/ipv4/netfilter/nf_nat_masquerade_ipv4.c +++ b/net/ipv4/netfilter/nf_nat_masquerade_ipv4.c @@ -149,16 +149,29 @@ static struct notifier_block masq_inet_notifier = { static atomic_t masquerade_notifier_refcount = ATOMIC_INIT(0); -void nf_nat_masquerade_ipv4_register_notifier(void) +int nf_nat_masquerade_ipv4_register_notifier(void) { + int ret; + /* check if the notifier was already set */ if (atomic_inc_return(&masquerade_notifier_refcount) > 1) - return; + return 0; /* Register for device down reports */ - register_netdevice_notifier(&masq_dev_notifier); + ret = register_netdevice_notifier(&masq_dev_notifier); + if (ret) + goto err_dec; /* Register IP address change reports */ - register_inetaddr_notifier(&masq_inet_notifier); + ret = register_inetaddr_notifier(&masq_inet_notifier); + if (ret) + goto err_unregister; + + return ret; +err_unregister: + unregister_netdevice_notifier(&masq_dev_notifier); +err_dec: + atomic_dec(&masquerade_notifier_refcount); + return ret; } EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv4_register_notifier); diff --git a/net/ipv4/netfilter/nft_masq_ipv4.c b/net/ipv4/netfilter/nft_masq_ipv4.c index f1193e1e928a..6847de1d1db8 100644 --- a/net/ipv4/netfilter/nft_masq_ipv4.c +++ b/net/ipv4/netfilter/nft_masq_ipv4.c @@ -69,7 +69,9 @@ static int __init nft_masq_ipv4_module_init(void) if (ret < 0) return ret; - nf_nat_masquerade_ipv4_register_notifier(); + ret = nf_nat_masquerade_ipv4_register_notifier(); + if (ret) + nft_unregister_expr(&nft_masq_ipv4_type); return ret; } -- cgit v1.2.3-59-g8ed1b From 095faf45e64be00bff4da2d6182dface3d69c9b7 Mon Sep 17 00:00:00 2001 From: Taehee Yoo Date: Thu, 22 Nov 2018 19:59:57 +0900 Subject: netfilter: nat: fix double register in masquerade modules There is a reference counter to ensure that masquerade modules register notifiers only once. However, the existing reference counter approach is not safe, test commands are: while : do modprobe ip6t_MASQUERADE & modprobe nft_masq_ipv6 & modprobe -rv ip6t_MASQUERADE & modprobe -rv nft_masq_ipv6 & done numbers below represent the reference counter. -------------------------------------------------------- CPU0 CPU1 CPU2 CPU3 CPU4 [insmod] [insmod] [rmmod] [rmmod] [insmod] -------------------------------------------------------- 0->1 register 1->2 returns 2->1 returns 1->0 0->1 register <-- unregister -------------------------------------------------------- The unregistation of CPU3 should be processed before the registration of CPU4. In order to fix this, use a mutex instead of reference counter. splat looks like: [ 323.869557] watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [modprobe:1381] [ 323.869574] Modules linked in: nf_tables(+) nf_nat_ipv6(-) nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 n] [ 323.869574] irq event stamp: 194074 [ 323.898930] hardirqs last enabled at (194073): [] trace_hardirqs_on_thunk+0x1a/0x1c [ 323.898930] hardirqs last disabled at (194074): [] trace_hardirqs_off_thunk+0x1a/0x1c [ 323.898930] softirqs last enabled at (182132): [] __do_softirq+0x6ec/0xa3b [ 323.898930] softirqs last disabled at (182109): [] irq_exit+0x1a6/0x1e0 [ 323.898930] CPU: 0 PID: 1381 Comm: modprobe Not tainted 4.20.0-rc2+ #27 [ 323.898930] RIP: 0010:raw_notifier_chain_register+0xea/0x240 [ 323.898930] Code: 3c 03 0f 8e f2 00 00 00 44 3b 6b 10 7f 4d 49 bc 00 00 00 00 00 fc ff df eb 22 48 8d 7b 10 488 [ 323.898930] RSP: 0018:ffff888101597218 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff13 [ 323.898930] RAX: 0000000000000000 RBX: ffffffffc04361c0 RCX: 0000000000000000 [ 323.898930] RDX: 1ffffffff26132ae RSI: ffffffffc04aa3c0 RDI: ffffffffc04361d0 [ 323.898930] RBP: ffffffffc04361c8 R08: 0000000000000000 R09: 0000000000000001 [ 323.898930] R10: ffff8881015972b0 R11: fffffbfff26132c4 R12: dffffc0000000000 [ 323.898930] R13: 0000000000000000 R14: 1ffff110202b2e44 R15: ffffffffc04aa3c0 [ 323.898930] FS: 00007f813ed41540(0000) GS:ffff88811ae00000(0000) knlGS:0000000000000000 [ 323.898930] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 323.898930] CR2: 0000559bf2c9f120 CR3: 000000010bc80000 CR4: 00000000001006f0 [ 323.898930] Call Trace: [ 323.898930] ? atomic_notifier_chain_register+0x2d0/0x2d0 [ 323.898930] ? down_read+0x150/0x150 [ 323.898930] ? sched_clock_cpu+0x126/0x170 [ 323.898930] ? nf_tables_core_module_init+0xe4/0xe4 [nf_tables] [ 323.898930] ? nf_tables_core_module_init+0xe4/0xe4 [nf_tables] [ 