[PATCH v11 02/13] PKCS#7: Refactor verify_pkcs7_signature()

[Thiago Jung Bauermann]

Hello David,

AFAIK Mimi is happy with this patch set, but I still need acks from
maintainers of other subsystems that my changes touch before she can
accept it.

Are this patch and the next one ("PKCS#7: Introduce pkcs7_get_digest()")
OK from your PoV?

--
Thiago Jung Bauermann
IBM Linux Technology Center


Thiago Jung Bauermann <bauerman at linux.ibm.com> writes:

> IMA will need to verify a PKCS#7 signature which has already been parsed.
> For this reason, factor out the code which does that from
> verify_pkcs7_signature() into a new function which takes a struct
> pkcs7_message instead of a data buffer.
>
> Signed-off-by: Thiago Jung Bauermann <bauerman at linux.ibm.com>
> Reviewed-by: Mimi Zohar <zohar at linux.ibm.com>
> Cc: David Howells <dhowells at redhat.com>
> Cc: David Woodhouse <dwmw2 at infradead.org>
> Cc: Herbert Xu <herbert at gondor.apana.org.au>
> Cc: "David S. Miller" <davem at davemloft.net>
> ---
>  certs/system_keyring.c       | 61 ++++++++++++++++++++++++++----------
>  include/linux/verification.h | 10 ++++++
>  2 files changed, 55 insertions(+), 16 deletions(-)
>
> diff --git a/certs/system_keyring.c b/certs/system_keyring.c
> index c05c29ae4d5d..4ba82e52e4b4 100644
> --- a/certs/system_keyring.c
> +++ b/certs/system_keyring.c
> @@ -194,33 +194,27 @@ late_initcall(load_system_certificate_list);
>  #ifdef CONFIG_SYSTEM_DATA_VERIFICATION
>
>  /**
> - * verify_pkcs7_signature - Verify a PKCS#7-based signature on system data.
> + * verify_pkcs7_message_sig - Verify a PKCS#7-based signature on system data.
>   * @data: The data to be verified (NULL if expecting internal data).
>   * @len: Size of @data.
> - * @raw_pkcs7: The PKCS#7 message that is the signature.
> - * @pkcs7_len: The size of @raw_pkcs7.
> + * @pkcs7: The PKCS#7 message that is the signature.
>   * @trusted_keys: Trusted keys to use (NULL for builtin trusted keys only,
>   *					(void *)1UL for all trusted keys).
>   * @usage: The use to which the key is being put.
>   * @view_content: Callback to gain access to content.
>   * @ctx: Context for callback.
>   */
> -int verify_pkcs7_signature(const void *data, size_t len,
> -			   const void *raw_pkcs7, size_t pkcs7_len,
> -			   struct key *trusted_keys,
> -			   enum key_being_used_for usage,
> -			   int (*view_content)(void *ctx,
> -					       const void *data, size_t len,
> -					       size_t asn1hdrlen),
> -			   void *ctx)
> +int verify_pkcs7_message_sig(const void *data, size_t len,
> +			     struct pkcs7_message *pkcs7,
> +			     struct key *trusted_keys,
> +			     enum key_being_used_for usage,
> +			     int (*view_content)(void *ctx,
> +						 const void *data, size_t len,
> +						 size_t asn1hdrlen),
> +			     void *ctx)
>  {
> -	struct pkcs7_message *pkcs7;
>  	int ret;
>
> -	pkcs7 = pkcs7_parse_message(raw_pkcs7, pkcs7_len);
> -	if (IS_ERR(pkcs7))
> -		return PTR_ERR(pkcs7);
> -
>  	/* The data should be detached - so we need to supply it. */
>  	if (data && pkcs7_supply_detached_data(pkcs7, data, len) < 0) {
>  		pr_err("PKCS#7 signature with non-detached data\n");
> @@ -273,6 +267,41 @@ int verify_pkcs7_signature(const void *data, size_t len,
>  	}
>
>  error:
> +	pr_devel("<==%s() = %d\n", __func__, ret);
> +	return ret;
> +}
> +
> +/**
> + * verify_pkcs7_signature - Verify a PKCS#7-based signature on system data.
> + * @data: The data to be verified (NULL if expecting internal data).
> + * @len: Size of @data.
> + * @raw_pkcs7: The PKCS#7 message that is the signature.
> + * @pkcs7_len: The size of @raw_pkcs7.
> + * @trusted_keys: Trusted keys to use (NULL for builtin trusted keys only,
> + *					(void *)1UL for all trusted keys).
> + * @usage: The use to which the key is being put.
> + * @view_content: Callback to gain access to content.
> + * @ctx: Context for callback.
> + */
> +int verify_pkcs7_signature(const void *data, size_t len,
> +			   const void *raw_pkcs7, size_t pkcs7_len,
> +			   struct key *trusted_keys,
> +			   enum key_being_used_for usage,
> +			   int (*view_content)(void *ctx,
> +					       const void *data, size_t len,
> +					       size_t asn1hdrlen),
> +			   void *ctx)
> +{
> +	struct pkcs7_message *pkcs7;
> +	int ret;
> +
> +	pkcs7 = pkcs7_parse_message(raw_pkcs7, pkcs7_len);
> +	if (IS_ERR(pkcs7))
> +		return PTR_ERR(pkcs7);
> +
> +	ret = verify_pkcs7_message_sig(data, len, pkcs7, trusted_keys, usage,
> +				       view_content, ctx);
> +
>  	pkcs7_free_message(pkcs7);
>  	pr_devel("<==%s() = %d\n", __func__, ret);
>  	return ret;
> diff --git a/include/linux/verification.h b/include/linux/verification.h
> index 018fb5f13d44..5e1d41f2b336 100644
> --- a/include/linux/verification.h
> +++ b/include/linux/verification.h
> @@ -36,6 +36,7 @@ extern const char *const key_being_used_for[NR__KEY_BEING_USED_FOR];
>  #ifdef CONFIG_SYSTEM_DATA_VERIFICATION
>
>  struct key;
> +struct pkcs7_message;
>
>  extern int verify_pkcs7_signature(const void *data, size_t len,
>  				  const void *raw_pkcs7, size_t pkcs7_len,
> @@ -45,6 +46,15 @@ extern int verify_pkcs7_signature(const void *data, size_t len,
>  						      const void *data, size_t len,
>  						      size_t asn1hdrlen),
>  				  void *ctx);
> +extern int verify_pkcs7_message_sig(const void *data, size_t len,
> +				    struct pkcs7_message *pkcs7,
> +				    struct key *trusted_keys,
> +				    enum key_being_used_for usage,
> +				    int (*view_content)(void *ctx,
> +							const void *data,
> +							size_t len,
> +							size_t asn1hdrlen),
> +				    void *ctx);
>
>  #ifdef CONFIG_SIGNED_PE_FILE_VERIFICATION
>  extern int verify_pefile_signature(const void *pebuf, unsigned pelen,