[PATCH net-next v2] mptcp: correct MPTCP_SUBFLOW_ATTR_SSN_OFFSET reserved size

[PATCH net-next v2] mptcp: correct MPTCP_SUBFLOW_ATTR_SSN_OFFSET reserved size

[Eugene Syromiatnikov]

ssn_offset field is u32 and is placed into the netlink response with
nla_put_u32(), but only 2 bytes are reserved for the attribute payload
in subflow_get_info_size() (even though it makes no difference
in the end, as it is aligned up to 4 bytes).  Supply the correct
argument to the relevant nla_total_size() call to make it less
confusing.

Fixes: 5147dfb50832 ("mptcp: allow dumping subflow context to userspace")
Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com>
---
v2:
  - Added prefix to the patch subject
  - Fixed commit message formatting (line width, "Fixes:" commit hash
    prefix size)
v1: https://lore.kernel.org/mptcp/20240809094321.GA8122@asgard.redhat.com/
---
 net/mptcp/diag.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/mptcp/diag.c b/net/mptcp/diag.c
index 3ae46b545d2c..2d3efb405437 100644
--- a/net/mptcp/diag.c
+++ b/net/mptcp/diag.c
@@ -94,7 +94,7 @@ static size_t subflow_get_info_size(const struct sock *sk)
 		nla_total_size(4) +	/* MPTCP_SUBFLOW_ATTR_RELWRITE_SEQ */
 		nla_total_size_64bit(8) +	/* MPTCP_SUBFLOW_ATTR_MAP_SEQ */
 		nla_total_size(4) +	/* MPTCP_SUBFLOW_ATTR_MAP_SFSEQ */
-		nla_total_size(2) +	/* MPTCP_SUBFLOW_ATTR_SSN_OFFSET */
+		nla_total_size(4) +	/* MPTCP_SUBFLOW_ATTR_SSN_OFFSET */
 		nla_total_size(2) +	/* MPTCP_SUBFLOW_ATTR_MAP_DATALEN */
 		nla_total_size(4) +	/* MPTCP_SUBFLOW_ATTR_FLAGS */
 		nla_total_size(1) +	/* MPTCP_SUBFLOW_ATTR_ID_REM */
-- 
2.28.0

Re: [PATCH net-next v2] mptcp: correct MPTCP_SUBFLOW_ATTR_SSN_OFFSET reserved size

[Matthieu Baerts]

Hi Eugene, Network maintainers,

On 12/08/2024 08:51, Eugene Syromiatnikov wrote:
> ssn_offset field is u32 and is placed into the netlink response with
> nla_put_u32(), but only 2 bytes are reserved for the attribute payload
> in subflow_get_info_size() (even though it makes no difference
> in the end, as it is aligned up to 4 bytes).  Supply the correct
> argument to the relevant nla_total_size() call to make it less
> confusing.
> 
> Fixes: 5147dfb50832 ("mptcp: allow dumping subflow context to userspace")
> Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com>
> ---
> v2:
>   - Added prefix to the patch subject
>   - Fixed commit message formatting (line width, "Fixes:" commit hash
>     prefix size)

Thank you for the v2!

The patch looks good to me:

Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>

Because it is a fix, I think it is a candidate for -net, not net-next.

@Network maintainers: is it OK for you to apply this v2 in "net", not
"net-next"? Or is it easier for you to have a v3 with a different prefix?

(No conflicts to apply this patch on -net, the code didn't change for 4
years.)

Cheers,
Matt
-- 
Sponsored by the NGI0 Core fund.

Re: [PATCH net-next v2] mptcp: correct MPTCP_SUBFLOW_ATTR_SSN_OFFSET reserved size

[Jakub Kicinski]

On Mon, 12 Aug 2024 09:43:29 +0200 Matthieu Baerts wrote:
> @Network maintainers: is it OK for you to apply this v2 in "net", not
> "net-next"? Or is it easier for you to have a v3 with a different prefix?
> 
> (No conflicts to apply this patch on -net, the code didn't change for 4
> years.)

Looks trivial, should be safe to cross-apply, no need for v3.

Re: [PATCH net-next v2] mptcp: correct MPTCP_SUBFLOW_ATTR_SSN_OFFSET reserved size

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Mon, 12 Aug 2024 08:51:23 +0200 you wrote:
> ssn_offset field is u32 and is placed into the netlink response with
> nla_put_u32(), but only 2 bytes are reserved for the attribute payload
> in subflow_get_info_size() (even though it makes no difference
> in the end, as it is aligned up to 4 bytes).  Supply the correct
> argument to the relevant nla_total_size() call to make it less
> confusing.
> 
> [...]

Here is the summary with links:
  - [net-next,v2] mptcp: correct MPTCP_SUBFLOW_ATTR_SSN_OFFSET reserved size
    https://git.kernel.org/netdev/net/c/655111b838cd

You are awesome, thank you!
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