* [PATCH1/7] X.509: Export certificate parse and free functions
2014-07-08 13:15 [PATCH 0/7] KEYS: PKCS#7 asymmetric key parser David Howells
@ 2014-07-08 13:15 ` David Howells
2014-07-08 13:15 ` [PATCH2/7] PKCS#7: Implement a parser [RFC 2315] David Howells
` (5 subsequent siblings)
6 siblings, 0 replies; 8+ messages in thread
From: David Howells @ 2014-07-08 13:15 UTC (permalink / raw)
To: keyrings
Cc: Kees Cook, Josh Boyer, kexec, linux-kernel,
linux-security-module, Vivek Goyal
Export certificate parse and free functions for use by modules.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Josh Boyer <jwboyer@redhat.com>
---
crypto/asymmetric_keys/x509_cert_parser.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c
index 4a8df29..ac72348 100644
--- a/crypto/asymmetric_keys/x509_cert_parser.c
+++ b/crypto/asymmetric_keys/x509_cert_parser.c
@@ -11,6 +11,7 @@
#define pr_fmt(fmt) "X.509: "fmt
#include <linux/kernel.h>
+#include <linux/export.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/oid_registry.h>
@@ -52,6 +53,7 @@ void x509_free_certificate(struct x509_certificate *cert)
kfree(cert);
}
}
+EXPORT_SYMBOL_GPL(x509_free_certificate);
/*
* Parse an X.509 certificate
@@ -97,6 +99,7 @@ error_no_ctx:
error_no_cert:
return ERR_PTR(ret);
}
+EXPORT_SYMBOL_GPL(x509_cert_parse);
/*
* Note an OID when we find one for later processing when we know how
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH2/7] PKCS#7: Implement a parser [RFC 2315]
2014-07-08 13:15 [PATCH 0/7] KEYS: PKCS#7 asymmetric key parser David Howells
2014-07-08 13:15 ` [PATCH1/7] X.509: Export certificate parse and free functions David Howells
@ 2014-07-08 13:15 ` David Howells
2014-07-08 13:15 ` [PATCH3/7] PKCS#7: Digest the data in a signed-data message David Howells
` (4 subsequent siblings)
6 siblings, 0 replies; 8+ messages in thread
From: David Howells @ 2014-07-08 13:15 UTC (permalink / raw)
To: keyrings
Cc: linux-security-module, kexec, Kees Cook, Vivek Goyal, linux-kernel
Implement a parser for a PKCS#7 signed-data message as described in part of
RFC 2315.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
---
crypto/asymmetric_keys/Kconfig | 9 +
crypto/asymmetric_keys/Makefile | 13 +
crypto/asymmetric_keys/pkcs7.asn1 | 127 +++++++++++
crypto/asymmetric_keys/pkcs7_parser.c | 396 +++++++++++++++++++++++++++++++++
crypto/asymmetric_keys/pkcs7_parser.h | 61 +++++
include/crypto/pkcs7.h | 23 ++
include/linux/oid_registry.h | 1
7 files changed, 630 insertions(+)
create mode 100644 crypto/asymmetric_keys/pkcs7.asn1
create mode 100644 crypto/asymmetric_keys/pkcs7_parser.c
create mode 100644 crypto/asymmetric_keys/pkcs7_parser.h
create mode 100644 include/crypto/pkcs7.h
diff --git a/crypto/asymmetric_keys/Kconfig b/crypto/asymmetric_keys/Kconfig
index 03a6eb9..a7cec9d 100644
--- a/crypto/asymmetric_keys/Kconfig
+++ b/crypto/asymmetric_keys/Kconfig
@@ -37,4 +37,13 @@ config X509_CERTIFICATE_PARSER
data and provides the ability to instantiate a crypto key from a
public key packet found inside the certificate.
+config PKCS7_MESSAGE_PARSER
+ tristate "PKCS#7 message parser"
+ depends on X509_CERTIFICATE_PARSER
+ select ASN1
+ select OID_REGISTRY
+ help
+ This option provides support for parsing PKCS#7 format messages for
+ signature data and provides the ability to verify the signature.
+
endif # ASYMMETRIC_KEY_TYPE
diff --git a/crypto/asymmetric_keys/Makefile b/crypto/asymmetric_keys/Makefile
index 0727204..59d8cad 100644
--- a/crypto/asymmetric_keys/Makefile
+++ b/crypto/asymmetric_keys/Makefile
@@ -25,3 +25,16 @@ $(obj)/x509_rsakey-asn1.o: $(obj)/x509_rsakey-asn1.c $(obj)/x509_rsakey-asn1.h
clean-files += x509-asn1.c x509-asn1.h
clean-files += x509_rsakey-asn1.c x509_rsakey-asn1.h
+
+#
+# PKCS#7 message handling
+#
+obj-$(CONFIG_PKCS7_MESSAGE_PARSER) += pkcs7_message.o
+pkcs7_message-y := \
+ pkcs7-asn1.o \
+ pkcs7_parser.o
+
+$(obj)/pkcs7_parser.o: $(obj)/pkcs7-asn1.h
+$(obj)/pkcs7-asn1.o: $(obj)/pkcs7-asn1.c $(obj)/pkcs7-asn1.h
+
+clean-files += pkcs7-asn1.c pkcs7-asn1.h
diff --git a/crypto/asymmetric_keys/pkcs7.asn1 b/crypto/asymmetric_keys/pkcs7.asn1
new file mode 100644
index 0000000..a5a14ef
--- /dev/null
+++ b/crypto/asymmetric_keys/pkcs7.asn1
@@ -0,0 +1,127 @@
+PKCS7ContentInfo ::= SEQUENCE {
+ contentType ContentType,
+ content [0] EXPLICIT SignedData OPTIONAL
+}
+
+ContentType ::= OBJECT IDENTIFIER ({ pkcs7_note_OID })
+
+SignedData ::= SEQUENCE {
+ version INTEGER,
+ digestAlgorithms DigestAlgorithmIdentifiers,
+ contentInfo ContentInfo,
+ certificates CHOICE {
+ certSet [0] IMPLICIT ExtendedCertificatesAndCertificates,
+ certSequence [2] IMPLICIT Certificates
+ } OPTIONAL ({ pkcs7_note_certificate_list }),
+ crls CHOICE {
+ crlSet [1] IMPLICIT CertificateRevocationLists,
+ crlSequence [3] IMPLICIT CRLSequence
+ } OPTIONAL,
+ signerInfos SignerInfos
+}
+
+ContentInfo ::= SEQUENCE {
+ contentType ContentType,
+ content [0] EXPLICIT Data OPTIONAL
+}
+
+Data ::= ANY ({ pkcs7_note_data })
+
+DigestAlgorithmIdentifiers ::= CHOICE {
+ daSet SET OF DigestAlgorithmIdentifier,
+ daSequence SEQUENCE OF DigestAlgorithmIdentifier
+}
+
+DigestAlgorithmIdentifier ::= SEQUENCE {
+ algorithm OBJECT IDENTIFIER ({ pkcs7_note_OID }),
+ parameters ANY OPTIONAL
+}
+
+--
+-- Certificates and certificate lists
+--
+ExtendedCertificatesAndCertificates ::= SET OF ExtendedCertificateOrCertificate
+
+ExtendedCertificateOrCertificate ::= CHOICE {
+ certificate Certificate, -- X.509
+ extendedCertificate [0] IMPLICIT ExtendedCertificate -- PKCS#6
+}
+
+ExtendedCertificate ::= Certificate -- cheating
+
+Certificates ::= SEQUENCE OF Certificate
+
+CertificateRevocationLists ::= SET OF CertificateList
+
+CertificateList ::= SEQUENCE OF Certificate -- This may be defined incorrectly
+
+CRLSequence ::= SEQUENCE OF CertificateList
+
+Certificate ::= ANY ({ pkcs7_extract_cert }) -- X.509
+
+--
+-- Signer information
+--
+SignerInfos ::= CHOICE {
+ siSet SET OF SignerInfo,
+ siSequence SEQUENCE OF SignerInfo
+}
+
+SignerInfo ::= SEQUENCE {
+ version INTEGER,
+ issuerAndSerialNumber IssuerAndSerialNumber,
+ digestAlgorithm DigestAlgorithmIdentifier ({ pkcs7_sig_note_digest_algo }),
+ authenticatedAttributes CHOICE {
+ aaSet [0] IMPLICIT SetOfAuthenticatedAttribute
+ ({ pkcs7_sig_note_set_of_authattrs }),
+ aaSequence [2] EXPLICIT SEQUENCE OF AuthenticatedAttribute
+ -- Explicit because easier to compute digest on
+ -- sequence of attributes and then reuse encoded
+ -- sequence in aaSequence.
