--- /dev/null
+/* X.509 certificate 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) "X.509: "fmt
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/oid_registry.h>
+#include "public_key.h"
+#include "x509_parser.h"
+#include "x509-asn1.h"
+#include "x509_rsakey-asn1.h"
+
+struct x509_parse_context {
+ struct x509_certificate *cert; /* Certificate being constructed */
+ unsigned long data; /* Start of data */
+ const void *cert_start; /* Start of cert content */
+ const void *key; /* Key data */
+ size_t key_size; /* Size of key data */
+ enum OID last_oid; /* Last OID encountered */
+ enum OID algo_oid; /* Algorithm OID */
+ unsigned char nr_mpi; /* Number of MPIs stored */
+ u8 o_size; /* Size of organizationName (O) */
+ u8 cn_size; /* Size of commonName (CN) */
+ u8 email_size; /* Size of emailAddress */
+ u16 o_offset; /* Offset of organizationName (O) */
+ u16 cn_offset; /* Offset of commonName (CN) */
+ u16 email_offset; /* Offset of emailAddress */
+};
+
+/*
+ * Free an X.509 certificate
+ */
+void x509_free_certificate(struct x509_certificate *cert)
+{
+ if (cert) {
+ public_key_destroy(cert->pub);
+ kfree(cert->issuer);
+ kfree(cert->subject);
+ kfree(cert->fingerprint);
+ kfree(cert->authority);
+ kfree(cert);
+ }
+}
+
+/*
+ * Parse an X.509 certificate
+ */
+struct x509_certificate *x509_cert_parse(const void *data, size_t datalen)
+{
+ struct x509_certificate *cert;
+ struct x509_parse_context *ctx;
+ long ret;
+
+ ret = -ENOMEM;
+ cert = kzalloc(sizeof(struct x509_certificate), GFP_KERNEL);
+ if (!cert)
+ goto error_no_cert;
+ cert->pub = kzalloc(sizeof(struct public_key), GFP_KERNEL);
+ if (!cert->pub)
+ goto error_no_ctx;
+ ctx = kzalloc(sizeof(struct x509_parse_context), GFP_KERNEL);
+ if (!ctx)
+ goto error_no_ctx;
+
+ ctx->cert = cert;
+ ctx->data = (unsigned long)data;
+
+ /* Attempt to decode the certificate */
+ ret = asn1_ber_decoder(&x509_decoder, ctx, data, datalen);
+ if (ret < 0)
+ goto error_decode;
+
+ /* Decode the public key */
+ ret = asn1_ber_decoder(&x509_rsakey_decoder, ctx,
+ ctx->key, ctx->key_size);
+ if (ret < 0)
+ goto error_decode;
+
+ kfree(ctx);
+ return cert;
+
+error_decode:
+ kfree(ctx);
+error_no_ctx:
+ x509_free_certificate(cert);
+error_no_cert:
+ return ERR_PTR(ret);
+}
+
+/*
+ * Note an OID when we find one for later processing when we know how
+ * to interpret it.
+ */
+int x509_note_OID(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct x509_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));
+ pr_debug("Unknown OID: [%zu] %s\n",
+ (unsigned long)value - ctx->data, buffer);
+ }
+ return 0;
+}
+
+/*
+ * Save the position of the TBS data so that we can check the signature over it
+ * later.
