From patchwork Tue Sep 22 02:32:17 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: James Bottomley X-Patchwork-Id: 11791389 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D78D36CA for ; Tue, 22 Sep 2020 02:33:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B66D7207C4 for ; Tue, 22 Sep 2020 02:33:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=hansenpartnership.com header.i=@hansenpartnership.com header.b="dqajqYx3" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729726AbgIVCdK (ORCPT ); Mon, 21 Sep 2020 22:33:10 -0400 Received: from bedivere.hansenpartnership.com ([66.63.167.143]:36142 "EHLO bedivere.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729379AbgIVCdK (ORCPT ); Mon, 21 Sep 2020 22:33:10 -0400 Received: from localhost (localhost [127.0.0.1]) by bedivere.hansenpartnership.com (Postfix) with ESMTP id F13098EE194; Mon, 21 Sep 2020 19:33:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=hansenpartnership.com; s=20151216; t=1600741990; bh=9Oz3j8Rm49y68CQ/O/Jo/dFoChafUYtrXBnD1w52nSY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dqajqYx3zC/O78hg4u2yw6L5QDDgvOGWnxVEw5obnHtkTYr/7C57dtrsV3rmbC9JG /1t4ft0oeVQql9M3ZHs01AodrZi8T903mH9Cy/2YX9bfJRyOww7r9pw4n4fyMq5sp2 wCyhkE+up7GW7dwinKtXsEz5anhTnd7MdvE8u3vw= 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 arkGVUn32qI5; Mon, 21 Sep 2020 19:33:09 -0700 (PDT) Received: from jarvis.int.hansenpartnership.com (jarvis.ext.hansenpartnership.com [153.66.160.226]) by bedivere.hansenpartnership.com (Postfix) with ESMTP id 117EC8EE0CF; Mon, 21 Sep 2020 19:33:09 -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 v13 2/3] security: keys: trusted: add ability to specify arbitrary policy Date: Mon, 21 Sep 2020 19:32:17 -0700 Message-Id: <20200922023218.7466-3-James.Bottomley@HansenPartnership.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200922023218.7466-1-James.Bottomley@HansenPartnership.com> References: <20200922023218.7466-1-James.Bottomley@HansenPartnership.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: keyrings@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 ++++++ 4 files changed, 85 insertions(+) diff --git a/Documentation/security/keys/trusted-encrypted.rst b/Documentation/security/keys/trusted-encrypted.rst index 8b7853a277bc..f001752adaa1 100644 --- a/Documentation/security/keys/trusted-encrypted.rst +++ b/Documentation/security/keys/trusted-encrypted.rst @@ -76,6 +76,9 @@ 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. @@ -168,6 +171,19 @@ 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 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 011f42e574db..78daa0310e9e 100644 --- a/security/keys/trusted-keys/tpm2-policy.c +++ b/security/keys/trusted-keys/tpm2-policy.c @@ -372,3 +372,56 @@ 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 2130a27fcbff..2f2e78a4f503 100644 --- a/security/keys/trusted-keys/trusted_tpm1.c +++ b/security/keys/trusted-keys/trusted_tpm1.c @@ -29,6 +29,8 @@ #include +#include "tpm2-policy.h" + static const char hmac_alg[] = "hmac(sha1)"; static const char hash_alg[] = "sha1"; static struct tpm_chip *chip; @@ -709,6 +711,7 @@ enum { Opt_hash, Opt_policydigest, Opt_policyhandle, + Opt_policy, }; static const match_table_t key_tokens = { @@ -724,6 +727,7 @@ 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} }; @@ -854,6 +858,17 @@ 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; }