| Message ID | 146668969255.2977.2158699976750892093.stgit@warthog.procyon.org.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
David, On Thu, 23 Jun 2016, David Howells wrote: > Provide a query function for the software public key implementation. This > permits information about such a key to be obtained using > query_asymmetric_key() or KEYCTL_PKEY_QUERY. > > Signed-off-by: David Howells <dhowells@redhat.com> > --- > > crypto/asymmetric_keys/public_key.c | 96 ++++++++++++++++++++++++++++++----- > 1 file changed, 82 insertions(+), 14 deletions(-) > > diff --git a/crypto/asymmetric_keys/public_key.c b/crypto/asymmetric_keys/public_key.c > index fd76b5fc3b3a..a48a47a1dff0 100644 > --- a/crypto/asymmetric_keys/public_key.c > +++ b/crypto/asymmetric_keys/public_key.c > @@ -57,6 +57,81 @@ static void public_key_destroy(void *payload0, void *payload3) > public_key_signature_free(payload3); > } > > +/* > + * Determine the crypto algorithm name. > + */ > +static > +int software_key_determine_akcipher(const char *encoding, > + const char *hash_algo, > + const struct public_key *pkey, > + char alg_name[CRYPTO_MAX_ALG_NAME]) > +{ > + int n; > + > + if (strcmp(encoding, "pkcs1") == 0) { > + /* The data wangled by the RSA algorithm is typically padded > + * and encoded in some manner, such as EMSA-PKCS1-1_5 [RFC3447 > + * sec 8.2]. > + */ > + if (!hash_algo) > + n = snprintf(alg_name, CRYPTO_MAX_ALG_NAME, > + "pkcs1pad(%s)", > + pkey->pkey_algo); Did you see Herbert's patch that strips out non-hash pkcs1pad capabilities (and the ensuing discussion)? http://www.spinics.net/lists/linux-crypto/index.html#20432 I'm making use of pkcs1pad(rsa) with a TLS implementation, so it's good to see it supported here. > + else > + n = snprintf(alg_name, CRYPTO_MAX_ALG_NAME, > + "pkcs1pad(%s,%s)", > + pkey->pkey_algo, hash_algo); > + return n >= CRYPTO_MAX_ALG_NAME ? -EINVAL : 0; > + } > + > + if (strcmp(encoding, "raw") == 0) { > + strcpy(alg_name, pkey->pkey_algo); > + return 0; > + } > + > + return -ENOPKG; > +} Regards, -- Mat Martineau Intel OTC -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Mat Martineau <mathew.j.martineau@linux.intel.com> wrote: > >> + if (strcmp(encoding, "pkcs1") == 0) { >> + /* The data wangled by the RSA algorithm is typically padded >> + * and encoded in some manner, such as EMSA-PKCS1-1_5 [RFC3447 >> + * sec 8.2]. >> + */ >> + if (!hash_algo) >> + n = snprintf(alg_name, CRYPTO_MAX_ALG_NAME, >> + "pkcs1pad(%s)", >> + pkey->pkey_algo); > > Did you see Herbert's patch that strips out non-hash pkcs1pad capabilities > (and the ensuing discussion)? > > http://www.spinics.net/lists/linux-crypto/index.html#20432 > > I'm making use of pkcs1pad(rsa) with a TLS implementation, so it's good to > see it supported here. Indeed I'm nacking this patch because it's exporting a purely software algorithm to user-space for no good reason. AFAICS there is nothing in the pkcs1pad code that cannot be done in user-space, even assuming that your private key is secret and only accessible from the kernel. IOW exporting the raw RSA might make sense because the key may not be visible to user-space, or that the RSA might be implemented in hardware offload, but there is no sane reason to export pkcs1pad. Cheers,
Herbert Xu <herbert@gondor.apana.org.au> wrote: > IOW exporting the raw RSA might make sense because the key may > not be visible to user-space, or that the RSA might be implemented > in hardware offload, but there is no sane reason to export pkcs1pad. The problem is that if I'm to produce consistency with, say, the TPM interface, then I have to deal in wrapped/padded data - leastways as far as I can tell from reading the docs. David -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, Jun 24, 2016 at 01:06:02PM +0100, David Howells wrote: > > The problem is that if I'm to produce consistency with, say, the TPM > interface, then I have to deal in wrapped/padded data - leastways as far as I > can tell from reading the docs. So the TPM device is accessed through the same interface? Where is the code for it? Thanks,
