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* Add a new access right LANDLOCK_ACCESS_FS_RESOLVE_UNIX, which controls the lookup operations for named UNIX domain sockets. The resolution happens during connect() and sendmsg() (depending on socket type). * Change access_mask_t from u16 to u32 (see below) * Hook into the path lookup in unix_find_bsd() in af_unix.c, using a LSM hook. Make policy decisions based on the new access rights * Increment the Landlock ABI version. * Minor test adaptations to keep the tests working. * Document the design rationale for scoped access rights, and cross-reference it from the header documentation. With this access right, access is granted if either of the following conditions is met: * The target socket's filesystem path was allow-listed using a LANDLOCK_RULE_PATH_BENEATH rule, *or*: * The target socket was created in the same Landlock domain in which LANDLOCK_ACCESS_FS_RESOLVE_UNIX was restricted. In case of a denial, connect() and sendmsg() return EACCES, which is the same error as it is returned if the user does not have the write bit in the traditional UNIX file system permissions of that file. The access_mask_t type grows from u16 to u32 to make space for the new access right. This also doubles the size of struct layer_access_masks from 32 byte to 64 byte. To avoid memory layout inconsistencies between architectures (especially m68k), pack and align struct access_masks [2]. Document the (possible future) interaction between scoped flags and other access rights in struct landlock_ruleset_attr, and summarize the rationale, as discussed in code review leading up to [3]. This feature was created with substantial discussion and input from Justin Suess, Tingmao Wang and Mickaël Salaün. Cc: Tingmao Wang <m@maowtm.org> Cc: Justin Suess <utilityemal77@gmail.com> Cc: Kuniyuki Iwashima <kuniyu@google.com> Suggested-by: Jann Horn <jannh@google.com> Link[1]: https://github.com/landlock-lsm/linux/issues/36 Link[2]: https://lore.kernel.org/all/20260401.Re1Eesu1Yaij@digikod.net/ Link[3]: https://lore.kernel.org/all/20260205.8531e4005118@gnoack.org/ Signed-off-by: Günther Noack <gnoack3000@gmail.com> Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Link: https://lore.kernel.org/r/20260327164838.38231-5-gnoack3000@gmail.com [mic: Fix kernel-doc formatting, pack and align access_masks] Signed-off-by: Mickaël Salaün <mic@digikod.net>
40 lines
1.3 KiB
C
40 lines
1.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Landlock - Limits for different components
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*
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* Copyright © 2016-2020 Mickaël Salaün <mic@digikod.net>
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* Copyright © 2018-2020 ANSSI
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* Copyright © 2021-2025 Microsoft Corporation
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*/
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#ifndef _SECURITY_LANDLOCK_LIMITS_H
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#define _SECURITY_LANDLOCK_LIMITS_H
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#include <linux/bitops.h>
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#include <linux/limits.h>
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#include <uapi/linux/landlock.h>
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/* clang-format off */
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#define LANDLOCK_MAX_NUM_LAYERS 16
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#define LANDLOCK_MAX_NUM_RULES U32_MAX
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#define LANDLOCK_LAST_ACCESS_FS LANDLOCK_ACCESS_FS_RESOLVE_UNIX
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#define LANDLOCK_MASK_ACCESS_FS ((LANDLOCK_LAST_ACCESS_FS << 1) - 1)
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#define LANDLOCK_NUM_ACCESS_FS __const_hweight64(LANDLOCK_MASK_ACCESS_FS)
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#define LANDLOCK_LAST_ACCESS_NET LANDLOCK_ACCESS_NET_CONNECT_TCP
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#define LANDLOCK_MASK_ACCESS_NET ((LANDLOCK_LAST_ACCESS_NET << 1) - 1)
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#define LANDLOCK_NUM_ACCESS_NET __const_hweight64(LANDLOCK_MASK_ACCESS_NET)
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#define LANDLOCK_LAST_SCOPE LANDLOCK_SCOPE_SIGNAL
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#define LANDLOCK_MASK_SCOPE ((LANDLOCK_LAST_SCOPE << 1) - 1)
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#define LANDLOCK_NUM_SCOPE __const_hweight64(LANDLOCK_MASK_SCOPE)
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#define LANDLOCK_LAST_RESTRICT_SELF LANDLOCK_RESTRICT_SELF_TSYNC
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#define LANDLOCK_MASK_RESTRICT_SELF ((LANDLOCK_LAST_RESTRICT_SELF << 1) - 1)
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/* clang-format on */
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#endif /* _SECURITY_LANDLOCK_LIMITS_H */
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