On Thu, Mar 04, 2021 at 07:51:59PM -0500, Stefan Berger wrote:
> From: Stefan Berger <stefanb@xxxxxxxxxxxxx>
>
> Detect whether a key is an sm2 type of key by its OID in the parameters
> array rather than assuming that everything under OID_id_ecPublicKey
> is sm2, which is not the case.
>
> Cc: David Howells <dhowells@xxxxxxxxxx>
> Cc: keyrings@xxxxxxxxxxxxxxx
> Signed-off-by: Stefan Berger <stefanb@xxxxxxxxxxxxx>
> Reviewed-by: Tianjia Zhang <tianjia.zhang@xxxxxxxxxxxxxxxxx>
> ---
> crypto/asymmetric_keys/x509_cert_parser.c | 12 +++++++++++-
> include/linux/oid_registry.h | 1 +
> lib/oid_registry.c | 13 +++++++++++++
> 3 files changed, 25 insertions(+), 1 deletion(-)
>
> diff --git a/crypto/asymmetric_keys/x509_cert_parser.c b/crypto/asymmetric_keys/x509_cert_parser.c
> index 52c9b455fc7d..1621ceaf5c95 100644
> --- a/crypto/asymmetric_keys/x509_cert_parser.c
> +++ b/crypto/asymmetric_keys/x509_cert_parser.c
> @@ -459,6 +459,7 @@ int x509_extract_key_data(void *context, size_t hdrlen,
> const void *value, size_t vlen)
> {
> struct x509_parse_context *ctx = context;
> + enum OID oid;
enum is not a real type, and it is hard to recall how much it allocates
from stack. I would replace this with plain int.
>
> ctx->key_algo = ctx->last_oid;
> switch (ctx->last_oid) {
> @@ -470,7 +471,16 @@ int x509_extract_key_data(void *context, size_t hdrlen,
> ctx->cert->pub->pkey_algo = "ecrdsa";
> break;
> case OID_id_ecPublicKey:
> - ctx->cert->pub->pkey_algo = "sm2";
> + if (parse_OID(ctx->params, ctx->params_size, &oid) != 0)
> + return -EBADMSG;
> +
> + switch (oid) {
> + case OID_sm2:
> + ctx->cert->pub->pkey_algo = "sm2";
> + break;
> + default:
> + return -ENOPKG;
> + }
> break;
> default:
> return -ENOPKG;
> diff --git a/include/linux/oid_registry.h b/include/linux/oid_registry.h
> index b504e2f36b25..f32d91895e4d 100644
> --- a/include/linux/oid_registry.h
> +++ b/include/linux/oid_registry.h
> @@ -121,6 +121,7 @@ enum OID {
> };
>
> extern enum OID look_up_OID(const void *data, size_t datasize);
> +extern int parse_OID(const void *data, size_t datasize, enum OID *oid);
> extern int sprint_oid(const void *, size_t, char *, size_t);
> extern int sprint_OID(enum OID, char *, size_t);
>
> diff --git a/lib/oid_registry.c b/lib/oid_registry.c
> index f7ad43f28579..508e0b34b5f0 100644
> --- a/lib/oid_registry.c
> +++ b/lib/oid_registry.c
> @@ -11,6 +11,7 @@
> #include <linux/kernel.h>
> #include <linux/errno.h>
> #include <linux/bug.h>
> +#include <linux/asn1.h>
> #include "oid_registry_data.c"
>
> MODULE_DESCRIPTION("OID Registry");
> @@ -92,6 +93,18 @@ enum OID look_up_OID(const void *data, size_t datasize)
> }
> EXPORT_SYMBOL_GPL(look_up_OID);
>
> +int parse_OID(const void *data, size_t datasize, enum OID *oid)
An exported function without kdoc.
> +{
> + const unsigned char *v = data;
> +
> + if (datasize < 2 || v[0] != ASN1_OID || v[1] != datasize - 2)
> + return -EBADMSG;
'1' and '2' are magic numbers unless you either have constants defining
them, or at least an inline comment with explanation.
> +
> + *oid = look_up_OID(data + 2, datasize - 2);
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(parse_OID);
> +
> /*
> * sprint_OID - Print an Object Identifier into a buffer
> * @data: The encoded OID to print
> --
> 2.29.2
>
>
/Jarkko
