[RFC v2 0/1] net/tls: add support for limiting the max record size

[RFC v2 0/1] net/tls: add support for limiting the max record size

[Wilfred Mallawa]

From: Wilfred Mallawa <wilfred.mallawa@wdc.com>

During a handshake, an endpoint may specify a maximum record size limit.
Currently, the kernel defaults to TLS_MAX_PAYLOAD_SIZE (16KB) for the
maximum record size. Meaning that, outgoing records from the kernel
can exceed the negotiated size during a handshake. In such a case,
the TLS endpoint must send a fatal "record_overflow" alert [1], and
thus the record is discarded.

Upcoming Western Digital NVMe-TCP hardware controllers implement TLS
support. For these devices, supporting TLS record size negotiation is
necessary because the maximum TLS record size supported by the controller
is less than the default 16KB currently used by the kernel.

This patch adds support for retrieving the negotiated record size limit
during a handshake, and enforcing it at the TLS layer such that outgoing
records are no larger than the size negotiated. This patch depends on
the respective userspace support in tlshd [2] and GnuTLS [3]. GnuTLS
patches have been merged.

[1] https://www.rfc-editor.org/rfc/rfc8449
[2] https://github.com/oracle/ktls-utils/pull/112
[3] https://gitlab.com/gnutls/gnutls/-/merge_requests/2005

Wilfred Mallawa (1):
  net/tls: allow limiting maximum record size

 Documentation/netlink/specs/handshake.yaml |  3 +++
 include/net/tls.h                          |  2 ++
 include/uapi/linux/handshake.h             |  1 +
 net/handshake/genl.c                       |  5 ++--
 net/handshake/tlshd.c                      | 29 +++++++++++++++++++++-
 net/tls/tls_sw.c                           |  6 ++++-
 6 files changed, 42 insertions(+), 4 deletions(-)

-- 
2.50.1

[RFC v2 1/1] net/tls: allow limiting maximum record size

[Wilfred Mallawa]

From: Wilfred Mallawa <wilfred.mallawa@wdc.com>

During a handshake, an endpoint may specify a maximum record size limit.
Currently, the kernel defaults to TLS_MAX_PAYLOAD_SIZE (16KB) for the
maximum record size. Meaning that, the outgoing records from the kernel
can exceed a lower size negotiated during the handshake. In such a case,
the TLS endpoint must send a fatal "record_overflow" alert [1], and
thus the record is discarded.

This patch adds support for retrieving the negotiated record size limit
during a handshake, and enforcing it at the TLS layer such that outgoing
records are no larger than the size negotiated. This patch depends on
the respective userspace support in tlshd [2] and GnuTLS [3].

[1] https://www.rfc-editor.org/rfc/rfc8449
[2] https://github.com/oracle/ktls-utils/pull/112
[3] https://gitlab.com/gnutls/gnutls/-/merge_requests/2005

Signed-off-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>
---
 Documentation/netlink/specs/handshake.yaml |  3 +++
 include/net/tls.h                          |  2 ++
 include/uapi/linux/handshake.h             |  1 +
 net/handshake/genl.c                       |  5 ++--
 net/handshake/tlshd.c                      | 29 +++++++++++++++++++++-
 net/tls/tls_sw.c                           |  6 ++++-
 6 files changed, 42 insertions(+), 4 deletions(-)

diff --git a/Documentation/netlink/specs/handshake.yaml b/Documentation/netlink/specs/handshake.yaml
index b934cc513e3d..4e6bc348f1fd 100644
--- a/Documentation/netlink/specs/handshake.yaml
+++ b/Documentation/netlink/specs/handshake.yaml
@@ -84,6 +84,9 @@ attribute-sets:
         name: remote-auth
         type: u32
         multi-attr: true
+      -
+          name: record-size-limit
+          type: u32
 
 operations:
   list:
diff --git a/include/net/tls.h b/include/net/tls.h
index 857340338b69..02e7b59fcc30 100644
--- a/include/net/tls.h
+++ b/include/net/tls.h
@@ -250,6 +250,8 @@ struct tls_context {
 			       */
 	unsigned long flags;
 
