From patchwork Tue Jan 11 18:03:14 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roberto Sassu X-Patchwork-Id: 12710317 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 044D3C433EF for ; Tue, 11 Jan 2022 18:04:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350158AbiAKSEM (ORCPT ); Tue, 11 Jan 2022 13:04:12 -0500 Received: from frasgout.his.huawei.com ([185.176.79.56]:4398 "EHLO frasgout.his.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345554AbiAKSD6 (ORCPT ); Tue, 11 Jan 2022 13:03:58 -0500 Received: from fraeml714-chm.china.huawei.com (unknown [172.18.147.207]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4JYJQs1ypdz6842D; Wed, 12 Jan 2022 02:01:09 +0800 (CST) Received: from roberto-ThinkStation-P620.huawei.com (10.204.63.22) by fraeml714-chm.china.huawei.com (10.206.15.33) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.20; Tue, 11 Jan 2022 19:03:54 +0100 From: Roberto Sassu To: , , , CC: , , , , , , , Roberto Sassu Subject: [PATCH 10/14] KEYS: Calculate key digest and get signature of the key Date: Tue, 11 Jan 2022 19:03:14 +0100 Message-ID: <20220111180318.591029-11-roberto.sassu@huawei.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220111180318.591029-1-roberto.sassu@huawei.com> References: <20220111180318.591029-1-roberto.sassu@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.204.63.22] X-ClientProxiedBy: lhreml754-chm.china.huawei.com (10.201.108.204) To fraeml714-chm.china.huawei.com (10.206.15.33) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: keyrings@vger.kernel.org Calculate the digest of the signature, according to the RFC4880 section 5.2.4, get the last suitable signature with type 0x13 (Positive certification of a User ID and Public Key packet), and store it in the asym_auth field of the key payload, so that it is available for validating a restriction on a keyring. The rationale of taking the last signature is that, if there are multiple signatures, that would be of a different issuer (not a self-signature), that likely has more chances to be useful for the restriction verification. If there is one (the self-signature), that will be used. Signed-off-by: Roberto Sassu --- crypto/asymmetric_keys/pgp_public_key.c | 81 +++++++++++++++++++++++++ 1 file changed, 81 insertions(+) diff --git a/crypto/asymmetric_keys/pgp_public_key.c b/crypto/asymmetric_keys/pgp_public_key.c index 378ed5ff0a3a..cecd67bab4e6 100644 --- a/crypto/asymmetric_keys/pgp_public_key.c +++ b/crypto/asymmetric_keys/pgp_public_key.c @@ -14,6 +14,7 @@ #include #include #include +#include #include "pgp_parser.h" @@ -61,6 +62,8 @@ struct pgp_key_data_parse_context { size_t raw_fingerprint_len; const char *user_id; size_t user_id_len; + const char *key_pkt; + size_t key_pkt_len; }; /* @@ -226,6 +229,12 @@ static int pgp_process_public_key(struct pgp_parse_context *context, return -EBADMSG; } + /* Pointer refers to data being processed. */ + if (type == PGP_PKT_PUBLIC_KEY) { + ctx->key_pkt = data; + ctx->key_pkt_len = datalen; + } + pub = kzalloc(sizeof(struct public_key), GFP_KERNEL); if (!pub) return -ENOMEM; @@ -314,6 +323,77 @@ static struct asymmetric_key_ids *pgp_key_generate_id( return NULL; } +/* + * Calculate the digest of the signature according to the RFC4880, section + * 5.2.4 (packet type 0x13). + */ +static int pgp_key_add_sig_data(struct pgp_key_data_parse_context *ctx, + struct pgp_sig_verify *sig_ctx) +{ + loff_t offset = 0; + u8 *data; + + if (!ctx->key_pkt_len || !ctx->user_id_len) + return 0; + + /* 0x99 + key pkt len + key pkt + 0xb4 + user ID len + user ID */ + data = kmalloc(1 + sizeof(u16) + ctx->key_pkt_len + + 1 + sizeof(u32) + ctx->user_id_len, GFP_KERNEL); + if (!data) + return -ENOMEM; + + data[offset++] = 0x99; + data[offset++] = ctx->key_pkt_len >> 8; + data[offset++] = ctx->key_pkt_len; + + memcpy(data + offset, ctx->key_pkt, ctx->key_pkt_len); + offset += ctx->key_pkt_len; + + if (pgp_sig_get_version(sig_ctx) == PGP_SIG_VERSION_4) { + data[offset++] = 0xb4; + data[offset++] = ctx->user_id_len >> 24; + data[offset++] = ctx->user_id_len >> 16; + data[offset++] = ctx->user_id_len >> 8; + data[offset++] = ctx->user_id_len; + } + + memcpy(data + offset, ctx->user_id, ctx->user_id_len); + offset += ctx->user_id_len; + + pgp_sig_add_data(sig_ctx, data, offset); + kfree(data); + return 0; +} + +static struct public_key_signature *pgp_key_get_sig( + struct key_preparsed_payload *prep, + struct pgp_key_data_parse_context *ctx) +{ + struct public_key_signature *sig = NULL; + struct pgp_sig_verify *sig_ctx; + bool keep_sig = false; + int ret; + + sig_ctx = pgp_sig_parse(prep->data, prep->datalen); + if (IS_ERR(sig_ctx)) + return NULL; + + ret = pgp_key_add_sig_data(ctx, sig_ctx); + if (ret < 0) + goto out; + + sig = pgp_sig_get_sig(sig_ctx); + if (IS_ERR(sig)) { + sig = NULL; + goto out; + } + + keep_sig = true; +out: + pgp_sig_verify_cancel(sig_ctx, keep_sig); + return sig; +} + /* * Attempt to parse the instantiation data blob for a key as a PGP packet * message holding a key. @@ -372,6 +452,7 @@ static int pgp_key_parse(struct key_preparsed_payload *prep) prep->payload.data[asym_subtype] = &public_key_subtype; prep->payload.data[asym_key_ids] = pgp_key_generate_id(&ctx); prep->payload.data[asym_crypto] = ctx.pub; + prep->payload.data[asym_auth] = pgp_key_get_sig(prep, &ctx); prep->quotalen = 100; return 0;