lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20240801003256.3937416-28-sashal@kernel.org>
Date: Wed, 31 Jul 2024 20:31:18 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Cc: Casey Schaufler <casey@...aufler-ca.com>,
	Konstantin Andreev <andreev@...mel.ru>,
	Sasha Levin <sashal@...nel.org>,
	paul@...l-moore.com,
	jmorris@...ei.org,
	serge@...lyn.com,
	linux-security-module@...r.kernel.org
Subject: [PATCH AUTOSEL 5.15 28/47] smack: tcp: ipv4, fix incorrect labeling

From: Casey Schaufler <casey@...aufler-ca.com>

[ Upstream commit 2fe209d0ad2e2729f7e22b9b31a86cc3ff0db550 ]

Currently, Smack mirrors the label of incoming tcp/ipv4 connections:
when a label 'foo' connects to a label 'bar' with tcp/ipv4,
'foo' always gets 'foo' in returned ipv4 packets. So,
1) returned packets are incorrectly labeled ('foo' instead of 'bar')
2) 'bar' can write to 'foo' without being authorized to write.

Here is a scenario how to see this:

* Take two machines, let's call them C and S,
   with active Smack in the default state
   (no settings, no rules, no labeled hosts, only builtin labels)

* At S, add Smack rule 'foo bar w'
   (labels 'foo' and 'bar' are instantiated at S at this moment)

* At S, at label 'bar', launch a program
   that listens for incoming tcp/ipv4 connections

* From C, at label 'foo', connect to the listener at S.
   (label 'foo' is instantiated at C at this moment)
   Connection succeedes and works.

* Send some data in both directions.
* Collect network traffic of this connection.

All packets in both directions are labeled with the CIPSO
of the label 'foo'. Hence, label 'bar' writes to 'foo' without
being authorized, and even without ever being known at C.

If anybody cares: exactly the same happens with DCCP.

This behavior 1st manifested in release 2.6.29.4 (see Fixes below)
and it looks unintentional. At least, no explanation was provided.

I changed returned packes label into the 'bar',
to bring it into line with the Smack documentation claims.

Signed-off-by: Konstantin Andreev <andreev@...mel.ru>
Signed-off-by: Casey Schaufler <casey@...aufler-ca.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 security/smack/smack_lsm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index e9d2ef3deccd1..25c46b56fae8d 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -4225,7 +4225,7 @@ static int smack_inet_conn_request(const struct sock *sk, struct sk_buff *skb,
 	rcu_read_unlock();
 
 	if (hskp == NULL)
-		rc = netlbl_req_setattr(req, &skp->smk_netlabel);
+		rc = netlbl_req_setattr(req, &ssp->smk_out->smk_netlabel);
 	else
 		netlbl_req_delattr(req);
 
-- 
2.43.0


Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