Diff: sastoken.c

Revision:

0:fa2de1b79154

Child:

1:9190c0f4d23a

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/sastoken.c	Fri Apr 08 12:01:36 2016 -0700
@@ -0,0 +1,126 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+#include <stdlib.h>
+#ifdef _CRTDBG_MAP_ALLOC
+#include <crtdbg.h>
+#endif
+#include "azure_c_shared_utility/gballoc.h"
+
+#include <time.h>
+#include <stddef.h>
+
+#include "azure_c_shared_utility/crt_abstractions.h"
+#include "azure_c_shared_utility/sastoken.h"
+#include "azure_c_shared_utility/urlencode.h"
+#include "azure_c_shared_utility/hmacsha256.h"
+#include "azure_c_shared_utility/base64.h"
+#include "azure_c_shared_utility/agenttime.h"
+#include "azure_c_shared_utility/strings.h"
+#include "azure_c_shared_utility/buffer_.h"
+#include "azure_c_shared_utility/iot_logging.h"
+
+STRING_HANDLE SASToken_Create(STRING_HANDLE key, STRING_HANDLE scope, STRING_HANDLE keyName, size_t expiry)
+{
+    STRING_HANDLE result = NULL;
+    char tokenExpirationTime[32] = { 0 };
+
+    /*Codes_SRS_SASTOKEN_06_001: [If key is NULL then SASToken_Create shall return NULL.]*/
+    /*Codes_SRS_SASTOKEN_06_003: [If scope is NULL then SASToken_Create shall return NULL.]*/
+    /*Codes_SRS_SASTOKEN_06_007: [If keyName is NULL then SASToken_Create shall return NULL.]*/
+    if ((key == NULL) ||
+        (scope == NULL) ||
+        (keyName == NULL))
+    {
+        LogError("Invalid Parameter to SASToken_Create. handle key: %p, handle scope: %p, handle keyName: %p\r\n", key, scope, keyName);
+    }
+    else
+    {
+        BUFFER_HANDLE decodedKey;
+        /*Codes_SRS_SASTOKEN_06_029: [The key parameter is decoded from base64.]*/
+        if ((decodedKey = Base64_Decoder(STRING_c_str(key))) == NULL)
+        {
+            /*Codes_SRS_SASTOKEN_06_030: [If there is an error in the decoding then SASToken_Create shall return NULL.]*/
+            LogError("Unable to decode the key for generating the SAS.\r\n");
+        }
+        else
+        {
+            /*Codes_SRS_SASTOKEN_06_026: [If the conversion to string form fails for any reason then SASToken_Create shall return NULL.]*/
+            if (size_tToString(tokenExpirationTime, sizeof(tokenExpirationTime), expiry) != 0)
+            {
+                LogError("For some reason converting seconds to a string failed.  No SAS can be generated.\r\n");
+            }
+            else
+            {
+                STRING_HANDLE toBeHashed = NULL;
+                BUFFER_HANDLE hash = NULL;
+                if (((hash = BUFFER_new()) == NULL) ||
+                    ((toBeHashed = STRING_new()) == NULL) ||
+                    ((result = STRING_new()) == NULL))
+                {
+                    LogError("Unable to allocate memory to prepare SAS token.\r\n");
+                }
+                else
+                {
+                    /*Codes_SRS_SASTOKEN_06_009: [The scope is the basis for creating a STRING_HANDLE.]*/
+                    /*Codes_SRS_SASTOKEN_06_010: [A "\n" is appended to that string.]*/
+                    /*Codes_SRS_SASTOKEN_06_011: [tokenExpirationTime is appended to that string.]*/
+                    if ((STRING_concat_with_STRING(toBeHashed, scope) != 0) ||
+                        (STRING_concat(toBeHashed, "\n") != 0) ||
+                        (STRING_concat(toBeHashed, tokenExpirationTime) != 0))
+                    {
+                        LogError("Unable to build the input to the HMAC to prepare SAS token.\r\n");
+                        STRING_delete(result);
+                        result = NULL;
+                    }
+                    else
+                    {
+                        STRING_HANDLE base64Signature = NULL;
+                        STRING_HANDLE urlEncodedSignature = NULL;
+                        /*Codes_SRS_SASTOKEN_06_013: [If an error is returned from the HMAC256 function then NULL is returned from SASToken_Create.]*/
+                        /*Codes_SRS_SASTOKEN_06_012: [An HMAC256 hash is calculated using the decodedKey, over toBeHashed.]*/
+                        /*Codes_SRS_SASTOKEN_06_014: [If there are any errors from the following operations then NULL shall be returned.]*/
+                        /*Codes_SRS_SASTOKEN_06_015: [The hash is base 64 encoded.]*/
+                        /*Codes_SRS_SASTOKEN_06_028: [base64Signature shall be url encoded.]*/
+                        /*Codes_SRS_SASTOKEN_06_016: [The string "SharedAccessSignature sr=" is the first part of the result of SASToken_Create.]*/
+                        /*Codes_SRS_SASTOKEN_06_017: [The scope parameter is appended to result.]*/
+                        /*Codes_SRS_SASTOKEN_06_018: [The string "&sig=" is appended to result.]*/
+                        /*Codes_SRS_SASTOKEN_06_019: [The string urlEncodedSignature shall be appended to result.]*/
+                        /*Codes_SRS_SASTOKEN_06_020: [The string "&se=" shall be appended to result.]*/
+                        /*Codes_SRS_SASTOKEN_06_021: [tokenExpirationTime is appended to result.]*/
+                        /*Codes_SRS_SASTOKEN_06_022: [The string "&skn=" is appended to result.]*/
+                        /*Codes_SRS_SASTOKEN_06_023: [The argument keyName is appended to result.]*/
+                        if ((HMACSHA256_ComputeHash(BUFFER_u_char(decodedKey), BUFFER_length(decodedKey), (const unsigned char*)STRING_c_str(toBeHashed), STRING_length(toBeHashed), hash) != HMACSHA256_OK) ||
+                            ((base64Signature = Base64_Encode(hash)) == NULL) ||
+                            ((urlEncodedSignature = URL_Encode(base64Signature)) == NULL) ||
+                            (STRING_copy(result, "SharedAccessSignature sr=") != 0) ||
+                            (STRING_concat_with_STRING(result, scope) != 0) ||
+                            (STRING_concat(result, "&sig=") != 0) ||
+                            (STRING_concat_with_STRING(result, urlEncodedSignature) != 0) ||
+                            (STRING_concat(result, "&se=") != 0) ||
+                            (STRING_concat(result, tokenExpirationTime) != 0) ||
+                            (STRING_concat(result, "&skn=") != 0) ||
+                            (STRING_concat_with_STRING(result, keyName) != 0))
+                        {
+                            LogError("Unable to build the SAS token.\r\n");
+                            STRING_delete(result);
+                            result = NULL;
+                        }
+                        else
+                        {
+                            /* everything OK */
+                        }
+                        STRING_delete(base64Signature);
+                        STRING_delete(urlEncodedSignature);
+                    }
+                }
+                STRING_delete(toBeHashed);
+                BUFFER_delete(hash);
+            }
+            BUFFER_delete(decodedKey);
+        }
+    }
+
+    return result;
+}
+