+ */
+int x509_note_tbs_certificate(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct x509_parse_context *ctx = context;
+
+ pr_debug("x509_note_tbs_certificate(,%zu,%02x,%ld,%zu)!\n",
+ hdrlen, tag, (unsigned long)value - ctx->data, vlen);
+
+ ctx->cert->tbs = value - hdrlen;
+ ctx->cert->tbs_size = vlen + hdrlen;
+ return 0;
+}
+
+/*
+ * Record the public key algorithm
+ */
+int x509_note_pkey_algo(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct x509_parse_context *ctx = context;
+
+ pr_debug("PubKey Algo: %u\n", ctx->last_oid);
+
+ switch (ctx->last_oid) {
+ case OID_md2WithRSAEncryption:
+ case OID_md3WithRSAEncryption:
+ default:
+ return -ENOPKG; /* Unsupported combination */
+
+ case OID_md4WithRSAEncryption:
+ ctx->cert->sig_hash_algo = PKEY_HASH_MD5;
+ ctx->cert->sig_pkey_algo = PKEY_ALGO_RSA;
+ break;
+
+ case OID_sha1WithRSAEncryption:
+ ctx->cert->sig_hash_algo = PKEY_HASH_SHA1;
+ ctx->cert->sig_pkey_algo = PKEY_ALGO_RSA;
+ break;
+
+ case OID_sha256WithRSAEncryption:
+ ctx->cert->sig_hash_algo = PKEY_HASH_SHA256;
+ ctx->cert->sig_pkey_algo = PKEY_ALGO_RSA;
+ break;
+
+ case OID_sha384WithRSAEncryption:
+ ctx->cert->sig_hash_algo = PKEY_HASH_SHA384;
+ ctx->cert->sig_pkey_algo = PKEY_ALGO_RSA;
+ break;
+
+ case OID_sha512WithRSAEncryption:
+ ctx->cert->sig_hash_algo = PKEY_HASH_SHA512;
+ ctx->cert->sig_pkey_algo = PKEY_ALGO_RSA;
+ break;
+
+ case OID_sha224WithRSAEncryption:
+ ctx->cert->sig_hash_algo = PKEY_HASH_SHA224;
+ ctx->cert->sig_pkey_algo = PKEY_ALGO_RSA;
+ break;
+ }
+
+ ctx->algo_oid = ctx->last_oid;
+ return 0;
+}
+
+/*
+ * Note the whereabouts and type of the signature.
+ */
+int x509_note_signature(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct x509_parse_context *ctx = context;
+
+ pr_debug("Signature type: %u size %zu\n", ctx->last_oid, vlen);
+
+ if (ctx->last_oid != ctx->algo_oid) {
+ pr_warn("Got cert with pkey (%u) and sig (%u) algorithm OIDs\n",
+ ctx->algo_oid, ctx->last_oid);
+ return -EINVAL;
+ }
+
+ ctx->cert->sig = value;
+ ctx->cert->sig_size = vlen;
+ return 0;
+}
+
+/*
+ * Note some of the name segments from which we'll fabricate a name.
+ */
+int x509_extract_name_segment(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct x509_parse_context *ctx = context;
+
+ switch (ctx->last_oid) {
+ case OID_commonName:
+ ctx->cn_size = vlen;
+ ctx->cn_offset = (unsigned long)value - ctx->data;
+ break;
+ case OID_organizationName:
+ ctx->o_size = vlen;
+ ctx->o_offset = (unsigned long)value - ctx->data;
+ break;
+ case OID_email_address:
+ ctx->email_size = vlen;
+ ctx->email_offset = (unsigned long)value - ctx->data;
+ break;
+ default:
+ break;
+ }
+
+ return 0;
+}
+
+/*
+ * Fabricate and save the issuer and subject names
+ */
+static int x509_fabricate_name(struct x509_parse_context *ctx, size_t hdrlen,
+ unsigned char tag,
+ char **_name, size_t vlen)
+{
+ const void *name, *data = (const void *)ctx->data;
+ size_t namesize;
+ char *buffer;
+
+ if (*_name)
+ return -EINVAL;
+
+ /* Empty name string if no material */
+ if (!ctx->cn_size && !ctx->o_size && !ctx->email_size) {
+ buffer = kmalloc(1, GFP_KERNEL);
+ if (!buffer)
+ return -ENOMEM;
+ buffer[0] = 0;
+ goto done;
+ }
+
+ if (ctx->cn_size && ctx->o_size) {
+ /* Consider combining O and CN, but use only the CN if it is
+ * prefixed by the O, or a significant portion thereof.