+	u32 tls_record_size_limit;
+
 	/* cache cold stuff */
 	struct proto *sk_proto;
 	struct sock *sk;
diff --git a/include/uapi/linux/handshake.h b/include/uapi/linux/handshake.h
index 3d7ea58778c9..0768eb8eb415 100644
--- a/include/uapi/linux/handshake.h
+++ b/include/uapi/linux/handshake.h
@@ -54,6 +54,7 @@ enum {
 	HANDSHAKE_A_DONE_STATUS = 1,
 	HANDSHAKE_A_DONE_SOCKFD,
 	HANDSHAKE_A_DONE_REMOTE_AUTH,
+	HANDSHAKE_A_DONE_RECORD_SIZE_LIMIT,
 
 	__HANDSHAKE_A_DONE_MAX,
 	HANDSHAKE_A_DONE_MAX = (__HANDSHAKE_A_DONE_MAX - 1)
diff --git a/net/handshake/genl.c b/net/handshake/genl.c
index f55d14d7b726..44c43ce18361 100644
--- a/net/handshake/genl.c
+++ b/net/handshake/genl.c
@@ -16,10 +16,11 @@ static const struct nla_policy handshake_accept_nl_policy[HANDSHAKE_A_ACCEPT_HAN
 };
 
 /* HANDSHAKE_CMD_DONE - do */
-static const struct nla_policy handshake_done_nl_policy[HANDSHAKE_A_DONE_REMOTE_AUTH + 1] = {
+static const struct nla_policy handshake_done_nl_policy[HANDSHAKE_A_DONE_RECORD_SIZE_LIMIT + 1] = {
 	[HANDSHAKE_A_DONE_STATUS] = { .type = NLA_U32, },
 	[HANDSHAKE_A_DONE_SOCKFD] = { .type = NLA_S32, },
 	[HANDSHAKE_A_DONE_REMOTE_AUTH] = { .type = NLA_U32, },
+	[HANDSHAKE_A_DONE_RECORD_SIZE_LIMIT] = { .type = NLA_U32, },
 };
 
 /* Ops table for handshake */
@@ -35,7 +36,7 @@ static const struct genl_split_ops handshake_nl_ops[] = {
 		.cmd		= HANDSHAKE_CMD_DONE,
 		.doit		= handshake_nl_done_doit,
 		.policy		= handshake_done_nl_policy,
-		.maxattr	= HANDSHAKE_A_DONE_REMOTE_AUTH,
+		.maxattr	= HANDSHAKE_A_DONE_RECORD_SIZE_LIMIT,
 		.flags		= GENL_CMD_CAP_DO,
 	},
 };
diff --git a/net/handshake/tlshd.c b/net/handshake/tlshd.c
index d6f52839827e..f4e793f6288d 100644
--- a/net/handshake/tlshd.c
+++ b/net/handshake/tlshd.c
@@ -19,6 +19,7 @@
 #include <net/handshake.h>
 #include <net/genetlink.h>
 #include <net/tls_prot.h>
+#include <net/tls.h>
 
 #include <uapi/linux/keyctl.h>
 #include <uapi/linux/handshake.h>
@@ -37,6 +38,8 @@ struct tls_handshake_req {
 	key_serial_t		th_certificate;
 	key_serial_t		th_privkey;
 
+	struct socket		*th_sock;
+
 	unsigned int		th_num_peerids;
 	key_serial_t		th_peerid[5];
 };
@@ -52,6 +55,7 @@ tls_handshake_req_init(struct handshake_req *req,
 	treq->th_consumer_data = args->ta_data;
 	treq->th_peername = args->ta_peername;
 	treq->th_keyring = args->ta_keyring;
+	treq->th_sock = args->ta_sock;
 	treq->th_num_peerids = 0;
 	treq->th_certificate = TLS_NO_CERT;
 	treq->th_privkey = TLS_NO_PRIVKEY;
@@ -85,6 +89,27 @@ static void tls_handshake_remote_peerids(struct tls_handshake_req *treq,
 	}
 }
 
