Re: memory leak in do_ipv6_setsockopt

From: Eric Dumazet
Date: Tue Dec 01 2015 - 08:37:05 EST


On Tue, 2015-12-01 at 13:27 +0100, Dmitry Vyukov wrote:
> Hello,
>
> The following program causes a memory leak :
>
> // autogenerated by syzkaller (http://github.com/google/syzkaller)
> #include <syscall.h>
> #include <sys/types.h>
> #include <sys/socket.h>
> #include <string.h>
> #include <stdint.h>
> #include <linux/in.h>
> #include <linux/socket.h>
>
> int main()
> {
> long r1 = syscall(SYS_socket, PF_INET6,
> SOCK_STREAM|SOCK_CLOEXEC|SOCK_NONBLOCK, IPPROTO_SCTP);
> const char *opt = "\x15\x53\x5e\x2d\x97\xab\xe1";
> long r3 = syscall(SYS_setsockopt, r1, 0x29ul, 0x6ul, opt, 0x7ul);
> return 0;
> }
>
>
> unreferenced object 0xffff880039a55260 (size 64):
> comm "executor", pid 11746, jiffies 4298984475 (age 16.078s)
> hex dump (first 32 bytes):
> 2f 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 /...............
> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> backtrace:
> [< inline >] kmalloc include/linux/slab.h:463
> [<ffffffff848a2f5f>] sock_kmalloc+0x7f/0xc0 net/core/sock.c:1774
> [<ffffffff84e5bea0>] do_ipv6_setsockopt.isra.7+0x15d0/0x2830
> net/ipv6/ipv6_sockglue.c:483
> [<ffffffff84e5d19b>] ipv6_setsockopt+0x9b/0x140 net/ipv6/ipv6_sockglue.c:885
> [<ffffffff8544616c>] sctp_setsockopt+0x15c/0x36c0 net/sctp/socket.c:3702
> [<ffffffff848a2035>] sock_common_setsockopt+0x95/0xd0 net/core/sock.c:2645
> [< inline >] SYSC_setsockopt net/socket.c:1757
> [<ffffffff8489f1d8>] SyS_setsockopt+0x158/0x240 net/socket.c:1736
>
>
> I confirmed that running this program in a loop steadily increases
> number of objects in kmalloc-64 slab. The leak does not happen with
> IPPROTO_TCP, so probably it is sctp-related.

Thanks for the report.

Probably fixed by :

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 897c01c029ca..8079ecd8465d 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -7375,6 +7375,12 @@ struct proto sctp_prot = {

#if IS_ENABLED(CONFIG_IPV6)

+static void sctp_v6_destroy_sock(struct sock *sk)
+{
+ sctp_destroy_sock(sk);
+ inet6_destroy_sock(sk);
+}
+
struct proto sctpv6_prot = {
.name = "SCTPv6",
.owner = THIS_MODULE,
@@ -7384,7 +7390,7 @@ struct proto sctpv6_prot = {
.accept = sctp_accept,
.ioctl = sctp_ioctl,
.init = sctp_init_sock,
- .destroy = sctp_destroy_sock,
+ .destroy = sctp_v6_destroy_sock,
.shutdown = sctp_shutdown,
.setsockopt = sctp_setsockopt,
.getsockopt = sctp_getsockopt,


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