+ } OPTIONAL,
+ digestEncryptionAlgorithm
+ DigestEncryptionAlgorithmIdentifier ({ pkcs7_sig_note_pkey_algo }),
+ encryptedDigest EncryptedDigest,
+ unauthenticatedAttributes CHOICE {
+ uaSet [1] IMPLICIT SET OF UnauthenticatedAttribute,
+ uaSequence [3] IMPLICIT SEQUENCE OF UnauthenticatedAttribute
+ } OPTIONAL
+} ({ pkcs7_note_signed_info })
+
+IssuerAndSerialNumber ::= SEQUENCE {
+ issuer Name ({ pkcs7_sig_note_issuer }),
+ serialNumber CertificateSerialNumber ({ pkcs7_sig_note_serial })
+}
+
+CertificateSerialNumber ::= INTEGER
+
+SetOfAuthenticatedAttribute ::= SET OF AuthenticatedAttribute
+
+AuthenticatedAttribute ::= SEQUENCE {
+ type OBJECT IDENTIFIER ({ pkcs7_note_OID }),
+ values SET OF ANY ({ pkcs7_sig_note_authenticated_attr })
+}
+
+UnauthenticatedAttribute ::= SEQUENCE {
+ type OBJECT IDENTIFIER ({ pkcs7_note_OID }),
+ values SET OF ANY
+}
+
+DigestEncryptionAlgorithmIdentifier ::= SEQUENCE {
+ algorithm OBJECT IDENTIFIER ({ pkcs7_note_OID }),
+ parameters ANY OPTIONAL
+}
+
+EncryptedDigest ::= OCTET STRING ({ pkcs7_sig_note_signature })
+
+---
+--- X.500 Name
+---
+Name ::= SEQUENCE OF RelativeDistinguishedName
+
+RelativeDistinguishedName ::= SET OF AttributeValueAssertion
+
+AttributeValueAssertion ::= SEQUENCE {
+ attributeType OBJECT IDENTIFIER ({ pkcs7_note_OID }),
+ attributeValue ANY
+}
diff --git a/crypto/asymmetric_keys/pkcs7_parser.c b/crypto/asymmetric_keys/pkcs7_parser.c
new file mode 100644
index 0000000..42e56aa
--- /dev/null
+++ b/crypto/asymmetric_keys/pkcs7_parser.c
@@ -0,0 +1,396 @@
+/* PKCS#7 parser
+ *
+ * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#define pr_fmt(fmt) "PKCS7: "fmt
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/oid_registry.h>
+#include "public_key.h"
+#include "pkcs7_parser.h"
+#include "pkcs7-asn1.h"
+
+struct pkcs7_parse_context {
+ struct pkcs7_message *msg; /* Message being constructed */
+ struct pkcs7_signed_info *sinfo; /* SignedInfo being constructed */
+ struct pkcs7_signed_info **ppsinfo;
+ struct x509_certificate *certs; /* Certificate cache */
+ struct x509_certificate **ppcerts;
+ unsigned long data; /* Start of data */
+ enum OID last_oid; /* Last OID encountered */
+ unsigned x509_index;
+ unsigned sinfo_index;
+};
+
+/**
+ * pkcs7_free_message - Free a PKCS#7 message
+ * @pkcs7: The PKCS#7 message to free
+ */
+void pkcs7_free_message(struct pkcs7_message *pkcs7)
+{
+ struct x509_certificate *cert;
+ struct pkcs7_signed_info *sinfo;
+
+ if (pkcs7) {
+ while (pkcs7->certs) {
+ cert = pkcs7->certs;
+ pkcs7->certs = cert->next;
+ x509_free_certificate(cert);
+ }
+ while (pkcs7->crl) {
+ cert = pkcs7->crl;
+ pkcs7->crl = cert->next;
+ x509_free_certificate(cert);
+ }
+ while (pkcs7->signed_infos) {
+ sinfo = pkcs7->signed_infos;
+ pkcs7->signed_infos = sinfo->next;
+ mpi_free(sinfo->sig.mpi[0]);
+ kfree(sinfo->sig.digest);
+ kfree(sinfo);
+ }
+ kfree(pkcs7);
+ }
+}
+EXPORT_SYMBOL_GPL(pkcs7_free_message);
+
+/**
+ * pkcs7_parse_message - Parse a PKCS#7 message
+ * @data: The raw binary ASN.1 encoded message to be parsed
+ * @datalen: The size of the encoded message
+ */
+struct pkcs7_message *pkcs7_parse_message(const void *data, size_t datalen)
+{
+ struct pkcs7_parse_context *ctx;
+ struct pkcs7_message *msg;
+ long ret;
+
+ ret = -ENOMEM;
+ msg = kzalloc(sizeof(struct pkcs7_message), GFP_KERNEL);
+ if (!msg)
+ goto error_no_sig;
+ ctx = kzalloc(sizeof(struct pkcs7_parse_context), GFP_KERNEL);
+ if (!ctx)
+ goto error_no_ctx;
+ ctx->sinfo = kzalloc(sizeof(struct pkcs7_signed_info), GFP_KERNEL);
+ if (!ctx->sinfo)
+ goto error_no_sinfo;
+
+ ctx->msg = msg;
+ ctx->data = (unsigned long)data;
+ ctx->ppcerts = &ctx->certs;
+ ctx->ppsinfo = &ctx->msg->signed_infos;
+
+ /* Attempt to decode the signature */
+ ret = asn1_ber_decoder(&pkcs7_decoder, ctx, data, datalen);
+ if (ret < 0)
+ goto error_decode;
+
+ while (ctx->certs) {
+ struct x509_certificate *cert = ctx->certs;
+ ctx->certs = cert->next;
+ x509_free_certificate(cert);
+ }
+ mpi_free(ctx->sinfo->sig.mpi[0]);
+ kfree(ctx->sinfo->sig.digest);
+ kfree(ctx->sinfo);
+ kfree(ctx);
+ return msg;
+
+error_decode:
+ mpi_free(ctx->sinfo->sig.mpi[0]);
+ kfree(ctx->sinfo->sig.digest);
+ kfree(ctx->sinfo);
+error_no_sinfo:
+ kfree(ctx);
+error_no_ctx:
+ pkcs7_free_message(msg);
+error_no_sig:
+ return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(pkcs7_parse_message);
+
+/**
+ * pkcs7_get_content_data - Get access to the PKCS#7 content
+ * @pkcs7: The preparsed PKCS#7 message to access
+ * @_data: Place to return a pointer to the data
+ * @_data_len: Place to return the data length
+ * @want_wrapper: True if the ASN.1 object header should be included in the data
+ *
+ * Get access to the data content of the PKCS#7 message, including, optionally,
+ * the header of the ASN.1 object that contains it. Returns -ENODATA if the
+ * data object was missing from the message.
+ */
+int pkcs7_get_content_data(const struct pkcs7_message *pkcs7,
+ const void **_data, size_t *_data_len,
+ bool want_wrapper)
+{
+ size_t wrapper;
+
+ if (!pkcs7->data)
+ return -ENODATA;
+
+ wrapper = want_wrapper ? pkcs7->data_hdrlen : 0;
+ *_data = pkcs7->data - wrapper;
+ *_data_len = pkcs7->data_len + wrapper;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(pkcs7_get_content_data);
+
+/*
+ * Note an OID when we find one for later processing when we know how
+ * to interpret it.
+ */
+int pkcs7_note_OID(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct pkcs7_parse_context *ctx = context;
+
+ ctx->last_oid = look_up_OID(value, vlen);
+ if (ctx->last_oid == OID__NR) {
+ char buffer[50];
+ sprint_oid(value, vlen, buffer, sizeof(buffer));
+ printk("PKCS7: Unknown OID: [%lu] %s\n",
+ (unsigned long)value - ctx->data, buffer);
+ }
+ return 0;
+}
+
+/*
+ * Note the digest algorithm for the signature.
