From de26a46f6c581b579f77bbe31cc7aef0b1fd14bc Mon Sep 17 00:00:00 2001 From: David Howells Date: Mon, 24 Sep 2012 17:11:48 +0100 Subject: X.509: Add a crypto key parser for binary (DER) X.509 certificates Add a crypto key parser for binary (DER) encoded X.509 certificates. The certificate is parsed and, if possible, the signature is verified. An X.509 key can be added like this: # keyctl padd crypto bar @s Signed-off-by: Rusty Russell --- crypto/asymmetric_keys/x509_public_key.c | 207 +++++++++++++++++++++++++++++++ 1 file changed, 207 insertions(+) create mode 100644 crypto/asymmetric_keys/x509_public_key.c (limited to 'crypto/asymmetric_keys/x509_public_key.c') diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c new file mode 100644 index 00000000..716917ce --- /dev/null +++ b/crypto/asymmetric_keys/x509_public_key.c @@ -0,0 +1,207 @@ +/* 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 +#include +#include +#include +#include +#include +#include +#include +#include +#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); -- cgit v1.2.3 From b704b28c01f94cf11495d9c97dc5be3b35900bb8 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 2 Oct 2012 14:36:16 +0100 Subject: MODSIGN: Fix 32-bit overflow in X.509 certificate validity date checking The current choice of lifetime for the autogenerated X.509 of 100 years, putting the validTo date in 2112, causes problems on 32-bit systems where a 32-bit time_t wraps in 2106. 64-bit x86_64 systems seem to be unaffected. This can result in something like: Loading module verification certificates X.509: Cert 6e03943da0f3b015ba6ed7f5e0cac4fe48680994 has expired MODSIGN: Problem loading in-kernel X.509 certificate (-127) Or: X.509: Cert 6e03943da0f3b015ba6ed7f5e0cac4fe48680994 is not yet valid MODSIGN: Problem loading in-kernel X.509 certificate (-129) Instead of turning the dates into time_t values and comparing, turn the system clock and the ASN.1 dates into tm structs and compare those piecemeal instead. Reported-by: Rusty Russell Signed-off-by: David Howells Acked-by: Josh Boyer Signed-off-by: Rusty Russell --- crypto/asymmetric_keys/x509_cert_parser.c | 25 +++++++++--------- crypto/asymmetric_keys/x509_parser.h | 4 +-- crypto/asymmetric_keys/x509_public_key.c | 42 +++++++++++++++++++++++++++---- 3 files changed, 51 insertions(+), 20 deletions(-) (limited to 'crypto/asymmetric_keys/x509_public_key.c') diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c index 8fcac949..db07e8c9 100644 --- a/crypto/asymmetric_keys/x509_cert_parser.c +++ b/crypto/asymmetric_keys/x509_cert_parser.c @@ -434,11 +434,10 @@ int x509_process_extension(void *context, size_t hdrlen, /* * Record a certificate time. */ -static int x509_note_time(time_t *_time, size_t hdrlen, +static int x509_note_time(struct tm *tm, 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') @@ -448,30 +447,30 @@ static int x509_note_time(time_t *_time, size_t hdrlen, /* UTCTime: YYMMDDHHMMSSZ */ if (vlen != 13) goto unsupported_time; - YY = DD2bin(p); - if (YY > 50) - YY += 1900; + tm->tm_year = DD2bin(p); + if (tm->tm_year >= 50) + tm->tm_year += 1900; else - YY += 2000; + tm->tm_year += 2000; } else if (tag == ASN1_GENTIM) { /* GenTime: YYYYMMDDHHMMSSZ */ if (vlen != 15) goto unsupported_time; - YY = DD2bin(p) * 100 + DD2bin(p); + tm->tm_year = DD2bin(p) * 100 + DD2bin(p); } else { goto unsupported_time; } - MM = DD2bin(p); - DD = DD2bin(p); - hh = DD2bin(p); - mm = DD2bin(p); - ss = DD2bin(p); + tm->tm_year -= 1900; + tm->tm_mon = DD2bin(p) - 1; + tm->tm_mday = DD2bin(p); + tm->tm_hour = DD2bin(p); + tm->tm_min = DD2bin(p); + tm->tm_sec = DD2bin(p); if (*p != 'Z') goto unsupported_time; - *_time = mktime(YY, MM, DD, hh, mm, ss); return 0; unsupported_time: diff --git a/crypto/asymmetric_keys/x509_parser.h b/crypto/asymmetric_keys/x509_parser.h index 635053f7..f86dc5fc 100644 --- a/crypto/asymmetric_keys/x509_parser.h +++ b/crypto/asymmetric_keys/x509_parser.h @@ -18,8 +18,8 @@ struct x509_certificate { char *subject; /* Name of certificate subject */ char *fingerprint; /* Key fingerprint as hex */ char *authority; /* Authority key fingerprint as hex */ - time_t valid_from; - time_t valid_to; + struct tm valid_from; + struct tm valid_to; enum pkey_algo pkey_algo : 8; /* Public key algorithm */ enum pkey_algo sig_pkey_algo : 8; /* Signature public key algorithm */ enum pkey_hash_algo sig_hash_algo : 8; /* Signature hash algorithm */ diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c index 716917ce..5ab736db 100644 --- a/crypto/asymmetric_keys/x509_public_key.c +++ b/crypto/asymmetric_keys/x509_public_key.c @@ -106,7 +106,7 @@ error_no_sig: static int x509_key_preparse(struct key_preparsed_payload *prep) { struct x509_certificate *cert; - time_t now; + struct tm now; size_t srlen, sulen; char *desc = NULL; int ret; @@ -118,7 +118,14 @@ static int x509_key_preparse(struct key_preparsed_payload *prep) 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); + printk("Cert Valid From: %04ld-%02d-%02d %02d:%02d:%02d\n", + cert->valid_from.tm_year + 1900, cert->valid_from.tm_mon + 1, + cert->valid_from.tm_mday, cert->valid_from.tm_hour, + cert->valid_from.tm_min, cert->valid_from.tm_sec); + printk("Cert Valid To: %04ld-%02d-%02d %02d:%02d:%02d\n", + cert->valid_to.tm_year + 1900, cert->valid_to.tm_mon + 1, + cert->valid_to.tm_mday, cert->valid_to.tm_hour, + cert->valid_to.tm_min, cert->valid_to.tm_sec); pr_devel("Cert Signature: %s + %s\n", pkey_algo[cert->sig_pkey_algo], pkey_hash_algo[cert->sig_hash_algo]); @@ -130,13 +137,38 @@ static int x509_key_preparse(struct key_preparsed_payload *prep) goto error_free_cert; } - now = CURRENT_TIME.tv_sec; - if (now < cert->valid_from) { + time_to_tm(CURRENT_TIME.tv_sec, 0, &now); + printk("Now: %04ld-%02d-%02d %02d:%02d:%02d\n", + now.tm_year + 1900, now.tm_mon + 1, now.tm_mday, + now.tm_hour, now.tm_min, now.tm_sec); + if (now.tm_year < cert->valid_from.tm_year || + (now.tm_year == cert->valid_from.tm_year && + (now.tm_mon < cert->valid_from.tm_mon || + (now.tm_mon == cert->valid_from.tm_mon && + (now.tm_mday < cert->valid_from.tm_mday || + (now.tm_mday == cert->valid_from.tm_mday && + (now.tm_hour < cert->valid_from.tm_hour || + (now.tm_hour == cert->valid_from.tm_hour && + (now.tm_min < cert->valid_from.tm_min || + (now.tm_min == cert->valid_from.tm_min && + (now.tm_sec < cert->valid_from.tm_sec + ))))))))))) { pr_warn("Cert %s is not yet valid\n", cert->fingerprint); ret = -EKEYREJECTED; goto error_free_cert; } - if (now >= cert->valid_to) { + if (now.tm_year > cert->valid_to.tm_year || + (now.tm_year == cert->valid_to.tm_year && + (now.tm_mon > cert->valid_to.tm_mon || + (now.tm_mon == cert->valid_to.tm_mon && + (now.tm_mday > cert->valid_to.tm_mday || + (now.tm_mday == cert->valid_to.tm_mday && + (now.tm_hour > cert->valid_to.tm_hour || + (now.tm_hour == cert->valid_to.tm_hour && + (now.tm_min > cert->valid_to.tm_min || + (now.tm_min == cert->valid_to.tm_min && + (now.tm_sec > cert->valid_to.tm_sec + ))))))))))) { pr_warn("Cert %s has expired\n", cert->fingerprint); ret = -EKEYEXPIRED; goto error_free_cert; -- cgit v1.2.3 From f1b6883a1e29f85809431bebe43a63f2fd46e7bb Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 4 Oct 2012 14:21:23 +0100 Subject: X.509: Convert some printk calls to pr_devel Some debugging printk() calls should've been converted to pr_devel() calls. Do that now. Signed-off-by: David Howells Signed-off-by: Rusty Russell --- crypto/asymmetric_keys/x509_public_key.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'crypto/asymmetric_keys/x509_public_key.c') diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c index 5ab736db..06007f0e 100644 --- a/crypto/asymmetric_keys/x509_public_key.c +++ b/crypto/asymmetric_keys/x509_public_key.c @@ -118,11 +118,11 @@ static int x509_key_preparse(struct key_preparsed_payload *prep) 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]); - printk("Cert Valid From: %04ld-%02d-%02d %02d:%02d:%02d\n", + pr_devel("Cert Valid From: %04ld-%02d-%02d %02d:%02d:%02d\n", cert->valid_from.tm_year + 1900, cert->valid_from.tm_mon + 1, cert->valid_from.tm_mday, cert->valid_from.tm_hour, cert->valid_from.tm_min, cert->valid_from.tm_sec); - printk("Cert Valid To: %04ld-%02d-%02d %02d:%02d:%02d\n", + pr_devel("Cert Valid To: %04ld-%02d-%02d %02d:%02d:%02d\n", cert->valid_to.tm_year + 1900, cert->valid_to.tm_mon + 1, cert->valid_to.tm_mday, cert->valid_to.tm_hour, cert->valid_to.tm_min, cert->valid_to.tm_sec); @@ -138,7 +138,7 @@ static int x509_key_preparse(struct key_preparsed_payload *prep) } time_to_tm(CURRENT_TIME.tv_sec, 0, &now); - printk("Now: %04ld-%02d-%02d %02d:%02d:%02d\n", + pr_devel("Now: %04ld-%02d-%02d %02d:%02d:%02d\n", now.tm_year + 1900, now.tm_mon + 1, now.tm_mday, now.tm_hour, now.tm_min, now.tm_sec); if (now.tm_year < cert->valid_from.tm_year || -- cgit v1.2.3