[RFC net-next v11 1/2] inet_diag: pass net_admin to get_info

[RFC net-next v11 1/2] inet_diag: pass net_admin to get_info

[Kalpan Jani]

Pass the request's CAP_NET_ADMIN status to idiag_get_info()
so protocol-specific diagnostic handlers can restrict privileged
information.

Socket-destruction notifications have no individual requesting user,
so the callback receives net_admin set to false for that path.

Signed-off-by: Kalpan Jani <kalpan.jani@mpiricsoftware.com>
---
 include/linux/inet_diag.h | 3 ++-
 net/ipv4/inet_diag.c      | 6 +++---
 net/ipv4/raw_diag.c       | 2 +-
 net/ipv4/tcp_diag.c       | 2 +-
 net/ipv4/udp_diag.c       | 2 +-
 net/mptcp/mptcp_diag.c    | 2 +-
 net/sctp/diag.c           | 6 +++---
 7 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/include/linux/inet_diag.h b/include/linux/inet_diag.h
index 704fd415c2b49..8db96bfd3e67f 100644
--- a/include/linux/inet_diag.h
+++ b/include/linux/inet_diag.h
@@ -18,7 +18,8 @@ struct inet_diag_handler {
 
 	void		(*idiag_get_info)(struct sock *sk,
 					  struct inet_diag_msg *r,
-					  void *info);
+					  void *info,
+					  bool net_admin);
 
 	int		(*idiag_get_aux)(struct sock *sk,
 					 bool net_admin,
diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
index 34b77aa87d0a4..362161bf39fe3 100644
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -276,7 +276,7 @@ int inet_sk_diag_fill(struct sock *sk, struct inet_connection_sock *icsk,
 	}
 
 	if (!icsk) {
-		handler->idiag_get_info(sk, r, NULL);
+		handler->idiag_get_info(sk, r, NULL, net_admin);
 		goto out;
 	}
 
@@ -327,7 +327,7 @@ int inet_sk_diag_fill(struct sock *sk, struct inet_connection_sock *icsk,
 			goto errout;
 	}
 
-	handler->idiag_get_info(sk, r, info);
+	handler->idiag_get_info(sk, r, info, net_admin);
 
 	if (ext & (1 << (INET_DIAG_INFO - 1)) && handler->idiag_get_aux)
 		if (handler->idiag_get_aux(sk, net_admin, skb) < 0)
@@ -1027,7 +1027,7 @@ int inet_diag_handler_get_info(struct sk_buff *skb, struct sock *sk)
 	if (attr)
 		info = nla_data(attr);
 
-	handler->idiag_get_info(sk, r, info);
+	handler->idiag_get_info(sk, r, info, false);
 	inet_diag_unlock_handler(handler);
 
 	nlmsg_end(skb, nlh);
diff --git a/net/ipv4/raw_diag.c b/net/ipv4/raw_diag.c
index 943e5998e0ad5..264912d0cb9fc 100644
--- a/net/ipv4/raw_diag.c
+++ b/net/ipv4/raw_diag.c
@@ -185,7 +185,7 @@ static void raw_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
 }
 
 static void raw_diag_get_info(struct sock *sk, struct inet_diag_msg *r,
-			      void *info)
+			      void *info, bool net_admin)
 {
 	r->idiag_rqueue = sk_rmem_alloc_get(sk);
 	r->idiag_wqueue = sk_wmem_alloc_get(sk);
diff --git a/net/ipv4/tcp_diag.c b/net/ipv4/tcp_diag.c
index ba1fdbe9807fd..cac32575282e3 100644
--- a/net/ipv4/tcp_diag.c
+++ b/net/ipv4/tcp_diag.c
@@ -19,7 +19,7 @@
 #include <net/tcp.h>
 
 static void tcp_diag_get_info(struct sock *sk, struct inet_diag_msg *r,
-			      void *_info)
+			      void *_info, bool net_admin)
 {
 	struct tcp_info *info = _info;
 
diff --git a/net/ipv4/udp_diag.c b/net/ipv4/udp_diag.c
index f4b24e628cf8d..5a1fa627cbee8 100644
--- a/net/ipv4/udp_diag.c
+++ b/net/ipv4/udp_diag.c
@@ -142,7 +142,7 @@ static void udp_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
 }
 
