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 4FB003909B8; Wed, 23 Sep 2026 03:13:53 +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=1790133234; cv=none; b=F5JElZN8d/NPXXkczdg5DdPTf6ZOHfVUW4XnlzeFkdvkGfmaq2QKZIrwq/XjW4iKbSzxxsticEH9xSpX0MZpGWqAIDAmQEf3zvwbFQpYoAj5nVsApPkxSYumgdveYxKzKncLGVRWK+QPLu7PONw9hxAGtlhPI2HdraYfZYf6Olw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790133234; c=relaxed/simple; bh=eQ1YqUTslb5dxOryo6W74H5gHamHrhSV+gWcsOV8LVs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=DOSqmSN0DJnD2EfWnMt7iLSsoHcrUh4BXjlCizEepQ+lVgZgnliUljGBqE/O6R/rb84Dokv3WzWaheDliXy7STn1tWpkDBMOfX4lq+1m2YGFGtXFeVQtkYdj/WnbnuYpwaUv5pSBoPz9MSxrBEKuvzAGnSJuWm6mSA01Ow35mmw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XyoLf2dP; 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="XyoLf2dP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EDEFD1F00898; Wed, 23 Sep 2026 03:13:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790133233; bh=unThhJ5PlV7XLz3f6cbDsSTG6/h/IqkEJcR1t8o4uxA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=XyoLf2dPUmzVfxYvTgVVz7oOmsyf/1YgXiSdqvjQWA4YSqJZdGQSJybY698i1WRXt a4pFsyy78z+WFAQ7Q0R0GYMZhoI+2Bwwt5vX5eib2YDm4Ebh7TL9226Bndf3ihGAO4 E/rjhTctQ+WdBVA85WjNOb0SGh9uHgDL3f+tlB/Aww2APeVpPjN0tm9Z+XAaVdIgEa RHL6/v5NwQN2mtzzaFsYH0uBriuJVxQtA689B9hdMKuCEk4VvCwVulS0yPz6Np+Vp2 ed93mugAS7vejtoKVgauAMwQaqLD4Ox26/Dr9zFcP2yJJXasZ5lgGxwbcvSxhbQT0/ Qmo/1k0AGHp2A== From: Fan Wu To: linux-security-module@vger.kernel.org Cc: paul@paul-moore.com, linux-kernel@vger.kernel.org Subject: [PATCH 2/2] ipe: protect the dm-verity root hash with RCU Date: Tue, 22 Sep 2026 20:13:49 -0700 Message-ID: <20260923031349.1216431-3-wufan@kernel.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260923031349.1216431-1-wufan@kernel.org> References: <20260923031349.1216431-1-wufan@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit ipe_bdev_setintegrity() frees the old root hash when dm-verity publishes a new one on ->preresume, while policy evaluation can still be dereferencing it. Protect the root hash with RCU. The evaluation path already runs under rcu_read_lock(). Fixes: e155858dd995 ("ipe: add support for dm-verity as a trust provider") Cc: stable@vger.kernel.org Assisted-by: claude-opus-5.5 Signed-off-by: Fan Wu --- security/ipe/eval.c | 12 ++++++++---- security/ipe/eval.h | 2 +- security/ipe/hooks.c | 22 +++++++++++++++++----- 3 files changed, 26 insertions(+), 10 deletions(-) diff --git a/security/ipe/eval.c b/security/ipe/eval.c index 21439c5be336..4a7be96c84f0 100644 --- a/security/ipe/eval.c +++ b/security/ipe/eval.c @@ -134,10 +134,14 @@ static bool evaluate_boot_verified(const struct ipe_eval_ctx *const ctx) static bool evaluate_dmv_roothash(const struct ipe_eval_ctx *const ctx, struct ipe_prop *p) { - return !!ctx->ipe_bdev && - !!ctx->ipe_bdev->root_hash && - ipe_digest_eval(p->value, - ctx->ipe_bdev->root_hash); + const struct digest_info *root_hash; + + if (!ctx->ipe_bdev) + return false; + + root_hash = rcu_dereference(ctx->ipe_bdev->root_hash); + + return root_hash && ipe_digest_eval(p->value, root_hash); } #else static bool evaluate_dmv_roothash(const struct ipe_eval_ctx *const ctx, diff --git a/security/ipe/eval.h b/security/ipe/eval.h index fef65a36468c..b26d1147d070 100644 --- a/security/ipe/eval.h +++ b/security/ipe/eval.h @@ -27,7 +27,7 @@ struct ipe_bdev { #ifdef CONFIG_IPE_PROP_DM_VERITY_SIGNATURE bool dm_verity_signed; #endif /* CONFIG_IPE_PROP_DM_VERITY_SIGNATURE */ - struct digest_info *root_hash; + struct digest_info __rcu *root_hash; }; #endif /* CONFIG_IPE_PROP_DM_VERITY */ diff --git a/security/ipe/hooks.c b/security/ipe/hooks.c index 0ae54a880405..d878b52ceec8 100644 --- a/security/ipe/hooks.c +++ b/security/ipe/hooks.c @@ -9,6 +9,7 @@ #include #include #include +#include #include "ipe.h" #include "hooks.h" @@ -232,7 +233,20 @@ void ipe_bdev_free_security(struct block_device *bdev) { struct ipe_bdev *blob = ipe_bdev(bdev); - ipe_digest_free(blob->root_hash); + ipe_digest_free(rcu_access_pointer(blob->root_hash)); +} + +static void ipe_set_dmverity_roothash(struct ipe_bdev *blob, + struct digest_info *info) +{ + struct digest_info *old; + + /* Protected by device-mapper's md->suspend_lock */ + old = rcu_replace_pointer(blob->root_hash, info, true); + if (old) { + synchronize_rcu(); + ipe_digest_free(old); + } } #ifdef CONFIG_IPE_PROP_DM_VERITY_SIGNATURE @@ -280,8 +294,7 @@ int ipe_bdev_setintegrity(struct block_device *bdev, enum lsm_integrity_type typ return -EINVAL; if (!value) { - ipe_digest_free(blob->root_hash); - blob->root_hash = NULL; + ipe_set_dmverity_roothash(blob, NULL); return 0; } @@ -301,8 +314,7 @@ int ipe_bdev_setintegrity(struct block_device *bdev, enum lsm_integrity_type typ info->digest_len = digest->digest_len; - ipe_digest_free(blob->root_hash); - blob->root_hash = info; + ipe_set_dmverity_roothash(blob, info); return 0; err: -- 2.55.0