diff options
Diffstat (limited to 'lib/crypto')
| -rw-r--r-- | lib/crypto/Kconfig | 12 | ||||
| -rw-r--r-- | lib/crypto/Makefile | 17 | ||||
| -rw-r--r-- | lib/crypto/x509.asn1 | 60 | ||||
| -rw-r--r-- | lib/crypto/x509_akid.asn1 | 35 | ||||
| -rw-r--r-- | lib/crypto/x509_cert_parser.c | 697 | ||||
| -rw-r--r-- | lib/crypto/x509_parser.h | 57 | ||||
| -rw-r--r-- | lib/crypto/x509_public_key.c | 292 |
7 files changed, 1170 insertions, 0 deletions
diff --git a/lib/crypto/Kconfig b/lib/crypto/Kconfig index 9572ea8c87f..aeb599c593a 100644 --- a/lib/crypto/Kconfig +++ b/lib/crypto/Kconfig @@ -27,4 +27,16 @@ config RSA_PUBLIC_KEY_PARSER public key data and provides the ability to instantiate a public key. +config X509_CERTIFICATE_PARSER + bool "X.509 certificate parser" + depends on ASYMMETRIC_PUBLIC_KEY_SUBTYPE + select ASN1_DECODER + select ASN1_COMPILER + select OID_REGISTRY + select LIB_DATE + help + This option provides support for parsing X.509 format blobs for key + data and provides the ability to instantiate a crypto key from a + public key packet found inside the certificate. + endif # ASYMMETRIC_KEY_TYPE diff --git a/lib/crypto/Makefile b/lib/crypto/Makefile index 69330a9ebd2..d7e27be568a 100644 --- a/lib/crypto/Makefile +++ b/lib/crypto/Makefile @@ -19,3 +19,20 @@ rsa_public_key-y := \ $(obj)/rsapubkey.asn1.o: $(obj)/rsapubkey.asn1.c $(obj)/rsapubkey.asn1.h $(obj)/rsa_helper.o: $(obj)/rsapubkey.asn1.h + +# +# X.509 Certificate handling +# +obj-$(CONFIG_X509_CERTIFICATE_PARSER) += x509_key_parser.o +x509_key_parser-y := \ + x509.asn1.o \ + x509_akid.asn1.o \ + x509_cert_parser.o \ + x509_public_key.o + +$(obj)/x509_cert_parser.o: \ + $(obj)/x509.asn1.h \ + $(obj)/x509_akid.asn1.h + +$(obj)/x509.asn1.o: $(obj)/x509.asn1.c $(obj)/x509.asn1.h +$(obj)/x509_akid.asn1.o: $(obj)/x509_akid.asn1.c $(obj)/x509_akid.asn1.h diff --git a/lib/crypto/x509.asn1 b/lib/crypto/x509.asn1 new file mode 100644 index 00000000000..5c9f4e4a523 --- /dev/null +++ b/lib/crypto/x509.asn1 @@ -0,0 +1,60 @@ +Certificate ::= SEQUENCE { + tbsCertificate TBSCertificate ({ x509_note_tbs_certificate }), + signatureAlgorithm AlgorithmIdentifier, + signature BIT STRING ({ x509_note_signature }) + } + +TBSCertificate ::= SEQUENCE { + version [ 0 ] Version DEFAULT, + serialNumber CertificateSerialNumber ({ x509_note_serial }), + signature AlgorithmIdentifier ({ x509_note_pkey_algo }), + issuer Name ({ x509_note_issuer }), + validity Validity, + subject Name ({ x509_note_subject }), + subjectPublicKeyInfo SubjectPublicKeyInfo, + issuerUniqueID [ 1 ] IMPLICIT UniqueIdentifier OPTIONAL, + subjectUniqueID [ 2 ] IMPLICIT UniqueIdentifier OPTIONAL, + extensions [ 3 ] Extensions OPTIONAL + } + +Version ::= INTEGER +CertificateSerialNumber ::= INTEGER + +AlgorithmIdentifier ::= SEQUENCE { + algorithm OBJECT IDENTIFIER ({ x509_note_OID }), + parameters ANY OPTIONAL ({ x509_note_params }) +} + +Name ::= SEQUENCE OF RelativeDistinguishedName + +RelativeDistinguishedName ::= SET OF AttributeValueAssertion + +AttributeValueAssertion ::= SEQUENCE { + attributeType OBJECT IDENTIFIER ({ x509_note_OID }), + attributeValue ANY ({ x509_extract_name_segment }) + } + +Validity ::= SEQUENCE { + notBefore Time ({ x509_note_not_before }), + notAfter Time ({ x509_note_not_after }) + } + +Time ::= CHOICE { + utcTime UTCTime, + generalTime GeneralizedTime + } + +SubjectPublicKeyInfo ::= SEQUENCE { + algorithm AlgorithmIdentifier, + subjectPublicKey BIT STRING ({ x509_extract_key_data }) + } + +UniqueIdentifier ::= BIT STRING + +Extensions ::= SEQUENCE OF Extension + +Extension ::= SEQUENCE { + extnid OBJECT IDENTIFIER ({ x509_note_OID }), + critical BOOLEAN DEFAULT, + extnValue OCTET STRING ({ x509_process_extension }) + } diff --git a/lib/crypto/x509_akid.asn1 b/lib/crypto/x509_akid.asn1 new file mode 100644 index 00000000000..1a33231a75a --- /dev/null +++ b/lib/crypto/x509_akid.asn1 @@ -0,0 +1,35 @@ +-- X.509 AuthorityKeyIdentifier +-- rfc5280 section 4.2.1.1 + +AuthorityKeyIdentifier ::= SEQUENCE { + keyIdentifier [0] IMPLICIT KeyIdentifier OPTIONAL, + authorityCertIssuer [1] IMPLICIT GeneralNames OPTIONAL, + authorityCertSerialNumber [2] IMPLICIT CertificateSerialNumber OPTIONAL + } + +KeyIdentifier ::= OCTET STRING ({ x509_akid_note_kid }) + +CertificateSerialNumber ::= INTEGER ({ x509_akid_note_serial }) + +GeneralNames ::= SEQUENCE OF GeneralName + +GeneralName ::= CHOICE { + otherName [0] ANY, + rfc822Name [1] IA5String, + dNSName [2] IA5String, + x400Address [3] ANY, + directoryName [4] Name ({ x509_akid_note_name }), + ediPartyName [5] ANY, + uniformResourceIdentifier [6] IA5String, + iPAddress [7] OCTET STRING, + registeredID [8] OBJECT IDENTIFIER + } + +Name ::= SEQUENCE OF RelativeDistinguishedName + +RelativeDistinguishedName ::= SET OF AttributeValueAssertion + +AttributeValueAssertion ::= SEQUENCE { + attributeType OBJECT IDENTIFIER ({ x509_note_OID }), + attributeValue ANY ({ x509_extract_name_segment }) + } diff --git a/lib/crypto/x509_cert_parser.c b/lib/crypto/x509_cert_parser.c new file mode 100644 index 00000000000..e6d2a426a0b --- /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; +} diff --git a/lib/crypto/x509_parser.h b/lib/crypto/x509_parser.h new file mode 100644 index 00000000000..c233f136fb3 --- /dev/null +++ b/lib/crypto/x509_parser.h @@ -0,0 +1,57 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* X.509 certificate parser internal definitions + * + * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#include <linux/time.h> +#include <crypto/public_key.h> +#include <keys/asymmetric-type.h> + +struct x509_certificate { + struct x509_certificate *next; + struct x509_certificate *signer; /* Certificate that signed this one */ + struct public_key *pub; /* Public key details */ + struct public_key_signature *sig; /* Signature parameters */ + char *issuer; /* Name of certificate issuer */ + char *subject; /* Name of certificate subject */ + struct asymmetric_key_id *id; /* Issuer + Serial number */ + struct asymmetric_key_id *skid; /* Subject + subjectKeyId (optional) */ + time64_t valid_from; + time64_t valid_to; + const void *tbs; /* Signed data */ + unsigned tbs_size; /* Size of signed data */ + unsigned raw_sig_size; /* Size of sigature */ + const void *raw_sig; /* Signature data */ + const void *raw_serial; /* Raw serial number in ASN.1 */ + unsigned raw_serial_size; + unsigned raw_issuer_size; + const void *raw_issuer; /* Raw issuer name in ASN.1 */ + const void *raw_subject; /* Raw subject name in ASN.1 */ + unsigned raw_subject_size; + unsigned raw_skid_size; + const void *raw_skid; /* Raw subjectKeyId in ASN.1 */ + unsigned index; + bool seen; /* Infinite recursion prevention */ + bool verified; + bool self_signed; /* T if self-signed (check unsupported_sig too) */ + bool unsupported_key; /* T if key uses unsupported crypto */ + bool unsupported_sig; /* T if signature uses unsupported crypto */ + bool blacklisted; +}; + +/* + * x509_cert_parser.c + */ +extern void x509_free_certificate(struct x509_certificate *cert); +extern struct x509_certificate *x509_cert_parse(const void *data, size_t datalen); +extern int x509_decode_time(time64_t *_t, size_t hdrlen, + unsigned char tag, + const unsigned char *value, size_t vlen); + +/* + * x509_public_key.c + */ +extern int x509_get_sig_params(struct x509_certificate *cert); +extern int x509_check_for_self_signed(struct x509_certificate *cert); diff --git a/lib/crypto/x509_public_key.c b/lib/crypto/x509_public_key.c new file mode 100644 index 00000000000..04bdb672b49 --- /dev/null +++ b/lib/crypto/x509_public_key.c @@ -0,0 +1,292 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* 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) + */ + +#define pr_fmt(fmt) "X.509: "fmt +#ifdef __UBOOT__ +#include <common.h> +#include <linux/compat.h> +#include <linux/errno.h> +#else +#include <linux/module.h> +#endif +#include <linux/kernel.h> +#ifndef __UBOOT__ +#include <linux/slab.h> +#include <keys/asymmetric-subtype.h> +#include <keys/asymmetric-parser.h> +#include <keys/system_keyring.h> +#include <crypto/hash.h> +#include "asymmetric_keys.h" +#endif +#include "x509_parser.h" + +/* + * Set up the signature parameters in an X.509 certificate. This involves + * digesting the signed data and extracting the signature. + */ +int x509_get_sig_params(struct x509_certificate *cert) +{ + struct public_key_signature *sig = cert->sig; +#ifndef __UBOOT__ + struct crypto_shash *tfm; + struct shash_desc *desc; + size_t desc_size; +#endif + int ret; + + pr_devel("==>%s()\n", __func__); + + if (!cert->pub->pkey_algo) + cert->unsupported_key = true; + + if (!sig->pkey_algo) + cert->unsupported_sig = true; + + /* We check the hash if we can - even if we can't then verify it */ + if (!sig->hash_algo) { + cert->unsupported_sig = true; + return 0; + } + + sig->s = kmemdup(cert->raw_sig, cert->raw_sig_size, GFP_KERNEL); + if (!sig->s) + return -ENOMEM; + + sig->s_size = cert->raw_sig_size; + +#ifdef __UBOOT__ + /* + * Note: + * This part (filling sig->digest) should be implemented if + * x509_check_for_self_signed() is enabled x509_cert_parse(). + * Currently, this check won't affect UEFI secure boot. + */ + ret = 0; +#else + /* Allocate the hashing algorithm we're going to need and find out how + * big the hash operational data will be. + */ + tfm = crypto_alloc_shash(sig->hash_algo, 0, 0); + if (IS_ERR(tfm)) { + if (PTR_ERR(tfm) == -ENOENT) { + cert->unsupported_sig = true; + return 0; + } + return PTR_ERR(tfm); + } + + desc_size = crypto_shash_descsize(tfm) + sizeof(*desc); + sig->digest_size = crypto_shash_digestsize(tfm); + + ret = -ENOMEM; + sig->digest = kmalloc(sig->digest_size, GFP_KERNEL); + if (!sig->digest) + goto error; + + desc = kzalloc(desc_size, GFP_KERNEL); + if (!desc) + goto error; + + desc->tfm = tfm; + + ret = crypto_shash_digest(desc, cert->tbs, cert->tbs_size, sig->digest); + if (ret < 0) + goto error_2; + + ret = is_hash_blacklisted(sig->digest, sig->digest_size, "tbs"); + if (ret == -EKEYREJECTED) { + pr_err("Cert %*phN is blacklisted\n", + sig->digest_size, sig->digest); + cert->blacklisted = true; + ret = 0; + } + +error_2: + kfree(desc); +error: + crypto_free_shash(tfm); +#endif /* __UBOOT__ */ + pr_devel("<==%s() = %d\n", __func__, ret); + return ret; +} + +#ifndef __UBOOT__ +/* + * Check for self-signedness in an X.509 cert and if found, check the signature + * immediately if we can. + */ +int