From patchwork Mon Feb 3 14:23:29 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 13957583 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4E93A20A5C9 for ; Mon, 3 Feb 2025 14:25:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738592726; cv=none; b=ioRRA596s5mZAXBDw43wTZ/maEWI9jMGI5r+/sOzdKxISO3vXaS9oZA76zwa42RWid9AVK6JymMVt43fnMuvC1UtpZ4RgVft5QDXIlChvf0KZ+896QOVhJBJ9G07Yx93xWeDjawyBwA7p/myVNd3UpEh4S+pxqu34l6YiqF+1FA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738592726; c=relaxed/simple; bh=8x96hgPuesNlUAGA+JMlvjxwTTAaMbEYDrU16OaAngQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=j1qIgF9WVUpWQ2HQ6F2de9fSNjf+qT6T2juuQ25G81M51Y/MJR1yo2Do2COdxnVgYeV0mvQsoHjCZri8wp4D7NlZrn32hkGjbUND+QO2EXxW+8o7/T04EEmgQYAZTR5ebt6EaZFg/XiHzEJbfP/EYRalHYWWfCVkphL+XpPcwb0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=g+e4a+xT; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="g+e4a+xT" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1738592723; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Sg1tiXasZdYVJfd0X98IXXCbsi9UiqsxMqNF6D78daY=; b=g+e4a+xTr0cygiDwG1ASpUDZoN6MEwRJPmF5izy76stPK79XbXOK5u3HLiyPNGccYHT7uO cmWLr3Uuge4VzZ0D8CMJFTL2/lHwn0GxXTUSaN/61jepcB309zow4ynH8/4qlbHhwgQy4z pGve9HFjEsUCbrVg8WqXQOJXVPF2jTA= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-203-HVjKrsO5NF6kI9dQyrPzPQ-1; Mon, 03 Feb 2025 09:25:18 -0500 X-MC-Unique: HVjKrsO5NF6kI9dQyrPzPQ-1 X-Mimecast-MFC-AGG-ID: HVjKrsO5NF6kI9dQyrPzPQ Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 6F7BF1801F28; Mon, 3 Feb 2025 14:25:13 +0000 (UTC) Received: from warthog.procyon.org.com (unknown [10.42.28.92]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 1A75C195608E; Mon, 3 Feb 2025 14:25:08 +0000 (UTC) From: David Howells To: netdev@vger.kernel.org, Herbert Xu Cc: David Howells , Marc Dionne , Jakub Kicinski , "David S. Miller" , Eric Dumazet , Paolo Abeni , Simon Horman , Trond Myklebust , Chuck Lever , Eric Biggers , Ard Biesheuvel , linux-crypto@vger.kernel.org, linux-afs@lists.infradead.org, linux-nfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net 13/24] crypto/krb5: Implement the Kerberos5 rfc3961 get_mic and verify_mic Date: Mon, 3 Feb 2025 14:23:29 +0000 Message-ID: <20250203142343.248839-14-dhowells@redhat.com> In-Reply-To: <20250203142343.248839-1-dhowells@redhat.com> References: <20250203142343.248839-1-dhowells@redhat.com> Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Add functions that sign and verify a message according to rfc3961 sec 5.4, using Kc to generate a checksum and insert it into the MIC field in the skbuff in the sign phase then checksum the data and compare it to the MIC in the verify phase. Signed-off-by: David Howells cc: Herbert Xu cc: "David S. Miller" cc: Chuck Lever cc: Marc Dionne cc: Eric Dumazet cc: Jakub Kicinski cc: Paolo Abeni cc: Simon Horman cc: linux-afs@lists.infradead.org cc: linux-nfs@vger.kernel.org cc: linux-crypto@vger.kernel.org cc: netdev@vger.kernel.org --- crypto/krb5/internal.h | 10 +++ crypto/krb5/rfc3961_simplified.c | 130 +++++++++++++++++++++++++++++++ 2 files changed, 140 insertions(+) diff --git a/crypto/krb5/internal.h b/crypto/krb5/internal.h index c8deb112b604..07a47ddf3ea9 100644 --- a/crypto/krb5/internal.h +++ b/crypto/krb5/internal.h @@ -169,3 +169,13 @@ int krb5_aead_decrypt(const struct krb5_enctype *krb5, struct crypto_aead *aead, struct scatterlist *sg, unsigned int nr_sg, size_t *_offset, size_t *_len); +ssize_t rfc3961_get_mic(const struct krb5_enctype *krb5, + struct crypto_shash *shash, + const struct krb5_buffer *metadata, + struct scatterlist *sg, unsigned int nr_sg, size_t sg_len, + size_t data_offset, size_t data_len); +int rfc3961_verify_mic(const struct krb5_enctype *krb5, + struct crypto_shash *shash, + const struct krb5_buffer *metadata, + struct scatterlist *sg, unsigned int nr_sg, + size_t *_offset, size_t *_len); diff --git a/crypto/krb5/rfc3961_simplified.c b/crypto/krb5/rfc3961_simplified.c index 58323ce5838a..c1dcb0dd3a00 100644 --- a/crypto/krb5/rfc3961_simplified.c +++ b/crypto/krb5/rfc3961_simplified.c @@ -653,6 +653,134 @@ int krb5_aead_decrypt(const struct krb5_enctype *krb5, return ret; } +/* + * Generate a checksum over some metadata and part of an skbuff and insert the + * MIC into the skbuff immediately prior to the data. + */ +ssize_t rfc3961_get_mic(const struct krb5_enctype *krb5, + struct crypto_shash *shash, + const struct krb5_buffer *metadata, + struct scatterlist *sg, unsigned int nr_sg, size_t sg_len, + size_t data_offset, size_t data_len) +{ + struct shash_desc *desc; + ssize_t ret, done; + size_t bsize; + void *buffer, *digest; + + if (WARN_ON(data_offset != krb5->cksum_len)) + return -EMSGSIZE; + + bsize = krb5_shash_size(shash) + + krb5_digest_size(shash); + buffer = kzalloc(bsize, GFP_NOFS); + if (!buffer) + return -ENOMEM; + + /* Calculate the MIC with key Kc and store it into the skb */ + desc = buffer; + desc->tfm = shash; + ret = crypto_shash_init(desc); + if (ret < 0) + goto error; + + if (metadata) { + ret = crypto_shash_update(desc, metadata->data, metadata->len); + if (ret < 0) + goto error; + } + + ret = crypto_shash_update_sg(desc, sg, data_offset, data_len); + if (ret < 0) + goto error; + + digest = buffer + krb5_shash_size(shash); + ret = crypto_shash_final(desc, digest); + if (ret < 0) + goto error; + + ret = -EFAULT; + done = sg_pcopy_from_buffer(sg, nr_sg, digest, krb5->cksum_len, + data_offset - krb5->cksum_len); + if (done != krb5->cksum_len) + goto error; + + ret = krb5->cksum_len + data_len; + +error: + kfree_sensitive(buffer); + return ret; +} + +/* + * Check the MIC on a region of an skbuff. The offset and length are updated + * to reflect the actual content of the secure region. + */ +int rfc3961_verify_mic(const struct krb5_enctype *krb5, + struct crypto_shash *shash, + const struct krb5_buffer *metadata, + struct scatterlist *sg, unsigned int nr_sg, + size_t *_offset, size_t *_len) +{ + struct shash_desc *desc; + ssize_t done; + size_t bsize, data_offset, data_len, offset = *_offset, len = *_len; + void *buffer = NULL; + int ret; + u8 *cksum, *cksum2; + + if (len < krb5->cksum_len) + return -EPROTO; + data_offset = offset + krb5->cksum_len; + data_len = len - krb5->cksum_len; + + bsize = krb5_shash_size(shash) + + krb5_digest_size(shash) * 2; + buffer = kzalloc(bsize, GFP_NOFS); + if (!buffer) + return -ENOMEM; + + cksum = buffer + + krb5_shash_size(shash); + cksum2 = buffer + + krb5_shash_size(shash) + + krb5_digest_size(shash); + + /* Calculate the MIC */ + desc = buffer; + desc->tfm = shash; + ret = crypto_shash_init(desc); + if (ret < 0) + goto error; + + if (metadata) { + ret = crypto_shash_update(desc, metadata->data, metadata->len); + if (ret < 0) + goto error; + } + + crypto_shash_update_sg(desc, sg, data_offset, data_len); + crypto_shash_final(desc, cksum); + + ret = -EFAULT; + done = sg_pcopy_to_buffer(sg, nr_sg, cksum2, krb5->cksum_len, offset); + if (done != krb5->cksum_len) + goto error; + + if (memcmp(cksum, cksum2, krb5->cksum_len) != 0) { + ret = -EBADMSG; + goto error; + } + + *_offset += krb5->cksum_len; + *_len -= krb5->cksum_len; + ret = 0; + +error: + kfree_sensitive(buffer); + return ret; +} + const struct krb5_crypto_profile rfc3961_simplified_profile = { .calc_PRF = rfc3961_calc_PRF, .calc_Kc = rfc3961_calc_DK, @@ -664,4 +792,6 @@ const struct krb5_crypto_profile rfc3961_simplified_profile = { .load_checksum_key = rfc3961_load_checksum_key, .encrypt = krb5_aead_encrypt, .decrypt = krb5_aead_decrypt, + .get_mic = rfc3961_get_mic, + .verify_mic = rfc3961_verify_mic, };