diff options
author | AKASHI Takahiro <takahiro.akashi@linaro.org> | 2019-11-13 09:45:00 +0900 |
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committer | Tom Rini <trini@konsulko.com> | 2019-12-06 16:44:20 -0500 |
commit | b4adf627d5b7bdff649d3b852eab97d6f9191111 (patch) | |
tree | b945bac17c3207bdcd6ab41cc04b39c927b3c30e /lib/crypto/x509_cert_parser.c | |
parent | 9b933bf6f4fa4db2f8ab94d3b977b7fefa2644dd (diff) |
lib: crypto: add x509 parser
Imported from linux kernel v5.3:
x509.asn1 without changes
x509_akid.asn1 without changes
x509_parser.h without changes
x509_cert_parser.c with changes marked as __UBOOT__
x509_public_key.c with changes marked as __UBOOT__
Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Diffstat (limited to 'lib/crypto/x509_cert_parser.c')
-rw-r--r-- | lib/crypto/x509_cert_parser.c | 697 |
1 files changed, 697 insertions, 0 deletions
diff --git a/lib/crypto/x509_cert_parser.c b/lib/crypto/x509_cert_parser.c new file mode 100644 index 0000000000..e6d2a426a0 --- /dev/null +++ b/lib/crypto/x509_cert_parser.c @@ -0,0 +1,697 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* X.509 certificate parser + * + * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#define pr_fmt(fmt) "X.509: "fmt +#include <linux/kernel.h> +#ifndef __UBOOT__ +#include <linux/export.h> +#include <linux/slab.h> +#endif +#include <linux/err.h> +#include <linux/oid_registry.h> +#ifdef __UBOOT__ +#include <linux/string.h> +#endif +#include <crypto/public_key.h> +#include "x509_parser.h" +#include "x509.asn1.h" +#include "x509_akid.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 */ + const void *params; /* Key parameters */ + size_t params_size; /* Size of key parameters */ + enum OID key_algo; /* Public key algorithm */ + 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 */ + unsigned raw_akid_size; + const void *raw_akid; /* Raw authorityKeyId in ASN.1 */ + const void *akid_raw_issuer; /* Raw directoryName in authorityKeyId */ + unsigned akid_raw_issuer_size; +}; + +/* + * Free an X.509 certificate + */ +void x509_free_certificate(struct x509_certificate *cert) +{ + if (cert) { + public_key_free(cert->pub); + public_key_signature_free(cert->sig); + kfree(cert->issuer); + kfree(cert->subject); + kfree(cert->id); + kfree(cert->skid); + kfree(cert); + } +} +EXPORT_SYMBOL_GPL(x509_free_certificate); + +/* + * 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; + struct asymmetric_key_id *kid; + 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; + cert->sig = kzalloc(sizeof(struct public_key_signature), GFP_KERNEL); + if (!cert->sig) + 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 AuthorityKeyIdentifier */ + if (ctx->raw_akid) { + pr_devel("AKID: %u %*phN\n", + ctx->raw_akid_size, ctx->raw_akid_size, ctx->raw_akid); + ret = asn1_ber_decoder(&x509_akid_decoder, ctx, + ctx->raw_akid, ctx->raw_akid_size); + if (ret < 0) { + pr_warn("Couldn't decode AuthKeyIdentifier\n"); + goto error_decode; + } + } + + ret = -ENOMEM; + cert->pub->key = kmemdup(ctx->key, ctx->key_size, GFP_KERNEL); + if (!cert->pub->key) + goto error_decode; + + cert->pub->keylen = ctx->key_size; + + cert->pub->params = kmemdup(ctx->params, ctx->params_size, GFP_KERNEL); + if (!cert->pub->params) + goto error_decode; + + cert->pub->paramlen = ctx->params_size; + cert->pub->algo = ctx->key_algo; + + /* Grab the signature bits */ + ret = x509_get_sig_params(cert); + if (ret < 0) + goto error_decode; + + /* Generate cert issuer + serial number key ID */ + kid = asymmetric_key_generate_id(cert->raw_serial, + cert->raw_serial_size, + cert->raw_issuer, + cert->raw_issuer_size); + if (IS_ERR(kid)) { + ret = PTR_ERR(kid); + goto error_decode; + } + cert->id = kid; + +#ifndef __UBOOT__ + /* Detect self-signed certificates */ + ret = x509_check_for_self_signed(cert); + if (ret < 0) + goto error_decode; +#endif + + kfree(ctx); + return cert; + +error_decode: + kfree(ctx); +error_no_ctx: + x509_free_certificate(cert); +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 + * 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: [%lu] %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 = "md4"; + goto rsa_pkcs1; + + case OID_sha1WithRSAEncryption: + ctx->cert->sig->hash_algo = "sha1"; + goto rsa_pkcs1; + + case OID_sha256WithRSAEncryption: + ctx->cert->sig->hash_algo = "sha256"; + goto rsa_pkcs1; + + case OID_sha384WithRSAEncryption: + ctx->cert->sig->hash_algo = "sha384"; + goto rsa_pkcs1; + + case OID_sha512WithRSAEncryption: + ctx->cert->sig->hash_algo = "sha512"; + goto rsa_pkcs1; + + case OID_sha224WithRSAEncryption: + ctx->cert->sig->hash_algo = "sha224"; + goto rsa_pkcs1; + + case OID_gost2012Signature256: + ctx->cert->sig->hash_algo = "streebog256"; + goto ecrdsa; + + case OID_gost2012Signature512: + ctx->cert->sig->hash_algo = "streebog512"; + goto ecrdsa; + } + +rsa_pkcs1: + ctx->cert->sig->pkey_algo = "rsa"; + ctx->cert->sig->encoding = "pkcs1"; + ctx->algo_oid = ctx->last_oid; + return 0; +ecrdsa: + ctx->cert->sig->pkey_algo = "ecrdsa"; + ctx->cert->sig->encoding = "raw"; + 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; + } + + if (strcmp(ctx->cert->sig->pkey_algo, "rsa") == 0 || + strcmp(ctx->cert->sig->pkey_algo, "ecrdsa") == 0) { + /* Discard the BIT STRING metadata */ + if (vlen < 1 || *(const u8 *)value != 0) + return -EBADMSG; + + value++; + vlen--; + } + + ctx->cert->raw_sig = value; + ctx->cert->raw_sig_size = vlen; + return 0; +} + +/* + * Note the certificate serial number + */ +int x509_note_serial(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct x509_parse_context *ctx = context; + ctx->cert->raw_serial = value; + ctx->cert->raw_serial_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; + ctx->cert->raw_issuer = value; + ctx->cert->raw_issuer_size = vlen; + 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; + ctx->cert->raw_subject = value; + ctx->cert->raw_subject_size = vlen; + return x509_fabricate_name(ctx, hdrlen, tag, &ctx->cert->subject, vlen); +} + +/* + * Extract the parameters for the public key + */ +int x509_note_params(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct x509_parse_context *ctx = context; + + /* + * AlgorithmIdentifier is used three times in the x509, we should skip + * first and ignore third, using second one which is after subject and + * before subjectPublicKey. + */ + if (!ctx->cert->raw_subject || ctx->key) + return 0; + ctx->params = value - hdrlen; + ctx->params_size = vlen + hdrlen; + return 0; +} + +/* + * 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; + + ctx->key_algo = ctx->last_oid; + if (ctx->last_oid == OID_rsaEncryption) + ctx->cert->pub->pkey_algo = "rsa"; + else if (ctx->last_oid == OID_gost2012PKey256 || + ctx->last_oid == OID_gost2012PKey512) + ctx->cert->pub->pkey_algo = "ecrdsa"; + else + return -ENOPKG; + + /* Discard the BIT STRING metadata */ + if (vlen < 1 || *(const u8 *)value != 0) + return -EBADMSG; + ctx->key = value + 1; + ctx->key_size = vlen - 1; + return 0; +} + +/* The keyIdentifier in AuthorityKeyIdentifier SEQUENCE is tag(CONT,PRIM,0) */ +#define SEQ_TAG_KEYID (ASN1_CONT << 6) + +/* + * 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; + struct asymmetric_key_id *kid; + const unsigned char *v = value; + + pr_debug("Extension: %u\n", ctx->last_oid); + + if (ctx->last_oid == OID_subjectKeyIdentifier) { + /* Get hold of the key fingerprint */ + if (ctx->cert->skid || vlen < 3) + return -EBADMSG; + if (v[0] != ASN1_OTS || v[1] != vlen - 2) + return -EBADMSG; + v += 2; + vlen -= 2; + + ctx->cert->raw_skid_size = vlen; + ctx->cert->raw_skid = v; + kid = asymmetric_key_generate_id(v, vlen, "", 0); + if (IS_ERR(kid)) + return PTR_ERR(kid); + ctx->cert->skid = kid; + pr_debug("subjkeyid %*phN\n", kid->len, kid->data); + return 0; + } + + if (ctx->last_oid == OID_authorityKeyIdentifier) { + /* Get hold of the CA key fingerprint */ + ctx->raw_akid = v; + ctx->raw_akid_size = vlen; + return 0; + } + + return 0; +} + +/** + * x509_decode_time - Decode an X.509 time ASN.1 object + * @_t: The