From patchwork Fri May 21 00:43:59 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: James Bottomley X-Patchwork-Id: 12271619 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AEFD3C433B4 for ; Fri, 21 May 2021 00:45:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8EF45613AC for ; Fri, 21 May 2021 00:45:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235175AbhEUAqn (ORCPT ); Thu, 20 May 2021 20:46:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53808 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234062AbhEUAqm (ORCPT ); Thu, 20 May 2021 20:46:42 -0400 Received: from bedivere.hansenpartnership.com (bedivere.hansenpartnership.com [IPv6:2607:fcd0:100:8a00::2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E0B20C061574; Thu, 20 May 2021 17:45:20 -0700 (PDT) Received: from localhost (localhost [127.0.0.1]) by bedivere.hansenpartnership.com (Postfix) with ESMTP id B8E6512806BA; Thu, 20 May 2021 17:45:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=hansenpartnership.com; s=20151216; t=1621557920; bh=g7Pav1Z/93yPRlFkuBLtk0OlOKI5UY3aQypTQCuxC38=; h=From:To:Subject:Date:Message-Id:In-Reply-To:References:From; b=AdrmgmaNz8AuCEWX4Exzeel0b7QUZF6coIoJ3sTPirtiHSVGx2WYCFZSIHVT+F54s qbUeoumWgxfgRu6A/xssRGSVWUF09TZO+HHomKW/5ro6cxmfTizRlX4lpQHgzwn6Qd tkuzXrukMCIO/IhZeFHzSFVK4r+S1a649hRQs2+g= Received: from bedivere.hansenpartnership.com ([127.0.0.1]) by localhost (bedivere.hansenpartnership.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 4OyU3DdHZOvE; Thu, 20 May 2021 17:45:20 -0700 (PDT) Received: from jarvis.int.hansenpartnership.com (jarvis.ext.hansenpartnership.com [153.66.160.226]) by bedivere.hansenpartnership.com (Postfix) with ESMTP id 22D7D12806B1; Thu, 20 May 2021 17:45:20 -0700 (PDT) From: James Bottomley To: linux-integrity@vger.kernel.org Cc: Mimi Zohar , Jarkko Sakkinen , David Woodhouse , keyrings@vger.kernel.org, David Howells Subject: [PATCH 2/4] security: keys: trusted: add ability to specify arbitrary policy Date: Thu, 20 May 2021 17:43:59 -0700 Message-Id: <20210521004401.4167-3-James.Bottomley@HansenPartnership.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20210521004401.4167-1-James.Bottomley@HansenPartnership.com> References: <20210521004401.4167-1-James.Bottomley@HansenPartnership.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org This patch adds a policy= argument to key creation. The policy is the standard tss policymaker format and each separate policy line must have a newline after it. Thus to construct a policy requiring authorized value and pcr 16 locking using a sha256 hash, the policy (policy.txt) file would be two lines: 0000017F00000001000B03000001303095B49BE85E381E5B20E557E46363EF55B0F43B132C2D8E3DE9AC436656F2 0000016b This can be inserted into the key with keyctl add trusted kmk "new 32 policy=`cat policy.txt` keyhandle=0x81000001 hash=sha256" @u Note that although a few policies work like this, most require special handling which must be added to the kernel policy construction routine. Signed-off-by: James Bottomley --- .../security/keys/trusted-encrypted.rst | 16 ++++++ security/keys/trusted-keys/tpm2-policy.c | 53 +++++++++++++++++++ security/keys/trusted-keys/tpm2-policy.h | 1 + security/keys/trusted-keys/trusted_tpm1.c | 15 ++++++ security/keys/trusted-keys/trusted_tpm2.c | 4 ++ 5 files changed, 89 insertions(+) diff --git a/Documentation/security/keys/trusted-encrypted.rst b/Documentation/security/keys/trusted-encrypted.rst index 5c66f29b7a1c..883844c95e91 100644 --- a/Documentation/security/keys/trusted-encrypted.rst +++ b/Documentation/security/keys/trusted-encrypted.rst @@ -172,6 +172,9 @@ Usage:: policyhandle= handle to an authorization policy session that defines the same policy and with the same hash algorithm as was used to seal the key. + policy= specify an arbitrary set of policies. These must + be in policymaker format with each separate + policy line newline terminated. "keyctl print" returns an ascii hex copy of the sealed key, which is in standard TPM_STORED_DATA format. The key length for new keys are always in bytes. @@ -271,6 +274,19 @@ zeros (the value of PCR 16):: $ dd if=/dev/zero