+ */
+int pkcs7_sig_note_digest_algo(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct pkcs7_parse_context *ctx = context;
+
+ switch (ctx->last_oid) {
+ case OID_md4:
+ ctx->sinfo->sig.pkey_hash_algo = HASH_ALGO_MD4;
+ break;
+ case OID_md5:
+ ctx->sinfo->sig.pkey_hash_algo = HASH_ALGO_MD5;
+ break;
+ case OID_sha1:
+ ctx->sinfo->sig.pkey_hash_algo = HASH_ALGO_SHA1;
+ break;
+ case OID_sha256:
+ ctx->sinfo->sig.pkey_hash_algo = HASH_ALGO_SHA256;
+ break;
+ default:
+ printk("Unsupported digest algo: %u\n", ctx->last_oid);
+ return -ENOPKG;
+ }
+ return 0;
+}
+
+/*
+ * Note the public key algorithm for the signature.
+ */
+int pkcs7_sig_note_pkey_algo(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct pkcs7_parse_context *ctx = context;
+
+ switch (ctx->last_oid) {
+ case OID_rsaEncryption:
+ ctx->sinfo->sig.pkey_algo = PKEY_ALGO_RSA;
+ break;
+ default:
+ printk("Unsupported pkey algo: %u\n", ctx->last_oid);
+ return -ENOPKG;
+ }
+ return 0;
+}
+
+/*
+ * Extract a certificate and store it in the context.
+ */
+int pkcs7_extract_cert(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct pkcs7_parse_context *ctx = context;
+ struct x509_certificate *x509;
+
+ if (tag != ((ASN1_UNIV << 6) | ASN1_CONS_BIT | ASN1_SEQ)) {
+ pr_debug("Cert began with tag %02x at %lu\n",
+ tag, (unsigned long)ctx - ctx->data);
+ return -EBADMSG;
+ }
+
+ /* We have to correct for the header so that the X.509 parser can start
+ * from the beginning. Note that since X.509 stipulates DER, there
+ * probably shouldn't be an EOC trailer - but it is in PKCS#7 (which
+ * stipulates BER).
+ */
+ value -= hdrlen;
+ vlen += hdrlen;
+
+ if (((u8*)value)[1] == 0x80)
+ vlen += 2; /* Indefinite length - there should be an EOC */
+
+ x509 = x509_cert_parse(value, vlen);
+ if (IS_ERR(x509))
+ return PTR_ERR(x509);
+
+ pr_debug("Got cert for %s\n", x509->subject);
+ pr_debug("- fingerprint %s\n", x509->fingerprint);
+
+ x509->index = ++ctx->x509_index;
+ *ctx->ppcerts = x509;
+ ctx->ppcerts = &x509->next;
+ return 0;
+}
+
+/*
+ * Save the certificate list
+ */
+int pkcs7_note_certificate_list(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct pkcs7_parse_context *ctx = context;
+
+ pr_devel("Got cert list (%02x)\n", tag);
+
+ *ctx->ppcerts = ctx->msg->certs;
+ ctx->msg->certs = ctx->certs;
+ ctx->certs = NULL;
+ ctx->ppcerts = &ctx->certs;
+ return 0;
+}
+
+/*
+ * Extract the data from the message and store that and its content type OID in
+ * the context.
+ */
+int pkcs7_note_data(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct pkcs7_parse_context *ctx = context;
+
+ pr_debug("Got data\n");
+
+ ctx->msg->data = value;
+ ctx->msg->data_len = vlen;
+ ctx->msg->data_hdrlen = hdrlen;
+ ctx->msg->data_type = ctx->last_oid;
+ return 0;
+}
+
+/*
+ * Parse authenticated attributes
+ */
+int pkcs7_sig_note_authenticated_attr(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct pkcs7_parse_context *ctx = context;
+
+ pr_devel("AuthAttr: %02x %zu [%*ph]\n", tag, vlen, (unsigned)vlen, value);
+
+ switch (ctx->last_oid) {
+ case OID_messageDigest:
+ if (tag != ASN1_OTS)
+ return -EBADMSG;
+ ctx->sinfo->msgdigest = value;
+ ctx->sinfo->msgdigest_len = vlen;
+ return 0;
+ default:
+ return 0;
+ }
+}
+
+/*
+ * Note the set of auth attributes for digestion purposes [RFC2315 9.3]
+ */
+int pkcs7_sig_note_set_of_authattrs(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct pkcs7_parse_context *ctx = context;
+
+ /* We need to switch the 'CONT 0' to a 'SET OF' when we digest */
+ ctx->sinfo->authattrs = value - (hdrlen - 1);
+ ctx->sinfo->authattrs_len = vlen + (hdrlen - 1);
+ return 0;
+}
+
+/*
+ * Note the issuing certificate serial number
+ */
+int pkcs7_sig_note_serial(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct pkcs7_parse_context *ctx = context;
+ ctx->sinfo->raw_serial = value;
+ ctx->sinfo->raw_serial_size = vlen;
+ return 0;
+}
+
+/*
+ * Note the issuer's name
+ */
+int pkcs7_sig_note_issuer(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct pkcs7_parse_context *ctx = context;
+ ctx->sinfo->raw_issuer = value;
+ ctx->sinfo->raw_issuer_size = vlen;
+ return 0;
+}
+
+/*
+ * Note the signature data
+ */
+int pkcs7_sig_note_signature(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct pkcs7_parse_context *ctx = context;
+ MPI mpi;
+
+ BUG_ON(ctx->sinfo->sig.pkey_algo != PKEY_ALGO_RSA);
+
+ mpi = mpi_read_raw_data(value, vlen);
+ if (!mpi)
+ return -ENOMEM;
+
+ ctx->sinfo->sig.mpi[0] = mpi;
+ ctx->sinfo->sig.nr_mpi = 1;
+ return 0;
+}
+
+/*
+ * Note a signature information block
+ */
+int pkcs7_note_signed_info(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct pkcs7_parse_context *ctx = context;
+
+ ctx->sinfo->index = ++ctx->sinfo_index;
+ *ctx->ppsinfo = ctx->sinfo;
+ ctx->ppsinfo = &ctx->sinfo->next;
+ ctx->sinfo = kzalloc(sizeof(struct pkcs7_signed_info), GFP_KERNEL);
+ if (!ctx->sinfo)
+ return -ENOMEM;
+ return 0;
+}
diff --git a/crypto/asymmetric_keys/pkcs7_parser.h b/crypto/asymmetric_keys/pkcs7_parser.h
new file mode 100644
index 0000000..d25f4d1
--- /dev/null
+++ b/crypto/asymmetric_keys/pkcs7_parser.h
@@ -0,0 +1,61 @@
+/* PKCS#7 crypto data parser internal definitions
+ *
+ * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/oid_registry.h>
+#include <crypto/pkcs7.h>
+#include "x509_parser.h"
+
+#define kenter(FMT, ...) \
+ pr_devel("==> %s("FMT")\n", __func__, ##__VA_ARGS__)
+#define kleave(FMT, ...) \
+ pr_devel("<== %s()"FMT"\n", __func__, ##__VA_ARGS__)
+
+struct pkcs7_signed_info {
+ struct pkcs7_signed_info *next;
+ struct x509_certificate *signer; /* Signing certificate (in msg->certs) */
+ unsigned index;
+ bool trusted;
+
+ /* Message digest - the digest of the Content Data (or NULL) */
+ const void *msgdigest;
+ unsigned msgdigest_len;
+
+ /* Authenticated Attribute data (or NULL) */
+ unsigned authattrs_len;
+ const void *authattrs;
+
+ /* Issuing cert serial number and issuer's name */
+ const void *raw_serial;
+ unsigned raw_serial_size;
+ unsigned raw_issuer_size;
+ const void *raw_issuer;
+
+ /* Message signature.
+ *
+ * This contains the generated digest of _either_ the Content Data or
+ * the Authenticated Attributes [RFC2315 9.3]. If the latter, one of
+ * the attributes contains the digest of the the Content Data within
+ * it.