323.898930] register_netdevice_notifier+0xbb/0x790 [ 323.898930] ? __dev_close_many+0x2d0/0x2d0 [ 323.898930] ? __mutex_unlock_slowpath+0x17f/0x740 [ 323.898930] ? wait_for_completion+0x710/0x710 [ 323.898930] ? nf_tables_core_module_init+0xe4/0xe4 [nf_tables] [ 323.898930] ? up_write+0x6c/0x210 [ 323.898930] ? nf_tables_core_module_init+0xe4/0xe4 [nf_tables] [ 324.127073] ? nf_tables_core_module_init+0xe4/0xe4 [nf_tables] [ 324.127073] nft_chain_filter_init+0x1e/0xe8a [nf_tables] [ 324.127073] nf_tables_module_init+0x37/0x92 [nf_tables] [ ... ] Fixes: 8dd33cc93ec9 ("netfilter: nf_nat: generalize IPv4 masquerading support for nf_tables") Fixes: be6b635cd674 ("netfilter: nf_nat: generalize IPv6 masquerading support for nf_tables") Signed-off-by: Taehee Yoo Signed-off-by: Pablo Neira Ayuso --- net/ipv4/netfilter/nf_nat_masquerade_ipv4.c | 23 ++++++++++++++++------- net/ipv6/netfilter/nf_nat_masquerade_ipv6.c | 23 ++++++++++++++++------- 2 files changed, 32 insertions(+), 14 deletions(-) (limited to 'net/ipv4') diff --git a/net/ipv4/netfilter/nf_nat_masquerade_ipv4.c b/net/ipv4/netfilter/nf_nat_masquerade_ipv4.c index c7d7fa4fc369..41327bb99093 100644 --- a/net/ipv4/netfilter/nf_nat_masquerade_ipv4.c +++ b/net/ipv4/netfilter/nf_nat_masquerade_ipv4.c @@ -147,15 +147,17 @@ static struct notifier_block masq_inet_notifier = { .notifier_call = masq_inet_event, }; -static atomic_t masquerade_notifier_refcount = ATOMIC_INIT(0); +static int masq_refcnt; +static DEFINE_MUTEX(masq_mutex); int nf_nat_masquerade_ipv4_register_notifier(void) { - int ret; + int ret = 0; + mutex_lock(&masq_mutex); /* check if the notifier was already set */ - if (atomic_inc_return(&masquerade_notifier_refcount) > 1) - return 0; + if (++masq_refcnt > 1) + goto out_unlock; /* Register for device down reports */ ret = register_netdevice_notifier(&masq_dev_notifier); @@ -166,22 +168,29 @@ int nf_nat_masquerade_ipv4_register_notifier(void) if (ret) goto err_unregister; + mutex_unlock(&masq_mutex); return ret; + err_unregister: unregister_netdevice_notifier(&masq_dev_notifier); err_dec: - atomic_dec(&masquerade_notifier_refcount); + masq_refcnt--; +out_unlock: + mutex_unlock(&masq_mutex); return ret; } EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv4_register_notifier); void nf_nat_masquerade_ipv4_unregister_notifier(void) { + mutex_lock(&masq_mutex); /* check if the notifier still has clients */ - if (atomic_dec_return(&masquerade_notifier_refcount) > 0) - return; + if (--masq_refcnt > 0) + goto out_unlock; unregister_netdevice_notifier(&masq_dev_notifier); unregister_inetaddr_notifier(&masq_inet_notifier); +out_unlock: + mutex_unlock(&masq_mutex); } EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv4_unregister_notifier); diff --git a/net/ipv6/netfilter/nf_nat_masquerade_ipv6.c b/net/ipv6/netfilter/nf_nat_masquerade_ipv6.c index 7afd1e63d2db..0ad0da5a2600 100644 --- a/net/ipv6/netfilter/nf_nat_masquerade_ipv6.c +++ b/net/ipv6/netfilter/nf_nat_masquerade_ipv6.c @@ -175,15 +175,17 @@ static struct notifier_block masq_inet6_notifier = { .notifier_call = masq_inet6_event, }; -static atomic_t masquerade_notifier_refcount = ATOMIC_INIT(0); +static int masq_refcnt; +static DEFINE_MUTEX(masq_mutex); int nf_nat_masquerade_ipv6_register_notifier(void) { - int ret; + int ret = 0; + mutex_lock(&masq_mutex); /* check if the notifier is already set */ - if (atomic_inc_return(&masquerade_notifier_refcount) > 1) - return 0; + if (++masq_refcnt > 1) + goto out_unlock; ret = register_netdevice_notifier(&masq_dev_notifier); if (ret) @@ -193,22 +195,29 @@ int nf_nat_masquerade_ipv6_register_notifier(void) if (ret) goto err_unregister; + mutex_unlock(&masq_mutex); return ret; + err_unregister: unregister_netdevice_notifier(&masq_dev_notifier); err_dec: - atomic_dec(&masquerade_notifier_refcount); + masq_refcnt--; +out_unlock: + mutex_unlock(&masq_mutex); return ret; } EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv6_register_notifier); void nf_nat_masquerade_ipv6_unregister_notifier(void) { + mutex_lock(&masq_mutex); /* check if the notifier still has clients */ - if (atomic_dec_return(&masquerade_notifier_refcount) > 0) - return; + if (--masq_refcnt > 0) + goto out_unlock; unregister_inet6addr_notifier(&masq_inet6_notifier); unregister_netdevice_notifier(&masq_dev_notifier); +out_unlock: + mutex_unlock(&masq_mutex); } EXPORT_SYMBOL_GPL(nf_nat_masquerade_ipv6_unregister_notifier); -- cgit v1.2.3-59-g8ed1b