diff mbox series

[v2,net-next,02/10] sctp: read sk->sk_bound_dev_if once in sctp_rcv()

Message ID 20220513185550.844558-3-eric.dumazet@gmail.com (mailing list archive)
State Accepted
Commit a20ea298071f46effa3aaf965bf9bb34c901db3f
Delegated to: Netdev Maintainers
Headers show
Series [v2,net-next,01/10] net: annotate races around sk->sk_bound_dev_if | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next, async
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 4 this patch: 4
netdev/cc_maintainers fail 1 blamed authors not CCed: sri@us.ibm.com; 2 maintainers not CCed: sri@us.ibm.com linux-sctp@vger.kernel.org
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 4 this patch: 4
netdev/checkpatch warning CHECK: Unnecessary parentheses around 'bound_dev_if != af->skb_iif(skb)'
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Eric Dumazet May 13, 2022, 6:55 p.m. UTC 
From: Eric Dumazet <edumazet@google.com>

sctp_rcv() reads sk->sk_bound_dev_if twice while the socket
is not locked. Another cpu could change this field under us.

Fixes: 0fd9a65a76e8 ("[SCTP] Support SO_BINDTODEVICE socket option on incoming packets.")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Vlad Yasevich <vyasevich@gmail.com>
Cc: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
---
 net/sctp/input.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Comments

Marcelo Ricardo Leitner May 13, 2022, 7:46 p.m. UTC | #1 
On Fri, May 13, 2022 at 11:55:42AM -0700, Eric Dumazet wrote:
> From: Eric Dumazet <edumazet@google.com>
> 
> sctp_rcv() reads sk->sk_bound_dev_if twice while the socket
> is not locked. Another cpu could change this field under us.
> 
> Fixes: 0fd9a65a76e8 ("[SCTP] Support SO_BINDTODEVICE socket option on incoming packets.")

2005.. :-)

> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Cc: Neil Horman <nhorman@tuxdriver.com>
> Cc: Vlad Yasevich <vyasevich@gmail.com>
> Cc: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>

Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
diff mbox series

Patch

diff --git a/net/sctp/input.c b/net/sctp/input.c
index 90e12bafdd4894624b3a63d625ed21c85b60a4f0..4f43afa8678f9febf2f02c2ce1a840ce3ab6a07d 100644
--- a/net/sctp/input.c
+++ b/net/sctp/input.c
@@ -92,6 +92,7 @@  int sctp_rcv(struct sk_buff *skb)
 	struct sctp_chunk *chunk;
 	union sctp_addr src;
 	union sctp_addr dest;
+	int bound_dev_if;
 	int family;
 	struct sctp_af *af;
 	struct net *net = dev_net(skb->dev);
@@ -169,7 +170,8 @@  int sctp_rcv(struct sk_buff *skb)
 	 * If a frame arrives on an interface and the receiving socket is
 	 * bound to another interface, via SO_BINDTODEVICE, treat it as OOTB
 	 */
-	if (sk->sk_bound_dev_if && (sk->sk_bound_dev_if != af->skb_iif(skb))) {
+	bound_dev_if = READ_ONCE(sk->sk_bound_dev_if);
+	if (bound_dev_if && (bound_dev_if != af->skb_iif(skb))) {
 		if (transport) {
 			sctp_transport_put(transport);
 			asoc = NULL;