use local array for hmac when calculating signature

Signed-off-by: Michael Krelin <hacker@klever.net>

1 files changed, 7 insertions, 4 deletions

diff --git a/lib/util.cc b/lib/util.cc
index b85a377..bb8a2e8 100644
--- a/lib/util.cc
+++ b/lib/util.cc
@@ -1,38 +1,40 @@
 #include <errno.h>
 #include <cassert>
 #include <cctype>
 #include <cstring>
 #include <vector>
 #include <string>
 #include <stack>
 #include <algorithm>
 #include <openssl/bio.h>
 #include <openssl/evp.h>
+#include <openssl/sha.h>
 #include <openssl/hmac.h>
 #include <curl/curl.h>
-#include "opkele/util.h"
-#include "opkele/exception.h"
+#include <opkele/util.h>
+#include <opkele/exception.h>
+#include <opkele/debug.h>
 
 #include <config.h>
 #ifdef HAVE_DEMANGLE
 # include <cxxabi.h>
 #endif
 
 namespace opkele {
     using namespace std;
 
     namespace util {
 
 	/*
 	 * base64
 	 */
 	string encode_base64(const void *data,size_t length) {
 	    BIO *b64 = 0, *bmem = 0;
 	    try {
 		b64 = BIO_new(BIO_f_base64());
 		if(!b64)
 		    throw exception_openssl(OPKELE_CP_ "failed to BIO_new() base64 encoder");
 		BIO_set_flags(b64,BIO_FLAGS_BASE64_NO_NL);
 		bmem = BIO_new(BIO_s_mem());
 		BIO_set_flags(b64,BIO_CLOSE);
 		if(!bmem)
@@ -399,34 +401,35 @@ namespace opkele {
 	    const string& slist = om.get_field("signed");
 	    string kv;
 	    string::size_type p=0;
 	    while(true) {
 		string::size_type co = slist.find(',',p);
 		string f = (co==string::npos)
 		    ?slist.substr(p):slist.substr(p,co-p);
 		kv += f;
 		kv += ':';
 		kv += om.get_field(f);
 		kv += '\n';
 		if(co==string::npos) break;
 		p = co+1;
 	    }
 	    const secret_t& secret = assoc->secret();
 	    const EVP_MD *evpmd;
 	    const string& at = assoc->assoc_type();
 	    if(at=="HMAC-SHA256")
 		evpmd = EVP_sha256();
 	    else if(at=="HMAC-SHA1")
 		evpmd = EVP_sha1();
 	    else
 		throw unsupported(OPKELE_CP_ "unknown association type");
 	    unsigned int md_len = 0;
-	    unsigned char *md = HMAC(evpmd,
+	    unsigned char md[SHA256_DIGEST_LENGTH];
+	    HMAC(evpmd,
 		    &(secret.front()),secret.size(),
 		    (const unsigned char*)kv.data(),kv.length(),
-		    0,&md_len);
+		    md,&md_len);
 	    return encode_base64(md,md_len);
 	}
 
     }
 
 }