From: Paolo Abeni pabeni@redhat.com
[ Upstream commit a0eea5f10eeb5180d115452b0d77afa6603dfe18 ]
The endpoint cleanup path is prone to a memory leak, as reported by syzkaller:
BUG: memory leak unreferenced object 0xffff88810680ea00 (size 64): comm "syz-executor.6", pid 6191, jiffies 4295756280 (age 24.138s) hex dump (first 32 bytes): 58 75 7d 3c 80 88 ff ff 22 01 00 00 00 00 ad de Xu}<...."....... 01 00 02 00 00 00 00 00 ac 1e 00 07 00 00 00 00 ................ backtrace: [<0000000072a9f72a>] kmalloc include/linux/slab.h:591 [inline] [<0000000072a9f72a>] mptcp_nl_cmd_add_addr+0x287/0x9f0 net/mptcp/pm_netlink.c:1170 [<00000000f6e931bf>] genl_family_rcv_msg_doit.isra.0+0x225/0x340 net/netlink/genetlink.c:731 [<00000000f1504a2c>] genl_family_rcv_msg net/netlink/genetlink.c:775 [inline] [<00000000f1504a2c>] genl_rcv_msg+0x341/0x5b0 net/netlink/genetlink.c:792 [<0000000097e76f6a>] netlink_rcv_skb+0x148/0x430 net/netlink/af_netlink.c:2504 [<00000000ceefa2b8>] genl_rcv+0x24/0x40 net/netlink/genetlink.c:803 [<000000008ff91aec>] netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline] [<000000008ff91aec>] netlink_unicast+0x537/0x750 net/netlink/af_netlink.c:1340 [<0000000041682c35>] netlink_sendmsg+0x846/0xd80 net/netlink/af_netlink.c:1929 [<00000000df3aa8e7>] sock_sendmsg_nosec net/socket.c:704 [inline] [<00000000df3aa8e7>] sock_sendmsg+0x14e/0x190 net/socket.c:724 [<000000002154c54c>] ____sys_sendmsg+0x709/0x870 net/socket.c:2403 [<000000001aab01d7>] ___sys_sendmsg+0xff/0x170 net/socket.c:2457 [<00000000fa3b1446>] __sys_sendmsg+0xe5/0x1b0 net/socket.c:2486 [<00000000db2ee9c7>] do_syscall_x64 arch/x86/entry/common.c:50 [inline] [<00000000db2ee9c7>] do_syscall_64+0x38/0x90 arch/x86/entry/common.c:80 [<000000005873517d>] entry_SYSCALL_64_after_hwframe+0x44/0xae
We should not require an allocation to cleanup stuff.
Rework the code a bit so that the additional RCU work is no more needed.
Fixes: 1729cf186d8a ("mptcp: create the listening socket for new port") Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Mat Martineau mathew.j.martineau@linux.intel.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/mptcp/pm_netlink.c | 44 ++++++++++++------------------------------ 1 file changed, 12 insertions(+), 32 deletions(-)
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c index fce1d057d19e..45b414efc001 100644 --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -1135,36 +1135,12 @@ next: return 0; }
-struct addr_entry_release_work { - struct rcu_work rwork; - struct mptcp_pm_addr_entry *entry; -}; - -static void mptcp_pm_release_addr_entry(struct work_struct *work) +/* caller must ensure the RCU grace period is already elapsed */ +static void __mptcp_pm_release_addr_entry(struct mptcp_pm_addr_entry *entry) { - struct addr_entry_release_work *w; - struct mptcp_pm_addr_entry *entry; - - w = container_of(to_rcu_work(work), struct addr_entry_release_work, rwork); - entry = w->entry; - if (entry) { - if (entry->lsk) - sock_release(entry->lsk); - kfree(entry); - } - kfree(w); -} - -static void mptcp_pm_free_addr_entry(struct mptcp_pm_addr_entry *entry) -{ - struct addr_entry_release_work *w; - - w = kmalloc(sizeof(*w), GFP_ATOMIC); - if (w) { - INIT_RCU_WORK(&w->rwork, mptcp_pm_release_addr_entry); - w->entry = entry; - queue_rcu_work(system_wq, &w->rwork); - } + if (entry->lsk) + sock_release(entry->lsk); + kfree(entry); }
static int mptcp_nl_remove_id_zero_address(struct net *net, @@ -1244,7 +1220,8 @@ static int mptcp_nl_cmd_del_addr(struct sk_buff *skb, struct genl_info *info) spin_unlock_bh(&pernet->lock);
mptcp_nl_remove_subflow_and_signal_addr(sock_net(skb->sk), &entry->addr); - mptcp_pm_free_addr_entry(entry); + synchronize_rcu(); + __mptcp_pm_release_addr_entry(entry);
return ret; } @@ -1297,6 +1274,7 @@ static void mptcp_nl_remove_addrs_list(struct net *net, } }
+/* caller must ensure the RCU grace period is already elapsed */ static void __flush_addrs(struct list_head *list) { while (!list_empty(list)) { @@ -1305,7 +1283,7 @@ static void __flush_addrs(struct list_head *list) cur = list_entry(list->next, struct mptcp_pm_addr_entry, list); list_del_rcu(&cur->list); - mptcp_pm_free_addr_entry(cur); + __mptcp_pm_release_addr_entry(cur); } }
@@ -1329,6 +1307,7 @@ static int mptcp_nl_cmd_flush_addrs(struct sk_buff *skb, struct genl_info *info) bitmap_zero(pernet->id_bitmap, MAX_ADDR_ID + 1); spin_unlock_bh(&pernet->lock); mptcp_nl_remove_addrs_list(sock_net(skb->sk), &free_list); + synchronize_rcu(); __flush_addrs(&free_list); return 0; } @@ -1936,7 +1915,8 @@ static void __net_exit pm_nl_exit_net(struct list_head *net_list) struct pm_nl_pernet *pernet = net_generic(net, pm_nl_pernet_id);
/* net is removed from namespace list, can't race with - * other modifiers + * other modifiers, also netns core already waited for a + * RCU grace period. */ __flush_addrs(&pernet->local_addr_list); }