From mboxrd@z Thu Jan 1 00:00:00 1970 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 A51B4C433F5 for ; Fri, 10 Dec 2021 15:00:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236607AbhLJPD4 (ORCPT ); Fri, 10 Dec 2021 10:03:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34862 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231735AbhLJPDz (ORCPT ); Fri, 10 Dec 2021 10:03:55 -0500 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DE742C061746 for ; Fri, 10 Dec 2021 07:00:20 -0800 (PST) Received: by mail-yb1-xb49.google.com with SMTP id l145-20020a25cc97000000b005c5d04a1d52so16863565ybf.23 for ; Fri, 10 Dec 2021 07:00:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:message-id:mime-version:subject:from:to:cc :content-transfer-encoding; bh=nEUf1o9A4RxiKViFceFWJItzMhzL2zLt++iCvnltIvU=; b=HACHGNiFoS5fHrsxBf5y8hRRKaujIayqlJ7rebAXVt4mA1umQXmko2DtmbRe848oZX mtEX5N6Kdjah5JhTM613c3eY847+z6zwamrBzpzpvxc4LoMhM9ON6J75aVBrdPmE9Rl1 cjW7AtiFmL2G5ExOcVF45KjjewQtxuqOPaaFGQSO2pfLvy7n4BsmxUFXp7XFFZJfi5gK emIQwspxWA/lvk5AqKZb7lIGxcClMpMAaGAep7R+OeSnP/PFSrsWKCcTQY3uNOfOF5K4 d7z5ZBZNSbvh/thEoNdoTNSanctLqzCD0n4dN5uIerQi65QzAh02SeiY+vIXWH98mTiW GaxQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc :content-transfer-encoding; bh=nEUf1o9A4RxiKViFceFWJItzMhzL2zLt++iCvnltIvU=; b=NyUat9SnysWY2JQO0Jqvk37HYIpcef/tkwSlw/nBT98iw/CzS/T9XtUMs17qfXwVih /hqTwPgH2LI23xR21dY0gvqn9FtO7E6J6WuF5pHhQ2FTwFn1WICJdXHKpOjPusGpNCfb rPYxeDzjNYI+Eld2P4GYbzwkntd9ed5O9sYEBBiAqyBWunxNoz2VXb1KfudONzLULDSB xGAe3yr8cyIVWYujQTSJixWZ97AWLKA8/+BiEIID4EoDZLGgh1EnYmScPwKaSep+y3g6 36dIWMYYGUKQ6mYVXmPmkasluIetlXMQBh3/lQNajXxqRdv8Fsn0Bug2a5TZJiRPeqaY JDhQ== X-Gm-Message-State: AOAM5333gQdQ9X7PpHhmWXp07uMCFVt5XpiGScR92Bb7+bpEeUHClH8U PfmQTHVCPWEWWT6faZrq1Yxu8uf0NUY2VuDA3nqrRWNKMZhaEBf15/oPWhwHyBZt2R4hmJ/Hxc7 P5adY+IdB1dnDMMCKzP1JTcWGndlrgTPycseGTr6OPDTp7rgYgFK6fc/W7MI1vMoJFaRWssQ= X-Google-Smtp-Source: ABdhPJzT6WbteBMu5E+XPj1emkvmyJ/2QmxHhsg7/eVq4kmauOS7DCwKW8B2iligUKPHJh1Ffo06pADUTA== X-Received: from yaelt.nyc.corp.google.com ([2620:0:1003:415:78e8:100b:1fab:e86a]) (user=yaelt job=sendgmr) by 2002:a05:6902:1248:: with SMTP id t8mr16892322ybu.185.1639148419972; Fri, 10 Dec 2021 07:00:19 -0800 (PST) Date: Fri, 10 Dec 2021 10:00:18 -0500 Message-Id: <20211210150018.2075133-1-yaelt@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.34.1.173.g76aa8bc2d0-goog Subject: [PATCH] Instantiate key with user-provided decrypted data. From: Yael Tiomkin To: linux-integrity@vger.kernel.org Cc: Yael Tiomkin Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org The encrypted.c class supports instantiation of encrypted keys with either an already-encrypted key material, or by generating new key material based on random numbers. To support encryption of user-provided decrypted data, this patch defines a new datablob format: [] . Signed-off-by: Yael Tiomkin --- .../security/keys/trusted-encrypted.rst | 25 +++++++--- security/keys/encrypted-keys/encrypted.c | 48 +++++++++++++------ 2 files changed, 52 insertions(+), 21 deletions(-) diff --git a/Documentation/security/keys/trusted-encrypted.rst b/Documentat= ion/security/keys/trusted-encrypted.rst index 80d5a5af62a1..2ea6fad394fe 100644 --- a/Documentation/security/keys/trusted-encrypted.rst +++ b/Documentation/security/keys/trusted-encrypted.rst @@ -107,12 +107,13 @@ Encrypted Keys -------------- =20 Encrypted keys do not depend on a trust source, and are faster, as they us= e AES -for encryption/decryption. New keys are created from kernel-generated rand= om -numbers, and are encrypted/decrypted using a specified =E2=80=98master=E2= =80=99 key. The -=E2=80=98master=E2=80=99 key can either be a trusted-key or user-key type.