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Commit 9b61d3f6 authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by Greg Kroah-Hartman
Browse files

ipv4: Fix data-races around sysctl_ip_dynaddr. 



[ Upstream commit e49e4aff7ec19b2d0d0957ee30e93dade57dab9e ]

While reading sysctl_ip_dynaddr, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its readers.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent cc9540ba

Documentation/networking/ip-sysctl.txt

+1 −1
Original line number Diff line number Diff line
@@ -953,7 +953,7 @@ ip_nonlocal_bind - BOOLEAN 
	which can be quite useful - but may break some applications.

	Default: 0



ip_dynaddr - BOOLEAN

ip_dynaddr - INTEGER

	If set non-zero, enables support for dynamic addresses.

	If set to a non-zero value larger than 1, a kernel log

	message will be printed when dynamic address rewriting

net/ipv4/af_inet.c

+2 −2
Original line number Diff line number Diff line
@@ -1215,7 +1215,7 @@ static int inet_sk_reselect_saddr(struct sock *sk) 
	if (new_saddr == old_saddr)

		return 0;



	if (sock_net(sk)->ipv4.sysctl_ip_dynaddr > 1) {

	if (READ_ONCE(sock_net(sk)->ipv4.sysctl_ip_dynaddr) > 1) {

		pr_info("%s(): shifting inet->saddr from %pI4 to %pI4\n",

			__func__, &old_saddr, &new_saddr);

	}
@@ -1270,7 +1270,7 @@ int inet_sk_rebuild_header(struct sock *sk) 
		 * Other protocols have to map its equivalent state to TCP_SYN_SENT.

		 * DCCP maps its DCCP_REQUESTING state to TCP_SYN_SENT. -acme

		 */

		if (!sock_net(sk)->ipv4.sysctl_ip_dynaddr ||

		if (!READ_ONCE(sock_net(sk)->ipv4.sysctl_ip_dynaddr) ||

		    sk->sk_state != TCP_SYN_SENT ||

		    (sk->sk_userlocks & SOCK_BINDADDR_LOCK) ||

		    (err = inet_sk_reselect_saddr(sk)) != 0)