From 34b349675af9f72eb822837a8772cc1ead7115c7 Mon Sep 17 00:00:00 2001
From: Aleksey Sanin <aleksey@aleksey.com>
Date: Mon, 15 Jun 2009 17:45:36 +0000
Subject: Fixed HMAC vuln with small values of HMAC length
---
diff --git a/include/xmlsec/gnutls/crypto.h b/include/xmlsec/gnutls/crypto.h
index dd80436..f7fbbad 100644
--- a/include/xmlsec/gnutls/crypto.h
+++ b/include/xmlsec/gnutls/crypto.h
@@ -113,6 +113,10 @@ XMLSEC_CRYPTO_EXPORT xmlSecTransformId xmlSecGnuTLSTransformDes3CbcGetKlass(void
*
*******************************************************************/
#ifndef XMLSEC_NO_HMAC
+
+XMLSEC_CRYPTO_EXPORT int xmlSecGnuTLSHmacGetMinOutputLength();
+XMLSEC_CRYPTO_EXPORT void xmlSecGnuTLSHmacSetMinOutputLength(int min_length);
+
/**
* xmlSecGnuTLSKeyDataHmacId:
*
diff --git a/include/xmlsec/nss/crypto.h b/include/xmlsec/nss/crypto.h
index f1cd44e..381ee1f 100644
--- a/include/xmlsec/nss/crypto.h
+++ b/include/xmlsec/nss/crypto.h
@@ -191,6 +191,10 @@ XMLSEC_CRYPTO_EXPORT xmlSecTransformId xmlSecNssTransformDsaSha1GetKlass(void);
*
*******************************************************************/
#ifndef XMLSEC_NO_HMAC
+
+XMLSEC_CRYPTO_EXPORT int xmlSecNssHmacGetMinOutputLength();
+XMLSEC_CRYPTO_EXPORT void xmlSecNssHmacSetMinOutputLength(int min_length);
+
/**
* xmlSecNssKeyDataHmacId:
*
diff --git a/include/xmlsec/openssl/crypto.h b/include/xmlsec/openssl/crypto.h
index 2274e35..3b50b40 100644
--- a/include/xmlsec/openssl/crypto.h
+++ b/include/xmlsec/openssl/crypto.h
@@ -200,6 +200,10 @@ XMLSEC_CRYPTO_EXPORT xmlSecTransformId xmlSecOpenSSLTransformDsaSha1GetKlass(voi
*
*******************************************************************/
#ifndef XMLSEC_NO_HMAC
+
+XMLSEC_CRYPTO_EXPORT int xmlSecOpenSSLHmacGetMinOutputLength();
+XMLSEC_CRYPTO_EXPORT void xmlSecOpenSSLHmacSetMinOutputLength(int min_length);
+
/**
* xmlSecOpenSSLKeyDataHmacId:
*
diff --git a/src/gnutls/hmac.c b/src/gnutls/hmac.c
index 1119110..5a0940c 100644
--- a/src/gnutls/hmac.c
+++ b/src/gnutls/hmac.c
@@ -23,10 +23,40 @@
#include <xmlsec/gnutls/app.h>
#include <xmlsec/gnutls/crypto.h>
+#define XMLSEC_GNUTLS_MIN_HMAC_SIZE 64
#define XMLSEC_GNUTLS_MAX_HMAC_SIZE 128
/**************************************************************************
*
+ * Configuration
+ *
+ *****************************************************************************/
+static int g_xmlsec_gnutls_hmac_min_length = XMLSEC_GNUTLS_MIN_HMAC_SIZE;
+
+/**
+ * xmlSecGnuTLSHmacGetMinOutputLength:
+ *
+ * Returns the min HMAC output length
+ */
+int xmlSecGnuTLSHmacGetMinOutputLength()
+{
+ return g_xmlsec_gnutls_hmac_min_length;
+}
+
+/**
+ * xmlSecGnuTLSHmacSetMinOutputLength:
+ *
+ * @min_length: the new min length
+ *
+ * Sets the min HMAC output length
+ */
+void xmlSecGnuTLSHmacSetMinOutputLength(int min_length)
+{
+ g_xmlsec_gnutls_hmac_min_length = min_length;
+}
+
+/**************************************************************************
+ *
* Internal GNUTLS HMAC CTX
*
*****************************************************************************/
@@ -178,7 +208,20 @@ xmlSecGnuTLSHmacNodeRead(xmlSecTransformPtr transform, xmlNodePtr node, xmlSecTr
ctx->dgstSize = atoi((char*)content);
xmlFree(content);
}
- /* todo: error if dgstSize == 0 ?*/
+
+ /* Ensure that HMAC length is greater than min specified.