= The main disadvantage -of encrypted keys is that if they are not rooted in a trusted key, they ar= e only -as secure as the user key encrypting them. The master user key should ther= efore -be loaded in as secure a way as possible, preferably early in boot. +for encryption/decryption. New keys are created either from kernel-generat= ed +random numbers or user-provided decrypted data, and are encrypted/decrypte= d +using a specified =E2=80=98master=E2=80=99 key. The =E2=80=98master=E2=80= =99 key can either be a trusted-key or +user-key type. The main disadvantage of encrypted keys is that if they are= not +rooted in a trusted key, they are only as secure as the user key encryptin= g +them. The master user key should therefore be loaded in as secure a way as +possible, preferably early in boot. =20 =20 Usage @@ -199,6 +200,8 @@ Usage:: =20 keyctl add encrypted name "new [format] key-type:master-key-name keyle= n" ring + keyctl add encrypted name "new [format] key-type:master-key-name keyle= n + decrypted-data" ring keyctl add encrypted name "load hex_blob" ring keyctl update keyid "update key-type:master-key-name" =20 @@ -303,6 +306,16 @@ Load an encrypted key "evm" from saved blob:: 82dbbc55be2a44616e4959430436dc4f2a7a9659aa60bb4652aeb2120f149ed197c564= e0 24717c64 5972dcb82ab2dde83376d82b2e3c09ffc =20 +Instantiate an encrypted key "evm" using user-provided decrypted data:: + + $ keyctl add encrypted evm "new default user:kmk 32 `cat evm.blob`" @u + 794890253 + + $ keyctl print 794890253 + default user:kmk 32 2375725ad57798846a9bbd240de8906f006e66c03af53b1b38= 2d + bbc55be2a44616e4959430436dc4f2a7a9659aa60bb4652aeb2120f149ed197c564e02= 47 + 17c64 5972dcb82ab2dde83376d82b2e3c09ffc + Other uses for trusted and encrypted keys, such as for disk and file encry= ption are anticipated. In particular the new format 'ecryptfs' has been defined in order to use encrypted keys to mount an eCryptfs filesystem. More deta= ils diff --git a/security/keys/encrypted-keys/encrypted.c b/security/keys/encry= pted-keys/encrypted.c index 87432b35d771..114da02c1131 100644 --- a/security/keys/encrypted-keys/encrypted.c +++ b/security/keys/encrypted-keys/encrypted.c @@ -159,6 +159,7 @@ static int valid_master_desc(const char *new_desc, cons= t char *orig_desc) * * datablob format: * new [] + * new [] * load [] * * update @@ -170,7 +171,7 @@ static int valid_master_desc(const char *new_desc, cons= t char *orig_desc) */ static int datablob_parse(char *datablob, const char **format, char **master_desc, char **decrypted_datalen, - char **hex_encoded_iv) + char **hex_encoded_iv, char **decrypted_data) { substring_t args[MAX_OPT_ARGS]; int ret =3D -EINVAL; @@ -231,6 +232,17 @@ static int datablob_parse(char *datablob, const char *= *format, "when called from .update method\n", keyword); break; } + *decrypted_data =3D strsep(&datablob, " \t"); + if (*decrypted_data) { + if (strlen(*decrypted_data) !