Add RSA encryption and decryption support.
This change was already reviewed, merged and reverted, so I'm skipping
the review step this time.
Change-Id: Ie5b7dba86a7ae7f62eedbdb6eec7b61ef83d0c73
diff --git a/rsa_operation.cpp b/rsa_operation.cpp
index a013b78..df39006 100644
--- a/rsa_operation.cpp
+++ b/rsa_operation.cpp
@@ -14,8 +14,11 @@
* limitations under the License.
*/
-#include <openssl/rsa.h>
+#include <limits.h>
+
+#include <openssl/err.h>
#include <openssl/evp.h>
+#include <openssl/rsa.h>
#include "rsa_operation.h"
#include "openssl_utils.h"
@@ -37,6 +40,8 @@
return KM_ERROR_UNIMPLEMENTED;
case KM_PURPOSE_SIGN:
case KM_PURPOSE_VERIFY:
+ case KM_PURPOSE_ENCRYPT:
+ case KM_PURPOSE_DECRYPT:
return StoreData(input);
}
}
@@ -61,13 +66,16 @@
keymaster_error_t RsaVerifyOperation::Finish(const Buffer& signature, Buffer* /* output */) {
#if defined(OPENSSL_IS_BORINGSSL)
- if (data_.available_read() != RSA_size(rsa_key_))
- return KM_ERROR_INVALID_INPUT_LENGTH;
+ size_t message_size = data_.available_read();
#else
- if ((int)data_.available_read() != RSA_size(rsa_key_))
+ if (data_.available_read() > INT_MAX)
return KM_ERROR_INVALID_INPUT_LENGTH;
+ int message_size = (int)data_.available_read();
#endif
+ if (message_size != RSA_size(rsa_key_))
+ return KM_ERROR_INVALID_INPUT_LENGTH;
+
if (data_.available_read() != signature.available_read())
return KM_ERROR_VERIFICATION_FAILED;
@@ -83,4 +91,81 @@
return KM_ERROR_VERIFICATION_FAILED;
}
+const int OAEP_PADDING_OVERHEAD = 41;
+const int PKCS1_PADDING_OVERHEAD = 11;
+
+keymaster_error_t RsaEncryptOperation::Finish(const Buffer& /* signature */, Buffer* output) {
+ int openssl_padding;
+
+#if defined(OPENSSL_IS_BORINGSSL)
+ size_t message_size = data_.available_read();
+#else
+ if (data_.available_read() > INT_MAX)
+ return KM_ERROR_INVALID_INPUT_LENGTH;
+ int message_size = (int)data_.available_read();
+#endif
+
+ switch (padding_) {
+ case KM_PAD_RSA_OAEP:
+ openssl_padding = RSA_PKCS1_OAEP_PADDING;
+ if (message_size >= RSA_size(rsa_key_) - OAEP_PADDING_OVERHEAD) {
+ logger().error("Cannot encrypt %d bytes with %d-byte key and OAEP padding",
+ data_.available_read(), RSA_size(rsa_key_));
+ return KM_ERROR_INVALID_INPUT_LENGTH;
+ }
+ break;
+ case KM_PAD_RSA_PKCS1_1_5_ENCRYPT:
+ openssl_padding = RSA_PKCS1_PADDING;
+ if (message_size >= RSA_size(rsa_key_) - PKCS1_PADDING_OVERHEAD) {
+ logger().error("Cannot encrypt %d bytes with %d-byte key and PKCS1 padding",
+ data_.available_read(), RSA_size(rsa_key_));
+ return KM_ERROR_INVALID_INPUT_LENGTH;
+ }
+ break;
+ default:
+ logger().error("Padding mode %d not supported", padding_);
+ return KM_ERROR_UNSUPPORTED_PADDING_MODE;
+ }
+
+ output->Reinitialize(RSA_size(rsa_key_));
+ int bytes_encrypted = RSA_public_encrypt(data_.available_read(), data_.peek_read(),
+ output->peek_write(), rsa_key_, openssl_padding);
+
+ if (bytes_encrypted < 0) {
+ logger().error("Error %d encrypting data with RSA", ERR_get_error());
+ return KM_ERROR_UNKNOWN_ERROR;
+ }
+ assert(bytes_encrypted == RSA_size(rsa_key_));
+ output->advance_write(bytes_encrypted);
+
+ return KM_ERROR_OK;
+}
+
+keymaster_error_t RsaDecryptOperation::Finish(const Buffer& /* signature */, Buffer* output) {
+ int openssl_padding;
+ switch (padding_) {
+ case KM_PAD_RSA_OAEP:
+ openssl_padding = RSA_PKCS1_OAEP_PADDING;
+ break;
+ case KM_PAD_RSA_PKCS1_1_5_ENCRYPT:
+ openssl_padding = RSA_PKCS1_PADDING;
+ break;
+ default:
+ logger().error("Padding mode %d not supported", padding_);
+ return KM_ERROR_UNSUPPORTED_PADDING_MODE;
+ }
+
+ output->Reinitialize(RSA_size(rsa_key_));
+ int bytes_decrypted = RSA_private_decrypt(data_.available_read(), data_.peek_read(),
+ output->peek_write(), rsa_key_, openssl_padding);
+
+ if (bytes_decrypted < 0) {
+ logger().error("Error %d decrypting data with RSA", ERR_get_error());
+ return KM_ERROR_UNKNOWN_ERROR;
+ }
+ output->advance_write(bytes_decrypted);
+
+ return KM_ERROR_OK;
+}
+
} // namespace keymaster