x509_check_for_self_signed(struct x509_certificate *cert) +{ + int ret = 0; + + pr_devel("==>%s()\n", __func__); + + if (cert->raw_subject_size != cert->raw_issuer_size || + memcmp(cert->raw_subject, cert->raw_issuer, + cert->raw_issuer_size) != 0) + goto not_self_signed; + + if (cert->sig->auth_ids[0] || cert->sig->auth_ids[1]) { + /* If the AKID is present it may have one or two parts. If + * both are supplied, both must match. + */ + bool a = asymmetric_key_id_same(cert->skid, cert->sig->auth_ids[1]); + bool b = asymmetric_key_id_same(cert->id, cert->sig->auth_ids[0]); + + if (!a && !b) + goto not_self_signed; + + ret = -EKEYREJECTED; + if (((a && !b) || (b && !a)) && + cert->sig->auth_ids[0] && cert->sig->auth_ids[1]) + goto out; + } + + ret = -EKEYREJECTED; + if (strcmp(cert->pub->pkey_algo, cert->sig->pkey_algo) != 0) + goto out; + + ret = public_key_verify_signature(cert->pub, cert->sig); + if (ret < 0) { + if (ret == -ENOPKG) { + cert->unsupported_sig = true; + ret = 0; + } + goto out; + } + + pr_devel("Cert Self-signature verified"); + cert->self_signed = true; + +out: + pr_devel("<==%s() = %d\n", __func__, ret); + return ret; + +not_self_signed: + pr_devel("<==%s() = 0 [not]\n", __func__); + return 0; +} + +/* + * Attempt to parse a data blob for a key as an X509 certificate. + */ +static int x509_key_preparse(struct key_preparsed_payload *prep) +{ + struct asymmetric_key_ids *kids; + struct x509_certificate *cert; + const char *q; + size_t srlen, sulen; + char *desc = NULL, *p; + 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); + + if (cert->unsupported_key) { + ret = -ENOPKG; + goto error_free_cert; + } + + pr_devel("Cert Key Algo: %s\n", cert->pub->pkey_algo); + pr_devel("Cert Valid period: %lld-%lld\n", cert->valid_from, cert->valid_to); + + cert->pub->id_type = "X509"; + + if (cert->unsupported_sig) { + public_key_signature_free(cert->sig); + cert->sig = NULL; + } else { + pr_devel("Cert Signature: %s + %s\n", + cert->sig->pkey_algo, cert->sig->hash_algo); + } + + /* Don't permit addition of blacklisted keys */ + ret = -EKEYREJECTED; + if (cert->blacklisted) + goto error_free_cert; + + /* Propose a description */ + sulen = strlen(cert->subject); + if (cert->raw_skid) { + srlen = cert->raw_skid_size; + q = cert->raw_skid; + } else { + srlen = cert->raw_serial_size; + q = cert->raw_serial; + } + + ret = -ENOMEM; + desc = kmalloc(sulen + 2 + srlen * 2 + 1, GFP_KERNEL); + if (!desc) + goto error_free_cert; + p = memcpy(desc, cert->subject, sulen); + p += sulen; + *p++ = ':'; + *p++ = ' '; + p = bin2hex(p, q, srlen); + *p = 0; + + kids = kmalloc(sizeof(struct asymmetric_key_ids), GFP_KERNEL); + if (!kids) + goto error_free_desc; + kids->id[0] = cert->id; + kids->id[1] = cert->skid; + + /* We're pinning the module by being linked against it */ + __module_get(public_key_subtype.owner); + prep->payload.data[asym_subtype] = &public_key_subtype; + prep->payload.data[asym_key_ids] = kids; + prep->payload.data[asym_crypto] = cert->pub; + prep->payload.data[asym_auth] = cert->sig; + prep->description = desc; + prep->quotalen = 100; + + /* We've finished with the certificate */ + cert->pub = NULL; + cert->id = NULL; + cert->skid = NULL; + cert->sig = NULL; + desc = NULL; + ret = 0; + +error_free_desc: + kfree(desc); +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); +#endif /* !__UBOOT__ */ + +MODULE_DESCRIPTION("X.509 certificate parser"); +MODULE_AUTHOR("Red Hat, Inc."); +MODULE_LICENSE("GPL"); |