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authorAndrey Ryabinin <aryabinin@virtuozzo.com>2017-02-22 12:35:27 +0300
committerDavid S. Miller <davem@davemloft.net>2017-02-22 16:14:07 -0500
commitec7cb62d18d854ea09df8b7194e7e710985f8b9a (patch)
tree0e548d50f40aef5ef9e961915355f0a74d1ce948 /net/dccp/ipv4.c
parentuapi: fix linux/if.h userspace compilation errors (diff)
downloadlinux-dev-ec7cb62d18d854ea09df8b7194e7e710985f8b9a.tar.xz
linux-dev-ec7cb62d18d854ea09df8b7194e7e710985f8b9a.zip
net/dccp: fix use after free in tw_timer_handler()
DCCP doesn't purge timewait sockets on network namespace shutdown. So, after net namespace destroyed we could still have an active timer which will trigger use after free in tw_timer_handler(): BUG: KASAN: use-after-free in tw_timer_handler+0x4a/0xa0 at addr ffff88010e0d1e10 Read of size 8 by task swapper/1/0 Call Trace: __asan_load8+0x54/0x90 tw_timer_handler+0x4a/0xa0 call_timer_fn+0x127/0x480 expire_timers+0x1db/0x2e0 run_timer_softirq+0x12f/0x2a0 __do_softirq+0x105/0x5b4 irq_exit+0xdd/0xf0 smp_apic_timer_interrupt+0x57/0x70 apic_timer_interrupt+0x90/0xa0 Object at ffff88010e0d1bc0, in cache net_namespace size: 6848 Allocated: save_stack_trace+0x1b/0x20 kasan_kmalloc+0xee/0x180 kasan_slab_alloc+0x12/0x20 kmem_cache_alloc+0x134/0x310 copy_net_ns+0x8d/0x280 create_new_namespaces+0x23f/0x340 unshare_nsproxy_namespaces+0x75/0xf0 SyS_unshare+0x299/0x4f0 entry_SYSCALL_64_fastpath+0x18/0xad Freed: save_stack_trace+0x1b/0x20 kasan_slab_free+0xae/0x180 kmem_cache_free+0xb4/0x350 net_drop_ns+0x3f/0x50 cleanup_net+0x3df/0x450 process_one_work+0x419/0xbb0 worker_thread+0x92/0x850 kthread+0x192/0x1e0 ret_from_fork+0x2e/0x40 Add .exit_batch hook to dccp_v4_ops()/dccp_v6_ops() which will purge timewait sockets on net namespace destruction and prevent above issue. Fixes: f2bf415cfed7 ("mib: add net to NET_ADD_STATS_BH") Reported-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/dccp/ipv4.c')
-rw-r--r--net/dccp/ipv4.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
index b043ec833785..409d0cfd3447 100644
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -1017,9 +1017,15 @@ static void __net_exit dccp_v4_exit_net(struct net *net)
inet_ctl_sock_destroy(net->dccp.v4_ctl_sk);
}
+static void __net_exit dccp_v4_exit_batch(struct list_head *net_exit_list)
+{
+ inet_twsk_purge(&dccp_hashinfo, AF_INET);
+}
+
static struct pernet_operations dccp_v4_ops = {
.init = dccp_v4_init_net,
.exit = dccp_v4_exit_net,
+ .exit_batch = dccp_v4_exit_batch,
};
static int __init dccp_v4_init(void)