+ */
+ namesize = ctx->cn_size;
+ name = data + ctx->cn_offset;
+ if (ctx->cn_size >= ctx->o_size &&
+ memcmp(data + ctx->cn_offset, data + ctx->o_offset,
+ ctx->o_size) == 0)
+ goto single_component;
+ if (ctx->cn_size >= 7 &&
+ ctx->o_size >= 7 &&
+ memcmp(data + ctx->cn_offset, data + ctx->o_offset, 7) == 0)
+ goto single_component;
+
+ buffer = kmalloc(ctx->o_size + 2 + ctx->cn_size + 1,
+ GFP_KERNEL);
+ if (!buffer)
+ return -ENOMEM;
+
+ memcpy(buffer,
+ data + ctx->o_offset, ctx->o_size);
+ buffer[ctx->o_size + 0] = ':';
+ buffer[ctx->o_size + 1] = ' ';
+ memcpy(buffer + ctx->o_size + 2,
+ data + ctx->cn_offset, ctx->cn_size);
+ buffer[ctx->o_size + 2 + ctx->cn_size] = 0;
+ goto done;
+
+ } else if (ctx->cn_size) {
+ namesize = ctx->cn_size;
+ name = data + ctx->cn_offset;
+ } else if (ctx->o_size) {
+ namesize = ctx->o_size;
+ name = data + ctx->o_offset;
+ } else {
+ namesize = ctx->email_size;
+ name = data + ctx->email_offset;
+ }
+
+single_component:
+ buffer = kmalloc(namesize + 1, GFP_KERNEL);
+ if (!buffer)
+ return -ENOMEM;
+ memcpy(buffer, name, namesize);
+ buffer[namesize] = 0;
+
+done:
+ *_name = buffer;
+ ctx->cn_size = 0;
+ ctx->o_size = 0;
+ ctx->email_size = 0;
+ return 0;
+}
+
+int x509_note_issuer(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct x509_parse_context *ctx = context;
+ return x509_fabricate_name(ctx, hdrlen, tag, &ctx->cert->issuer, vlen);
+}
+
+int x509_note_subject(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct x509_parse_context *ctx = context;
+ return x509_fabricate_name(ctx, hdrlen, tag, &ctx->cert->subject, vlen);
+}
+
+/*
+ * Extract the data for the public key algorithm
+ */
+int x509_extract_key_data(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct x509_parse_context *ctx = context;
+
+ if (ctx->last_oid != OID_rsaEncryption)
+ return -ENOPKG;
+
+ /* There seems to be an extraneous 0 byte on the front of the data */
+ ctx->cert->pkey_algo = PKEY_ALGO_RSA;
+ ctx->key = value + 1;
+ ctx->key_size = vlen - 1;
+ return 0;
+}
+
+/*
+ * Extract a RSA public key value
+ */
+int rsa_extract_mpi(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct x509_parse_context *ctx = context;
+ MPI mpi;
+
+ if (ctx->nr_mpi >= ARRAY_SIZE(ctx->cert->pub->mpi)) {
+ pr_err("Too many public key MPIs in certificate\n");
+ return -EBADMSG;
+ }
+
+ mpi = mpi_read_raw_data(value, vlen);
+ if (!mpi)
+ return -ENOMEM;
+
+ ctx->cert->pub->mpi[ctx->nr_mpi++] = mpi;
+ return 0;
+}
+
+/*
+ * Process certificate extensions that are used to qualify the certificate.
+ */
+int x509_process_extension(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct x509_parse_context *ctx = context;
+ const unsigned char *v = value;
+ char *f;
+ int i;
+
+ pr_debug("Extension: %u\n", ctx->last_oid);
+
+ if (ctx->last_oid == OID_subjectKeyIdentifier) {
+ /* Get hold of the key fingerprint */
+ if (vlen < 3)
+ return -EBADMSG;
+ if (v[0] != ASN1_OTS || v[1] != vlen - 2)
+ return -EBADMSG;
+ v += 2;
+ vlen -= 2;
+
+ f = kmalloc(vlen * 2 + 1, GFP_KERNEL);
+ if (!f)
+ return -ENOMEM;
+ for (i = 0; i < vlen; i++)
+ sprintf(f + i * 2, "%02x", v[i]);
+ pr_debug("fingerprint %s\n", f);
+ ctx->cert->fingerprint = f;
+ return 0;
+ }
+
+ if (ctx->last_oid == OID_authorityKeyIdentifier) {
+ /* Get hold of the CA key fingerprint */
+ if (vlen < 5)
+ return -EBADMSG;
+ if (v[0] != (ASN1_SEQ | (ASN1_CONS << 5)) ||
+ v[1] != vlen - 2 ||
+ v[2] != (ASN1_CONT << 6) ||
+ v[3] != vlen - 4)
+ return -EBADMSG;
+ v += 4;
+ vlen -= 4;
+
+ f = kmalloc(vlen * 2 + 1, GFP_KERNEL);
+ if (!f)
+ return -ENOMEM;
+ for (i = 0; i < vlen; i++)
+ sprintf(f + i * 2, "%02x", v[i]);
+ pr_debug("authority %s\n", f);
+ ctx->cert->authority = f;
+ return 0;
+ }
+
+ return 0;
+}
+
+/*
+ * Record a certificate time.