+ */
+ struct public_key_signature sig;
+};
+
+struct pkcs7_message {
+ struct x509_certificate *certs; /* Certificate list */
+ struct x509_certificate *crl; /* Revocation list */
+ struct pkcs7_signed_info *signed_infos;
+
+ /* Content Data (or NULL) */
+ enum OID data_type; /* Type of Data */
+ size_t data_len; /* Length of Data */
+ size_t data_hdrlen; /* Length of Data ASN.1 header */
+ const void *data; /* Content Data (or 0) */
+};
diff --git a/include/crypto/pkcs7.h b/include/crypto/pkcs7.h
new file mode 100644
index 0000000..8f2628f
--- /dev/null
+++ b/include/crypto/pkcs7.h
@@ -0,0 +1,23 @@
+/* PKCS#7 crypto data parser
+ *
+ * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+struct pkcs7_message;
+
+/*
+ * pkcs7_parser.c
+ */
+extern struct pkcs7_message *pkcs7_parse_message(const void *data,
+ size_t datalen);
+extern void pkcs7_free_message(struct pkcs7_message *pkcs7);
+
+extern int pkcs7_get_content_data(const struct pkcs7_message *pkcs7,
+ const void **_data, size_t *_datalen,
+ bool want_wrapper);
diff --git a/include/linux/oid_registry.h b/include/linux/oid_registry.h
index 6926db7..edeff85 100644
--- a/include/linux/oid_registry.h
+++ b/include/linux/oid_registry.h
@@ -55,6 +55,7 @@ enum OID {
OID_certAuthInfoAccess, /* 1.3.6.1.5.5.7.1.1 */
OID_msOutlookExpress, /* 1.3.6.1.4.1.311.16.4 */
OID_sha1, /* 1.3.14.3.2.26 */
+ OID_sha256, /* 2.16.840.1.101.3.4.2.1 */
/* Distinguished Name attribute IDs [RFC 2256] */
OID_commonName, /* 2.5.4.3 */
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH3/7] PKCS#7: Digest the data in a signed-data message
2014-07-08 13:15 [PATCH 0/7] KEYS: PKCS#7 asymmetric key parser David Howells
2014-07-08 13:15 ` [PATCH1/7] X.509: Export certificate parse and free functions David Howells
2014-07-08 13:15 ` [PATCH2/7] PKCS#7: Implement a parser [RFC 2315] David Howells
@ 2014-07-08 13:15 ` David Howells
2014-07-08 13:15 ` [PATCH4/7] PKCS#7: Find the right key in the PKCS#7 key list and verify the signature David Howells
` (3 subsequent siblings)
6 siblings, 0 replies; 8+ messages in thread
From: David Howells @ 2014-07-08 13:15 UTC (permalink / raw)
To: keyrings
Cc: linux-security-module, kexec, Kees Cook, Vivek Goyal, linux-kernel
Digest the data in a PKCS#7 signed-data message and attach to the
public_key_signature struct contained in the pkcs7_message struct.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
---
crypto/asymmetric_keys/Makefile | 3 -
crypto/asymmetric_keys/pkcs7_verify.c | 173 +++++++++++++++++++++++++++++++++
2 files changed, 175 insertions(+), 1 deletion(-)
create mode 100644 crypto/asymmetric_keys/pkcs7_verify.c
diff --git a/crypto/asymmetric_keys/Makefile b/crypto/asymmetric_keys/Makefile
index 59d8cad..b6b39e7 100644
--- a/crypto/asymmetric_keys/Makefile
+++ b/crypto/asymmetric_keys/Makefile
@@ -32,7 +32,8 @@ clean-files += x509_rsakey-asn1.c x509_rsakey-asn1.h
obj-$(CONFIG_PKCS7_MESSAGE_PARSER) += pkcs7_message.o
pkcs7_message-y := \
pkcs7-asn1.o \
- pkcs7_parser.o
+ pkcs7_parser.o \
+ pkcs7_verify.o
$(obj)/pkcs7_parser.o: $(obj)/pkcs7-asn1.h
$(obj)/pkcs7-asn1.o: $(obj)/pkcs7-asn1.c $(obj)/pkcs7-asn1.h
diff --git a/crypto/asymmetric_keys/pkcs7_verify.c b/crypto/asymmetric_keys/pkcs7_verify.c
new file mode 100644
index 0000000..0bb408a
--- /dev/null
+++ b/crypto/asymmetric_keys/pkcs7_verify.c
@@ -0,0 +1,173 @@
+/* Verify the signature on a PKCS#7 message.
+ *
+ * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#define pr_fmt(fmt) "PKCS7: "fmt
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/asn1.h>
+#include <crypto/hash.h>
+#include "public_key.h"
+#include "pkcs7_parser.h"
+
+/*
+ * Digest the relevant parts of the PKCS#7 data
+ */
+static int pkcs7_digest(struct pkcs7_message *pkcs7,
+ struct pkcs7_signed_info *sinfo)
+{
+ struct crypto_shash *tfm;
+ struct shash_desc *desc;
+ size_t digest_size, desc_size;
+ void *digest;
+ int ret;
+
+ kenter(",%u,%u", sinfo->index, sinfo->sig.pkey_hash_algo);
+
+ if (sinfo->sig.pkey_hash_algo >= PKEY_HASH__LAST ||
+ !hash_algo_name[sinfo->sig.pkey_hash_algo])
+ return -ENOPKG;
+
+ /* Allocate the hashing algorithm we're going to need and find out how
+ * big the hash operational data will be.
+ */
+ tfm = crypto_alloc_shash(hash_algo_name[sinfo->sig.pkey_hash_algo],
+ 0, 0);
+ if (IS_ERR(tfm))
+ return (PTR_ERR(tfm) == -ENOENT) ? -ENOPKG : PTR_ERR(tfm);
+
+ desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
+ sinfo->sig.digest_size = digest_size = crypto_shash_digestsize(tfm);
+
+ ret = -ENOMEM;
+ digest = kzalloc(digest_size + desc_size, GFP_KERNEL);
+ if (!digest)
+ goto error_no_desc;
+
+ desc = digest + digest_size;
+ desc->tfm = tfm;
+ desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
+
+ /* Digest the message [RFC2315 9.3] */
+ ret = crypto_shash_init(desc);
+ if (ret < 0)
+ goto error;
+ ret = crypto_shash_finup(desc, pkcs7->data, pkcs7->data_len, digest);
+ if (ret < 0)
+ goto error;
+ pr_devel("MsgDigest = [%*ph]\n", 8, digest);
+
+ /* However, if there are authenticated attributes, there must be a
+ * message digest attribute amongst them which corresponds to the
+ * digest we just calculated.
+ */
+ if (sinfo->msgdigest) {
+ u8 tag;
+
+ if (sinfo->msgdigest_len != sinfo->sig.digest_size) {
+ pr_debug("Sig %u: Invalid digest size (%u)\n",
+ sinfo->index, sinfo->msgdigest_len);
+ ret = -EBADMSG;
+ goto error;
+ }
+
+ if (memcmp(digest, sinfo->msgdigest, sinfo->msgdigest_len) != 0) {
+ pr_debug("Sig %u: Message digest doesn't match\n",
+ sinfo->index);
+ ret = -EKEYREJECTED;
+ goto error;
+ }
+
+ /* We then calculate anew, using the authenticated attributes
+ * as the contents of the digest instead. Note that we need to
+ * convert the attributes from a CONT.0 into a SET before we
+ * hash it.
+ */
+ memset(digest, 0, sinfo->sig.digest_size);
+
+ ret = crypto_shash_init(desc);
+ if (ret < 0)
+ goto error;
+ tag = ASN1_CONS_BIT | ASN1_SET;
+ ret = crypto_shash_update(desc, &tag, 1);
+ if (ret < 0)
+ goto error;
+ ret = crypto_shash_finup(desc, sinfo->authattrs,
+ sinfo->authattrs_len, digest);
+ if (ret < 0)
+ goto error;
+ pr_devel("AADigest = [%*ph]\n", 8, digest);
+ }
+
+ sinfo->sig.digest = digest;
+ digest = NULL;
+
+error:
+ kfree(digest);
+error_no_desc:
+ crypto_free_shash(tfm);
+ kleave(" = %d", ret);
+ return ret;
+}
+
+/*
+/*
+ * Verify one signed information block from a PKCS#7 message.
+ */
+static int pkcs7_verify_one(struct pkcs7_message *pkcs7,
+ struct pkcs7_signed_info *sinfo)
+{
+ int ret;
+
+ kenter(",%u", sinfo->index);
+
+ /* First of all, digest the data in the PKCS#7 message and the
+ * signed information block
+ */
+ ret = pkcs7_digest(pkcs7, sinfo);
+ if (ret < 0)
+ return ret;
+
+ return 0;
+}
+
+/**
+ * pkcs7_verify - Verify a PKCS#7 message
+ * @pkcs7: The PKCS#7 message to be verified
+ */
+int pkcs7_verify(struct pkcs7_message *pkcs7)
+{
+ struct pkcs7_signed_info *sinfo;
+ struct x509_certificate *x509;
+ int ret, n;
+
+ kenter("");
+
+ for (n = 0, x509 = pkcs7->certs; x509; x509 = x509->next, n++) {
+ ret = x509_get_sig_params(x509);
+ if (ret < 0)
+ return ret;
+ pr_debug("X.509[%u] %s\n", n, x509->authority);
+ }
+
+ for (sinfo = pkcs7->signed_infos; sinfo; sinfo = sinfo->next) {
+ ret = pkcs7_verify_one(pkcs7, sinfo);
+ if (ret < 0) {
+ kleave(" = %d", ret);
+ return ret;
+ }
+ }
+
+ kleave(" = 0");
+ return 0;
+}
+EXPORT_SYMBOL_GPL(pkcs7_verify);
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH4/7] PKCS#7: Find the right key in the PKCS#7 key list and verify the signature
2014-07-08 13:15 [PATCH 0/7] KEYS: PKCS#7 asymmetric key parser David Howells
` (2 preceding siblings ...)