time to fill in + * @hdrlen: The length of the object header + * @tag: The object tag + * @value: The object value + * @vlen: The size of the object value + * + * Decode an ASN.1 universal time or generalised time field into a struct the + * kernel can handle and check it for validity. The time is decoded thus: + * + * [RFC5280 ยง4.1.2.5] + * CAs conforming to this profile MUST always encode certificate validity + * dates through the year 2049 as UTCTime; certificate validity dates in + * 2050 or later MUST be encoded as GeneralizedTime. Conforming + * applications MUST be able to process validity dates that are encoded in + * either UTCTime or GeneralizedTime. + */ +int x509_decode_time(time64_t *_t, size_t hdrlen, + unsigned char tag, + const unsigned char *value, size_t vlen) +{ + static const unsigned char month_lengths[] = { 31, 28, 31, 30, 31, 30, + 31, 31, 30, 31, 30, 31 }; + const unsigned char *p = value; + unsigned year, mon, day, hour, min, sec, mon_len; + +#define dec2bin(X) ({ unsigned char x = (X) - '0'; if (x > 9) goto invalid_time; x; }) +#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; + year = DD2bin(p); + if (year >= 50) + year += 1900; + else + year += 2000; + } else if (tag == ASN1_GENTIM) { + /* GenTime: YYYYMMDDHHMMSSZ */ + if (vlen != 15) + goto unsupported_time; + year = DD2bin(p) * 100 + DD2bin(p); + if (year >= 1950 && year <= 2049) + goto invalid_time; + } else { + goto unsupported_time; + } + + mon = DD2bin(p); + day = DD2bin(p); + hour = DD2bin(p); + min = DD2bin(p); + sec = DD2bin(p); + + if (*p != 'Z') + goto unsupported_time; + + if (year < 1970 || + mon < 1 || mon > 12) + goto invalid_time; + + mon_len = month_lengths[mon - 1]; + if (mon == 2) { + if (year % 4 == 0) { + mon_len = 29; + if (year % 100 == 0) { + mon_len = 28; + if (year % 400 == 0) + mon_len = 29; + } + } + } + + if (day < 1 || day > mon_len || + hour > 24 || /* ISO 8601 permits 24:00:00 as midnight tomorrow */ + min > 59 || + sec > 60) /* ISO 8601 permits leap seconds [X.680 46.3] */ + goto invalid_time; + + *_t = mktime64(year, mon, day, hour, min, sec); + return 0; + +unsupported_time: + pr_debug("Got unsupported time [tag %02x]: '%*phN'\n", + tag, (int)vlen, value); + return -EBADMSG; +invalid_time: + pr_debug("Got invalid time [tag %02x]: '%*phN'\n", + tag, (int)vlen, value); + return -EBADMSG; +} +EXPORT_SYMBOL_GPL(x509_decode_time); + +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_decode_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_decode_time(&ctx->cert->valid_to, hdrlen, tag, value, vlen); +} + +/* + * Note a key identifier-based AuthorityKeyIdentifier + */ +int x509_akid_note_kid(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct x509_parse_context *ctx = context; + struct asymmetric_key_id *kid; + + pr_debug("AKID: keyid: %*phN\n", (int)vlen, value); + + if (ctx->cert->sig->auth_ids[1]) + return 0; + + kid = asymmetric_key_generate_id(value, vlen, "", 0); + if (IS_ERR(kid)) + return PTR_ERR(kid); + pr_debug("authkeyid %*phN\n", kid->len, kid->data); + ctx->cert->sig->auth_ids[1] = kid; + return 0; +} + +/* + * Note a directoryName in an AuthorityKeyIdentifier + */ +int x509_akid_note_name(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct x509_parse_context *ctx = context; + + pr_debug("AKID: name: %*phN\n", (int)vlen, value); + + ctx->akid_raw_issuer = value; + ctx->akid_raw_issuer_size = vlen; + return 0; +} + +/* + * Note a serial number in an AuthorityKeyIdentifier + */ +int x509_akid_note_serial(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct x509_parse_context *ctx = context; + struct asymmetric_key_id *kid; + + pr_debug("AKID: serial: %*phN\n", (int)vlen, value); + + if (!ctx->akid_raw_issuer || ctx->cert->sig->auth_ids[0]) + return 0; + + kid = asymmetric_key_generate_id(value, + vlen, + ctx->akid_raw_issuer, + ctx->akid_raw_issuer_size); + if (IS_ERR(kid)) + return PTR_ERR(kid); + + pr_debug("authkeyid %*phN\n", kid->len, kid->data); + ctx->cert->sig->auth_ids[0] = kid; + return 0; +} |