+ */
+static int x509_note_time(time_t *_time, size_t hdrlen,
+ unsigned char tag,
+ const unsigned char *value, size_t vlen)
+{
+ unsigned YY, MM, DD, hh, mm, ss;
+ const unsigned char *p = value;
+
+#define dec2bin(X) ((X) - '0')
+#define DD2bin(P) ({ unsigned x = dec2bin(P[0]) * 10 + dec2bin(P[1]); P += 2; x; })
+
+ if (tag == ASN1_UNITIM) {
+ /* UTCTime: YYMMDDHHMMSSZ */
+ if (vlen != 13)
+ goto unsupported_time;
+ YY = DD2bin(p);
+ if (YY > 50)
+ YY += 1900;
+ else
+ YY += 2000;
+ } else if (tag == ASN1_GENTIM) {
+ /* GenTime: YYYYMMDDHHMMSSZ */
+ if (vlen != 15)
+ goto unsupported_time;
+ YY = DD2bin(p) * 100 + DD2bin(p);
+ } else {
+ goto unsupported_time;
+ }
+
+ MM = DD2bin(p);
+ DD = DD2bin(p);
+ hh = DD2bin(p);
+ mm = DD2bin(p);
+ ss = DD2bin(p);
+
+ if (*p != 'Z')
+ goto unsupported_time;
+
+ *_time = mktime(YY, MM, DD, hh, mm, ss);
+ return 0;
+
+unsupported_time:
+ pr_debug("Got unsupported time [tag %02x]: '%*.*s'\n",
+ tag, (int)vlen, (int)vlen, value);
+ return -EBADMSG;
+}
+
+int x509_note_not_before(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct x509_parse_context *ctx = context;
+ return x509_note_time(&ctx->cert->valid_from, hdrlen, tag, value, vlen);
+}
+
+int x509_note_not_after(void *context, size_t hdrlen,
+ unsigned char tag,
+ const void *value, size_t vlen)
+{
+ struct x509_parse_context *ctx = context;
+ return x509_note_time(&ctx->cert->valid_to, hdrlen, tag, value, vlen);
+}
--- /dev/null
+/* Instantiate a public key crypto key from an X.509 Certificate
+ *
+ * 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) "X.509: "fmt
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/mpi.h>
+#include <linux/asn1_decoder.h>
+#include <keys/asymmetric-subtype.h>
+#include <keys/asymmetric-parser.h>
+#include <crypto/hash.h>
+#include "asymmetric_keys.h"
+#include "public_key.h"
+#include "x509_parser.h"
+
+static const
+struct public_key_algorithm *x509_public_key_algorithms[PKEY_ALGO__LAST] = {
+ [PKEY_ALGO_DSA] = NULL,
+#if defined(CONFIG_PUBLIC_KEY_ALGO_RSA) || \
+ defined(CONFIG_PUBLIC_KEY_ALGO_RSA_MODULE)
+ [PKEY_ALGO_RSA] = &RSA_public_key_algorithm,
+#endif
+};
+
+/*
+ * Check the signature on a certificate using the provided public key
+ */
+static int x509_check_signature(const struct public_key *pub,
+ const struct x509_certificate *cert)
+{
+ struct public_key_signature *sig;
+ struct crypto_shash *tfm;
+ struct shash_desc *desc;
+ size_t digest_size, desc_size;
+ int ret;
+
+ pr_devel("==>%s()\n", __func__);
+
+ /* Allocate the hashing algorithm we're going to need and find out how
+ * big the hash operational data will be.
+ */
+ tfm = crypto_alloc_shash(pkey_hash_algo[cert->sig_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);
+ digest_size = crypto_shash_digestsize(tfm);
+
+ /* We allocate the hash operational data storage on the end of our
+ * context data.
+ */
+ ret = -ENOMEM;
+ sig = kzalloc(sizeof(*sig) + desc_size + digest_size, GFP_KERNEL);
+ if (!sig)
+ goto error_no_sig;
+
+ sig->pkey_hash_algo = cert->sig_hash_algo;
+ sig->digest = (u8 *)sig + sizeof(*sig) + desc_size;
+ sig->digest_size = digest_size;
+
+ desc = (void *)sig + sizeof(*sig);
+ desc->tfm = tfm;
+ desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
+
+ ret = crypto_shash_init(desc);
+ if (ret < 0)
+ goto error;
+
+ ret = -ENOMEM;
+ sig->rsa.s = mpi_read_raw_data(cert->sig, cert->sig_size);
+ if (!sig->rsa.s)
+ goto error;
+
+ ret = crypto_shash_finup(desc, cert->tbs, cert->tbs_size, sig->digest);
+ if (ret < 0)
+ goto error_mpi;
+
+ ret = pub->algo->verify_signature(pub, sig);
+
+ pr_debug("Cert Verification: %d\n", ret);
+
+error_mpi:
+ mpi_free(sig->rsa.s);
+error:
+ kfree(sig);
+error_no_sig:
+ crypto_free_shash(tfm);
+
+ pr_devel("<==%s() = %d\n", __func__, ret);
+ return ret;
+}
+
+/*
+ * Attempt to parse a data blob for a key as an X509 certificate.