2014-07-08 13:15 ` [PATCH3/7] PKCS#7: Digest the data in a signed-data message David Howells
@ 2014-07-08 13:15 ` David Howells
2014-07-08 13:15 ` [PATCH5/7] PKCS#7: Verify internal certificate chain David Howells
` (2 subsequent siblings)
6 siblings, 0 replies; 8+ messages in thread
From: David Howells @ 2014-07-08 13:15 UTC (permalink / raw)
To: keyrings
Cc: linux-security-module, kexec, Kees Cook, Vivek Goyal, linux-kernel
Find the appropriate key in the PKCS#7 key list and verify the signature with
it. There may be several keys in there forming a chain. Any link in that
chain or the root of that chain may be in our keyrings.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
---
crypto/asymmetric_keys/pkcs7_verify.c | 64 +++++++++++++++++++++++++++++++++
include/crypto/pkcs7.h | 5 +++
2 files changed, 69 insertions(+)
diff --git a/crypto/asymmetric_keys/pkcs7_verify.c b/crypto/asymmetric_keys/pkcs7_verify.c
index 0bb408a..745e5c8 100644
--- a/crypto/asymmetric_keys/pkcs7_verify.c
+++ b/crypto/asymmetric_keys/pkcs7_verify.c
@@ -120,6 +120,55 @@ error_no_desc:
}
/*
+ * Find the key (X.509 certificate) to use to verify a PKCS#7 message. PKCS#7
+ * uses the issuer's name and the issuing certificate serial number for
+ * matching purposes. These must match the certificate issuer's name (not
+ * subject's name) and the certificate serial number [RFC 2315 6.7].
+ */
+static int pkcs7_find_key(struct pkcs7_message *pkcs7,
+ struct pkcs7_signed_info *sinfo)
+{
+ struct x509_certificate *x509;
+ unsigned certix = 1;
+
+ kenter("%u,%u,%u",
+ sinfo->index, sinfo->raw_serial_size, sinfo->raw_issuer_size);
+
+ for (x509 = pkcs7->certs; x509; x509 = x509->next, certix++) {
+ /* I'm _assuming_ that the generator of the PKCS#7 message will
+ * encode the fields from the X.509 cert in the same way in the
+ * PKCS#7 message - but I can't be 100% sure of that. It's
+ * possible this will need element-by-element comparison.
+ */
+ if (x509->raw_serial_size != sinfo->raw_serial_size ||
+ memcmp(x509->raw_serial, sinfo->raw_serial,
+ sinfo->raw_serial_size) != 0)
+ continue;
+ pr_devel("Sig %u: Found cert serial match X.509[%u]\n",
+ sinfo->index, certix);
+
+ if (x509->raw_issuer_size != sinfo->raw_issuer_size ||
+ memcmp(x509->raw_issuer, sinfo->raw_issuer,
+ sinfo->raw_issuer_size) != 0) {
+ pr_warn("Sig %u: X.509 subject and PKCS#7 issuer don't match\n",
+ sinfo->index);
+ continue;
+ }
+
+ if (x509->pub->pkey_algo != sinfo->sig.pkey_algo) {
+ pr_warn("Sig %u: X.509 algo and PKCS#7 sig algo don't match\n",
+ sinfo->index);
+ continue;
+ }
+
+ sinfo->signer = x509;
+ return 0;
+ }
+ pr_warn("Sig %u: Issuing X.509 cert not found (#%*ph)\n",
+ sinfo->index, sinfo->raw_serial_size, sinfo->raw_serial);
+ return -ENOKEY;
+}
+
/*
* Verify one signed information block from a PKCS#7 message.
*/
@@ -137,6 +186,21 @@ static int pkcs7_verify_one(struct pkcs7_message *pkcs7,
if (ret < 0)
return ret;
+ /* Find the key for the signature */
+ ret = pkcs7_find_key(pkcs7, sinfo);
+ if (ret < 0)
+ return ret;
+
+ pr_devel("Using X.509[%u] for sig %u\n",
+ sinfo->signer->index, sinfo->index);
+
+ /* Verify the PKCS#7 binary against the key */
+ ret = public_key_verify_signature(sinfo->signer->pub, &sinfo->sig);
+ if (ret < 0)
+ return ret;
+
+ pr_devel("Verified signature %u\n", sinfo->index);
+
return 0;
}
diff --git a/include/crypto/pkcs7.h b/include/crypto/pkcs7.h
index 8f2628f..8ba0f38 100644
--- a/include/crypto/pkcs7.h
+++ b/include/crypto/pkcs7.h
@@ -21,3 +21,8 @@ extern void pkcs7_free_message(struct pkcs7_message *pkcs7);
extern int pkcs7_get_content_data(const struct pkcs7_message *pkcs7,
const void **_data, size_t *_datalen,
bool want_wrapper);
+
+/*
+ * pkcs7_verify.c
+ */
+extern int pkcs7_verify(struct pkcs7_message *pkcs7);
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH5/7] PKCS#7: Verify internal certificate chain
2014-07-08 13:15 [PATCH 0/7] KEYS: PKCS#7 asymmetric key parser David Howells
` (3 preceding siblings ...)
2014-07-08 13:15 ` [PATCH4/7] PKCS#7: Find the right key in the PKCS#7 key list and verify the signature David Howells
@ 2014-07-08 13:15 ` David Howells
2014-07-08 13:15 ` [PATCH6/7] PKCS#7: Find intersection between PKCS#7 message and known, trusted keys David Howells
2014-07-08 13:15 ` [PATCH7/7] PKCS#7: Provide a key type for testing PKCS#7 David Howells
6 siblings, 0 replies; 8+ messages in thread
From: David Howells @ 2014-07-08 13:15 UTC (permalink / raw)
To: keyrings
Cc: linux-security-module, kexec, Kees Cook, Vivek Goyal, linux-kernel
Verify certificate chain in the X.509 certificates contained within the PKCS#7
message as far as possible. If any signature that we should be able to verify
fails, we reject the whole lot.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
---
crypto/asymmetric_keys/pkcs7_verify.c | 88 +++++++++++++++++++++++++++++++++
1 file changed, 87 insertions(+), 1 deletion(-)
diff --git a/crypto/asymmetric_keys/pkcs7_verify.c b/crypto/asymmetric_keys/pkcs7_verify.c
index 745e5c8..51ff36f 100644
--- a/crypto/asymmetric_keys/pkcs7_verify.c
+++ b/crypto/asymmetric_keys/pkcs7_verify.c
@@ -170,6 +170,91 @@ static int pkcs7_find_key(struct pkcs7_message *pkcs7,
}
/*
+ * Verify the internal certificate chain as best we can.
+ */
+static int pkcs7_verify_sig_chain(struct pkcs7_message *pkcs7,
+ struct pkcs7_signed_info *sinfo)
+{
+ struct x509_certificate *x509 = sinfo->signer, *p;
+ int ret;
+
+ kenter("");
+
+ for (p = pkcs7->certs; p; p = p->next)
+ p->seen = false;
+
+ for (;;) {
+ pr_debug("verify %s: %s\n", x509->subject, x509->fingerprint);
+ x509->seen = true;
+ ret = x509_get_sig_params(x509);
+ if (ret < 0)
+ return ret;
+
+ if (x509->issuer)
+ pr_debug("- issuer %s\n", x509->issuer);
+ if (x509->authority)
+ pr_debug("- authkeyid %s\n", x509->authority);
+
+ if (!x509->authority ||
+ (x509->subject &&
+ strcmp(x509->subject, x509->issuer) == 0)) {
+ /* If there's no authority certificate specified, then
+ * the certificate must be self-signed and is the root
+ * of the chain. Likewise if the cert is its own
+ * authority.
