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

Mickaël Salaün
2025-01-31T16:31:27Z

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@google.com>
Signed-off-by: Mickaël Salaün <mic@digikod.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