From patchwork Wed Jul 17 11:28:44 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Gstir X-Patchwork-Id: 13735417 Received: from mail-wm1-f49.google.com (mail-wm1-f49.google.com [209.85.128.49]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 91BED14A097 for ; Wed, 17 Jul 2024 11:29:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.49 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721215769; cv=none; b=Pmf39T3Rib7uAlM0enP2ywHpi+YSGoz6SyjsL8QawjlXWy78YeJX2NFipBzsd9SWUWUwrohiEvsfBi1aNwX++9Ozeme0ssgdvK3sd4PfIAvp0Er9oFby2wpRkqPoIYCcm75oOJXTaHwKTYOQcELQDs/zF+60FzmcEiFEcfdJr9g= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721215769; c=relaxed/simple; bh=DVb7x2gl14AvOaSEC+osM8d1bK0rFnQnBJXEeVyVkDM=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=gtouyO4+J8zi1d1XB+K12HdkkC95zW/hdA24+I2ABVlHUw9zH/HRLM89SHHwRHpVct7PGCknWR14rwkZupNOsqnpU6BEhFDfbu1Nboa5YBy5nzgV4uTuFAcaoeUcZvOq9tBXJeqWUjc2W8QAf1W0lDjzyecOGdqo9jLX6artJW8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sigma-star.at; spf=pass smtp.mailfrom=sigma-star.at; dkim=pass (2048-bit key) header.d=sigma-star.at header.i=@sigma-star.at header.b=oKWqSJZ1; arc=none smtp.client-ip=209.85.128.49 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sigma-star.at Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sigma-star.at Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=sigma-star.at header.i=@sigma-star.at header.b="oKWqSJZ1" Received: by mail-wm1-f49.google.com with SMTP id 5b1f17b1804b1-4266ea6a412so47007285e9.1 for ; Wed, 17 Jul 2024 04:29:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sigma-star.at; s=google; t=1721215765; x=1721820565; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=iY1y6wYGSjtZMnVjTLV+b3g/W0zFm2cTH9KXMU2ByiU=; b=oKWqSJZ1hyFwOKJwrUCvDHKo+CQ8b5gibp9SpP4aScELKyB6eOysfA2maV5pwP2goH 3a3DGA6JhYEvaBoFHIfLUKFmcHP2YXD9xgjGyhFjqbBg8x8lJ3NUuPyUPBSZ4zO4xqg3 HzIIczSFNAOd/Zg6/A+A9t4MB3bjChNvcrSLanFAdDhcgCvXfZnzxaIP7RIhzEi6QpdS iDeX8Iw89RqYmeYL6ru3WZGCPYoLFQC4GXVLacXnVYZ3vHqnp4XawVWntny19aWHmmC+ GG7n2ZHVhBrNJOK9vSdDbs7O3hB7EhxNAPVmwyz5LlTSiA89sfDupCftVFwhvVljjU7p 8ntA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1721215765; x=1721820565; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=iY1y6wYGSjtZMnVjTLV+b3g/W0zFm2cTH9KXMU2ByiU=; b=Ow6Q/e8/BLLeSEtzEAJqJbl9VUVGzqCUj7ZwGRbWQKPDaUj0Xg4VkGWlxnaV9OrD13 sgvcrWq0q6j81y/a3PtZQ+fYgS5lGg7VdhajxD6bCILnXTeIaIMTke020c0SU7tynS/A 6fyCG2rwoisK0scDkA8jiYdr8rVVr0SHh08+PDrgQ6+lXOXO/7EIuvuzgOJ8ytOGTaD6 mnIcgsfEAlM7PYrIxXMUB+frci5t+141cwATDHtZJGQ+A8DAFW1sTNLPxXgcFZBlFw2m iTES31gqvwTR0mj76cbW2+sPA6mlkzX3cxZpLE7jJ6RonqMOsmnizo4ZNe8eZ+e+Igzi FfiA== X-Gm-Message-State: AOJu0Yz/M+0A9OpakzuCZoZiomtTu1sE8KrItdYIn/qHUNAyh41WszX1 BbEnEpaT5XU4ns2tebADOwjf1YL+B82j6a8FQMHkdWhahtircGIskUyecsvWzH0= X-Google-Smtp-Source: AGHT+IFMWzVldVdBWF4pRxiboBHuzPXsITPpLZRME2GrWdHdWtJKHxsw917G8ATW2rXO4ut+o2+y6w== X-Received: by 2002:a05:6000:71d:b0:368:255e:ab13 with SMTP id ffacd0b85a97d-36831722ed8mr1384259f8f.50.1721215764667; Wed, 17 Jul 2024 04:29:24 -0700 (PDT) Received: from localhost ([82.150.214.1]) by smtp.gmail.com with UTF8SMTPSA id ffacd0b85a97d-3680db0492asm11375872f8f.103.2024.07.17.04.29.23 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 17 Jul 2024 04:29:24 -0700 (PDT) From: David Gstir To: sigma star Kernel Team , James Bottomley , Jarkko Sakkinen , Mimi Zohar , David Howells , Paul Moore , James Morris , "Serge E. Hallyn" , Richard Weinberger , David Oberhollenzer