+ */
+ pr_debug("- no auth?\n");
+ if (x509->raw_subject_size != x509->raw_issuer_size ||
+ memcmp(x509->raw_subject, x509->raw_issuer,
+ x509->raw_issuer_size) != 0)
+ return 0;
+
+ ret = x509_check_signature(x509->pub, x509);
+ if (ret < 0)
+ return ret;
+ x509->signer = x509;
+ pr_debug("- self-signed\n");
+ return 0;
+ }
+
+ /* Look through the X.509 certificates in the PKCS#7 message's
+ * list to see if the next one is there.
+ */
+ pr_debug("- want %s\n", x509->authority);
+ for (p = pkcs7->certs; p; p = p->next) {
+ pr_debug("- cmp [%u] %s\n", p->index, p->fingerprint);
+ if (p->raw_subject_size == x509->raw_issuer_size &&
+ strcmp(p->fingerprint, x509->authority) == 0 &&
+ memcmp(p->raw_subject, x509->raw_issuer,
+ x509->raw_issuer_size) == 0)
+ goto found_issuer;
+ }
+
+ /* We didn't find the root of this chain */
+ pr_debug("- top\n");
+ return 0;
+
+ found_issuer:
+ pr_debug("- issuer %s\n", p->subject);
+ if (p->seen) {
+ pr_warn("Sig %u: X.509 chain contains loop\n",
+ sinfo->index);
+ return 0;
+ }
+ ret = x509_check_signature(p->pub, x509);
+ if (ret < 0)
+ return ret;
+ x509->signer = p;
+ if (x509 == p) {
+ pr_debug("- self-signed\n");
+ return 0;
+ }
+ x509 = p;
+ might_sleep();
+ }
+}
+
+/*
* Verify one signed information block from a PKCS#7 message.
*/
static int pkcs7_verify_one(struct pkcs7_message *pkcs7,
@@ -201,7 +286,8 @@ static int pkcs7_verify_one(struct pkcs7_message *pkcs7,
pr_devel("Verified signature %u\n", sinfo->index);
- return 0;
+ /* Verify the internal certificate chain */
+ return pkcs7_verify_sig_chain(pkcs7, sinfo);
}
/**
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH6/7] PKCS#7: Find intersection between PKCS#7 message and known, trusted keys
2014-07-08 13:15 [PATCH 0/7] KEYS: PKCS#7 asymmetric key parser David Howells
` (4 preceding siblings ...)
2014-07-08 13:15 ` [PATCH5/7] PKCS#7: Verify internal certificate chain David Howells
@ 2014-07-08 13:15 ` David Howells
2014-07-08 13:15 ` [PATCH7/7] PKCS#7: Provide a key type for testing PKCS#7 David Howells
6 siblings, 0 replies; 8+ messages in thread
From: David Howells @ 2014-07-08 13:15 UTC (permalink / raw)
To: keyrings
Cc: linux-security-module, kexec, Kees Cook, Vivek Goyal, linux-kernel
Find the intersection between the X.509 certificate chain contained in a PKCS#7
message and a set of keys that we already know and trust.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
---
crypto/asymmetric_keys/Makefile | 1
crypto/asymmetric_keys/pkcs7_trust.c | 219 ++++++++++++++++++++++++++++++++++
include/crypto/pkcs7.h | 8 +
3 files changed, 228 insertions(+)
create mode 100644 crypto/asymmetric_keys/pkcs7_trust.c
diff --git a/crypto/asymmetric_keys/Makefile b/crypto/asymmetric_keys/Makefile
index b6b39e7..d63cb43 100644
--- a/crypto/asymmetric_keys/Makefile
+++ b/crypto/asymmetric_keys/Makefile
@@ -33,6 +33,7 @@ obj-$(CONFIG_PKCS7_MESSAGE_PARSER) += pkcs7_message.o
pkcs7_message-y := \
pkcs7-asn1.o \
pkcs7_parser.o \
+ pkcs7_trust.o \
pkcs7_verify.o
$(obj)/pkcs7_parser.o: $(obj)/pkcs7-asn1.h
diff --git a/crypto/asymmetric_keys/pkcs7_trust.c b/crypto/asymmetric_keys/pkcs7_trust.c
new file mode 100644
index 0000000..b6b0451
--- /dev/null
+++ b/crypto/asymmetric_keys/pkcs7_trust.c
@@ -0,0 +1,219 @@
+/* Validate the trust chain of a PKCS#7 message.
+ *
+ * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#define pr_fmt(fmt) "PKCS7: "fmt
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/asn1.h>
+#include <linux/key.h>
+#include <keys/asymmetric-type.h>
+#include "public_key.h"
+#include "pkcs7_parser.h"
+
+/*
+ * Request an asymmetric key.
+ */
+static struct key *pkcs7_request_asymmetric_key(
+ struct key *keyring,
+ const char *signer, size_t signer_len,
+ const char *authority, size_t auth_len)
+{
+ key_ref_t key;
+ char *id;
+
+ kenter(",%zu,,%zu", signer_len, auth_len);
+
+ /* Construct an identifier. */
+ id = kmalloc(signer_len + 2 + auth_len + 1, GFP_KERNEL);
+ if (!id)
+ return ERR_PTR(-ENOMEM);
+
+ memcpy(id, signer, signer_len);
+ id[signer_len + 0] = ':';
+ id[signer_len + 1] = ' ';
+ memcpy(id + signer_len + 2, authority, auth_len);
+ id[signer_len + 2 + auth_len] = 0;
+
+ pr_debug("Look up: \"%s\"\n", id);
+
+ key = keyring_search(make_key_ref(keyring, 1),
+ &key_type_asymmetric, id);
+ if (IS_ERR(key))
+ pr_debug("Request for module key '%s' err %ld\n",
+ id, PTR_ERR(key));
+ kfree(id);
+
+ if (IS_ERR(key)) {
+ switch (PTR_ERR(key)) {
+ /* Hide some search errors */
+ case -EACCES:
+ case -ENOTDIR:
+ case -EAGAIN:
+ return ERR_PTR(-ENOKEY);
+ default:
+ return ERR_CAST(key);
+ }
+ }
+
+ pr_devel("<==%s() = 0 [%x]\n", __func__, key_serial(key_ref_to_ptr(key)));
+ return key_ref_to_ptr(key);
+}
+
+/**
+ * Check the trust on one PKCS#7 SignedInfo block.
+ */
+int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7,
+ struct pkcs7_signed_info *sinfo,
+ struct key *trust_keyring)
+{
+ struct public_key_signature *sig = &sinfo->sig;
+ struct x509_certificate *x509, *last = NULL, *p;
+ struct key *key;
+ bool trusted;
+ int ret;
+
+ kenter(",%u,", sinfo->index);
+
+ for (x509 = sinfo->signer; x509; x509 = x509->signer) {
+ if (x509->seen) {
+ if (x509->verified) {
+ trusted = x509->trusted;
+ goto verified;
+ }
+ kleave(" = -ENOKEY [cached]");
+ return -ENOKEY;
+ }
+ x509->seen = true;
+
+ /* Look to see if this certificate is present in the trusted
+ * keys.
+ */
+ key = pkcs7_request_asymmetric_key(
+ trust_keyring,
+ x509->subject, strlen(x509->subject),
+ x509->fingerprint, strlen(x509->fingerprint));
+ if (!IS_ERR(key))
+ /* One of the X.509 certificates in the PKCS#7 message
+ * is apparently the same as one we already trust.
+ * Verify that the trusted variant can also validate
+ * the signature on the descendant.
+ */
+ goto matched;
+ if (key == ERR_PTR(-ENOMEM))
+ return -ENOMEM;
+
+ /* Self-signed certificates form roots of their own, and if we
+ * don't know them, then we can't accept them.
+ */
+ if (x509->next == x509) {
+ kleave(" = -ENOKEY [unknown self-signed]");
+ return -ENOKEY;
+ }
+
+ might_sleep();
+ last = x509;
+ sig = &last->sig;
+ }
+
+ /* No match - see if the root certificate has a signer amongst the
+ * trusted keys.
