trustbridge: common/binverify.c comparison

comparison common/binverify.c @ 771:2798f1869eee

(issue43) Add first draft of signature verification for GNU/Linux

author	Andre Heinecke <andre.heinecke@intevation.de>
date	Thu, 10 Jul 2014 19:15:22 +0200
parents	be30d50bc4f0
children	44fa5de02b52

comparison

equal deleted inserted replaced

-:7861950f7637
+:2798f1869eee
 #include "pubkey-test.h"
 #endif
 bin_verify_result
 verify_binary(const char *filename, size_t name_len) {
+if (!filename || !name_len)
+return VerifyUnknownError;
 #ifdef WIN32
 return verify_binary_win(filename, name_len);
 #else
-/* TODO */
+return verify_binary_linux(filename, name_len);
-if (filename && name_len)
-return VerifyValid;
-return VerifyUnknownError;
 #endif
 }
 #ifdef WIN32
 {
 CryptMsgClose(hMsg);
 }
 return retval;
 }
+#else /* WIN32 */
+#include "listutil.h"
+#pragma GCC diagnostic ignored "-Wconversion"
+/* Polarssl mh.h contains a conversion which gcc warns about */
+#include <polarssl/pk.h>
+#include <polarssl/base64.h>
+#include <polarssl/sha256.h>
+#pragma GCC diagnostic pop
+bin_verify_result
+verify_binary_linux(const char *filename, size_t name_len)
+{
+int ret = -1;
+const size_t sig_b64_size = TRUSTBRIDGE_RSA_KEY_SIZE / 8 * 4 / 3;
+char *data = NULL,
+signature_b64[sig_b64_size + 1];
+size_t data_size = 0,
+sig_size = TRUSTBRIDGE_RSA_KEY_SIZE / 8;
+unsigned char signature[sig_size],
+hash[32];
+bin_verify_result retval = VerifyUnknownError;
+pk_context pub_key_ctx;
+if (strnlen(filename, name_len + 1) != name_len || name_len == 0)
+{
+ERRORPRINTF ("Invalid call to verify_binary_linux\n");
+return VerifyUnknownError;
+}
+ret = read_file(filename, &data, &data_size, MAX_VALID_BIN_SIZE);
+if (ret != 0)
+{
+ERRORPRINTF ("Read file failed with error: %i\n", ret);
+return VerifyReadFailed;
+}
+/* Fetch the signature from the end of data */
+if (data_size < sig_b64_size + 4)
+{
+ERRORPRINTF ("File to small to contain a signature.\n");
+retval = VerifyInvalidSignature;
+goto done;
+}
+if (data[data_size - sig_b64_size - 1] != ':' ||
+data[data_size - sig_b64_size - 2] != 'S' ||
+data[data_size - sig_b64_size - 3] != '\n'||
+data[data_size - sig_b64_size - 4] != '\r')
+{
+ERRORPRINTF ("Failed to find valid signature line.\n");
+retval = VerifyInvalidSignature;
+goto done;
+}
+strncpy(signature_b64, data - sig_b64_size, sig_b64_size);
+signature_b64[sig_b64_size] = '\0';
+ret = base64_decode(signature, &sig_size,
+(unsigned char *)signature_b64, sig_b64_size);
+if (ret != 0 || sig_size != TRUSTBRIDGE_RSA_KEY_SIZE / 8)
+{
+goto done;
+}
+/* Hash is calculated over the data without the signature at the end. */
+sha256((unsigned char *)data, data_size - sig_b64_size - 4, hash, 0);
+pk_init(&pub_key_ctx);
+ret = pk_parse_public_key(&pub_key_ctx, public_key_codesign_pem,
+public_key_codesign_pem_size);
+if (ret != 0)
+{
+ERRORPRINTF ("pk_parse_public_key failed with -0x%04x\n\n", -ret);
+pk_free(&pub_key_ctx);
+return VerifyUnknownError;
+}
+ret = pk_verify(&pub_key_ctx, POLARSSL_MD_SHA256, hash, 0,
+signature, sig_size);
+if (ret != 0)
+{
+ERRORPRINTF ("pk_verify failed with -0x%04x\n\n", -ret);
+}
+pk_free(&pub_key_ctx);
+return VerifyValid;
+done:
+xfree (data);
+return retval;
+}
 #endif /* WIN32 */

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comparison common/binverify.c @ 771:2798f1869eee