bs=1 count=20 2>/dev/null|sha1sum 6768033e216468247bd031a0a2d9876d79818f8f +You can also specify arbitrary policy in policymaker format, so a two +value policy (the pcr example above and authvalue) would look like +this in policymaker format:: + + 0000017F000000010004030000016768033e216468247bd031a0a2d9876d79818f8f + 0000016b + +This can be placed in a file (say policy.txt) and then added to the key as:: + + $ keyctl add trusted kmk "new 32 keyhandle=0x81000001 hash=sha1 policy=`cat policy.txt`" @u + +The newlines in the file policy.txt will be automatically processed. + Reseal (TPM specific) a trusted key under new PCR values:: $ keyctl update 268728824 "update pcrinfo=`cat pcr.blob`" diff --git a/security/keys/trusted-keys/tpm2-policy.c b/security/keys/trusted-keys/tpm2-policy.c index b05b2953d5ea..bb28c864fa9b 100644 --- a/security/keys/trusted-keys/tpm2-policy.c +++ b/security/keys/trusted-keys/tpm2-policy.c @@ -357,3 +357,56 @@ int tpm2_get_policy_session(struct tpm_chip *chip, struct tpm2_policies *pols, return 0; } + +int tpm2_parse_policies(struct tpm2_policies **ppols, char *str) +{ + struct tpm2_policies *pols; + char *p; + u8 *ptr; + int i = 0, left = PAGE_SIZE, res; + + pols = kmalloc(left, GFP_KERNEL); + if (!pols) + return -ENOMEM; + + ptr = (u8 *)(pols + 1); + left -= ptr - (u8 *)pols; + + while ((p = strsep(&str, "\n"))) { + if (*p == '\0' || *p == '\n') + continue; + + pols->len[i] = strlen(p)/2; + if (pols->len[i] > left) { + res = -E2BIG; + goto err; + } + + res = hex2bin(ptr, p, pols->len[i]); + if (res) + goto err; + + /* get command code and skip past */ + pols->code[i] = get_unaligned_be32(ptr); + pols->policies[i] = ptr + 4; + ptr += pols->len[i]; + left -= pols->len[i]; + pols->len[i] -= 4; + + /* + * FIXME: this does leave the code embedded in dead + * regions of the memory, but it's easier than + * hexdumping to a temporary or copying over + */ + i++; + } + + pols->count = i; + *ppols = pols; + + return 0; + + err: + kfree(pols); + return res; +} diff --git a/security/keys/trusted-keys/tpm2-policy.h b/security/keys/trusted-keys/tpm2-policy.h index 46bf1f0a9325..0da013116c1c 100644 --- a/security/keys/trusted-keys/tpm2-policy.h +++ b/security/keys/trusted-keys/tpm2-policy.h @@ -28,3 +28,4 @@ int tpm2_generate_policy_digest(struct tpm2_policies *pols, u32 hash, int tpm2_encode_policy(struct tpm2_policies *pols, u8 **data, u32 *len); int tpm2_get_policy_session(struct tpm_chip *chip, struct tpm2_policies *pols, u32 *handle); +int tpm2_parse_policies(struct tpm2_policies **ppols, char *str); diff --git a/security/keys/trusted-keys/trusted_tpm1.c b/security/keys/trusted-keys/trusted_tpm1.c index aa108bea6739..6ed7303e36b5 100644 --- a/security/keys/trusted-keys/trusted_tpm1.c +++ b/security/keys/trusted-keys/trusted_tpm1.c @@ -22,6 +22,8 @@ #include +#include "tpm2-policy.h" + static const char hmac_alg[] = "hmac(sha1)"; static const char hash_alg[] = "sha1"; static struct tpm_chip *chip; @@ -713,6 +715,7 @@ enum { Opt_hash, Opt_policydigest, Opt_policyhandle, + Opt_policy, }; static const match_table_t key_tokens = { @@ -725,6 +728,7 @@ static const match_table_t key_tokens = { {Opt_hash, "hash=%s"}, {Opt_policydigest, "policydigest=%s"}, {Opt_policyhandle, "policyhandle=%s"}, + {Opt_policy, "policy=%s"}, {Opt_err, NULL} }; @@ -858,6 +862,17 @@ static int getoptions(char *c, struct trusted_key_payload *pay, return -EINVAL; opt->policyhandle = handle; break; + + case Opt_policy: + if (pay->policies) + return -EINVAL; + if (!tpm2) + return -EINVAL; + res = tpm2_parse_policies(&pay->policies, args[0].from); + if (res) + return res; + break; + default: return -EINVAL; } diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c index a218f982fef5..afe9cc41885e 100644 --- a/security/keys/trusted-keys/trusted_tpm2.c +++ b/security/keys/trusted-keys/trusted_tpm2.c @@ -268,6 +268,10 @@ int tpm2_seal_trusted(struct tpm_chip *chip, /* 4 array len, 2 hash alg */ const int len = 4 + 2 + options->pcrinfo_len; + if (payload->policies) + /* can't specify pcr and general policy */ + return -EINVAL; + pols = kmalloc(sizeof(*pols) + len, GFP_KERNEL); if (!pols) return -ENOMEM;