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authorEric Dumazet <edumazet@google.com>2017-10-30 22:47:09 -0700
committerDavid S. Miller <davem@davemloft.net>2017-11-01 21:18:13 +0900
commite669b86945478b3d90d2d87e3793a6eed06d332f (patch)
tree71cf1128afbda7ec26fea06cbfd4daa1e6969aea
parent93161922c658c714715686cd0cf69b090cb9bf1d (diff)
ipv6: addrconf: increment ifp refcount before ipv6_del_addr()
In the (unlikely) event fixup_permanent_addr() returns a failure, addrconf_permanent_addr() calls ipv6_del_addr() without the mandatory call to in6_ifa_hold(), leading to a refcount error, spotted by syzkaller : WARNING: CPU: 1 PID: 3142 at lib/refcount.c:227 refcount_dec+0x4c/0x50 lib/refcount.c:227 Kernel panic - not syncing: panic_on_warn set ... CPU: 1 PID: 3142 Comm: ip Not tainted 4.14.0-rc4-next-20171009+ #33 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:16 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:52 panic+0x1e4/0x41c kernel/panic.c:181 __warn+0x1c4/0x1e0 kernel/panic.c:544 report_bug+0x211/0x2d0 lib/bug.c:183 fixup_bug+0x40/0x90 arch/x86/kernel/traps.c:178 do_trap_no_signal arch/x86/kernel/traps.c:212 [inline] do_trap+0x260/0x390 arch/x86/kernel/traps.c:261 do_error_trap+0x120/0x390 arch/x86/kernel/traps.c:298 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:311 invalid_op+0x18/0x20 arch/x86/entry/entry_64.S:905 RIP: 0010:refcount_dec+0x4c/0x50 lib/refcount.c:227 RSP: 0018:ffff8801ca49e680 EFLAGS: 00010286 RAX: 000000000000002c RBX: ffff8801d07cfcdc RCX: 0000000000000000 RDX: 000000000000002c RSI: 1ffff10039493c90 RDI: ffffed0039493cc4 RBP: ffff8801ca49e688 R08: ffff8801ca49dd70 R09: 0000000000000000 R10: ffff8801ca49df58 R11: 0000000000000000 R12: 1ffff10039493cd9 R13: ffff8801ca49e6e8 R14: ffff8801ca49e7e8 R15: ffff8801d07cfcdc __in6_ifa_put include/net/addrconf.h:369 [inline] ipv6_del_addr+0x42b/0xb60 net/ipv6/addrconf.c:1208 addrconf_permanent_addr net/ipv6/addrconf.c:3327 [inline] addrconf_notify+0x1c66/0x2190 net/ipv6/addrconf.c:3393 notifier_call_chain+0x136/0x2c0 kernel/notifier.c:93 __raw_notifier_call_chain kernel/notifier.c:394 [inline] raw_notifier_call_chain+0x2d/0x40 kernel/notifier.c:401 call_netdevice_notifiers_info+0x32/0x60 net/core/dev.c:1697 call_netdevice_notifiers net/core/dev.c:1715 [inline] __dev_notify_flags+0x15d/0x430 net/core/dev.c:6843 dev_change_flags+0xf5/0x140 net/core/dev.c:6879 do_setlink+0xa1b/0x38e0 net/core/rtnetlink.c:2113 rtnl_newlink+0xf0d/0x1a40 net/core/rtnetlink.c:2661 rtnetlink_rcv_msg+0x733/0x1090 net/core/rtnetlink.c:4301 netlink_rcv_skb+0x216/0x440 net/netlink/af_netlink.c:2408 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:4313 netlink_unicast_kernel net/netlink/af_netlink.c:1273 [inline] netlink_unicast+0x4e8/0x6f0 net/netlink/af_netlink.c:1299 netlink_sendmsg+0xa4a/0xe70 net/netlink/af_netlink.c:1862 sock_sendmsg_nosec net/socket.c:633 [inline] sock_sendmsg+0xca/0x110 net/socket.c:643 ___sys_sendmsg+0x75b/0x8a0 net/socket.c:2049 __sys_sendmsg+0xe5/0x210 net/socket.c:2083 SYSC_sendmsg net/socket.c:2094 [inline] SyS_sendmsg+0x2d/0x50 net/socket.c:2090 entry_SYSCALL_64_fastpath+0x1f/0xbe RIP: 0033:0x7fa9174d3320 RSP: 002b:00007ffe302ae9e8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007ffe302b2ae0 RCX: 00007fa9174d3320 RDX: 0000000000000000 RSI: 00007ffe302aea20 RDI: 0000000000000016 RBP: 0000000000000082 R08: 0000000000000000 R09: 000000000000000f R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe302b32a0 R13: 0000000000000000 R14: 00007ffe302b2ab8 R15: 00007ffe302b32b8 Fixes: f1705ec197e7 ("net: ipv6: Make address flushing on ifdown optional") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: David Ahern <dsahern@gmail.com> Acked-by: David Ahern <dsahern@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/ipv6/addrconf.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 4a96ebbf8eda..8a1c846d3df9 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -3335,6 +3335,7 @@ static void addrconf_permanent_addr(struct net_device *dev)
if ((ifp->flags & IFA_F_PERMANENT) &&
fixup_permanent_addr(idev, ifp) < 0) {
write_unlock_bh(&idev->lock);
+ in6_ifa_hold(ifp);
ipv6_del_addr(ifp);
write_lock_bh(&idev->lock);