Messages in this thread Patch in this message | | | Subject | [PATCH 11/13] PKCS#7: Allow detached data to be supplied for signature checking purposes | From | David Howells <> | Date | Mon, 08 Sep 2014 16:39:02 +0100 |
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It is possible for a PKCS#7 message to have detached data. However, to verify the signatures on a PKCS#7 message, we have to be able to digest the data. Provide a function to supply that data. An error is given if the PKCS#7 message included embedded data.
Signed-off-by: David Howells <dhowells@redhat.com> ---
crypto/asymmetric_keys/pkcs7_verify.c | 26 ++++++++++++++++++++++++++ include/crypto/pkcs7.h | 3 +++ 2 files changed, 29 insertions(+)
diff --git a/crypto/asymmetric_keys/pkcs7_verify.c b/crypto/asymmetric_keys/pkcs7_verify.c index b3059f2ad0f7..f7897272a5b2 100644 --- a/crypto/asymmetric_keys/pkcs7_verify.c +++ b/crypto/asymmetric_keys/pkcs7_verify.c @@ -362,3 +362,29 @@ int pkcs7_verify(struct pkcs7_message *pkcs7) return enopkg; } EXPORT_SYMBOL_GPL(pkcs7_verify); + +/** + * pkcs7_supply_detached_data - Supply the data needed to verify a PKCS#7 message + * @pkcs7: The PKCS#7 message + * @data: The data to be verified + * @datalen: The amount of data + * + * Supply the detached data needed to verify a PKCS#7 message. Note that no + * attempt to retain/pin the data is made. That is left to the caller. The + * data will not be modified by pkcs7_verify() and will not be freed when the + * PKCS#7 message is freed. + * + * Returns -EINVAL if data is already supplied in the message, 0 otherwise. + */ +int pkcs7_supply_detached_data(struct pkcs7_message *pkcs7, + const void *data, size_t datalen) +{ + if (pkcs7->data) { + pr_debug("Data already supplied\n"); + return -EINVAL; + } + pkcs7->data = data; + pkcs7->data_len = datalen; + return 0; +} +EXPORT_SYMBOL_GPL(pkcs7_supply_detached_data); diff --git a/include/crypto/pkcs7.h b/include/crypto/pkcs7.h index 691c79172a26..e235ab4957ee 100644 --- a/include/crypto/pkcs7.h +++ b/include/crypto/pkcs7.h @@ -34,3 +34,6 @@ extern int pkcs7_validate_trust(struct pkcs7_message *pkcs7, * pkcs7_verify.c */ extern int pkcs7_verify(struct pkcs7_message *pkcs7); + +extern int pkcs7_supply_detached_data(struct pkcs7_message *pkcs7, + const void *data, size_t datalen);
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