Re: [PATCH v5 13/18] PKCS#7: Introduce pkcs7_get_message_sig and verify_pkcs7_message_sig

[Mimi Zohar]

On Tue, 2017-10-17 at 22:53 -0200, Thiago Jung Bauermann wrote:
> IMA will need to access the digest used in the signature so that it can
> verify files containing module-style appended signatures. For this purpose,
> add function pkcs7_get_message_sig.
> 
> It will also need to verify an already parsed PKCS#7 message. For this
> purpose, add function verify_pkcs7_message_signature which takes a struct
> pkcs7_message for verification instead of the raw bytes that
> verify_pkcs7_signature takes.
> 
> Signed-off-by: Thiago Jung Bauermann 

Reviewed-by: Mimi Zohar 

> ---
>  certs/system_keyring.c| 60 
> +--
>  crypto/asymmetric_keys/pkcs7_parser.c | 12 +++
>  include/crypto/pkcs7.h|  2 ++
>  include/linux/verification.h  | 10 ++
>  4 files changed, 68 insertions(+), 16 deletions(-)
> 
> diff --git a/certs/system_keyring.c b/certs/system_keyring.c
> index 6251d1b27f0c..6a8684959780 100644
> --- a/certs/system_keyring.c
> +++ b/certs/system_keyring.c
> @@ -190,33 +190,26 @@ 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");
> @@ -258,6 +251,41 @@ 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/crypto/asymmetric_keys/pkcs7_parser.c 

[PATCH v5 13/18] PKCS#7: Introduce pkcs7_get_message_sig and verify_pkcs7_message_sig

[Thiago Jung Bauermann]

IMA will need to access the digest used in the signature so that it can
verify files containing module-style appended signatures. For this purpose,
add function pkcs7_get_message_sig.

It will also need to verify an already parsed PKCS#7 message. For this
purpose, add function verify_pkcs7_message_signature which takes a struct
pkcs7_message for verification instead of the raw bytes that
verify_pkcs7_signature takes.

Signed-off-by: Thiago Jung Bauermann 
---
 certs/system_keyring.c| 60 +--
 crypto/asymmetric_keys/pkcs7_parser.c | 12 +++
 include/crypto/pkcs7.h|  2 ++
 include/linux/verification.h  | 10 ++
 4 files changed, 68 insertions(+), 16 deletions(-)

diff --git a/certs/system_keyring.c b/certs/system_keyring.c
index 6251d1b27f0c..6a8684959780 100644
--- a/certs/system_keyring.c
+++ b/certs/system_keyring.c
@@ -190,33 +190,26 @@ 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");
@@ -258,6 +251,41 @@ 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/crypto/asymmetric_keys/pkcs7_parser.c 
b/crypto/asymmetric_keys/pkcs7_parser.c
index af4cd8649117..e41beda297a8 100644
--- a/crypto/asymmetric_keys/pkcs7_parser.c
+++ b/crypto/asymmetric_keys/pkcs7_parser.c
@@ -673,3 +673,15 @@ int pkcs7_note_signed_info(void *context, size_t