=3D decrypted_datalen) { + pr_info("encrypted_key: decrypted data provided does not match decrypt= ed data length provided\n"); + break; + } + if (!isalnum(*decrypted_data)) { + pr_info("encrypted_key: decrypted data provided must be alphanumeric\n= "); + break; + } + } ret =3D 0; break; case Opt_load: @@ -740,13 +752,14 @@ static void __ekey_init(struct encrypted_key_payload = *epayload, /* * encrypted_init - initialize an encrypted key * - * For a new key, use a random number for both the iv and data - * itself. For an old key, decrypt the hex encoded data. + * For a new key, use either a random number or user-provided decrypted da= ta in + * case it is provided. A random number is used for the iv in both cases. = For + * an old key, decrypt the hex encoded data. */ static int encrypted_init(struct encrypted_key_payload *epayload, const char *key_desc, const char *format, const char *master_desc, const char *datalen, - const char *hex_encoded_iv) + const char *hex_encoded_iv, const char *decrypted_data) { int ret =3D 0; =20 @@ -760,21 +773,25 @@ static int encrypted_init(struct encrypted_key_payloa= d *epayload, } =20 __ekey_init(epayload, format, master_desc, datalen); - if (!hex_encoded_iv) { - get_random_bytes(epayload->iv, ivsize); - - get_random_bytes(epayload->decrypted_data, - epayload->decrypted_datalen); - } else + if (hex_encoded_iv) { ret =3D encrypted_key_decrypt(epayload, format, hex_encoded_iv); + } else if (decrypted_data) { + get_random_bytes(epayload->iv, ivsize); + memcpy(epayload->decrypted_data, decrypted_data, epayload->decrypted_dat= alen); + } else { + get_random_bytes(epayload->iv, ivsize); + get_random_bytes(epayload->decrypted_data, epayload->decrypted_datalen); + } return ret; } =20 /* * encrypted_instantiate - instantiate an encrypted key * - * Decrypt an existing encrypted datablob or create a new encrypted key - * based on a kernel random number. + * Instantiates the key: + * - by decrypting an existing encrypted datablob, or + * - by creating a new encrypted key based on a kernel random number, or + * - using provided decrypted data. * * On success, return 0. Otherwise return errno. */ @@ -787,6 +804,7 @@ static int encrypted_instantiate(struct key *key, char *master_desc =3D NULL; char *decrypted_datalen =3D NULL; char *hex_encoded_iv =3D NULL; + char *decrypted_data =3D NULL; size_t datalen =3D prep->datalen; int ret; =20 @@ -799,7 +817,7 @@ static int encrypted_instantiate(struct key *key, datablob[datalen] =3D 0; memcpy(datablob, prep->data, datalen); ret =3D datablob_parse(datablob, &format, &master_desc, - &decrypted_datalen, &hex_encoded_iv); + &decrypted_datalen, &hex_encoded_iv, &decrypted_data); if (ret < 0) goto out; =20 @@ -810,7 +828,7 @@ static int encrypted_instantiate(struct key *key, goto out; } ret =3D encrypted_init(epayload, key->description, format, master_desc, - decrypted_datalen, hex_encoded_iv); + decrypted_datalen, hex_encoded_iv, decrypted_data); if (ret < 0) { kfree_sensitive(epayload); goto out; @@ -860,7 +878,7 @@ static int encrypted_update(struct key *key, struct key= _preparsed_payload *prep) =20 buf[datalen] =3D 0; memcpy(buf, prep->data, datalen); - ret =3D datablob_parse(buf, &format, &new_master_desc, NULL, NULL); + ret =3D datablob_parse(buf, &format, &new_master_desc, NULL, NULL, NULL); if (ret < 0) goto out; =20 --=20 2.34.1.173.g76aa8bc2d0-goog