Herbert Xu <herbert@gondor.apana.org.au> wrote: > > The problem is that if I'm to produce consistency with, say, the TPM > > interface, then I have to deal in wrapped/padded data - leastways as far > > as I can tell from reading the docs. > > So the TPM device is accessed through the same interface? Where is > the code for it? I have some patches I need to finish revamping. I had it kind of working (though with a slightly different user interface) - then TPMv2 support was added to the TPM driver before I finished and I need to redo the patches. David -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Jun 27, 2016 at 03:27:13PM +0100, David Howells wrote: > > I have some patches I need to finish revamping. I had it kind of working > (though with a slightly different user interface) - then TPMv2 support was > added to the TPM driver before I finished and I need to redo the patches. In that case can we wait until this is ready before pushing the user-space interface? Once you add a user-space interface it's very difficult to change it again so we should be absolutely sure what it's supposed to look like before we add a new interace. Thanks,
diff --git a/crypto/asymmetric_keys/public_key.c b/crypto/asymmetric_keys/public_key.c index fd76b5fc3b3a..a48a47a1dff0 100644 --- a/crypto/asymmetric_keys/public_key.c +++ b/crypto/asymmetric_keys/public_key.c @@ -57,6 +57,81 @@ static void public_key_destroy(void *payload0, void *payload3) public_key_signature_free(payload3); } +/* + * Determine the crypto algorithm name. + */ +static +int software_key_determine_akcipher(const char *encoding, + const char *hash_algo, + const struct public_key *pkey, + char alg_name[CRYPTO_MAX_ALG_NAME]) +{ + int n; + + if (strcmp(encoding, "pkcs1") == 0) { + /* The data wangled by the RSA algorithm is typically padded + * and encoded in some manner, such as EMSA-PKCS1-1_5 [RFC3447 + * sec 8.2]. + */ + if (!hash_algo) + n = snprintf(alg_name, CRYPTO_MAX_ALG_NAME, + "pkcs1pad(%s)", + pkey->pkey_algo); + else + n = snprintf(alg_name, CRYPTO_MAX_ALG_NAME, + "pkcs1pad(%s,%s)", + pkey->pkey_algo, hash_algo); + return n >= CRYPTO_MAX_ALG_NAME ? -EINVAL : 0; + } + + if (strcmp(encoding, "raw") == 0) { + strcpy(alg_name, pkey->pkey_algo); + return 0; + } + + return -ENOPKG; +} + +/* + * Query information about a key. + */ +static int software_key_query(const struct kernel_pkey_params *params, + struct kernel_pkey_query *info) +{ + struct crypto_akcipher *tfm; + struct public_key *pkey = params->key->payload.data[asym_crypto]; + char alg_name[CRYPTO_MAX_ALG_NAME]; + int ret, len; + + ret = software_key_determine_akcipher(params->encoding, + params->hash_algo, + pkey, alg_name); + if (ret < 0) + return ret; + + tfm = crypto_alloc_akcipher(alg_name, 0, 0); + if (IS_ERR(tfm)) + return PTR_ERR(tfm); + + ret = crypto_akcipher_set_pub_key(tfm, pkey->key, pkey->keylen); + if (ret < 0) + goto error_free_tfm; + + len = crypto_akcipher_maxsize(tfm); + info->key_size = len * 8; + info->max_data_size = len; + info->max_sig_size = len; + info->max_enc_size = len; + info->max_dec_size = len; + info->supported_ops = KEYCTL_SUPPORTS_VERIFY; + ret = 0; + +error_free_tfm: + crypto_free_akcipher(tfm); + pr_devel("<==%s() = %d\n", __func__, ret); + return ret; +} + struct public_key_completion { struct completion completion; int err; @@ -83,8 +158,7 @@ int public_key_verify_signature(const struct public_key *pkey, struct crypto_akcipher *tfm; struct akcipher_request *req; struct scatterlist sig_sg, digest_sg; - const char *alg_name; - char alg_name_buf[CRYPTO_MAX_ALG_NAME]; + char alg_name[CRYPTO_MAX_ALG_NAME]; void *output; unsigned int outlen; int ret = -ENOMEM; @@ -96,18 +170,11 @@ int public_key_verify_signature(const struct public_key *pkey, BUG_ON(!sig->digest); BUG_ON(!sig->s); - alg_name = sig->pkey_algo; - if (strcmp(sig->pkey_algo, "rsa") == 0) { - /* The data wangled by the RSA algorithm is typically padded - * and encoded in some manner, such as EMSA-PKCS1-1_5 [RFC3447 - * sec 8.2]. - */ - if (snprintf(alg_name_buf, CRYPTO_MAX_ALG_NAME, - "pkcs1pad(rsa,%s)", sig->hash_algo - ) >= CRYPTO_MAX_ALG_NAME) - return -EINVAL; - alg_name = alg_name_buf; - } + ret = software_key_determine_akcipher(sig->encoding, + sig->hash_algo, + pkey, alg_name); + if (ret < 0) + return ret; tfm = crypto_alloc_akcipher(alg_name, 0, 0); if (IS_ERR(tfm)) @@ -179,6 +246,7 @@ struct asymmetric_key_subtype public_key_subtype = { .name_len = sizeof("public_key") - 1, .describe = public_key_describe, .destroy = public_key_destroy, + .query = software_key_query, .verify_signature = public_key_verify_signature_2, }; EXPORT_SYMBOL_GPL(public_key_subtype);
Provide a query function for the software public key implementation. This permits information about such a key to be obtained using query_asymmetric_key() or KEYCTL_PKEY_QUERY. Signed-off-by: David Howells <dhowells@redhat.com> --- crypto/asymmetric_keys/public_key.c | 96 ++++++++++++++++++++++++++++++----- 1 file changed, 82 insertions(+), 14 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html