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[71.132.185.69]) by smtp.gmail.com with ESMTPSA id 00721157ae682-78a7993cedesm10954757b3.41.2025.11.20.14.24.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 Nov 2025 14:24:03 -0800 (PST) From: Justin Suess To: linux-security-module@vger.kernel.org Cc: Tingmao Wang , =?UTF-8?q?G=C3=BCnther=20Noack?= , Jan Kara , Abhinav Saxena , =?UTF-8?q?Micka=C3=ABl=20Sala=C3=BCn?= , Justin Suess Subject: [PATCH 2/6] landlock: Implement LANDLOCK_ADD_RULE_NO_INHERIT userspace api Date: Thu, 20 Nov 2025 17:23:42 -0500 Message-ID: <20251120222346.1157004-3-utilityemal77@gmail.com> X-Mailer: git-send-email 2.51.2 In-Reply-To: <20251120222346.1157004-1-utilityemal77@gmail.com> References: <20251120222346.1157004-1-utilityemal77@gmail.com> Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Implements the syscall side flag handling and kernel api headers for the LANDLOCK_ADD_RULE_NO_INHERIT flag. Signed-off-by: Justin Suess --- include/uapi/linux/landlock.h | 9 +++++++++ security/landlock/syscalls.c | 5 ++++- 2 files changed, 13 insertions(+), 1 deletion(-) diff --git a/include/uapi/linux/landlock.h b/include/uapi/linux/landlock.h index 50f0806b7e33..d9daef551d96 100644 --- a/include/uapi/linux/landlock.h +++ b/include/uapi/linux/landlock.h @@ -127,10 +127,19 @@ struct landlock_ruleset_attr { * allowed_access in the passed in rule_attr. When this flag is * present, the caller is also allowed to pass in an empty * allowed_access. + * %LANDLOCK_ADD_RULE_NO_INHERIT + * When this flag is set while adding a rule to a ruleset, the rule + * will not inherit allowed accesses from rules on parent objects + * within the same layer. (currently only applies to filesystem objects) + * By default, Landlock rules added to a ruleset inherit allowed accesses + * from parent objects, meaning that if a parent directory has been granted + * certain access rights, those rights will also apply to its child objects. + * This flag prevents such inheritance for the specific rule being added. */ /* clang-format off */ #define LANDLOCK_ADD_RULE_QUIET (1U << 0) +#define LANDLOCK_ADD_RULE_NO_INHERIT (1U << 1) /* clang-format on */ /** diff --git a/security/landlock/syscalls.c b/security/landlock/syscalls.c index 93396bfc1500..200287a34895 100644 --- a/security/landlock/syscalls.c +++ b/security/landlock/syscalls.c @@ -463,7 +463,10 @@ SYSCALL_DEFINE4(landlock_add_rule, const int, ruleset_fd, if (!is_initialized()) return -EOPNOTSUPP; - if (flags && flags != LANDLOCK_ADD_RULE_QUIET) + if (flags && flags & ~(LANDLOCK_ADD_RULE_QUIET | LANDLOCK_ADD_RULE_NO_INHERIT)) + return -EINVAL; + if ((flags & LANDLOCK_ADD_RULE_NO_INHERIT) && + rule_type != LANDLOCK_RULE_PATH_BENEATH) return -EINVAL; /* Gets and checks the ruleset. */ -- 2.51.2