From patchwork Wed May 4 23:20:55 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Evan Green X-Patchwork-Id: 569490 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CE5F5C4167B for ; Wed, 4 May 2022 23:59:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1383756AbiEEAAb (ORCPT ); Wed, 4 May 2022 20:00:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41704 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1359763AbiEDXZK (ORCPT ); Wed, 4 May 2022 19:25:10 -0400 Received: from mail-pg1-x530.google.com (mail-pg1-x530.google.com [IPv6:2607:f8b0:4864:20::530]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 755F24DF49 for ; Wed, 4 May 2022 16:21:32 -0700 (PDT) Received: by mail-pg1-x530.google.com with SMTP id x12so2318038pgj.7 for ; Wed, 04 May 2022 16:21:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=Yhdb5Bb/HPOT7rt6ZFl1SIPi2sOZMgAuPW9HJM+UwR0=; b=Lk4xT28VP//2/ipug2hDVNsFxT9ZIxqyDHb0zfUWgwzqxrDXikdUEYcZVll3q4j94i ztdggJgt0+wJWipyAMzuue+sqAj5cr1iqrjXU6TY0KlGJi2k7/sLjz4SzJeD6C1FqUri Vuh+XJBEfDQcKfui50SG/RlDJ8yjXNcYwrQew= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=Yhdb5Bb/HPOT7rt6ZFl1SIPi2sOZMgAuPW9HJM+UwR0=; b=vYj5COKKVGnRmOUbzkJJjO3LuYNoWOibRS4klnNiUyfton04JciUcdHcEVsDs2Kh+x pnvIzqwDYdz0ecgyGkYLGKt5YpadqjMki+WIWQAzZK+FxXDQt1tMkB+eW7BwZ3N7+u8t IiR3yNQPRIi8sabCs54ZaJbnuYtkvHo7pndX9Usx/yqM/l5CqCQeRzwd2mlkNpc6vaeS 6ieWKCP+GljvV5y4DRb+kIu2griyD/shyzIIspOrO7zZv2RraIqjQfiVDxDBoeOynYNw 4xgGgRy58ASBOy6g56Ij+uPPHTrOFwFTRtJRrOvyvCZUicCBLgDPvR2BazR4ry1wJzYW V3nA== X-Gm-Message-State: AOAM530ad7ZmKu3VLczpip514wgBKVF3aojjxHY6llp/Cl8vOfnYWvHl xaYc5jza3PRwcemDEYbG+fs1xA== X-Google-Smtp-Source: ABdhPJw5P1NIDRBbT4jMlDGJLeiA/MnnIE6iVTPAa0LCmNhzVLp/2G2suU9nzhm2DtywpArEruqEYA== X-Received: by 2002:a62:ce82:0:b0:50d:512f:7b76 with SMTP id y124-20020a62ce82000000b0050d512f7b76mr23214566pfg.79.1651706491900; Wed, 04 May 2022 16:21:31 -0700 (PDT) Received: from evgreen-glaptop.lan ([98.47.98.87]) by smtp.gmail.com with ESMTPSA id q12-20020a170902f78c00b0015e8d4eb2d6sm1901pln.288.2022.05.04.16.21.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 04 May 2022 16:21:31 -0700 (PDT) From: Evan Green To: linux-kernel@vger.kernel.org Cc: Matthew Garrett , dlunev@google.com, zohar@linux.ibm.com, jejb@linux.ibm.com, linux-integrity@vger.kernel.org, corbet@lwn.net, rjw@rjwysocki.net, gwendal@chromium.org, jarkko@kernel.org, linux-pm@vger.kernel.org, Matthew Garrett , Matthew Garrett , Evan Green , David Howells , James Morris , "Serge E. Hallyn" , keyrings@vger.kernel.org, linux-security-module@vger.kernel.org Subject: [PATCH 03/10] security: keys: trusted: Parse out individual components of the key blob Date: Wed, 4 May 2022 16:20:55 -0700 Message-Id: <20220504161439.3.Id409e0cf397bd98b76df6eb60ff16454679dd23d@changeid> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20220504232102.469959-1-evgreen@chromium.org> References: <20220504232102.469959-1-evgreen@chromium.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org From: Matthew Garrett Performing any sort of state validation of a sealed TPM blob requires being able to access the individual members in the response. Parse the blob sufficiently to be able to stash pointers to each member, along with the length. From: Matthew Garrett Signed-off-by: Matthew Garrett Signed-off-by: Evan Green --- Matthew's original version of this patch is at: https://patchwork.kernel.org/patch/12096489/ include/keys/trusted-type.h | 8 +++ security/keys/trusted-keys/trusted_tpm2.c | 67 ++++++++++++++++++++++- 2 files changed, 73 insertions(+), 