+ */
+ if (!last || !last->issuer || !last->authority) {
+ kleave(" = -ENOKEY [no backref]");
+ return -ENOKEY;
+ }
+
+ key = pkcs7_request_asymmetric_key(
+ trust_keyring,
+ last->issuer, strlen(last->issuer),
+ last->authority, strlen(last->authority));
+ if (IS_ERR(key))
+ return PTR_ERR(key) == -ENOMEM ? -ENOMEM : -ENOKEY;
+ x509 = last;
+
+matched:
+ ret = verify_signature(key, sig);
+ trusted = test_bit(KEY_FLAG_TRUSTED, &key->flags);
+ key_put(key);
+ if (ret < 0) {
+ if (ret == -ENOMEM)
+ return ret;
+ kleave(" = -EKEYREJECTED [verify %d]", ret);
+ return -EKEYREJECTED;
+ }
+
+verified:
+ x509->verified = true;
+ for (p = sinfo->signer; p != x509; p = p->signer) {
+ p->verified = true;
+ p->trusted = trusted;
+ }
+ sinfo->trusted = trusted;
+ kleave(" = 0");
+ return 0;
+}
+
+/**
+ * pkcs7_validate_trust - Validate PKCS#7 trust chain
+ * @pkcs7: The PKCS#7 certificate to validate
+ * @trust_keyring: Signing certificates to use as starting points
+ * @_trusted: Set to true if trustworth, false otherwise
+ *
+ * Validate that the certificate chain inside the PKCS#7 message intersects
+ * keys we already know and trust.
+ *
+ * Returns, in order of descending priority:
+ *
+ * (*) -EKEYREJECTED if a signature failed to match for which we have a valid
+ * key, or:
+ *
+ * (*) 0 if at least one signature chain intersects with the keys in the trust
+ * keyring, or:
+ *
+ * (*) -ENOPKG if a suitable crypto module couldn't be found for a check on a
+ * chain.
+ *
+ * (*) -ENOKEY if we couldn't find a match for any of the signature chains in
+ * the message.
+ *
+ * May also return -ENOMEM.
+ */
+int pkcs7_validate_trust(struct pkcs7_message *pkcs7,
+ struct key *trust_keyring,
+ bool *_trusted)
+{
+ struct pkcs7_signed_info *sinfo;
+ struct x509_certificate *p;
+ int cached_ret = 0, ret;
+
+ for (p = pkcs7->certs; p; p = p->next)
+ p->seen = false;
+
+ for (sinfo = pkcs7->signed_infos; sinfo; sinfo = sinfo->next) {
+ ret = pkcs7_validate_trust_one(pkcs7, sinfo, trust_keyring);
+ if (ret < 0) {
+ if (ret == -ENOPKG) {
+ cached_ret = -ENOPKG;
+ } else if (ret == -ENOKEY) {
+ if (cached_ret == 0)
+ cached_ret = -ENOKEY;
+ } else {
+ return ret;
+ }
+ }
+ *_trusted |= sinfo->trusted;
+ }
+
+ return cached_ret;
+}
+EXPORT_SYMBOL_GPL(pkcs7_validate_trust);
diff --git a/include/crypto/pkcs7.h b/include/crypto/pkcs7.h
index 8ba0f38..691c791 100644
--- a/include/crypto/pkcs7.h
+++ b/include/crypto/pkcs7.h
@@ -9,6 +9,7 @@
* 2 of the Licence, or (at your option) any later version.
*/
+struct key;
struct pkcs7_message;
/*
@@ -23,6 +24,13 @@ extern int pkcs7_get_content_data(const struct pkcs7_message *pkcs7,
bool want_wrapper);
/*
+ * pkcs7_trust.c
+ */
+extern int pkcs7_validate_trust(struct pkcs7_message *pkcs7,
+ struct key *trust_keyring,
+ bool *_trusted);
+
+/*
* pkcs7_verify.c
*/
extern int pkcs7_verify(struct pkcs7_message *pkcs7);
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH7/7] PKCS#7: Provide a key type for testing PKCS#7
2014-07-08 13:15 [PATCH 0/7] KEYS: PKCS#7 asymmetric key parser David Howells
` (5 preceding siblings ...)
2014-07-08 13:15 ` [PATCH6/7] PKCS#7: Find intersection between PKCS#7 message and known, trusted keys David Howells
@ 2014-07-08 13:15 ` David Howells
6 siblings, 0 replies; 8+ messages in thread
From: David Howells @ 2014-07-08 13:15 UTC (permalink / raw)
To: keyrings; +Cc: linux-security-module, kexec, linux-kernel
Provide a key type for testing the PKCS#7 parser. It is given a non-detached
PKCS#7 message as payload:
keyctl padd pkcs7_test a @s <stuff.pkcs7
The PKCS#7 wrapper is validated against the trusted certificates available and
then stripped off. If successful, the key can be read, which will give the
data content of the PKCS#7 message.
A suitable message can be created by running make on the attached Makefile.
This will produce a file called stuff.pkcs7 for test loading. The key3.x509
file should be put into the kernel source tree before it is built and
converted to DER form:
openssl x509 -in .../pkcs7/key3.x509 -outform DER -out key3.x509
###############################################################################
#
# Create a pkcs7 message and sign it twice
#
# openssl x509 -text -inform PEM -noout -in key2.x509
#
###############################################################################
stuff.pkcs7: stuff.txt key2.priv key2.x509 key4.priv key4.x509 certs
$(RM) $@
openssl smime -sign \
-signer key2.x509 \
-inkey key2.priv \
-signer key4.x509 \
-inkey key4.priv \
-in stuff.txt \
-certfile certs \
-out $@ -binary -outform DER -nodetach
openssl pkcs7 -inform DER -in stuff.pkcs7 -print_certs -noout
openssl asn1parse -inform DER -in stuff.pkcs7 -i >out
stuff.txt:
echo "The quick red fox jumped over the lazy brown dog" >stuff.txt
certs: key1.x509 key2.x509 key3.x509 key4.x509
cat key{1,3}.x509 >$@
###############################################################################
#
# Generate a signed key
#
# openssl x509 -text -inform PEM -noout -in key2.x509
#
###############################################################################
key2.x509: key2.x509_unsigned key1.priv key1.x509
openssl x509 \
-req -in key2.x509_unsigned \
-out key2.x509 \
-extfile key2.genkey -extensions myexts \
-CA key1.x509 \
-CAkey key1.priv \
-CAcreateserial
key2.priv key2.x509_unsigned: key2.genkey
openssl req -new -nodes -utf8 -sha1 -days 36500 \
-batch -outform PEM \
-config key2.genkey \
-keyout key2.priv \
-out key2.x509_unsigned
key2.genkey:
@echo Generating X.509 key generation config
@echo >$@ "[ req ]"
@echo >>$@ "default_bits = 4096"
@echo >>$@ "distinguished_name = req_distinguished_name"
@echo >>$@ "prompt = no"
@echo >>$@ "string_mask = utf8only"
@echo >>$@ "x509_extensions = myexts"
@echo >>$@
@echo >>$@ "[ req_distinguished_name ]"
@echo >>$@ "O = Magrathea"
@echo >>$@ "CN = PKCS7 key 2"
@echo >>$@ "emailAddress = slartibartfast@magrathea.h2g2"
@echo >>$@
@echo >>$@ "[ myexts ]"
@echo >>$@ "basicConstraints=critical,CA:FALSE"
@echo >>$@ "keyUsage=digitalSignature"
@echo >>$@ "subjectKeyIdentifier=hash"
@echo >>$@ "authorityKeyIdentifier=keyid"
###############################################################################
#
# Generate a couple of signing keys
#
# openssl x509 -text -inform PEM -noout -in key1.x509
#
###############################################################################
key1.x509: key1.x509_unsigned key4.priv key4.x509
openssl x509 \
-req -in key1.x509_unsigned \
-out key1.x509 \
-extfile key1.genkey -extensions myexts \
-CA key4.x509 \
-CAkey key4.priv \
-CAcreateserial
key1.priv key1.x509_unsigned: key1.genkey
openssl req -new -nodes -utf8 -sha1 -days 36500 \
-batch -outform PEM \
-config key1.genkey \
-keyout key1.priv \
-out key1.x509_unsigned
key1.genkey:
@echo Generating X.509 key generation config
@echo >$@ "[ req ]"
@echo >>$@ "default_bits = 4096"
@echo >>$@ "distinguished_name = req_distinguished_name"
@echo >>$@ "prompt = no"
