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https://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git
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ae2483a260
This cosmetic change is needed for audit support, specifically to be able to filter according to cross-execution boundaries. Add landlock_get_applicable_subject(), mainly a copy of landlock_get_applicable_domain(), which will fully replace it in a following commit. Optimize current_check_access_path() to only handle the access request. Partially replace get_current_fs_domain() with explicit calls to landlock_get_applicable_subject(). The remaining ones will follow with more changes. Remove explicit domain->num_layers check which is now part of the landlock_get_applicable_subject() call. Cc: Günther Noack <gnoack@google.com> Link: https://lore.kernel.org/r/20250320190717.2287696-5-mic@digikod.net Signed-off-by: Mickaël Salaün <mic@digikod.net>
110 lines
2.6 KiB
C
110 lines
2.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Landlock - Credential hooks
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*
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* Copyright © 2019-2020 Mickaël Salaün <mic@digikod.net>
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* Copyright © 2019-2020 ANSSI
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* Copyright © 2021-2025 Microsoft Corporation
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*/
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#ifndef _SECURITY_LANDLOCK_CRED_H
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#define _SECURITY_LANDLOCK_CRED_H
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#include <linux/cred.h>
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#include <linux/init.h>
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#include <linux/rcupdate.h>
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#include "access.h"
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#include "ruleset.h"
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#include "setup.h"
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struct landlock_cred_security {
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struct landlock_ruleset *domain;
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};
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static inline struct landlock_cred_security *
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landlock_cred(const struct cred *cred)
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{
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return cred->security + landlock_blob_sizes.lbs_cred;
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}
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static inline struct landlock_ruleset *landlock_get_current_domain(void)
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{
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return landlock_cred(current_cred())->domain;
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}
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/*
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* The call needs to come from an RCU read-side critical section.
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*/
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static inline const struct landlock_ruleset *
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landlock_get_task_domain(const struct task_struct *const task)
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{
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return landlock_cred(__task_cred(task))->domain;
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}
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static inline bool landlocked(const struct task_struct *const task)
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{
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bool has_dom;
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if (task == current)
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return !!landlock_get_current_domain();
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rcu_read_lock();
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has_dom = !!landlock_get_task_domain(task);
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rcu_read_unlock();
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return has_dom;
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}
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/**
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* landlock_get_applicable_subject - Return the subject's Landlock credential
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* if its enforced domain applies to (i.e.
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* handles) at least one of the access rights
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* specified in @masks
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*
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* @cred: credential
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* @masks: access masks
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* @handle_layer: returned youngest layer handling a subset of @masks. Not set
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* if the function returns NULL.
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*
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* Returns: landlock_cred(@cred) if any access rights specified in @masks is
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* handled, or NULL otherwise.
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*/
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static inline const struct landlock_cred_security *
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landlock_get_applicable_subject(const struct cred *const cred,
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const struct access_masks masks,
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size_t *const handle_layer)
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{
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const union access_masks_all masks_all = {
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.masks = masks,
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};
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const struct landlock_ruleset *domain;
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ssize_t layer_level;
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if (!cred)
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return NULL;
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domain = landlock_cred(cred)->domain;
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if (!domain)
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return NULL;
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for (layer_level = domain->num_layers - 1; layer_level >= 0;
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layer_level--) {
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union access_masks_all layer = {
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.masks = domain->access_masks[layer_level],
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};
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if (layer.all & masks_all.all) {
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if (handle_layer)
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*handle_layer = layer_level;
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return landlock_cred(cred);
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}
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}
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return NULL;
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}
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__init void landlock_add_cred_hooks(void);
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#endif /* _SECURITY_LANDLOCK_CRED_H */
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