2 deletions(-) diff --git a/include/keys/trusted-type.h b/include/keys/trusted-type.h index d89fa2579ac056..8a793ae1ad9f70 100644 --- a/include/keys/trusted-type.h +++ b/include/keys/trusted-type.h @@ -22,15 +22,23 @@ #define MAX_BLOB_SIZE 512 #define MAX_PCRINFO_SIZE 64 #define MAX_DIGEST_SIZE 64 +#define MAX_CREATION_DATA 412 +#define MAX_TK 76 struct trusted_key_payload { struct rcu_head rcu; unsigned int key_len; unsigned int blob_len; + unsigned int creation_len; + unsigned int creation_hash_len; + unsigned int tk_len; unsigned char migratable; unsigned char old_format; unsigned char key[MAX_KEY_SIZE + 1]; unsigned char blob[MAX_BLOB_SIZE]; + unsigned char *creation; + unsigned char *creation_hash; + unsigned char *tk; }; struct trusted_key_options { diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c index 0165da386289c3..296a00f872ba40 100644 --- a/security/keys/trusted-keys/trusted_tpm2.c +++ b/security/keys/trusted-keys/trusted_tpm2.c @@ -215,6 +215,63 @@ static void tpm2_buf_append_auth(struct tpm_buf *buf, u32 session_handle, tpm_buf_append(buf, hmac, hmac_len); } +static int tpm2_unpack_blob(struct trusted_key_payload *payload) +{ + int tmp, offset; + + /* Find the length of the private data */ + tmp = be16_to_cpup((__be16 *) &payload->blob[0]); + offset = tmp + 2; + if (offset > payload->blob_len) + return -EFAULT; + + /* Find the length of the public data */ + tmp = be16_to_cpup((__be16 *) &payload->blob[offset]); + offset += tmp + 2; + if (offset > payload->blob_len) + return -EFAULT; + + /* Find the length of the creation data and store it */ + tmp = be16_to_cpup((__be16 *) &payload->blob[offset]); + if (tmp > MAX_CREATION_DATA) + return -E2BIG; + + if ((offset + tmp + 2) > payload->blob_len) + return -EFAULT; + + payload->creation = &payload->blob[offset + 2]; + payload->creation_len = tmp; + offset += tmp + 2; + + /* Find the length of the creation hash and store it */ + tmp = be16_to_cpup((__be16 *) &payload->blob[offset]); + if (tmp > MAX_DIGEST_SIZE) + return -E2BIG; + + if ((offset + tmp + 2) > payload->blob_len) + return -EFAULT; + + payload->creation_hash = &payload->blob[offset + 2]; + payload->creation_hash_len = tmp; + offset += tmp + 2; + + /* + * Store the creation ticket. TPMT_TK_CREATION is two bytes of tag, + * four bytes of handle, and then the digest length and digest data + */ + tmp = be16_to_cpup((__be16 *) &payload->blob[offset + 6]); + if (tmp > MAX_TK) + return -E2BIG; + + if ((offset + tmp + 8) > payload->blob_len) + return -EFAULT; + + payload->tk = &payload->blob[offset]; + payload->tk_len = tmp + 8; + + return 0; +} + /** * tpm2_seal_trusted() - seal the payload of a trusted key * @@ -229,6 +286,7 @@ int tpm2_seal_trusted(struct tpm_chip *chip, struct trusted_key_options *options) { int blob_len = 0; + unsigned int offset; struct tpm_buf buf; u32 hash; u32 flags; @@ -317,15 +375,17 @@ int tpm2_seal_trusted(struct tpm_chip *chip, rc = -E2BIG; goto out; } - if (tpm_buf_length(&buf) < TPM_HEADER_SIZE + 4 + blob_len) { + offset = TPM_HEADER_SIZE + 4; + if (tpm_buf_length(&buf) < offset + blob_len) { rc = -EFAULT; goto out; } blob_len = tpm2_key_encode(payload, options, - &buf.data[TPM_HEADER_SIZE + 4], + &buf.data[offset], blob_len); + rc = tpm2_unpack_blob(payload); out: tpm_buf_destroy(&buf); @@ -431,7 +491,10 @@ static int tpm2_load_cmd(struct tpm_chip *chip, if (!rc) *blob_handle = be32_to_cpup( (__be32 *) &buf.data[TPM_HEADER_SIZE]); + else + goto out; + rc = tpm2_unpack_blob(payload); out: if (blob != payload->blob) kfree(blob);