Cc: linux-integrity@vger.kernel.org, keyrings@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, David Gstir , stable@vger.kernel.org, kernel test robot Subject: [PATCH v2 1/2] KEYS: trusted: fix DCP blob payload length assignment Date: Wed, 17 Jul 2024 13:28:44 +0200 Message-ID: <20240717112845.92088-1-david@sigma-star.at> X-Mailer: git-send-email 2.45.2 Precedence: bulk X-Mailing-List: linux-integrity@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 The DCP trusted key type uses the wrong helper function to store the blob's payload length which can lead to the wrong byte order being used in case this would ever run on big endian architectures. Fix by using correct helper function. Cc: stable@vger.kernel.org # v6.10+ Fixes: 2e8a0f40a39c ("KEYS: trusted: Introduce NXP DCP-backed trusted keys") Suggested-by: Richard Weinberger Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202405240610.fj53EK0q-lkp@intel.com/ Signed-off-by: David Gstir Signed-off-by: Jarkko Sakkinen --- v1 -> v2: fix ordering of commit tags, add s-o-b from Jarkko Sakkinen security/keys/trusted-keys/trusted_dcp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/security/keys/trusted-keys/trusted_dcp.c b/security/keys/trusted-keys/trusted_dcp.c index b5f81a05be36..b0947f072a98 100644 --- a/security/keys/trusted-keys/trusted_dcp.c +++ b/security/keys/trusted-keys/trusted_dcp.c @@ -222,7 +222,7 @@ static int trusted_dcp_seal(struct trusted_key_payload *p, char *datablob) return ret; } - b->payload_len = get_unaligned_le32(&p->key_len); + put_unaligned_le32(p->key_len, &b->payload_len); p->blob_len = blen; return 0; } From patchwork Wed Jul 17 11:28:45 2024 Content-Type: text/plain; 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Wed, 17 Jul 2024 04:29:27 -0700 (PDT) Received: from localhost ([82.150.214.1]) by smtp.gmail.com with UTF8SMTPSA id ffacd0b85a97d-368119970e7sm10640354f8f.21.2024.07.17.04.29.26 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 17 Jul 2024 04:29:26 -0700 (PDT) From: David Gstir To: sigma star Kernel Team , James Bottomley , Jarkko Sakkinen , Mimi Zohar , David Howells , Paul Moore , James Morris , "Serge E. Hallyn" , Richard Weinberger , David Oberhollenzer Cc: linux-integrity@vger.kernel.org, keyrings@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, David Gstir , stable@vger.kernel.org Subject: [PATCH v2 2/2] KEYS: trusted: dcp: fix leak of blob encryption key Date: Wed, 17 Jul 2024 13:28:45 +0200 Message-ID: <20240717112845.92088-2-david@sigma-star.at> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240717112845.92088-1-david@sigma-star.at> References: <20240717112845.92088-1-david@sigma-star.at> Precedence: bulk X-Mailing-List: linux-integrity@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Trusted keys unseal the key blob on load, but keep the sealed payload in the blob field so that every subsequent read (export) will simply convert this field to hex and send it to userspace. With DCP-based trusted keys, we decrypt the blob encryption key (BEK) in the Kernel due hardware limitations and then decrypt the blob payload. BEK decryption is done in-place which means that the trusted key blob field is modified and it consequently holds the BEK in plain text. Every subsequent read of that key thus send the plain text BEK instead of the encrypted BEK to userspace. This issue only occurs when importing a trusted DCP-based key and then exporting it again. This should rarely happen