From: Eric Dumazet edumazet@google.com
commit b7469e83d2add567e4e0b063963db185f3167cea upstream.
Similar to commit 38f88c454042 ("bonding/alb: properly access headers in bond_alb_xmit()"), we need to make sure arp header was pulled in skb->head before blindly accessing it in rlb_arp_xmit().
Remove arp_pkt() private helper, since it is more readable/obvious to have the following construct back to back :
if (!pskb_network_may_pull(skb, sizeof(*arp))) return NULL; arp = (struct arp_pkt *)skb_network_header(skb);
syzbot reported :
BUG: KMSAN: uninit-value in bond_slave_has_mac_rx include/net/bonding.h:704 [inline] BUG: KMSAN: uninit-value in rlb_arp_xmit drivers/net/bonding/bond_alb.c:662 [inline] BUG: KMSAN: uninit-value in bond_alb_xmit+0x575/0x25e0 drivers/net/bonding/bond_alb.c:1477 CPU: 0 PID: 12743 Comm: syz-executor.4 Not tainted 5.6.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1c9/0x220 lib/dump_stack.c:118 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:118 __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:215 bond_slave_has_mac_rx include/net/bonding.h:704 [inline] rlb_arp_xmit drivers/net/bonding/bond_alb.c:662 [inline] bond_alb_xmit+0x575/0x25e0 drivers/net/bonding/bond_alb.c:1477 __bond_start_xmit drivers/net/bonding/bond_main.c:4257 [inline] bond_start_xmit+0x85d/0x2f70 drivers/net/bonding/bond_main.c:4282 __netdev_start_xmit include/linux/netdevice.h:4524 [inline] netdev_start_xmit include/linux/netdevice.h:4538 [inline] xmit_one net/core/dev.c:3470 [inline] dev_hard_start_xmit+0x531/0xab0 net/core/dev.c:3486 __dev_queue_xmit+0x37de/0x4220 net/core/dev.c:4063 dev_queue_xmit+0x4b/0x60 net/core/dev.c:4096 packet_snd net/packet/af_packet.c:2967 [inline] packet_sendmsg+0x8347/0x93b0 net/packet/af_packet.c:2992 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg net/socket.c:672 [inline] __sys_sendto+0xc1b/0xc50 net/socket.c:1998 __do_sys_sendto net/socket.c:2010 [inline] __se_sys_sendto+0x107/0x130 net/socket.c:2006 __x64_sys_sendto+0x6e/0x90 net/socket.c:2006 do_syscall_64+0xb8/0x160 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45c479 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fc77ffbbc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007fc77ffbc6d4 RCX: 000000000045c479 RDX: 000000000000000e RSI: 00000000200004c0 RDI: 0000000000000003 RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000a04 R14: 00000000004cc7b0 R15: 000000000076bf2c
Uninit was created at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:144 [inline] kmsan_internal_poison_shadow+0x66/0xd0 mm/kmsan/kmsan.c:127 kmsan_slab_alloc+0x8a/0xe0 mm/kmsan/kmsan_hooks.c:82 slab_alloc_node mm/slub.c:2793 [inline] __kmalloc_node_track_caller+0xb40/0x1200 mm/slub.c:4401 __kmalloc_reserve net/core/skbuff.c:142 [inline] __alloc_skb+0x2fd/0xac0 net/core/skbuff.c:210 alloc_skb include/linux/skbuff.h:1051 [inline] alloc_skb_with_frags+0x18c/0xa70 net/core/skbuff.c:5766 sock_alloc_send_pskb+0xada/0xc60 net/core/sock.c:2242 packet_alloc_skb net/packet/af_packet.c:2815 [inline] packet_snd net/packet/af_packet.c:2910 [inline] packet_sendmsg+0x66a0/0x93b0 net/packet/af_packet.c:2992 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg net/socket.c:672 [inline] __sys_sendto+0xc1b/0xc50 net/socket.c:1998 __do_sys_sendto net/socket.c:2010 [inline] __se_sys_sendto+0x107/0x130 net/socket.c:2006 __x64_sys_sendto+0x6e/0x90 net/socket.c:2006 do_syscall_64+0xb8/0x160 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x44/0xa9
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet edumazet@google.com Reported-by: syzbot syzkaller@googlegroups.com Cc: Jay Vosburgh j.vosburgh@gmail.com Cc: Veaceslav Falico vfalico@gmail.com Cc: Andy Gospodarek andy@greyhouse.net Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/bonding/bond_alb.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-)
--- a/drivers/net/bonding/bond_alb.c +++ b/drivers/net/bonding/bond_alb.c @@ -74,11 +74,6 @@ struct arp_pkt { }; #pragma pack()
-static inline struct arp_pkt *arp_pkt(const struct sk_buff *skb) -{ - return (struct arp_pkt *)skb_network_header(skb); -} - /* Forward declaration */ static void alb_send_learning_packets(struct slave *slave, u8 mac_addr[], bool strict_match); @@ -577,10 +572,11 @@ static void rlb_req_update_subnet_client spin_unlock(&bond->mode_lock); }
-static struct slave *rlb_choose_channel(struct sk_buff *skb, struct bonding *bond) +static struct slave *rlb_choose_channel(struct sk_buff *skb, + struct bonding *bond, + const struct arp_pkt *arp) { struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond)); - struct arp_pkt *arp = arp_pkt(skb); struct slave *assigned_slave, *curr_active_slave; struct rlb_client_info *client_info; u32 hash_index = 0; @@ -677,8 +673,12 @@ static struct slave *rlb_choose_channel( */ static struct slave *rlb_arp_xmit(struct sk_buff *skb, struct bonding *bond) { - struct arp_pkt *arp = arp_pkt(skb); struct slave *tx_slave = NULL; + struct arp_pkt *arp; + + if (!pskb_network_may_pull(skb, sizeof(*arp))) + return NULL; + arp = (struct arp_pkt *)skb_network_header(skb);
/* Don't modify or load balance ARPs that do not originate locally * (e.g.,arrive via a bridge). @@ -688,7 +688,7 @@ static struct slave *rlb_arp_xmit(struct
if (arp->op_code == htons(ARPOP_REPLY)) { /* the arp must be sent on the selected rx channel */ - tx_slave = rlb_choose_channel(skb, bond); + tx_slave = rlb_choose_channel(skb, bond, arp); if (tx_slave) ether_addr_copy(arp->mac_src, tx_slave->dev->dev_addr); netdev_dbg(bond->dev, "Server sent ARP Reply packet\n"); @@ -698,7 +698,7 @@ static struct slave *rlb_arp_xmit(struct * When the arp reply is received the entry will be updated * with the correct unicast address of the client. */ - rlb_choose_channel(skb, bond); + rlb_choose_channel(skb, bond, arp);
/* The ARP reply packets must be delayed so that * they can cancel out the influence of the ARP request.