+ */
+static int x509_key_preparse(struct key_preparsed_payload *prep)
+{
+ struct x509_certificate *cert;
+ time_t now;
+ size_t srlen, sulen;
+ char *desc = NULL;
+ int ret;
+
+ cert = x509_cert_parse(prep->data, prep->datalen);
+ if (IS_ERR(cert))
+ return PTR_ERR(cert);
+
+ pr_devel("Cert Issuer: %s\n", cert->issuer);
+ pr_devel("Cert Subject: %s\n", cert->subject);
+ pr_devel("Cert Key Algo: %s\n", pkey_algo[cert->pkey_algo]);
+ pr_devel("Cert Valid: %lu - %lu\n", cert->valid_from, cert->valid_to);
+ pr_devel("Cert Signature: %s + %s\n",
+ pkey_algo[cert->sig_pkey_algo],
+ pkey_hash_algo[cert->sig_hash_algo]);
+
+ if (!cert->fingerprint || !cert->authority) {
+ pr_warn("Cert for '%s' must have SubjKeyId and AuthKeyId extensions\n",
+ cert->subject);
+ ret = -EKEYREJECTED;
+ goto error_free_cert;
+ }
+
+ now = CURRENT_TIME.tv_sec;
+ if (now < cert->valid_from) {
+ pr_warn("Cert %s is not yet valid\n", cert->fingerprint);
+ ret = -EKEYREJECTED;
+ goto error_free_cert;
+ }
+ if (now >= cert->valid_to) {
+ pr_warn("Cert %s has expired\n", cert->fingerprint);
+ ret = -EKEYEXPIRED;
+ goto error_free_cert;
+ }
+
+ cert->pub->algo = x509_public_key_algorithms[cert->pkey_algo];
+ cert->pub->id_type = PKEY_ID_X509;
+
+ /* Check the signature on the key */
+ if (strcmp(cert->fingerprint, cert->authority) == 0) {
+ ret = x509_check_signature(cert->pub, cert);
+ if (ret < 0)
+ goto error_free_cert;
+ }
+
+ /* Propose a description */
+ sulen = strlen(cert->subject);
+ srlen = strlen(cert->fingerprint);
+ ret = -ENOMEM;
+ desc = kmalloc(sulen + 2 + srlen + 1, GFP_KERNEL);
+ if (!desc)
+ goto error_free_cert;
+ memcpy(desc, cert->subject, sulen);
+ desc[sulen] = ':';
+ desc[sulen + 1] = ' ';
+ memcpy(desc + sulen + 2, cert->fingerprint, srlen);
+ desc[sulen + 2 + srlen] = 0;
+
+ /* We're pinning the module by being linked against it */
+ __module_get(public_key_subtype.owner);
+ prep->type_data[0] = &public_key_subtype;
+ prep->type_data[1] = cert->fingerprint;
+ prep->payload = cert->pub;
+ prep->description = desc;
+ prep->quotalen = 100;
+
+ /* We've finished with the certificate */
+ cert->pub = NULL;
+ cert->fingerprint = NULL;
+ desc = NULL;
+ ret = 0;
+
+error_free_cert:
+ x509_free_certificate(cert);
+ return ret;
+}
+
+static struct asymmetric_key_parser x509_key_parser = {
+ .owner = THIS_MODULE,
+ .name = "x509",
+ .parse = x509_key_preparse,
+};
+
+/*
+ * Module stuff
+ */
+static int __init x509_key_init(void)
+{
+ return register_asymmetric_key_parser(&x509_key_parser);
+}
+
+static void __exit x509_key_exit(void)
+{
+ unregister_asymmetric_key_parser(&x509_key_parser);
+}
+
+module_init(x509_key_init);
+module_exit(x509_key_exit);
projects / GitHub / LineageOS / android_kernel_motorola_exynos9610.git / commitdiff