as the common use cases are to either create a new trusted key and export it, or import a key blob and then just use it without exporting it again. Fix this by performing BEK decryption and encryption in a dedicated buffer. Further always wipe the plain text BEK buffer to prevent leaking the key via uninitialized memory. Cc: stable@vger.kernel.org # v6.10+ Fixes: 2e8a0f40a39c ("KEYS: trusted: Introduce NXP DCP-backed trusted keys") Signed-off-by: David Gstir Signed-off-by: Jarkko Sakkinen --- security/keys/trusted-keys/trusted_dcp.c | 33 +++++++++++++++--------- 1 file changed, 21 insertions(+), 12 deletions(-) diff --git a/security/keys/trusted-keys/trusted_dcp.c b/security/keys/trusted-keys/trusted_dcp.c index b0947f072a98..4edc5bbbcda3 100644 --- a/security/keys/trusted-keys/trusted_dcp.c +++ b/security/keys/trusted-keys/trusted_dcp.c @@ -186,20 +186,21 @@ static int do_aead_crypto(u8 *in, u8 *out, size_t len, u8 *key, u8 *nonce, return ret; } -static int decrypt_blob_key(u8 *key) +static int decrypt_blob_key(u8 *encrypted_key, u8 *plain_key) { - return do_dcp_crypto(key, key, false); + return do_dcp_crypto(encrypted_key, plain_key, false); } -static int encrypt_blob_key(u8 *key) +static int encrypt_blob_key(u8 *plain_key, u8 *encrypted_key) { - return do_dcp_crypto(key, key, true); + return do_dcp_crypto(plain_key, encrypted_key, true); } static int trusted_dcp_seal(struct trusted_key_payload *p, char *datablob) { struct dcp_blob_fmt *b = (struct dcp_blob_fmt *)p->blob; int blen, ret; + u8 plain_blob_key[AES_KEYSIZE_128]; blen = calc_blob_len(p->key_len); if (blen > MAX_BLOB_SIZE) @@ -207,30 +208,36 @@ static int trusted_dcp_seal(struct trusted_key_payload *p, char *datablob) b->fmt_version = DCP_BLOB_VERSION; get_random_bytes(b->nonce, AES_KEYSIZE_128); - get_random_bytes(b->blob_key, AES_KEYSIZE_128); + get_random_bytes(plain_blob_key, AES_KEYSIZE_128); - ret = do_aead_crypto(p->key, b->payload, p->key_len, b->blob_key, + ret = do_aead_crypto(p->key, b->payload, p->key_len, plain_blob_key, b->nonce, true); if (ret) { pr_err("Unable to encrypt blob payload: %i\n", ret); - return ret; + goto out; } - ret = encrypt_blob_key(b->blob_key); + ret = encrypt_blob_key(plain_blob_key, b->blob_key); if (ret) { pr_err("Unable to encrypt blob key: %i\n", ret); - return ret; + goto out; } put_unaligned_le32(p->key_len, &b->payload_len); p->blob_len = blen; - return 0; + ret = 0; + +out: + memzero_explicit(plain_blob_key, sizeof(plain_blob_key)); + + return ret; } static int trusted_dcp_unseal(struct trusted_key_payload *p, char *datablob) { struct dcp_blob_fmt *b = (struct dcp_blob_fmt *)p->blob; int blen, ret; + u8 plain_blob_key[AES_KEYSIZE_128]; if (b->fmt_version != DCP_BLOB_VERSION) { pr_err("DCP blob has bad version: %i, expected %i\n", @@ -248,14 +255,14 @@ static int trusted_dcp_unseal(struct trusted_key_payload *p, char *datablob) goto out; } - ret = decrypt_blob_key(b->blob_key); + ret = decrypt_blob_key(b->blob_key, plain_blob_key); if (ret) { pr_err("Unable to decrypt blob key: %i\n", ret); goto out; } ret = do_aead_crypto(b->payload, p->key, p->key_len + DCP_BLOB_AUTHLEN, - b->blob_key, b->nonce, false); + plain_blob_key, b->nonce, false); if (ret) { pr_err("Unwrap of DCP payload failed: %i\n", ret); goto out; @@ -263,6 +270,8 @@ static int trusted_dcp_unseal(struct trusted_key_payload *p, char *datablob) ret = 0; out: + memzero_explicit(plain_blob_key, sizeof(plain_blob_key)); + return ret; }