+static void tls_handshake_record_size(struct tls_handshake_req *treq,
+				      struct genl_info *info)
+{
+	struct tls_context *tls_ctx;
+	struct nlattr *head = nlmsg_attrdata(info->nlhdr, GENL_HDRLEN);
+	struct nlattr *nla;
+	u32 record_size_limit;
+	int rem, len = nlmsg_attrlen(info->nlhdr, GENL_HDRLEN);
+
+	nla_for_each_attr(nla, head, len, rem) {
+		if (nla_type(nla) == HANDSHAKE_A_DONE_RECORD_SIZE_LIMIT) {
+			record_size_limit = nla_get_u32(nla);
+			if (treq->th_sock) {
+				tls_ctx = tls_get_ctx(treq->th_sock->sk);
+				tls_ctx->tls_record_size_limit = record_size_limit;
+			}
+			break;
+		}
+	}
+}
+
 /**
  * tls_handshake_done - callback to handle a CMD_DONE request
  * @req: socket on which the handshake was performed
@@ -98,8 +123,10 @@ static void tls_handshake_done(struct handshake_req *req,
 	struct tls_handshake_req *treq = handshake_req_private(req);
 
 	treq->th_peerid[0] = TLS_NO_PEERID;
-	if (info)
+	if (info) {
 		tls_handshake_remote_peerids(treq, info);
+		tls_handshake_record_size(treq, info);
+	}
 
 	if (!status)
 		set_bit(HANDSHAKE_F_REQ_SESSION, &req->hr_flags);
diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index fc88e34b7f33..70ffc4f5e382 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -1024,6 +1024,7 @@ static int tls_sw_sendmsg_locked(struct sock *sk, struct msghdr *msg,
 	ssize_t copied = 0;
 	struct sk_msg *msg_pl, *msg_en;
 	struct tls_rec *rec;
+	u32 tls_record_size_limit;
 	int required_size;
 	int num_async = 0;
 	bool full_record;
@@ -1045,6 +1046,9 @@ static int tls_sw_sendmsg_locked(struct sock *sk, struct msghdr *msg,
 		}
 	}
 
+	tls_record_size_limit = min_not_zero(tls_ctx->tls_record_size_limit,
+					     TLS_MAX_PAYLOAD_SIZE);
+
 	while (msg_data_left(msg)) {
 		if (sk->sk_err) {
 			ret = -sk->sk_err;
@@ -1066,7 +1070,7 @@ static int tls_sw_sendmsg_locked(struct sock *sk, struct msghdr *msg,
 		orig_size = msg_pl->sg.size;
 		full_record = false;
 		try_to_copy = msg_data_left(msg);
-		record_room = TLS_MAX_PAYLOAD_SIZE - msg_pl->sg.size;
+		record_room = tls_record_size_limit - msg_pl->sg.size;
 		if (try_to_copy >= record_room) {
 			try_to_copy = record_room;
 			full_record = true;
-- 
2.50.1

Re: [RFC v2 1/1] net/tls: allow limiting maximum record size

[Hannes Reinecke]

