From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8875C377EB8 for ; Thu, 17 Sep 2026 01:39:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789609184; cv=none; b=E5Rr5m+iWDoU3TUE6rUMr63/251pD0B170VRk66iG3zhoUhaVHIMYYKjz76ngDuH92qGMID+ZUZBIcagsq/5Vwz+Pn4+posPrugDbsIVhwqcU4pB+QHsJaN2FxruzjbqLYXqj5EOJJ5R/JfbFxNakyuJJfzFPqaecPOnIYxPJtA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789609184; c=relaxed/simple; bh=yx6zfZGR9nOwtWVhAs9ttTqZcWCXjQdd2JlzPj88shc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=qXacs01+vaGnvMTjv3ACGDgNgb/Ds1zBR1g1ERLGiWpOCNL2tovrKQmtHeSFfbt4dGHtpKX18USXcd/NhhZryF1mjEGV2RX8k44lo4+rXhPMKoPhov6RRBvewzeFjQPiBWWlTp7TA3tZq+MBkiuJxeX3Nuk1LOLvEMVLS9MQ/k0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=K1M8AERf; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="K1M8AERf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C3CC31F00893; Thu, 17 Sep 2026 01:39:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789609183; bh=bd1vX4I+bqG2/3/N3SO0u/Ps50MCXk87/wWu1g+hsTE=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=K1M8AERfgvEj4zgCRvrk5+fie/rvCvW9rwGQ2GRchTRAG+b/EoaPAzeoWztDODt35 y//o35lDZqcRzd8DMxW5mgkxa0CX1p7K0DdTbhmMbC/nHKvrn5XQ7fxmcTCQDfajt2 4uIol4gsdNARwZt7pLQs2jU+a2vJQNuYnAKKeB6abiUEpGMM07GFcrDXm+m2tCT804 7j2hBTXOQPNyGaVlP23Fw0GeGVQocPW5JOGDLPaZxdh8s0uoJHPWRTBeJRBerH5WdW WRbNbLw5Wgj4qyvXSL00PQSiOi283xq5uKIDQ0GHQ7OT94108K5//G9UNDIrz/QGgK 4v5n/rZvNjWmA== From: Sasha Levin To: stable@vger.kernel.org Cc: =?UTF-8?q?G=C3=BCnther=20Noack?= , =?UTF-8?q?Micka=C3=ABl=20Sala=C3=BCn?= , Sasha Levin Subject: [PATCH 6.18.y 2/5] landlock: Add access_mask_subset() helper Date: Wed, 16 Sep 2026 21:39:37 -0400 Message-ID: <20260917013940.3651217-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260917013940.3651217-1-sashal@kernel.org> References: <2026091639-trophy-refract-3155@gregkh> <20260917013940.3651217-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Günther Noack [ Upstream commit 45f2a2926b2187d1b08132d2728af50785b007a7 ] This helper function checks whether an access_mask_t has a subset of the bits enabled than another one. This expresses the intent a bit smoother in the code and does not cost us anything when it gets inlined. Signed-off-by: Günther Noack Link: https://lore.kernel.org/r/20260206151154.97915-4-gnoack3000@gmail.com [mic: Improve subject] Signed-off-by: Mickaël Salaün Stable-dep-of: 2c6dc7925382 ("landlock: Fix use-after-free of the source's parent directory") Signed-off-by: Sasha Levin --- security/landlock/access.h | 7 +++++++ security/landlock/fs.c | 4 ++-- 2 files changed, 9 insertions(+), 2 deletions(-) diff --git a/security/landlock/access.h b/security/landlock/access.h index 7961c6630a2d7..bab403470a6c2 100644 --- a/security/landlock/access.h +++ b/security/landlock/access.h @@ -97,4 +97,11 @@ landlock_upgrade_handled_access_masks(struct access_masks access_masks) return access_masks; } +/* Checks the subset relation between access masks. */ +static inline bool access_mask_subset(access_mask_t subset, + access_mask_t superset) +{ + return (subset | superset) == superset; +} + #endif /* _SECURITY_LANDLOCK_ACCESS_H */ diff --git a/security/landlock/fs.c b/security/landlock/fs.c index d741ed3e55680..13a15127f3ce0 100644 --- a/security/landlock/fs.c +++ b/security/landlock/fs.c @@ -332,7 +332,7 @@ int landlock_append_fs_rule(struct landlock_ruleset *const ruleset, /* Files only get access rights that make sense. */ if (!d_is_dir(path->dentry) && - (access_rights | ACCESS_FILE) != ACCESS_FILE) + !access_mask_subset(access_rights, ACCESS_FILE)) return -EINVAL; if (WARN_ON_ONCE(ruleset->num_layers != 1)) return -EINVAL; @@ -1717,7 +1717,7 @@ static int hook_file_open(struct file *const file) ARRAY_SIZE(layer_masks)); #endif /* CONFIG_AUDIT */ - if ((open_access_request & allowed_access) == open_access_request) + if (access_mask_subset(open_access_request, allowed_access)) return 0; /* Sets access to reflect the actual request. */ -- 2.53.0