+ Otherwise, an attacker can set this lenght to 0 or very
+ small value
+ */
+ if(ctx->dgstSize < xmlSecGnuTLSHmacGetMinOutputLength()) {
+ xmlSecError(XMLSEC_ERRORS_HERE,
+ xmlSecErrorsSafeString(xmlSecTransformGetName(transform)),
+ xmlSecNodeHMACOutputLength,
+ XMLSEC_ERRORS_R_INVALID_NODE_ATTRIBUTE,
+ "HMAC output length is too small");
+ return(-1);
+ }
+
cur = xmlSecGetNextElementNode(cur->next);
}
diff --git a/src/nss/hmac.c b/src/nss/hmac.c
index f67ec9d..a7c2018 100644
--- a/src/nss/hmac.c
+++ b/src/nss/hmac.c
@@ -26,10 +26,40 @@
#include <xmlsec/nss/app.h>
#include <xmlsec/nss/crypto.h>
+#define XMLSEC_NSS_MIN_HMAC_SIZE 64
#define XMLSEC_NSS_MAX_HMAC_SIZE 128
/**************************************************************************
*
+ * Configuration
+ *
+ *****************************************************************************/
+static int g_xmlsec_nss_hmac_min_length = XMLSEC_NSS_MIN_HMAC_SIZE;
+
+/**
+ * xmlSecNssHmacGetMinOutputLength:
+ *
+ * Returns the min HMAC output length
+ */
+int xmlSecNssHmacGetMinOutputLength()
+{
+ return g_xmlsec_nss_hmac_min_length;
+}
+
+/**
+ * xmlSecNssHmacSetMinOutputLength:
+ *
+ * @min_length: the new min length
+ *
+ * Sets the min HMAC output length
+ */
+void xmlSecNssHmacSetMinOutputLength(int min_length)
+{
+ g_xmlsec_nss_hmac_min_length = min_length;
+}
+
+/**************************************************************************
+ *
* Internal NSS HMAC CTX
*
*****************************************************************************/
@@ -162,7 +192,20 @@ xmlSecNssHmacNodeRead(xmlSecTransformPtr transform, xmlNodePtr node, xmlSecTrans
ctx->dgstSize = atoi((char*)content);
xmlFree(content);
}
- /* todo: error if dgstSize == 0 ?*/
+
+ /* Ensure that HMAC length is greater than min specified.
+ Otherwise, an attacker can set this lenght to 0 or very
+ small value
+ */
+ if(ctx->dgstSize < xmlSecNssHmacGetMinOutputLength()) {
+ xmlSecError(XMLSEC_ERRORS_HERE,
+ xmlSecErrorsSafeString(xmlSecTransformGetName(transform)),
+ xmlSecNodeHMACOutputLength,
+ XMLSEC_ERRORS_R_INVALID_NODE_ATTRIBUTE,
+ "HMAC output length is too small");
+ return(-1);
+ }
+
cur = xmlSecGetNextElementNode(cur->next);
}
diff --git a/src/openssl/hmac.c b/src/openssl/hmac.c
index 492663b..76fca0e 100644
--- a/src/openssl/hmac.c
+++ b/src/openssl/hmac.c
@@ -32,6 +32,36 @@
#include <xmlsec/openssl/crypto.h>
+#define XMLSEC_OPENSSL_MIN_HMAC_SIZE 64
+
+/**************************************************************************
+ *
+ * Configuration
+ *
+ *****************************************************************************/
+static int g_xmlsec_openssl_hmac_min_length = XMLSEC_OPENSSL_MIN_HMAC_SIZE;
+
+/**
+ * xmlSecOpenSSLHmacGetMinOutputLength:
+ *
+ * Returns the min HMAC output length
+ */
+int xmlSecOpenSSLHmacGetMinOutputLength()
+{
+ return g_xmlsec_openssl_hmac_min_length;
+}
+
+/**
+ * xmlSecOpenSSLHmacSetMinOutputLength:
+ *
+ * @min_length: the new min length
+ *
+ * Sets the min HMAC output length
+ */
+void xmlSecOpenSSLHmacSetMinOutputLength(int min_length)
+{
+ g_xmlsec_openssl_hmac_min_length = min_length;
+}
/**************************************************************************
*
@@ -240,7 +270,20 @@ xmlSecOpenSSLHmacNodeRead(xmlSecTransformPtr transform, xmlNodePtr node, xmlSecT
ctx->dgstSize = atoi((char*)content);
xmlFree(content);
}
- /* todo: error if dgstSize == 0 ?*/
+
+ /* Ensure that HMAC length is greater than min specified.
+ Otherwise, an attacker can set this lenght to 0 or very
+ small value
+ */
+ if(ctx->dgstSize < xmlSecOpenSSLHmacGetMinOutputLength()) {
+ xmlSecError(XMLSEC_ERRORS_HERE,
+ xmlSecErrorsSafeString(xmlSecTransformGetName(transform)),
+ xmlSecNodeHMACOutputLength,
+ XMLSEC_ERRORS_R_INVALID_NODE_ATTRIBUTE,
+ "HMAC output length is too small");
+ return(-1);
+ }
+
cur = xmlSecGetNextElementNode(cur->next);
}