On 8/8/25 09:24, Wilfred Mallawa wrote:
> From: Wilfred Mallawa <wilfred.mallawa@wdc.com>
> 
> During a handshake, an endpoint may specify a maximum record size limit.
> Currently, the kernel defaults to TLS_MAX_PAYLOAD_SIZE (16KB) for the
> maximum record size. Meaning that, the outgoing records from the kernel
> can exceed a lower size negotiated during the handshake. In such a case,
> the TLS endpoint must send a fatal "record_overflow" alert [1], and
> thus the record is discarded.
> 
> This patch adds support for retrieving the negotiated record size limit
> during a handshake, and enforcing it at the TLS layer such that outgoing
> records are no larger than the size negotiated. This patch depends on
> the respective userspace support in tlshd [2] and GnuTLS [3].
> 
> [1] https://www.rfc-editor.org/rfc/rfc8449
> [2] https://github.com/oracle/ktls-utils/pull/112
> [3] https://gitlab.com/gnutls/gnutls/-/merge_requests/2005
> 
> Signed-off-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>
> ---
>   Documentation/netlink/specs/handshake.yaml |  3 +++
>   include/net/tls.h                          |  2 ++
>   include/uapi/linux/handshake.h             |  1 +
>   net/handshake/genl.c                       |  5 ++--
>   net/handshake/tlshd.c                      | 29 +++++++++++++++++++++-
>   net/tls/tls_sw.c                           |  6 ++++-
>   6 files changed, 42 insertions(+), 4 deletions(-)
> 
> diff --git a/Documentation/netlink/specs/handshake.yaml b/Documentation/netlink/specs/handshake.yaml
> index b934cc513e3d..4e6bc348f1fd 100644
> --- a/Documentation/netlink/specs/handshake.yaml
> +++ b/Documentation/netlink/specs/handshake.yaml
> @@ -84,6 +84,9 @@ attribute-sets:
>           name: remote-auth
>           type: u32
>           multi-attr: true
> +      -
> +          name: record-size-limit
> +          type: u32
>   
>   operations:
>     list:
> diff --git a/include/net/tls.h b/include/net/tls.h
> index 857340338b69..02e7b59fcc30 100644
> --- a/include/net/tls.h
> +++ b/include/net/tls.h
> @@ -250,6 +250,8 @@ struct tls_context {
>   			       */
>   	unsigned long flags;
>   
> +	u32 tls_record_size_limit;
> +
>   	/* cache cold stuff */
>   	struct proto *sk_proto;
>   	struct sock *sk;
> diff --git a/include/uapi/linux/handshake.h b/include/uapi/linux/handshake.h
> index 3d7ea58778c9..0768eb8eb415 100644
> --- a/include/uapi/linux/handshake.h
> +++ b/include/uapi/linux/handshake.h
> @@ -54,6 +54,7 @@ enum {
>   	HANDSHAKE_A_DONE_STATUS = 1,
>   	HANDSHAKE_A_DONE_SOCKFD,
>   	HANDSHAKE_A_DONE_REMOTE_AUTH,
> +	HANDSHAKE_A_DONE_RECORD_SIZE_LIMIT,
>   
>   	__HANDSHAKE_A_DONE_MAX,
>   	HANDSHAKE_A_DONE_MAX = (__HANDSHAKE_A_DONE_MAX - 1)
> diff --git a/net/handshake/genl.c b/net/handshake/genl.c
> index f55d14d7b726..44c43ce18361 100644
> --- a/net/handshake/genl.c
> +++ b/net/handshake/genl.c
> @@ -16,10 +16,11 @@ static const struct nla_policy handshake_accept_nl_policy[HANDSHAKE_A_ACCEPT_HAN
>   };
>   
>   /* HANDSHAKE_CMD_DONE - do */
> -static const struct nla_policy handshake_done_nl_policy[HANDSHAKE_A_DONE_REMOTE_AUTH + 1] = {
> +static const struct nla_policy handshake_done_nl_policy[HANDSHAKE_A_DONE_RECORD_SIZE_LIMIT + 1] = {

Shouldn't that be 'HANDSHAKE_A_DONE_MAX'?

>   	[HANDSHAKE_A_DONE_STATUS] = { .type = NLA_U32, },
>   	[HANDSHAKE_A_DONE_SOCKFD] = { .type = NLA_S32, },
>   	[HANDSHAKE_A_DONE_REMOTE_AUTH] = { .type = NLA_U32, },
> +	[HANDSHAKE_A_DONE_RECORD_SIZE_LIMIT] = { .type = NLA_U32, },
>   };
>   
>   /* Ops table for handshake */
> @@ -35,7 +36,7 @@ static const struct genl_split_ops handshake_nl_ops[] = {
>   		.cmd		= HANDSHAKE_CMD_DONE,
>   		.doit		= handshake_nl_done_doit,
>   		.policy		= handshake_done_nl_policy,
> -		.maxattr	= HANDSHAKE_A_DONE_REMOTE_AUTH,
> +		.maxattr	= HANDSHAKE_A_DONE_RECORD_SIZE_LIMIT,

HANDSHAKE_A_DONE_MAX - 1?

