Skip to content

Commit

Permalink
X.509: Embed public_key_signature struct and create filler function
Browse files Browse the repository at this point in the history 
Embed a public_key_signature struct in struct x509_certificate, eliminating
now unnecessary fields, and split x509_check_signature() to create a filler
function for it that attaches a digest of the signed data and an MPI that
represents the signature data.  x509_free_certificate() is then modified to
deal with these.

Whilst we're at it, export both x509_check_signature() and the new
x509_get_sig_params().

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Josh Boyer <jwboyer@redhat.com>
  • Loading branch information
David Howells committed Sep 25, 2013
1 parent 57be4a7 commit b426beb
Show file tree
Hide file tree
Showing 3 changed files with 74 additions and 55 deletions.
30 changes: 16 additions & 14 deletions crypto/asymmetric_keys/x509_cert_parser.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -47,6 +47,8 @@ void x509_free_certificate(struct x509_certificate *cert)
kfree(cert->subject);
kfree(cert->fingerprint);
kfree(cert->authority);
kfree(cert->sig.digest);
mpi_free(cert->sig.rsa.s);
kfree(cert);
}
}
Expand Down Expand Up @@ -152,33 +154,33 @@ int x509_note_pkey_algo(void *context, size_t hdrlen,
return -ENOPKG; /* Unsupported combination */

case OID_md4WithRSAEncryption:
ctx->cert->sig_hash_algo = PKEY_HASH_MD5;
ctx->cert->sig_pkey_algo = PKEY_ALGO_RSA;
ctx->cert->sig.pkey_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;
ctx->cert->sig.pkey_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;
ctx->cert->sig.pkey_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;
ctx->cert->sig.pkey_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;
ctx->cert->sig.pkey_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;
ctx->cert->sig.pkey_hash_algo = PKEY_HASH_SHA224;
ctx->cert->sig.pkey_algo = PKEY_ALGO_RSA;
break;
}

Expand All @@ -203,8 +205,8 @@ int x509_note_signature(void *context, size_t hdrlen,
return -EINVAL;
}

ctx->cert->sig = value;
ctx->cert->sig_size = vlen;
ctx->cert->raw_sig = value;
ctx->cert->raw_sig_size = vlen;
return 0;
}

Expand Down
16 changes: 11 additions & 5 deletions crypto/asymmetric_keys/x509_parser.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -21,16 +21,22 @@ struct x509_certificate {
char *authority; /* Authority key fingerprint as hex */
struct tm valid_from;
struct tm valid_to;
enum pkey_algo sig_pkey_algo : 8; /* Signature public key algorithm */
enum pkey_hash_algo sig_hash_algo : 8; /* Signature hash algorithm */
const void *tbs; /* Signed data */
size_t tbs_size; /* Size of signed data */
const void *sig; /* Signature data */
size_t sig_size; /* Size of sigature */
unsigned tbs_size; /* Size of signed data */
unsigned raw_sig_size; /* Size of sigature */
const void *raw_sig; /* Signature data */
struct public_key_signature sig; /* Signature parameters */
};

/*
* 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);

/*
* x509_public_key.c
*/
extern int x509_get_sig_params(struct x509_certificate *cert);
extern int x509_check_signature(const struct public_key *pub,
struct x509_certificate *cert);
83 changes: 47 additions & 36 deletions crypto/asymmetric_keys/x509_public_key.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -24,72 +24,83 @@
#include "x509_parser.h"

/*
* Check the signature on a certificate using the provided public key
* Set up the signature parameters in an X.509 certificate. This involves
* digesting the signed data and extracting the signature.
*/
static int x509_check_signature(const struct public_key *pub,
const struct x509_certificate *cert)
int x509_get_sig_params(struct x509_certificate *cert)
{
struct public_key_signature *sig;
struct crypto_shash *tfm;
struct shash_desc *desc;
size_t digest_size, desc_size;
void *digest;
int ret;

pr_devel("==>%s()\n", __func__);


if (cert->sig.rsa.s)
return 0;

cert->sig.rsa.s = mpi_read_raw_data(cert->raw_sig, cert->raw_sig_size);
if (!cert->sig.rsa.s)
return -ENOMEM;
cert->sig.nr_mpi = 1;

/* 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_name[cert->sig_hash_algo], 0, 0);
tfm = crypto_alloc_shash(pkey_hash_algo_name[cert->sig.pkey_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.
/* We allocate the hash operational data storage on the end of the
* digest storage space.
*/
ret = -ENOMEM;
sig = kzalloc(sizeof(*sig) + desc_size + digest_size, GFP_KERNEL);
if (!sig)
goto error_no_sig;
digest = kzalloc(digest_size + desc_size, GFP_KERNEL);
if (!digest)
goto error;

sig->pkey_hash_algo = cert->sig_hash_algo;
sig->digest = (u8 *)sig + sizeof(*sig) + desc_size;
sig->digest_size = digest_size;
cert->sig.digest = digest;
cert->sig.digest_size = digest_size;

desc = (void *)sig + sizeof(*sig);
desc->tfm = tfm;
desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
desc = digest + digest_size;
desc->tfm = tfm;
desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;

ret = crypto_shash_init(desc);
if (ret < 0)
goto error;
might_sleep();
ret = crypto_shash_finup(desc, cert->tbs, cert->tbs_size, digest);
error:
crypto_free_shash(tfm);
pr_devel("<==%s() = %d\n", __func__, ret);
return ret;
}
EXPORT_SYMBOL_GPL(x509_get_sig_params);

ret = -ENOMEM;
sig->rsa.s = mpi_read_raw_data(cert->sig, cert->sig_size);
if (!sig->rsa.s)
goto error;
/*
* Check the signature on a certificate using the provided public key
*/
int x509_check_signature(const struct public_key *pub,
struct x509_certificate *cert)
{
int ret;

ret = crypto_shash_finup(desc, cert->tbs, cert->tbs_size, sig->digest);
if (ret < 0)
goto error_mpi;
pr_devel("==>%s()\n", __func__);

ret = public_key_verify_signature(pub, sig);
ret = x509_get_sig_params(cert);
if (ret < 0)
return ret;

ret = public_key_verify_signature(pub, &cert->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;
}
EXPORT_SYMBOL_GPL(x509_check_signature);

/*
* Attempt to parse a data blob for a key as an X509 certificate.
Expand Down Expand Up @@ -118,8 +129,8 @@ static int x509_key_preparse(struct key_preparsed_payload *prep)
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_name[cert->sig_pkey_algo],
pkey_hash_algo_name[cert->sig_hash_algo]);
pkey_algo_name[cert->sig.pkey_algo],
pkey_hash_algo_name[cert->sig.pkey_hash_algo]);

if (!cert->fingerprint || !cert->authority) {
pr_warn("Cert for '%s' must have SubjKeyId and AuthKeyId extensions\n",
Expand Down

0 comments on commit b426beb

Please sign in to comment.