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3c52c6bb83
syzbot reported a memory leak [0] related to IPV6_ADDRFORM.
The scenario is that while one thread is converting an IPv6 socket into
IPv4 with IPV6_ADDRFORM, another thread calls do_ipv6_setsockopt() and
allocates memory to inet6_sk(sk)->XXX after conversion.
Then, the converted sk with (tcp|udp)_prot never frees the IPv6 resources,
which inet6_destroy_sock() should have cleaned up.
setsockopt(IPV6_ADDRFORM) setsockopt(IPV6_DSTOPTS)
+-----------------------+ +----------------------+
- do_ipv6_setsockopt(sk, ...)
- sockopt_lock_sock(sk) - do_ipv6_setsockopt(sk, ...)
- lock_sock(sk) ^._ called via tcpv6_prot
- WRITE_ONCE(sk->sk_prot, &tcp_prot) before WRITE_ONCE()
- xchg(&np->opt, NULL)
- txopt_put(opt)
- sockopt_release_sock(sk)
- release_sock(sk) - sockopt_lock_sock(sk)
- lock_sock(sk)
- ipv6_set_opt_hdr(sk, ...)
- ipv6_update_options(sk, opt)
- xchg(&inet6_sk(sk)->opt, opt)
^._ opt is never freed.
- sockopt_release_sock(sk)
- release_sock(sk)
Since IPV6_DSTOPTS allocates options under lock_sock(), we can avoid this
memory leak by testing whether sk_family is changed by IPV6_ADDRFORM after
acquiring the lock.
This issue exists from the initial commit between IPV6_ADDRFORM and
IPV6_PKTOPTIONS.
[0]:
BUG: memory leak
unreferenced object 0xffff888009ab9f80 (size 96):
comm "syz-executor583", pid 328, jiffies 4294916198 (age 13.034s)
hex dump (first 32 bytes):
01 00 00 00 48 00 00 00 08 00 00 00 00 00 00 00 ....H...........
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<000000002ee98ae1>] kmalloc include/linux/slab.h:605 [inline]
[<000000002ee98ae1>] sock_kmalloc+0xb3/0x100 net/core/sock.c:2566
[<0000000065d7b698>] ipv6_renew_options+0x21e/0x10b0 net/ipv6/exthdrs.c:1318
[<00000000a8c756d7>] ipv6_set_opt_hdr net/ipv6/ipv6_sockglue.c:354 [inline]
[<00000000a8c756d7>] do_ipv6_setsockopt.constprop.0+0x28b7/0x4350 net/ipv6/ipv6_sockglue.c:668
[<000000002854d204>] ipv6_setsockopt+0xdf/0x190 net/ipv6/ipv6_sockglue.c:1021
[<00000000e69fdcf8>] tcp_setsockopt+0x13b/0x2620 net/ipv4/tcp.c:3789
[<0000000090da4b9b>] __sys_setsockopt+0x239/0x620 net/socket.c:2252
[<00000000b10d192f>] __do_sys_setsockopt net/socket.c:2263 [inline]
[<00000000b10d192f>] __se_sys_setsockopt net/socket.c:2260 [inline]
[<00000000b10d192f>] __x64_sys_setsockopt+0xbe/0x160 net/socket.c:2260
[<000000000a80d7aa>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
[<000000000a80d7aa>] do_syscall_64+0x38/0x90 arch/x86/entry/common.c:80
[<000000004562b5c6>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
Fixes:
|
||
|---|---|---|
| .. | ||
| ila | ||
| netfilter | ||
| addrconf.c | ||
| addrconf_core.c | ||
| addrlabel.c | ||
| af_inet6.c | ||
| ah6.c | ||
| anycast.c | ||
| calipso.c | ||
| datagram.c | ||
| esp6.c | ||
| esp6_offload.c | ||
| exthdrs.c | ||
| exthdrs_core.c | ||
| exthdrs_offload.c | ||
| fib6_notifier.c | ||
| fib6_rules.c | ||
| fou6.c | ||
| icmp.c | ||
| inet6_connection_sock.c | ||
| inet6_hashtables.c | ||
| ioam6.c | ||
| ioam6_iptunnel.c | ||
| ip6_checksum.c | ||
| ip6_fib.c | ||
| ip6_flowlabel.c | ||
| ip6_gre.c | ||
| ip6_icmp.c | ||
| ip6_input.c | ||
| ip6_offload.c | ||
| ip6_offload.h | ||
| ip6_output.c | ||
| ip6_tunnel.c | ||
| ip6_udp_tunnel.c | ||
| ip6_vti.c | ||
| ip6mr.c | ||
| ipcomp6.c | ||
| ipv6_sockglue.c | ||
| Kconfig | ||
| Makefile | ||
| mcast.c | ||
| mcast_snoop.c | ||
| mip6.c | ||
| ndisc.c | ||
| netfilter.c | ||
| output_core.c | ||
| ping.c | ||
| proc.c | ||
| protocol.c | ||
| raw.c | ||
| reassembly.c | ||
| route.c | ||
| rpl.c | ||
| rpl_iptunnel.c | ||
| seg6.c | ||
| seg6_hmac.c | ||
| seg6_iptunnel.c | ||
| seg6_local.c | ||
| sit.c | ||
| syncookies.c | ||
| sysctl_net_ipv6.c | ||
| tcp_ipv6.c | ||
| tcpv6_offload.c | ||
| tunnel6.c | ||
| udp.c | ||
| udp_impl.h | ||
| udp_offload.c | ||
| udplite.c | ||
| xfrm6_input.c | ||
| xfrm6_output.c | ||
| xfrm6_policy.c | ||
| xfrm6_protocol.c | ||
| xfrm6_state.c | ||
| xfrm6_tunnel.c | ||