[PATCH] net: smc: fix error return code of smc_diag_dump_proto()

[PATCH] net: smc: fix error return code of smc_diag_dump_proto()

[Jia-Ju Bai]

When the list of head is empty, no error return code of
smc_diag_dump_proto() is assigned.
To fix this bug, rc is assigned with -ENOENT as error return code.

Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
---
 net/smc/smc_diag.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/smc/smc_diag.c b/net/smc/smc_diag.c
index c952986a6aca..a90889482842 100644
--- a/net/smc/smc_diag.c
+++ b/net/smc/smc_diag.c
@@ -201,8 +201,10 @@ static int smc_diag_dump_proto(struct proto *prot, struct sk_buff *skb,
 
 	read_lock(&prot->h.smc_hash->lock);
 	head = &prot->h.smc_hash->ht;
-	if (hlist_empty(head))
+	if (hlist_empty(head)) {
+		rc = -ENOENT;
 		goto out;
+	}
 
 	sk_for_each(sk, head) {
 		if (!net_eq(sock_net(sk), net))
-- 
2.17.1

Re: [PATCH] net: smc: fix error return code of smc_diag_dump_proto()

[Karsten Graul]

On 05/03/2021 11:13, Jia-Ju Bai wrote:
> When the list of head is empty, no error return code of
> smc_diag_dump_proto() is assigned.
> To fix this bug, rc is assigned with -ENOENT as error return code.

Your change would break smc_diag_dump().
When there are no IPv4 sockets (SMCPROTO_SMC) in the list and -ENOENT 
is returned then smc_diag_dump() will not try to dump any IPv6 sockets
(SMCPROTO_SMC6). Returning zero is correct here.

> 
> Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
> ---
>  net/smc/smc_diag.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/net/smc/smc_diag.c b/net/smc/smc_diag.c
> index c952986a6aca..a90889482842 100644
> --- a/net/smc/smc_diag.c
> +++ b/net/smc/smc_diag.c
> @@ -201,8 +201,10 @@ static int smc_diag_dump_proto(struct proto *prot, struct sk_buff *skb,
>  
>  	read_lock(&prot->h.smc_hash->lock);
>  	head = &prot->h.smc_hash->ht;
> -	if (hlist_empty(head))
> +	if (hlist_empty(head)) {
> +		rc = -ENOENT;
>  		goto out;
> +	}
>  
>  	sk_for_each(sk, head) {
>  		if (!net_eq(sock_net(sk), net))
> 

-- 
Karsten

(I'm a dude)