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Currently, a sandbox process is not restricted to sending a signal (e.g. SIGKILL) to a process outside the sandbox environment. The ability to send a signal for a sandboxed process should be scoped the same way abstract UNIX sockets are scoped. Therefore, we extend the "scoped" field in a ruleset with LANDLOCK_SCOPE_SIGNAL to specify that a ruleset will deny sending any signal from within a sandbox process to its parent (i.e. any parent sandbox or non-sandboxed processes). This patch adds file_set_fowner and file_free_security hooks to set and release a pointer to the file owner's domain. This pointer, fown_domain in landlock_file_security will be used in file_send_sigiotask to check if the process can send a signal. The ruleset_with_unknown_scope test is updated to support LANDLOCK_SCOPE_SIGNAL. This depends on two new changes: - commit1934b21261("file: reclaim 24 bytes from f_owner"): replace container_of(fown, struct file, f_owner) with fown->file . - commit26f204380a("fs: Fix file_set_fowner LSM hook inconsistencies"): lock before calling the hook. Signed-off-by: Tahera Fahimi <fahimitahera@gmail.com> Closes: https://github.com/landlock-lsm/linux/issues/8 Link: https://lore.kernel.org/r/df2b4f880a2ed3042992689a793ea0951f6798a5.1725657727.git.fahimitahera@gmail.com [mic: Update landlock_get_current_domain()'s return type, improve and fix locking in hook_file_set_fowner(), simplify and fix sleepable call and locking issue in hook_file_send_sigiotask() and rebase on the latest VFS tree, simplify hook_task_kill() and quickly return when not sandboxed, improve comments, rename LANDLOCK_SCOPED_SIGNAL] Co-developed-by: Mickaël Salaün <mic@digikod.net> Signed-off-by: Mickaël Salaün <mic@digikod.net>
59 lines
1.3 KiB
C
59 lines
1.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Landlock LSM - 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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*/
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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 "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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__init void landlock_add_cred_hooks(void);
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#endif /* _SECURITY_LANDLOCK_CRED_H */
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