>   		.flags		= GENL_CMD_CAP_DO,
>   	},
>   };
> diff --git a/net/handshake/tlshd.c b/net/handshake/tlshd.c
> index d6f52839827e..f4e793f6288d 100644
> --- a/net/handshake/tlshd.c
> +++ b/net/handshake/tlshd.c
> @@ -19,6 +19,7 @@
>   #include <net/handshake.h>
>   #include <net/genetlink.h>
>   #include <net/tls_prot.h>
> +#include <net/tls.h>
>   
>   #include <uapi/linux/keyctl.h>
>   #include <uapi/linux/handshake.h>
> @@ -37,6 +38,8 @@ struct tls_handshake_req {
>   	key_serial_t		th_certificate;
>   	key_serial_t		th_privkey;
>   
> +	struct socket		*th_sock;
> +
>   	unsigned int		th_num_peerids;
>   	key_serial_t		th_peerid[5];
>   };
> @@ -52,6 +55,7 @@ tls_handshake_req_init(struct handshake_req *req,
>   	treq->th_consumer_data = args->ta_data;
>   	treq->th_peername = args->ta_peername;
>   	treq->th_keyring = args->ta_keyring;
> +	treq->th_sock = args->ta_sock;
>   	treq->th_num_peerids = 0;
>   	treq->th_certificate = TLS_NO_CERT;
>   	treq->th_privkey = TLS_NO_PRIVKEY;
> @@ -85,6 +89,27 @@ static void tls_handshake_remote_peerids(struct tls_handshake_req *treq,
>   	}
>   }
>   
> +static void tls_handshake_record_size(struct tls_handshake_req *treq,
> +				      struct genl_info *info)
> +{
> +	struct tls_context *tls_ctx;
> +	struct nlattr *head = nlmsg_attrdata(info->nlhdr, GENL_HDRLEN);
> +	struct nlattr *nla;
> +	u32 record_size_limit;
> +	int rem, len = nlmsg_attrlen(info->nlhdr, GENL_HDRLEN);
> +
> +	nla_for_each_attr(nla, head, len, rem) {
> +		if (nla_type(nla) == HANDSHAKE_A_DONE_RECORD_SIZE_LIMIT) {
> +			record_size_limit = nla_get_u32(nla);
> +			if (treq->th_sock) {
> +				tls_ctx = tls_get_ctx(treq->th_sock->sk);
> +				tls_ctx->tls_record_size_limit = record_size_limit;
> +			}
> +			break;
> +		}
> +	}
> +}
> +
>   /**
>    * tls_handshake_done - callback to handle a CMD_DONE request
>    * @req: socket on which the handshake was performed
> @@ -98,8 +123,10 @@ static void tls_handshake_done(struct handshake_req *req,
>   	struct tls_handshake_req *treq = handshake_req_private(req);
>   
>   	treq->th_peerid[0] = TLS_NO_PEERID;
> -	if (info)
> +	if (info) {
>   		tls_handshake_remote_peerids(treq, info);
> +		tls_handshake_record_size(treq, info);
> +	}
>   
>   	if (!status)
>   		set_bit(HANDSHAKE_F_REQ_SESSION, &req->hr_flags);
> diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
> index fc88e34b7f33..70ffc4f5e382 100644
> --- a/net/tls/tls_sw.c
> +++ b/net/tls/tls_sw.c
> @@ -1024,6 +1024,7 @@ static int tls_sw_sendmsg_locked(struct sock *sk, struct msghdr *msg,
>   	ssize_t copied = 0;
>   	struct sk_msg *msg_pl, *msg_en;
>   	struct tls_rec *rec;
> +	u32 tls_record_size_limit;
>   	int required_size;
>   	int num_async = 0;
>   	bool full_record;
> @@ -1045,6 +1046,9 @@ static int tls_sw_sendmsg_locked(struct sock *sk, struct msghdr *msg,
>   		}
>   	}
>   
> +	tls_record_size_limit = min_not_zero(tls_ctx->tls_record_size_limit,
> +					     TLS_MAX_PAYLOAD_SIZE);
> +
>   	while (msg_data_left(msg)) {
>   		if (sk->sk_err) {
>   			ret = -sk->sk_err;
> @@ -1066,7 +1070,7 @@ static int tls_sw_sendmsg_locked(struct sock *sk, struct msghdr *msg,
>   		orig_size = msg_pl->sg.size;
>   		full_record = false;
>   		try_to_copy = msg_data_left(msg);
> -		record_room = TLS_MAX_PAYLOAD_SIZE - msg_pl->sg.size;
> +		record_room = tls_record_size_limit - msg_pl->sg.size;
>   		if (try_to_copy >= record_room) {
>   			try_to_copy = record_room;
>   			full_record = true;