@echo >>$@ "string_mask = utf8only"
@echo >>$@ "x509_extensions = myexts"
@echo >>$@
@echo >>$@ "[ req_distinguished_name ]"
@echo >>$@ "O = Magrathea"
@echo >>$@ "CN = PKCS7 key 1"
@echo >>$@ "emailAddress = slartibartfast@magrathea.h2g2"
@echo >>$@
@echo >>$@ "[ myexts ]"
@echo >>$@ "basicConstraints=critical,CA:TRUE"
@echo >>$@ "keyUsage=digitalSignature,keyCertSign"
@echo >>$@ "subjectKeyIdentifier=hash"
@echo >>$@ "authorityKeyIdentifier=keyid"
###############################################################################
#
# Generate a signed key
#
# openssl x509 -text -inform PEM -noout -in key4.x509
#
###############################################################################
key4.x509: key4.x509_unsigned key3.priv key3.x509
openssl x509 \
-req -in key4.x509_unsigned \
-out key4.x509 \
-extfile key4.genkey -extensions myexts \
-CA key3.x509 \
-CAkey key3.priv \
-CAcreateserial
key4.priv key4.x509_unsigned: key4.genkey
openssl req -new -nodes -utf8 -sha1 -days 36500 \
-batch -outform PEM \
-config key4.genkey \
-keyout key4.priv \
-out key4.x509_unsigned
key4.genkey:
@echo Generating X.509 key generation config
@echo >$@ "[ req ]"
@echo >>$@ "default_bits = 4096"
@echo >>$@ "distinguished_name = req_distinguished_name"
@echo >>$@ "prompt = no"
@echo >>$@ "string_mask = utf8only"
@echo >>$@ "x509_extensions = myexts"
@echo >>$@
@echo >>$@ "[ req_distinguished_name ]"
@echo >>$@ "O = Magrathea"
@echo >>$@ "CN = PKCS7 key 4"
@echo >>$@ "emailAddress = slartibartfast@magrathea.h2g2"
@echo >>$@
@echo >>$@ "[ myexts ]"
@echo >>$@ "basicConstraints=critical,CA:TRUE"
@echo >>$@ "keyUsage=digitalSignature,keyCertSign"
@echo >>$@ "subjectKeyIdentifier=hash"
@echo >>$@ "authorityKeyIdentifier=keyid"
###############################################################################
#
# Generate a couple of signing keys
#
# openssl x509 -text -inform PEM -noout -in key3.x509
#
###############################################################################
key3.priv key3.x509: key3.genkey
openssl req -new -nodes -utf8 -sha1 -days 36500 \
-batch -x509 -outform PEM \
-config key3.genkey \
-keyout key3.priv \
-out key3.x509
key3.genkey:
@echo Generating X.509 key generation config
@echo >$@ "[ req ]"
@echo >>$@ "default_bits = 4096"
@echo >>$@ "distinguished_name = req_distinguished_name"
@echo >>$@ "prompt = no"
@echo >>$@ "string_mask = utf8only"
@echo >>$@ "x509_extensions = myexts"
@echo >>$@
@echo >>$@ "[ req_distinguished_name ]"
@echo >>$@ "O = Magrathea"
@echo >>$@ "CN = PKCS7 key 3"
@echo >>$@ "emailAddress = slartibartfast@magrathea.h2g2"
@echo >>$@
@echo >>$@ "[ myexts ]"
@echo >>$@ "basicConstraints=critical,CA:TRUE"
@echo >>$@ "keyUsage=digitalSignature,keyCertSign"
@echo >>$@ "subjectKeyIdentifier=hash"
@echo >>$@ "authorityKeyIdentifier=keyid"
clean:
$(RM) *~
$(RM) key1.* key2.* key3.* key4.* stuff.* out certs
Signed-off-by: David Howells <dhowells@redhat.com>
---
crypto/asymmetric_keys/Kconfig | 13 ++++
crypto/asymmetric_keys/Makefile | 7 ++
crypto/asymmetric_keys/pkcs7_key_type.c | 97 +++++++++++++++++++++++++++++++
3 files changed, 117 insertions(+)
create mode 100644 crypto/asymmetric_keys/pkcs7_key_type.c
diff --git a/crypto/asymmetric_keys/Kconfig b/crypto/asymmetric_keys/Kconfig
index a7cec9d..b6df198 100644
--- a/crypto/asymmetric_keys/Kconfig
+++ b/crypto/asymmetric_keys/Kconfig
@@ -46,4 +46,17 @@ config PKCS7_MESSAGE_PARSER
This option provides support for parsing PKCS#7 format messages for
signature data and provides the ability to verify the signature.
+config PKCS7_TEST_KEY
+ tristate "PKCS#7 testing key type"
+ depends on PKCS7_MESSAGE_PARSER
+ select SYSTEM_TRUSTED_KEYRING
+ help
+ This option provides a type of key that can be loaded up from a
+ PKCS#7 message - provided the message is signed by a trusted key. If
+ it is, the PKCS#7 wrapper is discarded and reading the key returns
+ just the payload. If it isn't, adding the key will fail with an
+ error.
+
+ This is intended for testing the PKCS#7 parser.
+
endif # ASYMMETRIC_KEY_TYPE
diff --git a/crypto/asymmetric_keys/Makefile b/crypto/asymmetric_keys/Makefile
index d63cb43..92d0e9a 100644
--- a/crypto/asymmetric_keys/Makefile
+++ b/crypto/asymmetric_keys/Makefile
@@ -40,3 +40,10 @@ $(obj)/pkcs7_parser.o: $(obj)/pkcs7-asn1.h
$(obj)/pkcs7-asn1.o: $(obj)/pkcs7-asn1.c $(obj)/pkcs7-asn1.h
clean-files += pkcs7-asn1.c pkcs7-asn1.h
+
+#
+# PKCS#7 parser testing key
+#
+obj-$(CONFIG_PKCS7_TEST_KEY) += pkcs7_test_key.o
+pkcs7_test_key-y := \
+ pkcs7_key_type.o
diff --git a/crypto/asymmetric_keys/pkcs7_key_type.c b/crypto/asymmetric_keys/pkcs7_key_type.c
new file mode 100644
index 0000000..b1797d2
--- /dev/null
+++ b/crypto/asymmetric_keys/pkcs7_key_type.c
@@ -0,0 +1,97 @@
+/* Testing module to load key from trusted PKCS#7 message
+ *
+ * Copyright (C) 2014 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#define pr_fmt(fmt) "PKCS7key: "fmt
+#include <linux/key.h>
+#include <linux/key-type.h>
+#include <crypto/pkcs7.h>
+#include <keys/user-type.h>
+#include <keys/system_keyring.h>
+#include "pkcs7_parser.h"
+
+/*
+ * Instantiate a PKCS#7 wrapped and validated key.
+ */
+int pkcs7_instantiate(struct key *key, struct key_preparsed_payload *prep)
+{
+ struct pkcs7_message *pkcs7;
+ const void *data, *saved_prep_data;
+ size_t datalen, saved_prep_datalen;
+ bool trusted;
+ int ret;
+
+ kenter("");
+
+ saved_prep_data = prep->data;
+ saved_prep_datalen = prep->datalen;
+ pkcs7 = pkcs7_parse_message(saved_prep_data, saved_prep_datalen);
+ if (IS_ERR(pkcs7)) {
+ ret = PTR_ERR(pkcs7);
+ goto error;
+ }
+
+ ret = pkcs7_verify(pkcs7);
+ if (ret < 0)
+ goto error_free;
+
+ ret = pkcs7_validate_trust(pkcs7, system_trusted_keyring, &trusted);
+ if (ret < 0)
+ goto error_free;
+ if (!trusted)
+ pr_warn("PKCS#7 message doesn't chain back to a trusted key\n");
+
+ ret = pkcs7_get_content_data(pkcs7, &data, &datalen, false);
+ if (ret < 0)
+ goto error_free;
+
+ prep->data = data;
+ prep->datalen = datalen;
+ ret = user_instantiate(key, prep);
+ prep->data = saved_prep_data;
+ prep->datalen = saved_prep_datalen;
+
+error_free:
+ pkcs7_free_message(pkcs7);
+error:
+ kleave(" = %d", ret);
+ return ret;
+}
+
+/*
+ * user defined keys take an arbitrary string as the description and an
+ * arbitrary blob of data as the payload
+ */
+struct key_type key_type_pkcs7 = {
+ .name = "pkcs7_test",
+ .def_lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT,
+ .instantiate = pkcs7_instantiate,
+ .match = user_match,
+ .revoke = user_revoke,
+ .destroy = user_destroy,
+ .describe = user_describe,
+ .read = user_read,
+};
+
+/*
+ * Module stuff
+ */
+static int __init pkcs7_key_init(void)
+{
+ return register_key_type(&key_type_pkcs7);
+}
+
+static void __exit pkcs7_key_cleanup(void)
+{
+ unregister_key_type(&key_type_pkcs7);
+}
+
+module_init(pkcs7_key_init);
+module_exit(pkcs7_key_cleanup);
^ permalink raw reply related [flat|nested] 8+ messages in thread