linux/crypto/asymmetric_keys/x509_cert_parser.c
Dmitry Kasatkin 8dd609805b KEYS: use swapped SKID for performing partial matching
Earlier KEYS code used pure subject key identifiers (fingerprint)
for searching keys. Latest merged code removed that and broke
compatibility with integrity subsytem signatures and original
format of module signatures.

This patch returns back partial matching on SKID.

Reported-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: David Howells <dhowells@redhat.com>
2014-10-06 16:56:08 +01:00

572 lines
14 KiB
C

/* 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/export.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->id);
kfree(cert->skid);
kfree(cert->authority);
kfree(cert->sig.digest);
mpi_free(cert->sig.rsa.s);
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;
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;
/* 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;
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.pkey_hash_algo = HASH_ALGO_MD5;
ctx->cert->sig.pkey_algo = PKEY_ALGO_RSA;
break;
case OID_sha1WithRSAEncryption:
ctx->cert->sig.pkey_hash_algo = HASH_ALGO_SHA1;
ctx->cert->sig.pkey_algo = PKEY_ALGO_RSA;
break;
case OID_sha256WithRSAEncryption:
ctx->cert->sig.pkey_hash_algo = HASH_ALGO_SHA256;
ctx->cert->sig.pkey_algo = PKEY_ALGO_RSA;
break;
case OID_sha384WithRSAEncryption:
ctx->cert->sig.pkey_hash_algo = HASH_ALGO_SHA384;
ctx->cert->sig.pkey_algo = PKEY_ALGO_RSA;
break;
case OID_sha512WithRSAEncryption:
ctx->cert->sig.pkey_hash_algo = HASH_ALGO_SHA512;
ctx->cert->sig.pkey_algo = PKEY_ALGO_RSA;
break;
case OID_sha224WithRSAEncryption:
ctx->cert->sig.pkey_hash_algo = HASH_ALGO_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->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 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;
ctx->cert->pub->pkey_algo = PKEY_ALGO_RSA;
/* Discard the BIT STRING metadata */
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;
}
/* 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;
int i;
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(ctx->cert->raw_subject,
ctx->cert->raw_subject_size,
v, vlen);
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 */
if (ctx->cert->authority || vlen < 5)
return -EBADMSG;
/* Authority Key Identifier must be a Constructed SEQUENCE */
if (v[0] != (ASN1_SEQ | (ASN1_CONS << 5)))
return -EBADMSG;
/* Authority Key Identifier is not indefinite length */
if (unlikely(vlen == ASN1_INDEFINITE_LENGTH))
return -EBADMSG;
if (vlen < ASN1_INDEFINITE_LENGTH) {
/* Short Form length */
if (v[1] != vlen - 2 ||
v[2] != SEQ_TAG_KEYID ||
v[3] > vlen - 4)
return -EBADMSG;
vlen = v[3];
v += 4;
} else {
/* Long Form length */
size_t seq_len = 0;
size_t sub = v[1] - ASN1_INDEFINITE_LENGTH;
if (sub > 2)
return -EBADMSG;
/* calculate the length from subsequent octets */
v += 2;
for (i = 0; i < sub; i++) {
seq_len <<= 8;
seq_len |= v[i];
}
if (seq_len != vlen - 2 - sub ||
v[sub] != SEQ_TAG_KEYID ||
v[sub + 1] > vlen - 4 - sub)
return -EBADMSG;
vlen = v[sub + 1];
v += (sub + 2);
}
kid = asymmetric_key_generate_id(ctx->cert->raw_issuer,
ctx->cert->raw_issuer_size,
v, vlen);
if (IS_ERR(kid))
return PTR_ERR(kid);
pr_debug("authkeyid %*phN\n", kid->len, kid->data);
ctx->cert->authority = kid;
return 0;
}
return 0;
}
/*
* Record a certificate time.
*/
static int x509_note_time(struct tm *tm, size_t hdrlen,
unsigned char tag,
const unsigned char *value, size_t vlen)
{
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;
tm->tm_year = DD2bin(p);
if (tm->tm_year >= 50)
tm->tm_year += 1900;
else
tm->tm_year += 2000;
} else if (tag == ASN1_GENTIM) {
/* GenTime: YYYYMMDDHHMMSSZ */
if (vlen != 15)
goto unsupported_time;
tm->tm_year = DD2bin(p) * 100 + DD2bin(p);
} else {
goto unsupported_time;
}
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;
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);
}