 static void udp_diag_get_info(struct sock *sk, struct inet_diag_msg *r,
-		void *info)
+		void *info, bool net_admin)
 {
 	r->idiag_rqueue = udp_rqueue_get(sk);
 	r->idiag_wqueue = sk_wmem_alloc_get(sk);
diff --git a/net/mptcp/mptcp_diag.c b/net/mptcp/mptcp_diag.c
index 136c2d05c0eeb..9ed7a6be1e628 100644
--- a/net/mptcp/mptcp_diag.c
+++ b/net/mptcp/mptcp_diag.c
@@ -190,7 +190,7 @@ static void mptcp_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
 }
 
 static void mptcp_diag_get_info(struct sock *sk, struct inet_diag_msg *r,
-				void *_info)
+				void *_info, bool net_admin)
 {
 	struct mptcp_sock *msk = mptcp_sk(sk);
 	struct mptcp_info *info = _info;
diff --git a/net/sctp/diag.c b/net/sctp/diag.c
index c2a0de2adf6fd..ab6c560fde053 100644
--- a/net/sctp/diag.c
+++ b/net/sctp/diag.c
@@ -20,7 +20,7 @@
 #include <net/sctp/sctp.h>
 
 static void sctp_diag_get_info(struct sock *sk, struct inet_diag_msg *r,
-			       void *info);
+			       void *info, bool net_admin);
 
 /* define some functions to make asoc/ep fill look clean */
 static void inet_diag_msg_sctpasoc_fill(struct inet_diag_msg *r,
@@ -200,7 +200,7 @@ static int inet_sctp_diag_fill(struct sock *sk, struct sctp_association *asoc,
 	}
 	infox.sctpinfo = (struct sctp_info *)info;
 	infox.asoc = asoc;
-	sctp_diag_get_info(sk, r, &infox);
+	sctp_diag_get_info(sk, r, &infox, net_admin);
 
 	addr_list = asoc ? &asoc->base.bind_addr.address_list
 			 : &ep->base.bind_addr.address_list;
@@ -412,7 +412,7 @@ static int sctp_ep_dump(struct sctp_endpoint *ep, void *p)
 
 /* define the functions for sctp_diag_handler*/
 static void sctp_diag_get_info(struct sock *sk, struct inet_diag_msg *r,
-			       void *info)
+			       void *info, bool net_admin)
 {
 	struct sctp_infox *infox = (struct sctp_infox *)info;
 
-- 
2.43.0

[RFC net-next v11 2/2] mptcp: hide seq counters without net_admin

[Kalpan Jani]

The MPTCP inet-diag response includes data sequence numbers that
should not be exposed to users without CAP_NET_ADMIN.

Clear mptcpi_write_seq, mptcpi_snd_una and mptcpi_rcv_nxt in diagnostic
responses for unprivileged users. Apply this restriction in the
inet-diag callback, leaving the MPTCP_INFO getsockopt path unchanged.

Signed-off-by: Kalpan Jani <kalpan.jani@mpiricsoftware.com>
---
 net/mptcp/mptcp_diag.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/net/mptcp/mptcp_diag.c b/net/mptcp/mptcp_diag.c
index 9ed7a6be1e628..970f849f4345c 100644
--- a/net/mptcp/mptcp_diag.c
+++ b/net/mptcp/mptcp_diag.c
@@ -215,6 +215,12 @@ static void mptcp_diag_get_info(struct sock *sk, struct inet_diag_msg *r,
 		return;
 
 	mptcp_diag_fill_info(msk, info);
+
+	if (!net_admin) {
+		info->mptcpi_write_seq = 0;
+		info->mptcpi_snd_una = 0;
+		info->mptcpi_rcv_nxt = 0;
+	}
 }
 
 static const struct inet_diag_handler mptcp_diag_handler = {
-- 
2.43.0

Re: [RFC net-next v11 1/2] inet_diag: pass net_admin to get_info

[netdev-bot+sinfo]

Hi!

This is an automated message. This series looks like a fix, but its
commit messages seem to be missing some information:

 - How the issue was discovered, e.g. hit in production, hit during
   development, syzbot report, manual code inspection, LLM or static
   analysis tool scan.

 - Whether the issue was actually triggered, or is only theoretical
   (e.g. found by code inspection). If it was triggered please include
   the symptoms, like the stack trace or error messages.

Please do not repost the series just to address the above. Instead,
reply to this email with the missing information, so that reviewers
can take it into account. If the series needs another revision for
other reasons, please include the information in the commit messages
then.

The evaluation is done by an LLM so it may be wrong, if you think
that is the case please reply and explain.