From 2a762e9e8cd1cf1242e4269a2244666ed02eecd1 Mon Sep 17 00:00:00 2001 From: Taehee Yoo Date: Thu, 2 Jul 2020 17:08:18 +0000 Subject: net: rmnet: fix lower interface leak There are two types of the lower interface of rmnet that are VND and BRIDGE. Each lower interface can have only one type either VND or BRIDGE. But, there is a case, which uses both lower interface types. Due to this unexpected behavior, lower interface leak occurs. Test commands: ip link add dummy0 type dummy ip link add dummy1 type dummy ip link add rmnet0 link dummy0 type rmnet mux_id 1 ip link set dummy1 master rmnet0 ip link add rmnet1 link dummy1 type rmnet mux_id 2 ip link del rmnet0 The dummy1 was attached as BRIDGE interface of rmnet0. Then, it also was attached as VND interface of rmnet1. This is unexpected behavior and there is no code for handling this case. So that below splat occurs when the rmnet0 interface is deleted. Splat looks like: [ 53.254112][ C1] WARNING: CPU: 1 PID: 1192 at net/core/dev.c:8992 rollback_registered_many+0x986/0xcf0 [ 53.254117][ C1] Modules linked in: rmnet dummy openvswitch nsh nf_conncount nf_nat nf_conntrack nf_defrag_ipv6 nfx [ 53.254182][ C1] CPU: 1 PID: 1192 Comm: ip Not tainted 5.8.0-rc1+ #620 [ 53.254188][ C1] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 [ 53.254192][ C1] RIP: 0010:rollback_registered_many+0x986/0xcf0 [ 53.254200][ C1] Code: 41 8b 4e cc 45 31 c0 31 d2 4c 89 ee 48 89 df e8 e0 47 ff ff 85 c0 0f 84 cd fc ff ff 0f 0b e5 [ 53.254205][ C1] RSP: 0018:ffff888050a5f2e0 EFLAGS: 00010287 [ 53.254214][ C1] RAX: ffff88805756d658 RBX: ffff88804d99c000 RCX: ffffffff8329d323 [ 53.254219][ C1] RDX: 1ffffffff0be6410 RSI: 0000000000000008 RDI: ffffffff85f32080 [ 53.254223][ C1] RBP: dffffc0000000000 R08: fffffbfff0be6411 R09: fffffbfff0be6411 [ 53.254228][ C1] R10: ffffffff85f32087 R11: 0000000000000001 R12: ffff888050a5f480 [ 53.254233][ C1] R13: ffff88804d99c0b8 R14: ffff888050a5f400 R15: ffff8880548ebe40 [ 53.254238][ C1] FS: 00007f6b86b370c0(0000) GS:ffff88806c200000(0000) knlGS:0000000000000000 [ 53.254243][ C1] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 53.254248][ C1] CR2: 0000562c62438758 CR3: 000000003f600005 CR4: 00000000000606e0 [ 53.254253][ C1] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 53.254257][ C1] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 53.254261][ C1] Call Trace: [ 53.254266][ C1] ? lockdep_hardirqs_on_prepare+0x379/0x540 [ 53.254270][ C1] ? netif_set_real_num_tx_queues+0x780/0x780 [ 53.254275][ C1] ? rmnet_unregister_real_device+0x56/0x90 [rmnet] [ 53.254279][ C1] ? __kasan_slab_free+0x126/0x150 [ 53.254283][ C1] ? kfree+0xdc/0x320 [ 53.254288][ C1] ? rmnet_unregister_real_device+0x56/0x90 [rmnet] [ 53.254293][ C1] unregister_netdevice_many.part.135+0x13/0x1b0 [ 53.254297][ C1] rtnl_delete_link+0xbc/0x100 [ 53.254301][ C1] ? rtnl_af_register+0xc0/0xc0 [ 53.254305][ C1] rtnl_dellink+0x2dc/0x840 [ 53.254309][ C1] ? find_held_lock+0x39/0x1d0 [ 53.254314][ C1] ? valid_fdb_dump_strict+0x620/0x620 [ 53.254318][ C1] ? rtnetlink_rcv_msg+0x457/0x890 [ 53.254322][ C1] ? lock_contended+0xd20/0xd20 [ 53.254326][ C1] rtnetlink_rcv_msg+0x4a8/0x890 [ ... ] [ 73.813696][ T1192] unregister_netdevice: waiting for rmnet0 to become free. Usage count = 1 Fixes: 037f9cdf72fb ("net: rmnet: use upper/lower device infrastructure") Signed-off-by: Taehee Yoo Signed-off-by: David S. Miller --- drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c index 40efe60eff8d..2c8c252b7b97 100644 --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c @@ -47,15 +47,23 @@ static int rmnet_unregister_real_device(struct net_device *real_dev) return 0; } -static int rmnet_register_real_device(struct net_device *real_dev) +static int rmnet_register_real_device(struct net_device *real_dev, + struct netlink_ext_ack *extack) { struct rmnet_port *port; int rc, entry; ASSERT_RTNL(); - if (rmnet_is_real_dev_registered(real_dev)) + if (rmnet_is_real_dev_registered(real_dev)) { + port = rmnet_get_port_rtnl(real_dev); + if (port->rmnet_mode != RMNET_EPMODE_VND) { + NL_SET_ERR_MSG_MOD(extack, "bridge device already exists"); + return -EINVAL; + } + return 0; + } port = kzalloc(sizeof(*port), GFP_KERNEL); if (!port) @@ -133,7 +141,7 @@ static int rmnet_newlink(struct net *src_net, struct net_device *dev, mux_id = nla_get_u16(data[IFLA_RMNET_MUX_ID]); - err = rmnet_register_real_device(real_dev); + err = rmnet_register_real_device(real_dev, extack); if (err) goto err0; @@ -421,11 +429,6 @@ int rmnet_add_bridge(struct net_device *rmnet_dev, return -EINVAL; } - if (port->rmnet_mode != RMNET_EPMODE_VND) { - NL_SET_ERR_MSG_MOD(extack, "bridge device already exists"); - return -EINVAL; - } - if (rmnet_is_real_dev_registered(slave_dev)) { NL_SET_ERR_MSG_MOD(extack, "slave cannot be another rmnet dev"); @@ -433,7 +436,7 @@ int rmnet_add_bridge(struct net_device *rmnet_dev, return -EBUSY; } - err = rmnet_register_real_device(slave_dev); + err = rmnet_register_real_device(slave_dev, extack); if (err) return -EBUSY; -- cgit v1.2.3 From 2fb2799a2abb39d7dbb48abb3baa1133bf5e921a Mon Sep 17 00:00:00 2001 From: Taehee Yoo Date: Thu, 2 Jul 2020 17:08:55 +0000 Subject: net: rmnet: do not allow to add multiple bridge interfaces rmnet can have only two bridge interface. One of them is a link interface and another one is added by the master operation. rmnet interface shouldn't allow adding additional bridge interfaces by mater operation. But, there is no code to deny additional interfaces. So, interface leak occurs. Test commands: ip link add dummy0 type dummy ip link add dummy1 type dummy ip link add dummy2 type dummy ip link add rmnet0 link dummy0 type rmnet mux_id 1 ip link set dummy1 master rmnet0 ip link set dummy2 master rmnet0 ip link del rmnet0 In the above test command, the dummy0 was attached to rmnet as VND mode. Then, dummy1 was attached to rmnet0 as BRIDGE mode. At this point, dummy0 mode is switched from VND to BRIDGE automatically. Then, dummy2 is attached to rmnet as BRIDGE mode. At this point, rmnet0 should deny this operation. But, rmnet0 doesn't deny this. So that below splat occurs when the rmnet0 interface is deleted. Splat looks like: [ 186.684787][ C2] WARNING: CPU: 2 PID: 1009 at net/core/dev.c:8992 rollback_registered_many+0x986/0xcf0 [ 186.684788][ C2] Modules linked in: rmnet dummy openvswitch nsh nf_conncount nf_nat nf_conntrack nf_defrag_x [ 186.684805][ C2] CPU: 2 PID: 1009 Comm: ip Not tainted 5.8.0-rc1+ #621 [ 186.684807][ C2] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 [ 186.684808][ C2] RIP: 0010:rollback_registered_many+0x986/0xcf0 [ 186.684811][ C2] Code: 41 8b 4e cc 45 31 c0 31 d2 4c 89 ee 48 89 df e8 e0 47 ff ff 85 c0 0f 84 cd fc ff ff 5 [ 186.684812][ C2] RSP: 0018:ffff8880cd9472e0 EFLAGS: 00010287 [ 186.684815][ C2] RAX: ffff8880cc56da58 RBX: ffff8880ab21c000 RCX: ffffffff9329d323 [ 186.684816][ C2] RDX: 1ffffffff2be6410 RSI: 0000000000000008 RDI: ffffffff95f32080 [ 186.684818][ C2] RBP: dffffc0000000000 R08: fffffbfff2be6411 R09: fffffbfff2be6411 [ 186.684819][ C2] R10: ffffffff95f32087 R11: 0000000000000001 R12: ffff8880cd947480 [ 186.684820][ C2] R13: ffff8880ab21c0b8 R14: ffff8880cd947400 R15: ffff8880cdf10640 [ 186.684822][ C2] FS: 00007f00843890c0(0000) GS:ffff8880d4e00000(0000) knlGS:0000000000000000 [ 186.684823][ C2] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 186.684825][ C2] CR2: 000055b8ab1077b8 CR3: 00000000ab612006 CR4: 00000000000606e0 [ 186.684826][ C2] Call Trace: [ 186.684827][ C2] ? lockdep_hardirqs_on_prepare+0x379/0x540 [ 186.684829][ C2] ? netif_set_real_num_tx_queues+0x780/0x780 [ 186.684830][ C2] ? rmnet_unregister_real_device+0x56/0x90 [rmnet] [ 186.684831][ C2] ? __kasan_slab_free+0x126/0x150 [ 186.684832][ C2] ? kfree+0xdc/0x320 [ 186.684834][ C2] ? rmnet_unregister_real_device+0x56/0x90 [rmnet] [ 186.684835][ C2] unregister_netdevice_many.part.135+0x13/0x1b0 [ 186.684836][ C2] rtnl_delete_link+0xbc/0x100 [ ... ] [ 238.440071][ T1009] unregister_netdevice: waiting for rmnet0 to become free. Usage count = 1 Fixes: 037f9cdf72fb ("net: rmnet: use upper/lower device infrastructure") Signed-off-by: Taehee Yoo Signed-off-by: David S. Miller --- drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c index 2c8c252b7b97..fcdecddb2812 100644 --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c @@ -429,6 +429,11 @@ int rmnet_add_bridge(struct net_device *rmnet_dev, return -EINVAL; } + if (port->rmnet_mode != RMNET_EPMODE_VND) { + NL_SET_ERR_MSG_MOD(extack, "more than one bridge dev attached"); + return -EINVAL; + } + if (rmnet_is_real_dev_registered(slave_dev)) { NL_SET_ERR_MSG_MOD(extack, "slave cannot be another rmnet dev"); -- cgit v1.2.3