Otherwise:
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                  Kernel Storage Architect
hare@suse.de                                +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich

Re: [RFC v2 1/1] net/tls: allow limiting maximum record size

[Wilfred Mallawa]

On Mon, 2025-08-18 at 08:31 +0200, Hannes Reinecke wrote:
> 
[snip]
> > --- a/include/uapi/linux/handshake.h
> > +++ b/include/uapi/linux/handshake.h
> > @@ -54,6 +54,7 @@ enum {
> >   	HANDSHAKE_A_DONE_STATUS = 1,
> >   	HANDSHAKE_A_DONE_SOCKFD,
> >   	HANDSHAKE_A_DONE_REMOTE_AUTH,
> > +	HANDSHAKE_A_DONE_RECORD_SIZE_LIMIT,
> >   
> >   	__HANDSHAKE_A_DONE_MAX,
> >   	HANDSHAKE_A_DONE_MAX = (__HANDSHAKE_A_DONE_MAX - 1)
> > diff --git a/net/handshake/genl.c b/net/handshake/genl.c
> > index f55d14d7b726..44c43ce18361 100644
> > --- a/net/handshake/genl.c
> > +++ b/net/handshake/genl.c
> > @@ -16,10 +16,11 @@ static const struct nla_policy
> > handshake_accept_nl_policy[HANDSHAKE_A_ACCEPT_HAN
> >   };
> >   
> >   /* HANDSHAKE_CMD_DONE - do */
> > -static const struct nla_policy
> > handshake_done_nl_policy[HANDSHAKE_A_DONE_REMOTE_AUTH + 1] = {
> > +static const struct nla_policy
> > handshake_done_nl_policy[HANDSHAKE_A_DONE_RECORD_SIZE_LIMIT + 1] =
> > {
> 
Hey Hannes,

I did consider using HANDSHAKE_A_DONE_MAX, but wasn't sure if the
existing convention is there for some reason. But I can switch over if
you think that is best.

> Shouldn't that be 'HANDSHAKE_A_DONE_MAX'?
> 
> >   	[HANDSHAKE_A_DONE_STATUS] = { .type = NLA_U32, },
> >   	[HANDSHAKE_A_DONE_SOCKFD] = { .type = NLA_S32, },
> >   	[HANDSHAKE_A_DONE_REMOTE_AUTH] = { .type = NLA_U32, },
> > +	[HANDSHAKE_A_DONE_RECORD_SIZE_LIMIT] = { .type = NLA_U32,
> > },
> >   };
> >   
> >   /* Ops table for handshake */
> > @@ -35,7 +36,7 @@ static const struct genl_split_ops
> > handshake_nl_ops[] = {
> >   		.cmd		= HANDSHAKE_CMD_DONE,
> >   		.doit		= handshake_nl_done_doit,
> >   		.policy		=
> > handshake_done_nl_policy,
> > -		.maxattr	= HANDSHAKE_A_DONE_REMOTE_AUTH,
> > +		.maxattr	=
> > HANDSHAKE_A_DONE_RECORD_SIZE_LIMIT,
> 
> HANDSHAKE_A_DONE_MAX - 1?

