[PATCH v8 02/14] PKCS#7: Refactor verify_pkcs7_signature() and add pkcs7_get_message_sig()
Thiago Jung Bauermann
bauerman at linux.ibm.com
Fri Nov 16 20:07:00 UTC 2018
IMA will need to verify a PKCS#7 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.
In addition, IMA will need to know the key that signed a given PKCS#7
message, so add pkcs7_get_message_sig().
Signed-off-by: Thiago Jung Bauermann <bauerman at linux.ibm.com>
Reviewed-by: Mimi Zohar <zohar at linux.vnet.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 ++++++++++++++++++++-------
crypto/asymmetric_keys/pkcs7_parser.c | 16 +++++++
include/crypto/pkcs7.h | 2 +
include/linux/verification.h | 10 +++++
4 files changed, 73 insertions(+), 16 deletions(-)
diff --git a/certs/system_keyring.c b/certs/system_keyring.c
index 81728717523d..dd8c5ef941ce 100644
--- a/certs/system_keyring.c
+++ b/certs/system_keyring.c
@@ -191,33 +191,27 @@ 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");
@@ -259,6 +253,41 @@ 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 f0d56e1a8b7e..8df9693f659f 100644
--- a/crypto/asymmetric_keys/pkcs7_parser.c
+++ b/crypto/asymmetric_keys/pkcs7_parser.c
@@ -684,3 +684,19 @@ int pkcs7_note_signed_info(void *context, size_t hdrlen,
return -ENOMEM;
return 0;
}
+
+/**
+ * pkcs7_get_message_sig - get signature in @pkcs7
+ */
+const struct public_key_signature *pkcs7_get_message_sig(
+ const struct pkcs7_message *pkcs7)
+{
+ /*
+ * This function doesn't support messages with more than one signature,
+ * so don't return anything in that case.
+ */
+ if (pkcs7->signed_infos == NULL || pkcs7->signed_infos->next != NULL)
+ return NULL;
+
+ return pkcs7->signed_infos->sig;
+}
diff --git a/include/crypto/pkcs7.h b/include/crypto/pkcs7.h
index 583f199400a3..6f51d0cb6d12 100644
--- a/include/crypto/pkcs7.h
+++ b/include/crypto/pkcs7.h
@@ -28,6 +28,8 @@ extern void pkcs7_free_message(struct pkcs7_message *pkcs7);
extern int pkcs7_get_content_data(const struct pkcs7_message *pkcs7,
const void **_data, size_t *_datalen,
size_t *_headerlen);
+extern const struct public_key_signature *pkcs7_get_message_sig(
+ const struct pkcs7_message *pkcs7);
/*
* pkcs7_trust.c
diff --git a/include/linux/verification.h b/include/linux/verification.h
index cfa4730d607a..7b09a55674a7 100644
--- a/include/linux/verification.h
+++ b/include/linux/verification.h
@@ -35,6 +35,7 @@ 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,
@@ -44,6 +45,15 @@ 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,
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