linux-kernel - [PATCH v5 05/24] landlock: Prepare to use credential instead of domain for network

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Message-ID: <20250131163059.1139617-6-mic@digikod.net>
Date: Fri, 31 Jan 2025 17:30:40 +0100
From: Mickaël Salaün <mic@...ikod.net>
To: Eric Paris <eparis@...hat.com>,
	Paul Moore <paul@...l-moore.com>,
	Günther Noack <gnoack@...gle.com>,
	"Serge E . Hallyn" <serge@...lyn.com>
Cc: Mickaël Salaün <mic@...ikod.net>,
	Ben Scarlato <akhna@...gle.com>,
	Casey Schaufler <casey@...aufler-ca.com>,
	Charles Zaffery <czaffery@...lox.com>,
	Daniel Burgener <dburgener@...ux.microsoft.com>,
	Francis Laniel <flaniel@...ux.microsoft.com>,
	James Morris <jmorris@...ei.org>,
	Jann Horn <jannh@...gle.com>,
	Jeff Xu <jeffxu@...gle.com>,
	Jorge Lucangeli Obes <jorgelo@...gle.com>,
	Kees Cook <kees@...nel.org>,
	Konstantin Meskhidze <konstantin.meskhidze@...wei.com>,
	Matt Bobrowski <mattbobrowski@...gle.com>,
	Mikhail Ivanov <ivanov.mikhail1@...wei-partners.com>,
	Phil Sutter <phil@....cc>,
	Praveen K Paladugu <prapal@...ux.microsoft.com>,
	Robert Salvet <robert.salvet@...lox.com>,
	Shervin Oloumi <enlightened@...gle.com>,
	Song Liu <song@...nel.org>,
	Tahera Fahimi <fahimitahera@...il.com>,
	Tyler Hicks <code@...icks.com>,
	audit@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-security-module@...r.kernel.org
Subject: [PATCH v5 05/24] landlock: Prepare to use credential instead of domain for network

This cosmetic change that is needed for audit support, specifically to
be able to filter according to cross-execution boundaries.

Optimize current_check_access_socket() to only handle the access
request.

Remove explicit domain->num_layers check which is now part of the
landlock_get_applicable_subject() call.

Cc: Günther Noack <gnoack@...gle.com>
Signed-off-by: Mickaël Salaün <mic@...ikod.net>
Link: https://lore.kernel.org/r/20250131163059.1139617-6-mic@digikod.net
---

Changes since v4:
- New patch.
---
 security/landlock/net.c | 23 ++++++++++-------------
 1 file changed, 10 insertions(+), 13 deletions(-)

diff --git a/security/landlock/net.c b/security/landlock/net.c
index d5dcc4407a19..53dc9d94a5c2 100644
--- a/security/landlock/net.c
+++ b/security/landlock/net.c
@@ -39,10 +39,6 @@ int landlock_append_net_rule(struct landlock_ruleset *const ruleset,
 	return err;
 }
 
-static const struct access_masks any_net = {
-	.net = ~0,
-};
-
 static int current_check_access_socket(struct socket *const sock,
 				       struct sockaddr *const address,
 				       const int addrlen,
@@ -54,14 +50,14 @@ static int current_check_access_socket(struct socket *const sock,
 	struct landlock_id id = {
 		.type = LANDLOCK_KEY_NET_PORT,
 	};
-	const struct landlock_ruleset *const dom =
-		landlock_get_applicable_domain(landlock_get_current_domain(),
-					       any_net);
+	const struct access_masks masks = {
+		.net = access_request,
+	};
+	const struct landlock_cred_security *const subject =
+		landlock_get_applicable_subject(current_cred(), masks, NULL);
 
-	if (!dom)
+	if (!subject)
 		return 0;
-	if (WARN_ON_ONCE(dom->num_layers < 1))
-		return -EACCES;
 
 	/* Checks if it's a (potential) TCP socket. */
 	if (sock->type != SOCK_STREAM)
@@ -146,9 +142,10 @@ static int current_check_access_socket(struct socket *const sock,
 	id.key.data = (__force uintptr_t)port;
 	BUILD_BUG_ON(sizeof(port) > sizeof(id.key.data));
 
-	rule = landlock_find_rule(dom, id);
-	access_request = landlock_init_layer_masks(
-		dom, access_request, &layer_masks, LANDLOCK_KEY_NET_PORT);
+	rule = landlock_find_rule(subject->domain, id);
+	access_request = landlock_init_layer_masks(subject->domain,
+						   access_request, &layer_masks,
+						   LANDLOCK_KEY_NET_PORT);
 	if (landlock_unmask_layers(rule, access_request, &layer_masks,
 				   ARRAY_SIZE(layer_masks)))
 		return 0;
-- 
2.48.1