Shouldn't it be `HANDSHAKE_A_DONE_MAX`? Unless the existing
`HANDSHAKE_A_DONE_REMOTE_AUTH` is incorrect?

Thanks for the review!

Regards,
Wilfred
> 

Re: [RFC v2 1/1] net/tls: allow limiting maximum record size

[Hannes Reinecke]

On 8/21/25 08:18, Wilfred Mallawa wrote:
> On Mon, 2025-08-18 at 08:31 +0200, Hannes Reinecke wrote:
>>
> [snip]
>>> --- a/include/uapi/linux/handshake.h
>>> +++ b/include/uapi/linux/handshake.h
>>> @@ -54,6 +54,7 @@ enum {
>>>    	HANDSHAKE_A_DONE_STATUS = 1,
>>>    	HANDSHAKE_A_DONE_SOCKFD,
>>>    	HANDSHAKE_A_DONE_REMOTE_AUTH,
>>> +	HANDSHAKE_A_DONE_RECORD_SIZE_LIMIT,
>>>    
>>>    	__HANDSHAKE_A_DONE_MAX,
>>>    	HANDSHAKE_A_DONE_MAX = (__HANDSHAKE_A_DONE_MAX - 1)
>>> diff --git a/net/handshake/genl.c b/net/handshake/genl.c
>>> index f55d14d7b726..44c43ce18361 100644
>>> --- a/net/handshake/genl.c
>>> +++ b/net/handshake/genl.c
>>> @@ -16,10 +16,11 @@ static const struct nla_policy
>>> handshake_accept_nl_policy[HANDSHAKE_A_ACCEPT_HAN
>>>    };
>>>    
>>>    /* HANDSHAKE_CMD_DONE - do */
>>> -static const struct nla_policy
>>> handshake_done_nl_policy[HANDSHAKE_A_DONE_REMOTE_AUTH + 1] = {
>>> +static const struct nla_policy
>>> handshake_done_nl_policy[HANDSHAKE_A_DONE_RECORD_SIZE_LIMIT + 1] =
>>> {
>>
> Hey Hannes,
> 
> I did consider using HANDSHAKE_A_DONE_MAX, but wasn't sure if the
> existing convention is there for some reason. But I can switch over if
> you think that is best.
> 
I guess, no reason, just an oversight.

>> Shouldn't that be 'HANDSHAKE_A_DONE_MAX'?
>>
>>>    	[HANDSHAKE_A_DONE_STATUS] = { .type = NLA_U32, },
>>>    	[HANDSHAKE_A_DONE_SOCKFD] = { .type = NLA_S32, },
>>>    	[HANDSHAKE_A_DONE_REMOTE_AUTH] = { .type = NLA_U32, },
>>> +	[HANDSHAKE_A_DONE_RECORD_SIZE_LIMIT] = { .type = NLA_U32,
>>> },
>>>    };
>>>    
>>>    /* Ops table for handshake */
>>> @@ -35,7 +36,7 @@ static const struct genl_split_ops
>>> handshake_nl_ops[] = {
>>>    		.cmd		= HANDSHAKE_CMD_DONE,
>>>    		.doit		= handshake_nl_done_doit,
>>>    		.policy		=
>>> handshake_done_nl_policy,
>>> -		.maxattr	= HANDSHAKE_A_DONE_REMOTE_AUTH,
>>> +		.maxattr	=
>>> HANDSHAKE_A_DONE_RECORD_SIZE_LIMIT,
>>
>> HANDSHAKE_A_DONE_MAX - 1?
> 
> Shouldn't it be `HANDSHAKE_A_DONE_MAX`? Unless the existing
> `HANDSHAKE_A_DONE_REMOTE_AUTH` is incorrect?
> 
Yes, you are right.

Cheers,
Hannes
-- 
Dr. Hannes Reinecke                  Kernel Storage Architect
hare@suse.de                                +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich