[pki] add RSA-2048 signature validation for all server downloads

* Closes #1172
* Also fix a MinGW warning in badblocks.c

src/badblocks.c

@@ -430,7 +430,7 @@ static unsigned int test_rw(HANDLE hDrive, blk_t last_block, size_t block_size,
 	int i, pat_idx;
 	unsigned int bb_count = 0;
 	blk_t got, tryout, recover_block = ~0, *blk_id;
-	size_t id_offset;
+	size_t id_offset = 0;
 
 	if ((pattern_type < 0) || (pattern_type >= BADLOCKS_PATTERN_TYPES)) {
 		uprintf("%sInvalid pattern type\n", bb_prefix);

src/msapi_utf8.h

@@ -512,6 +512,22 @@ static __inline int PathGetDriveNumberU(char* lpPath)
 	return ret;
 }
 
+// This one is tricky since we can't blindly convert a
+// UTF-16 position to a UTF-8 one. So we do it manually.
+static __inline const char* PathFindFileNameU(const char* szPath)
+{
+	size_t i;
+	if (szPath == NULL)
+		return NULL;
+	for (i = strlen(szPath); i != 0; i--) {
+		if ((szPath[i] == '/') || (szPath[i] == '\\')) {
+			i++;
+			break;
+		}
+	}
+	return &szPath[i];
+}
+
 // This function differs from regular GetTextExtentPoint in that it uses a zero terminated string
 static __inline BOOL GetTextExtentPointU(HDC hdc, const char* lpString, LPSIZE lpSize)
 {

src/net.c

@@ -29,6 +29,7 @@
 #include <malloc.h>
 #include <string.h>
 #include <inttypes.h>
+#include <assert.h>
 
 #include "rufus.h"
 #include "missing.h"
@@ -216,13 +217,14 @@ const char* WinInetErrorString(void)
 }
 
 /*
- * Download a file from an URL
+ * Download a file or fill a buffer from an URL
  * Mostly taken from http://support.microsoft.com/kb/234913
+ * If file is NULL, a buffer is allocated for the download (that needs to be freed by the caller)
  * If hProgressDialog is not NULL, this function will send INIT and EXIT messages
  * to the dialog in question, with WPARAM being set to nonzero for EXIT on success
  * and also attempt to indicate progress using an IDC_PROGRESS control
  */
-DWORD DownloadFile(const char* url, const char* file, HWND hProgressDialog)
+static DWORD DownloadToFileOrBuffer(const char* url, const char* file, BYTE** buffer, HWND hProgressDialog)
 {
 	HWND hProgressBar = NULL;
 	BOOL r = FALSE;
@@ -234,8 +236,8 @@ DWORD DownloadFile(const char* url, const char* file, HWND hProgressDialog)
 	HINTERNET hSession = NULL, hConnection = NULL, hRequest = NULL;
 	URL_COMPONENTSA UrlParts = {sizeof(URL_COMPONENTSA), NULL, 1, (INTERNET_SCHEME)0,
 		hostname, sizeof(hostname), 0, NULL, 1, urlpath, sizeof(urlpath), NULL, 1};
-	size_t last_slash;
+	const char* short_name;
-	int i;
+	size_t i;
 
 	// Can't link with wininet.lib because of sideloading issues
 	PF_TYPE_DECL(WINAPI, BOOL, InternetCrackUrlA, (LPCSTR, DWORD, DWORD, LPURL_COMPONENTSA));
@@ -257,7 +259,7 @@ DWORD DownloadFile(const char* url, const char* file, HWND hProgressDialog)
 	PF_INIT_OR_OUT(HttpSendRequestA, WinInet);
 	PF_INIT_OR_OUT(HttpQueryInfoA, WinInet);
 
-	DownloadStatus = 0;
+	DownloadStatus = 404;
 	if (hProgressDialog != NULL) {
 		// Use the progress control provided, if any
 		hProgressBar = GetDlgItem(hProgressDialog, IDC_PROGRESS);
@@ -268,22 +270,18 @@ DWORD DownloadFile(const char* url, const char* file, HWND hProgressDialog)
 		SendMessage(hProgressDialog, UM_PROGRESS_INIT, 0, 0);
 	}
 
-	if (file == NULL)
+	if (url == NULL)
 		goto out;
 
-	for (last_slash = safe_strlen(file); last_slash != 0; last_slash--) {
+	short_name = (file != NULL) ? PathFindFileNameU(file) : PathFindFileNameU(url);
-		if ((file[last_slash] == '/') || (file[last_slash] == '\\')) {
-			last_slash++;
-			break;
-		}
-	}
 
-	PrintInfo(0, MSG_085, &file[last_slash]);
+	if (hProgressDialog != NULL)
-	uprintf("Downloading '%s' from %s\n", &file[last_slash], url);
+		PrintInfo(0, MSG_085, short_name);
+	uprintf("Downloading %s", url);
 
 	if ( (!pfInternetCrackUrlA(url, (DWORD)safe_strlen(url), 0, &UrlParts))
 	  || (UrlParts.lpszHostName == NULL) || (UrlParts.lpszUrlPath == NULL)) {
-		uprintf("Unable to decode URL: %s\n", WinInetErrorString());
+		uprintf("Unable to decode URL: %s", WinInetErrorString());
 		goto out;
 	}
 	hostname[sizeof(hostname)-1] = 0;
@@ -295,7 +293,7 @@ DWORD DownloadFile(const char* url, const char* file, HWND hProgressDialog)
 	if (i <= 0) {
 		// http://msdn.microsoft.com/en-us/library/windows/desktop/aa384702.aspx is wrong...
 		SetLastError(ERROR_INTERNET_NOT_INITIALIZED);
-		uprintf("Network is unavailable: %s\n", WinInetErrorString());
+		uprintf("Network is unavailable: %s", WinInetErrorString());
 		goto out;
 	}
 	static_sprintf(agent, APPLICATION_NAME "/%d.%d.%d (Windows NT %d.%d%s)",
@@ -303,13 +301,13 @@ DWORD DownloadFile(const char* url, const char* file, HWND hProgressDialog)
 		nWindowsVersion>>4, nWindowsVersion&0x0F, is_x64()?"; WOW64":"");
 	hSession = pfInternetOpenA(agent, INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL, 0);
 	if (hSession == NULL) {
-		uprintf("Could not open Internet session: %s\n", WinInetErrorString());
+		uprintf("Could not open Internet session: %s", WinInetErrorString());
 		goto out;
 	}
 
 	hConnection = pfInternetConnectA(hSession, UrlParts.lpszHostName, UrlParts.nPort, NULL, NULL, INTERNET_SERVICE_HTTP, 0, (DWORD_PTR)NULL);
 	if (hConnection == NULL) {
-		uprintf("Could not connect to server %s:%d: %s\n", UrlParts.lpszHostName, UrlParts.nPort, WinInetErrorString());
+		uprintf("Could not connect to server %s:%d: %s", UrlParts.lpszHostName, UrlParts.nPort, WinInetErrorString());
 		goto out;
 	}
 
@@ -318,64 +316,84 @@ DWORD DownloadFile(const char* url, const char* file, HWND hProgressDialog)
 		INTERNET_FLAG_NO_COOKIES|INTERNET_FLAG_NO_UI|INTERNET_FLAG_NO_CACHE_WRITE|INTERNET_FLAG_HYPERLINK|
 		((UrlParts.nScheme==INTERNET_SCHEME_HTTPS)?INTERNET_FLAG_SECURE:0), (DWORD_PTR)NULL);
 	if (hRequest == NULL) {
-		uprintf("Could not open URL %s: %s\n", url, WinInetErrorString());
+		uprintf("Could not open URL %s: %s", url, WinInetErrorString());
 		goto out;
 	}
 
 	if (!pfHttpSendRequestA(hRequest, NULL, 0, NULL, 0)) {
-		uprintf("Unable to send request: %s\n", WinInetErrorString());
+		uprintf("Unable to send request: %s", WinInetErrorString());
 		goto out;
 	}
 
 	// Get the file size
 	dwSize = sizeof(DownloadStatus);
-	DownloadStatus = 404;
 	pfHttpQueryInfoA(hRequest, HTTP_QUERY_STATUS_CODE|HTTP_QUERY_FLAG_NUMBER, (LPVOID)&DownloadStatus, &dwSize, NULL);
 	if (DownloadStatus != 200) {
 		error_code = ERROR_INTERNET_ITEM_NOT_FOUND;
-		uprintf("Unable to access file: %d\n", DownloadStatus);
+		uprintf("Unable to access file: %d", DownloadStatus);
 		goto out;
 	}
 	dwSize = sizeof(dwTotalSize);
 	if (!pfHttpQueryInfoA(hRequest, HTTP_QUERY_CONTENT_LENGTH|HTTP_QUERY_FLAG_NUMBER, (LPVOID)&dwTotalSize, &dwSize, NULL)) {
-		uprintf("Unable to retrieve file length: %s\n", WinInetErrorString());
+		uprintf("Unable to retrieve file length: %s", WinInetErrorString());
 		goto out;
 	}
-	uprintf("File length: %d bytes\n", dwTotalSize);
+	uprintf("File length: %d bytes", dwTotalSize);
 
+	if (file != NULL) {
 		hFile = CreateFileU(file, GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
 		if (hFile == INVALID_HANDLE_VALUE) {
-		uprintf("Unable to create file '%s': %s\n", &file[last_slash], WinInetErrorString());
+			uprintf("Unable to create file '%s': %s", short_name, WinInetErrorString());
 			goto out;
 		}
+	} else {
+		if (buffer == NULL) {
+			uprintf("No buffer pointer provided for download");
+			goto out;
+		}
+		*buffer = malloc(dwTotalSize);
+		if (*buffer == NULL) {
+			uprintf("Could not allocate buffer for download");
+			goto out;
+		}
+	}
 
 	// Keep checking for data until there is nothing left.
 	dwSize = 0;
 	while (1) {
 		if (IS_ERROR(FormatStatus))
 			goto out;
-
 		if (!pfInternetReadFile(hRequest, buf, sizeof(buf), &dwDownloaded) || (dwDownloaded == 0))
 			break;
-		dwSize += dwDownloaded;
+		if (hProgressDialog != NULL) {
 			SendMessage(hProgressBar, PBM_SETPOS, (WPARAM)(MAX_PROGRESS*((1.0f*dwSize) / (1.0f*dwTotalSize))), 0);
 			PrintInfo(0, MSG_241, (100.0f*dwSize) / (1.0f*dwTotalSize));
+		}
+		if (file != NULL) {
 			if (!WriteFile(hFile, buf, dwDownloaded, &dwWritten, NULL)) {
-			uprintf("Error writing file '%s': %s\n", &file[last_slash], WinInetErrorString());
+				uprintf("Error writing file '%s': %s", short_name, WinInetErrorString());
 				goto out;
 			} else if (dwDownloaded != dwWritten) {
-			uprintf("Error writing file '%s': Only %d/%d bytes written\n", dwWritten, dwDownloaded);
+				uprintf("Error writing file '%s': Only %d/%d bytes written", short_name, dwWritten, dwDownloaded);
 				goto out;
 			}
+		} else {
+			memcpy(&(*buffer)[dwSize], buf, dwDownloaded);
+		}
+		dwSize += dwDownloaded;
 	}
 
 	if (dwSize != dwTotalSize) {
-		uprintf("Could not download complete file - read: %d bytes, expected: %d bytes\n", dwSize, dwTotalSize);
+		uprintf("Could not download complete file - read: %d bytes, expected: %d bytes", dwSize, dwTotalSize);
 		FormatStatus = ERROR_SEVERITY_ERROR|FAC(FACILITY_STORAGE)|ERROR_WRITE_FAULT;
 		goto out;
 	} else {
 		r = TRUE;
-		uprintf("Successfully downloaded '%s'\n", &file[last_slash]);
+		uprintf("Successfully downloaded '%s'", short_name);
+		if (hProgressDialog != NULL) {
+			SendMessage(hProgressBar, PBM_SETPOS, (WPARAM)MAX_PROGRESS, 0);
+			PrintInfo(0, MSG_241, 100.0f);
+		}
 	}
 
 out:
@@ -406,20 +424,76 @@ out:
 	return r?dwSize:0;
 }
 
+// Download and validate a signed file. The file must have a corresponding '.sig' on the server.
+DWORD DownloadSignedFile(const char* url, const char* file, HWND hProgressDialog)
+{
+	char* url_sig = NULL;
+	BYTE *buf = NULL, *sig = NULL;
+	DWORD buf_len = 0, sig_len = 0;
+	DWORD ret = 0;
+	HANDLE hFile = INVALID_HANDLE_VALUE;
+
+	if (url == NULL)
+		goto out;
+
+	url_sig = malloc(strlen(url) + 5);
+	if (url_sig == NULL) {
+		uprintf("Could not allocate signature URL");
+		goto out;
+	}
+	strcpy(url_sig, url);
+	strcat(url_sig, ".sig");
+
+	buf_len = DownloadToFileOrBuffer(url, NULL, &buf, hProgressDialog);
+	if (buf_len == 0)
+		goto out;
+	sig_len = DownloadToFileOrBuffer(url_sig, NULL, &sig, NULL);
+	if ((sig_len != RSA_SIGNATURE_SIZE) || (!ValidateOpensslSignature(buf, buf_len, sig, sig_len))) {
+		uprintf("FATAL: Server signature is invalid!");
+		DownloadStatus = 403;	// Forbidden
+		goto out;
+	}
+
+	uprintf("Download signature is valid");
+	DownloadStatus = 206;	// Partial content
+	hFile = CreateFileU(file, GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
+	if (hFile == INVALID_HANDLE_VALUE) {
+		uprintf("Unable to create file '%s': %s", PathFindFileNameU(file), WinInetErrorString());
+		goto out;
+	}
+	if (!WriteFile(hFile, buf, buf_len, &ret, NULL)) {
+		uprintf("Error writing file '%s': %s", PathFindFileNameU(file), WinInetErrorString());
+		ret = 0;
+		goto out;
+	} else if (ret != buf_len) {
+		uprintf("Error writing file '%s': Only %d/%d bytes written", PathFindFileNameU(file), ret, buf_len);
+		ret = 0;
+		goto out;
+	}
+	DownloadStatus = 200;	// Full content
+
+out:
+	safe_closehandle(hFile);
+	free(url_sig);
+	free(buf);
+	free(sig);
+	return ret;
+}
+
 /* Threaded download */
 static const char *_url, *_file;
 static HWND _hProgressDialog;
-static DWORD WINAPI _DownloadFileThread(LPVOID param)
+static DWORD WINAPI _DownloadSignedFileThread(LPVOID param)
 {
-	ExitThread(DownloadFile(_url, _file, _hProgressDialog) != 0);
+	ExitThread(DownloadSignedFile(_url, _file, _hProgressDialog) != 0);
 }
 
-HANDLE DownloadFileThreaded(const char* url, const char* file, HWND hProgressDialog)
+HANDLE DownloadSignedFileThreaded(const char* url, const char* file, HWND hProgressDialog)
 {
 	_url = url;
 	_file = file;
 	_hProgressDialog = hProgressDialog;
-	return CreateThread(NULL, 0, _DownloadFileThread, NULL, 0, NULL);
+	return CreateThread(NULL, 0, _DownloadSignedFileThread, NULL, 0, NULL);
 }
 
 static __inline uint64_t to_uint64_t(uint16_t x[4]) {
@@ -443,8 +517,9 @@ static DWORD WINAPI CheckForUpdatesThread(LPVOID param)
 	static const char* channel[] = {"release", "beta", "test"};		// release channel
 	const char* accept_types[] = {"*/*\0", NULL};
 	DWORD dwFlags, dwSize, dwDownloaded, dwTotalSize, dwStatus;
+	BYTE *sig = NULL;
 	char* buf = NULL;
-	char agent[64], hostname[64], urlpath[128], mime[32];
+	char agent[64], hostname[64], urlpath[128], sigpath[256], mime[32];
 	OSVERSIONINFOA os_version = {sizeof(OSVERSIONINFOA), 0, 0, 0, 0, ""};
 	HINTERNET hSession = NULL, hConnection = NULL, hRequest = NULL;
 	URL_COMPONENTSA UrlParts = {sizeof(URL_COMPONENTSA), NULL, 1, (INTERNET_SCHEME)0,
@@ -487,7 +562,7 @@ static DWORD WINAPI CheckForUpdatesThread(LPVOID param)
 		} while ((!force_update_check) && ((iso_op_in_progress || format_op_in_progress || (dialog_showing>0))));
 		if (!force_update_check) {
 			if ((ReadSetting32(SETTING_UPDATE_INTERVAL) == -1)) {
-				vuprintf("Check for updates disabled, as per settings.\n");
+				vuprintf("Check for updates disabled, as per settings.");
 				goto out;
 			}
 			reg_time = ReadSetting64(SETTING_LAST_UPDATE);
@@ -500,9 +575,9 @@ static DWORD WINAPI CheckForUpdatesThread(LPVOID param)
 			if (!SystemTimeToFileTime(&LocalTime, &FileTime))
 				goto out;
 			local_time = ((((int64_t)FileTime.dwHighDateTime)<<32) + FileTime.dwLowDateTime) / 10000000;
-			vvuprintf("Local time: %" PRId64 "\n", local_time);
+			vvuprintf("Local time: %" PRId64, local_time);
 			if (local_time < reg_time + update_interval) {
-				vuprintf("Next update check in %" PRId64 " seconds.\n", reg_time + update_interval - local_time);
+				vuprintf("Next update check in %" PRId64 " seconds.", reg_time + update_interval - local_time);
 				goto out;
 			}
 		}
@@ -512,7 +587,7 @@ static DWORD WINAPI CheckForUpdatesThread(LPVOID param)
 	status++;	// 1
 
 	if (!GetVersionExA(&os_version)) {
-		uprintf("Could not read Windows version - Check for updates cancelled.\n");
+		uprintf("Could not read Windows version - Check for updates cancelled.");
 		goto out;
 	}
 
@@ -540,7 +615,7 @@ static DWORD WINAPI CheckForUpdatesThread(LPVOID param)
 	max_channel = releases_only ? 1 : (int)ARRAYSIZE(channel) - 1;
 #endif
 	for (k=0; (k<max_channel) && (!found_new_version); k++) {
-		uprintf("Checking %s channel...\n", channel[k]);
+		uprintf("Checking %s channel...", channel[k]);
 		// At this stage we can query the server for various update version files.
 		// We first try to lookup for "<appname>_<os_arch>_<os_version_major>_<os_version_minor>.ver"
 		// and then remove each each of the <os_> components until we find our match. For instance, we may first
@@ -548,21 +623,18 @@ static DWORD WINAPI CheckForUpdatesThread(LPVOID param)
 		// This allows sunsetting OS versions (eg XP) or providing different downloads for different archs/groups.
 		static_sprintf(urlpath, "%s%s%s_%s_%lu.%lu.ver", APPLICATION_NAME, (k==0)?"":"_",
 			(k==0)?"":channel[k], archname[is_x64()?1:0], os_version.dwMajorVersion, os_version.dwMinorVersion);
-		vuprintf("Base update check: %s\n", urlpath);
+		vuprintf("Base update check: %s", urlpath);
 		for (i=0, j=(int)safe_strlen(urlpath)-5; (j>0)&&(i<ARRAYSIZE(verpos)); j--) {
 			if ((urlpath[j] == '.') || (urlpath[j] == '_')) {
 				verpos[i++] = j;
 			}
 		}
-		if (i != ARRAYSIZE(verpos)) {
+		assert(i == ARRAYSIZE(verpos));
-			uprintf("Broken code in CheckForUpdatesThread()!\n");
-			goto out;
-		}
 
 		UrlParts.lpszUrlPath = urlpath;
 		UrlParts.dwUrlPathLength = sizeof(urlpath);
 		for (i=0; i<ARRAYSIZE(verpos); i++) {
-			vvuprintf("Trying %s\n", UrlParts.lpszUrlPath);
+			vvuprintf("Trying %s", UrlParts.lpszUrlPath);
 			hRequest = pfHttpOpenRequestA(hConnection, "GET", UrlParts.lpszUrlPath, NULL, NULL, accept_types,
 				INTERNET_FLAG_IGNORE_REDIRECT_TO_HTTP|INTERNET_FLAG_IGNORE_REDIRECT_TO_HTTPS|
 				INTERNET_FLAG_NO_COOKIES|INTERNET_FLAG_NO_UI|INTERNET_FLAG_NO_CACHE_WRITE|INTERNET_FLAG_HYPERLINK|
@@ -607,7 +679,7 @@ static DWORD WINAPI CheckForUpdatesThread(LPVOID param)
 			|| (!SystemTimeToFileTime(&ServerTime, &FileTime)) )
 			goto out;
 		server_time = ((((int64_t)FileTime.dwHighDateTime)<<32) + FileTime.dwLowDateTime) / 10000000;
-		vvuprintf("Server time: %" PRId64 "\n", server_time);
+		vvuprintf("Server time: %" PRId64, server_time);
 		// Always store the server response time - the only clock we trust!
 		WriteSetting64(SETTING_LAST_UPDATE, server_time);
 		// Might as well let the user know
@@ -625,29 +697,39 @@ static DWORD WINAPI CheckForUpdatesThread(LPVOID param)
 		safe_free(buf);
 		// Make sure the file is NUL terminated
 		buf = (char*)calloc(dwTotalSize+1, 1);
-		if (buf == NULL) goto out;
+		if (buf == NULL)
+			goto out;
 		// This is a version file - we should be able to gulp it down in one go
 		if (!pfInternetReadFile(hRequest, buf, dwTotalSize, &dwDownloaded) || (dwDownloaded != dwTotalSize))
 			goto out;
+		vuprintf("Successfully downloaded version file (%d bytes)", dwTotalSize);
+
+		// Now download the signature file
+		static_sprintf(sigpath, "%s/%s.sig", server_url, urlpath);
+		dwDownloaded = DownloadToFileOrBuffer(sigpath, NULL, &sig, NULL);
+		if ((dwDownloaded != RSA_SIGNATURE_SIZE) || (!ValidateOpensslSignature(buf, dwTotalSize, sig, dwDownloaded))) {
+			uprintf("FATAL: Version signature is invalid!");
+			goto out;
+		}
+		vuprintf("Version signature is valid");
 
 		status++;
-		vuprintf("Successfully downloaded version file (%d bytes)\n", dwTotalSize);
-
 		parse_update(buf, dwTotalSize+1);
 
-		vuprintf("UPDATE DATA:\n");
+		vuprintf("UPDATE DATA:");
-		vuprintf("  version: %d.%d.%d (%s)\n", update.version[0], update.version[1], update.version[2], channel[k]);
+		vuprintf("  version: %d.%d.%d (%s)", update.version[0], update.version[1], update.version[2], channel[k]);
-		vuprintf("  platform_min: %d.%d\n", update.platform_min[0], update.platform_min[1]);
+		vuprintf("  platform_min: %d.%d", update.platform_min[0], update.platform_min[1]);
-		vuprintf("  url: %s\n", update.download_url);
+		vuprintf("  url: %s", update.download_url);
 
 		found_new_version = ((to_uint64_t(update.version) > to_uint64_t(rufus_version)) || (force_update))
 			&& ( (os_version.dwMajorVersion > update.platform_min[0])
 			  || ( (os_version.dwMajorVersion == update.platform_min[0]) && (os_version.dwMinorVersion >= update.platform_min[1])) );
-		uprintf("N%sew %s version found%c\n", found_new_version?"":"o n", channel[k], found_new_version?'!':'.');
+		uprintf("N%sew %s version found%c", found_new_version?"":"o n", channel[k], found_new_version?'!':'.');
 	}
 
 out:
 	safe_free(buf);
+	safe_free(sig);
 	if (hRequest)
 		pfInternetCloseHandle(hRequest);
 	if (hConnection)

src/pki.c

@@ -27,6 +27,7 @@
 #include <stdio.h>
 #include <wincrypt.h>
 #include <wintrust.h>
+#include <assert.h>
 
 #include "rufus.h"
 #include "resource.h"
@@ -52,6 +53,63 @@ typedef struct {
 	LPWSTR lpszMoreInfoLink;
 } SPROG_PUBLISHERINFO, *PSPROG_PUBLISHERINFO;
 
+// https://msdn.microsoft.com/en-us/library/ee442238.aspx
+typedef struct {
+	BLOBHEADER BlobHeader;
+	RSAPUBKEY  RsaHeader;
+	BYTE       Modulus[256];	// 2048 bit modulus
+} RSA_2048_PUBKEY;
+
+// The RSA public key modulus for the private key we use to sign the files on the server.
+// NOTE 1: This openssl modulus must be *REVERSED* to be usable with Microsoft APIs
+// NOTE 2: Also, this modulus is 2052 bits, and not 2048, because openssl adds an extra
+// 0x00 at the beginning to force an integer sign. These extra 8 bits *MUST* be removed.
+static uint8_t rsa_pubkey_modulus[] = {
+	/*
+		$ openssl genrsa -aes256 -out private.pem 2048
+		$ openssl rsa -in private.pem -pubout -out public.pem
+		$ openssl rsa -pubin -inform PEM -text -noout < public.pem
+		Public-Key: (2048 bit)
+		Modulus:
+			00:b6:40:7d:d1:98:7b:81:9e:be:23:0f:32:5d:55:
+			60:c6:bf:b4:41:bb:43:1b:f1:e1:e6:f9:2b:d6:dd:
+			11:50:e8:b9:3f:19:97:5e:a7:8b:4a:30:c6:76:58:
+			72:1c:ac:ff:a1:f8:96:6c:51:5d:13:11:e3:5b:11:
+			82:f5:9a:69:e4:28:97:0f:ca:1f:02:ea:1f:7d:dc:
+			f9:fc:79:2f:61:ff:8e:45:60:65:ba:37:9b:de:49:
+			05:6a:a8:fd:70:d0:0c:79:b6:d7:81:aa:54:c3:c6:
+			4a:87:a0:45:ee:ca:d5:d5:c5:c2:ac:86:42:b3:58:
+			27:d2:43:b9:37:f2:e6:75:66:17:53:d0:38:d0:c6:
+			57:c2:55:36:a2:43:87:ea:24:f0:96:ec:34:dd:79:
+			4d:80:54:9d:84:81:a7:cf:0c:a5:7c:d6:63:fa:7a:
+			66:30:a9:50:ee:f0:e5:f8:a2:2d:ac:fc:24:21:fe:
+			ef:e8:d3:6f:0e:27:b0:64:22:95:3e:6d:a6:66:97:
+			c6:98:c2:47:b3:98:69:4d:b1:b5:d3:6f:43:f5:d7:
+			a5:13:5e:8c:28:4f:62:4e:01:48:0a:63:89:e7:ca:
+			34:aa:7d:2f:bb:70:e0:31:bb:39:49:a3:d2:c9:2e:
+			a6:30:54:9a:5c:4d:58:17:d9:fc:3a:43:e6:8e:2a:
+			18:e9
+		Exponent: 65537 (0x10001)
+	*/
+	0x00, 0xb6, 0x40, 0x7d, 0xd1, 0x98, 0x7b, 0x81, 0x9e, 0xbe, 0x23, 0x0f, 0x32, 0x5d, 0x55,
+	0x60, 0xc6, 0xbf, 0xb4, 0x41, 0xbb, 0x43, 0x1b, 0xf1, 0xe1, 0xe6, 0xf9, 0x2b, 0xd6, 0xdd,
+	0x11, 0x50, 0xe8, 0xb9, 0x3f, 0x19, 0x97, 0x5e, 0xa7, 0x8b, 0x4a, 0x30, 0xc6, 0x76, 0x58,
+	0x72, 0x1c, 0xac, 0xff, 0xa1, 0xf8, 0x96, 0x6c, 0x51, 0x5d, 0x13, 0x11, 0xe3, 0x5b, 0x11,
+	0x82, 0xf5, 0x9a, 0x69, 0xe4, 0x28, 0x97, 0x0f, 0xca, 0x1f, 0x02, 0xea, 0x1f, 0x7d, 0xdc,
+	0xf9, 0xfc, 0x79, 0x2f, 0x61, 0xff, 0x8e, 0x45, 0x60, 0x65, 0xba, 0x37, 0x9b, 0xde, 0x49,
+	0x05, 0x6a, 0xa8, 0xfd, 0x70, 0xd0, 0x0c, 0x79, 0xb6, 0xd7, 0x81, 0xaa, 0x54, 0xc3, 0xc6,
+	0x4a, 0x87, 0xa0, 0x45, 0xee, 0xca, 0xd5, 0xd5, 0xc5, 0xc2, 0xac, 0x86, 0x42, 0xb3, 0x58,
+	0x27, 0xd2, 0x43, 0xb9, 0x37, 0xf2, 0xe6, 0x75, 0x66, 0x17, 0x53, 0xd0, 0x38, 0xd0, 0xc6,
+	0x57, 0xc2, 0x55, 0x36, 0xa2, 0x43, 0x87, 0xea, 0x24, 0xf0, 0x96, 0xec, 0x34, 0xdd, 0x79,
+	0x4d, 0x80, 0x54, 0x9d, 0x84, 0x81, 0xa7, 0xcf, 0x0c, 0xa5, 0x7c, 0xd6, 0x63, 0xfa, 0x7a,
+	0x66, 0x30, 0xa9, 0x50, 0xee, 0xf0, 0xe5, 0xf8, 0xa2, 0x2d, 0xac, 0xfc, 0x24, 0x21, 0xfe,
+	0xef, 0xe8, 0xd3, 0x6f, 0x0e, 0x27, 0xb0, 0x64, 0x22, 0x95, 0x3e, 0x6d, 0xa6, 0x66, 0x97,
+	0xc6, 0x98, 0xc2, 0x47, 0xb3, 0x98, 0x69, 0x4d, 0xb1, 0xb5, 0xd3, 0x6f, 0x43, 0xf5, 0xd7,
+	0xa5, 0x13, 0x5e, 0x8c, 0x28, 0x4f, 0x62, 0x4e, 0x01, 0x48, 0x0a, 0x63, 0x89, 0xe7, 0xca,
+	0x34, 0xaa, 0x7d, 0x2f, 0xbb, 0x70, 0xe0, 0x31, 0xbb, 0x39, 0x49, 0xa3, 0xd2, 0xc9, 0x2e,
+	0xa6, 0x30, 0x54, 0x9a, 0x5c, 0x4d, 0x58, 0x17, 0xd9, 0xfc, 0x3a, 0x43, 0xe6, 0x8e, 0x2a,
+	0x18, 0xe9
+};
 
 /*
  * FormatMessage does not handle PKI errors
@@ -65,8 +123,19 @@ const char* WinPKIErrorString(void)
 		return WindowsErrorString();
 
 	switch (error_code) {
+	// See also https://docs.microsoft.com/en-gb/windows/desktop/com/com-error-codes-4
 	case NTE_BAD_UID:
 		return "Bad UID.";
+	case NTE_NO_KEY:
+		return "Key does not exist.";
+	case NTE_BAD_KEYSET:
+		return "Keyset does not exist.";
+	case NTE_BAD_ALGID:
+		return "Invalid algorithm specified.";
+	case NTE_BAD_VER:
+		return "Bad version of provider.";
+	case NTE_BAD_SIGNATURE:
+		return "Invalid Signature.";
 	case CRYPT_E_MSG_ERROR:
 		return "An error occurred while performing an operation on a cryptographic message.";
 	case CRYPT_E_UNKNOWN_ALGO:
@@ -581,3 +650,80 @@ LONG ValidateSignature(HWND hDlg, const char* path)
 
 	return r;
 }
+
+// Why-oh-why am I the only one on github doing this openssl vs MS signature validation?!?
+// For once, I'd like to find code samples from *OTHER PEOPLE* who went through this ordeal first...
+BOOL ValidateOpensslSignature(BYTE* pbBuffer, DWORD dwBufferLen, BYTE* pbSignature, DWORD dwSigLen)
+{
+	HCRYPTPROV hProv = 0;
+	HCRYPTHASH hHash = 0;
+	HCRYPTKEY hPubKey;
+	// We could load and convert an openssl PEM, but since we know what we need...
+	RSA_2048_PUBKEY pbMyPubKey = {
+		{ PUBLICKEYBLOB, CUR_BLOB_VERSION, 0, CALG_RSA_KEYX },
+		// $ openssl genrsa -aes256 -out private.pem 2048
+		// Generating RSA private key, 2048 bit long modulus
+		// e is 65537 (0x010001)
+		// => 0x010001 below. Also 0x31415352 = "RSA1"
+		{ 0x31415352, sizeof(pbMyPubKey.Modulus) * 8, 0x010001 },
+		{ 0 }	// Modulus is initialized below
+	};
+	USHORT dwMyPubKeyLen = sizeof(pbMyPubKey);
+	BOOL r;
+	BYTE t;
+	int i, j;
+
+	// Get a handle to the default PROV_RSA_AES provider (AES so we get SHA-256 support).
+	// 2 passes in case we need to create a new container.
+	r = CryptAcquireContext(&hProv, NULL, NULL, PROV_RSA_AES, CRYPT_NEWKEYSET | CRYPT_VERIFYCONTEXT);
+	if (!r) {
+		uprintf("PKI: Could not create the default key container: %s", WinPKIErrorString());
+		goto out;
+	}
+
+	// Reverse the modulus bytes from openssl (and also remove the extra unwanted 0x00)
+	assert(sizeof(rsa_pubkey_modulus) >= sizeof(pbMyPubKey.Modulus));
+	for (i = 0; i < sizeof(pbMyPubKey.Modulus); i++)
+		pbMyPubKey.Modulus[i] = rsa_pubkey_modulus[sizeof(rsa_pubkey_modulus) -1 - i];
+
+	// Import our RSA public key so that the MS API can use it
+	r = CryptImportKey(hProv, (BYTE*)&pbMyPubKey.BlobHeader, dwMyPubKeyLen, 0, 0, &hPubKey);
+	if (!r) {
+		uprintf("Could not import public key: %s", WinPKIErrorString());
+		goto out;
+	}
+
+	// Create the hash object.
+	r = CryptCreateHash(hProv, CALG_SHA_256, 0, 0, &hHash);
+	if (!r) {
+		uprintf("Could not create empty hash: %s", WinPKIErrorString());
+		goto out;
+	}
+
+	// Compute the cryptographic hash of the buffer.
+	r = CryptHashData(hHash, pbBuffer, dwBufferLen, 0);
+	if (!r) {
+		uprintf("Could not hash data: %s", WinPKIErrorString());
+		goto out;
+	}
+
+	// Reverse the signature bytes
+	for (i = 0, j = dwSigLen - 1; i < j; i++, j--) {
+		t = pbSignature[i];
+		pbSignature[i] = pbSignature[j];
+		pbSignature[j] = t;
+	}
+
+	// Now that we have all of the public key, hash and signature data in a
+	// format that Microsoft can handle, we can call CryptVerifySignature().
+	r = CryptVerifySignature(hHash, pbSignature, dwSigLen, hPubKey, NULL, 0);
+	if (!r)
+		uprintf("Signature validation failed: %s", WinPKIErrorString());
+
+out:
+	if (hHash)
+		CryptDestroyHash(hHash);
+	if (hProv)
+		CryptReleaseContext(hProv, 0);
+	return r;
+}

src/rufus.c

@@ -1567,7 +1567,7 @@ static BOOL BootCheck(void)
 					IGNORE_RETVAL(_chdir(tmp));
 					static_sprintf(tmp, "%s/%s-%s/%s", FILES_URL, grub, img_report.grub2_version, core_img);
 					PromptOnError = FALSE;
-					grub2_len = (long)DownloadFile(tmp, core_img, hMainDialog);
+					grub2_len = (long)DownloadSignedFile(tmp, core_img, hMainDialog);
 					PromptOnError = TRUE;
 					if ((grub2_len == 0) && (DownloadStatus == 404)) {
 						// Couldn't locate the file on the server => try to download without the version extra
@@ -1578,7 +1578,7 @@ static BOOL BootCheck(void)
 						tmp2[i] = 0;
 						static_sprintf(tmp, "%s/%s-%s/%s", FILES_URL, grub, tmp2, core_img);
 						PromptOnError = FALSE;
-						grub2_len = (long)DownloadFile(tmp, core_img, hMainDialog);
+						grub2_len = (long)DownloadSignedFile(tmp, core_img, hMainDialog);
 						PromptOnError = TRUE;
 						static_sprintf(tmp, "%s/%s-%s/%s", FILES_URL, grub, img_report.grub2_version, core_img);
 					}
@@ -1624,7 +1624,7 @@ static BOOL BootCheck(void)
 								static_sprintf(tmp, "%s-%s", syslinux, embedded_sl_version_str[0]);
 								IGNORE_RETVAL(_mkdir(tmp));
 								static_sprintf(tmp, "%s/%s-%s/%s", FILES_URL, syslinux, embedded_sl_version_str[0], old_c32_name[i]);
-								len = DownloadFile(tmp, &tmp[sizeof(FILES_URL)], hMainDialog);
+								len = DownloadSignedFile(tmp, &tmp[sizeof(FILES_URL)], hMainDialog);
 								if (len == 0) {
 									uprintf("Could not download file - cancelling");
 									return FALSE;
@@ -1672,14 +1672,14 @@ static BOOL BootCheck(void)
 						static_sprintf(tmp, "%s/%s-%s%s/%s.%s", FILES_URL, syslinux, img_report.sl_version_str,
 							img_report.sl_version_ext, ldlinux, ldlinux_ext[i]);
 						PromptOnError = (*img_report.sl_version_ext == 0);
-						syslinux_ldlinux_len[i] = DownloadFile(tmp, &tmp[sizeof(FILES_URL)], hMainDialog);
+						syslinux_ldlinux_len[i] = DownloadSignedFile(tmp, &tmp[sizeof(FILES_URL)], hMainDialog);
 						PromptOnError = TRUE;
 						if ((syslinux_ldlinux_len[i] == 0) && (DownloadStatus == 404) && (*img_report.sl_version_ext != 0)) {
 							// Couldn't locate the file on the server => try to download without the version extra
 							uprintf("Extended version was not found, trying main version...");
 							static_sprintf(tmp, "%s/%s-%s/%s.%s", FILES_URL, syslinux, img_report.sl_version_str,
 								ldlinux, ldlinux_ext[i]);
-							syslinux_ldlinux_len[i] = DownloadFile(tmp, &tmp[sizeof(FILES_URL)], hMainDialog);
+							syslinux_ldlinux_len[i] = DownloadSignedFile(tmp, &tmp[sizeof(FILES_URL)], hMainDialog);
 							if (syslinux_ldlinux_len[i] != 0) {
 								// Duplicate the file so that the user won't be prompted to download again
 								static_sprintf(tmp, "%s-%s\\%s.%s", syslinux, img_report.sl_version_str, ldlinux, ldlinux_ext[i]);
@@ -1722,7 +1722,7 @@ static BOOL BootCheck(void)
 				static_sprintf(tmp, "%s-%s", syslinux, embedded_sl_version_str[1]);
 				IGNORE_RETVAL(_mkdir(tmp));
 				static_sprintf(tmp, "%s/%s-%s/%s.%s", FILES_URL, syslinux, embedded_sl_version_str[1], ldlinux, ldlinux_ext[2]);
-				if (DownloadFile(tmp, &tmp[sizeof(FILES_URL)], hMainDialog) == 0)
+				if (DownloadSignedFile(tmp, &tmp[sizeof(FILES_URL)], hMainDialog) == 0)
 					return FALSE;
 			}
 		}
@@ -1752,7 +1752,7 @@ static BOOL BootCheck(void)
 				static_sprintf(tmp, "grub4dos-%s", GRUB4DOS_VERSION);
 				IGNORE_RETVAL(_mkdir(tmp));
 				static_sprintf(tmp, "%s/grub4dos-%s/grldr", FILES_URL, GRUB4DOS_VERSION);
-				if (DownloadFile(tmp, &tmp[sizeof(FILES_URL)], hMainDialog) == 0)
+				if (DownloadSignedFile(tmp, &tmp[sizeof(FILES_URL)], hMainDialog) == 0)
 					return FALSE;
 			}
 		}
@@ -2978,7 +2978,7 @@ static INT_PTR CALLBACK MainCallback(HWND hDlg, UINT message, WPARAM wParam, LPA
 	case WM_COMMAND:
 #ifdef RUFUS_TEST
 		if (LOWORD(wParam) == IDC_TEST) {
-			Notification(MSG_ERROR, NULL, lmprintf(MSG_042), lmprintf(MSG_043, lmprintf(MSG_055)));
+			DownloadSignedFile(FILES_URL "/gendb.sh", "C:\\Downloads\\gendb.sh", hProgress);
 			break;
 		}
 #endif

src/rufus.h

@@ -80,6 +80,7 @@
 #define FAT32_CLUSTER_THRESHOLD     1.011f		// For FAT32, cluster size changes don't occur at power of 2 boundaries but sligthly above
 #define DD_BUFFER_SIZE              65536		// Minimum size of the buffer we use for DD operations
 #define UBUFFER_SIZE                2048
+#define RSA_SIGNATURE_SIZE          256
 #define CBN_SELCHANGE_INTERNAL      (CBN_SELCHANGE + 256)
 #define RUFUS_URL                   "https://rufus.ie"
 #define DOWNLOAD_URL                RUFUS_URL "/downloads"
@@ -475,8 +476,8 @@ extern BOOL ResetDevice(int index);
 extern BOOL GetOpticalMedia(IMG_SAVE* img_save);
 extern BOOL SetLGP(BOOL bRestore, BOOL* bExistingKey, const char* szPath, const char* szPolicy, DWORD dwValue);
 extern LONG GetEntryWidth(HWND hDropDown, const char* entry);
-extern DWORD DownloadFile(const char* url, const char* file, HWND hProgressDialog);
+extern DWORD DownloadSignedFile(const char* url, const char* file, HWND hProgressDialog);
-extern HANDLE DownloadFileThreaded(const char* url, const char* file, HWND hProgressDialog);
+extern HANDLE DownloadSignedFileThreaded(const char* url, const char* file, HWND hProgressDialog);
 extern INT_PTR CALLBACK UpdateCallback(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam);
 extern BOOL SetUpdateCheck(void);
 extern BOOL CheckForUpdates(BOOL force);
@@ -503,6 +504,7 @@ extern int IsHDD(DWORD DriveIndex, uint16_t vid, uint16_t pid, const char* strid
 extern char* GetSignatureName(const char* path, const char* country_code);
 extern uint64_t GetSignatureTimeStamp(const char* path);
 extern LONG ValidateSignature(HWND hDlg, const char* path);
+extern BOOL ValidateOpensslSignature(BYTE* pbBuffer, DWORD dwBufferLen, BYTE* pbSignature, DWORD dwSigLen);
 extern BOOL IsFontAvailable(const char* font_name);
 extern BOOL WriteFileWithRetry(HANDLE hFile, LPCVOID lpBuffer, DWORD nNumberOfBytesToWrite,
 	LPDWORD lpNumberOfBytesWritten, DWORD nNumRetries);

src/rufus.rc

@@ -33,7 +33,7 @@ LANGUAGE LANG_NEUTRAL, SUBLANG_NEUTRAL
 IDD_DIALOG DIALOGEX 12, 12, 232, 326
 STYLE DS_SETFONT | DS_MODALFRAME | DS_CENTER | WS_MINIMIZEBOX | WS_POPUP | WS_CAPTION | WS_SYSMENU
 EXSTYLE WS_EX_ACCEPTFILES
-CAPTION "Rufus 3.2.1324"
+CAPTION "Rufus 3.2.1325"
 FONT 9, "Segoe UI Symbol", 400, 0, 0x0
 BEGIN
     LTEXT           "Drive Properties",IDS_DRIVE_PROPERTIES_TXT,8,6,53,12,NOT WS_GROUP
@@ -389,8 +389,8 @@ END
 //
 
 VS_VERSION_INFO VERSIONINFO
- FILEVERSION 3,2,1324,0
+ FILEVERSION 3,2,1325,0
- PRODUCTVERSION 3,2,1324,0
+ PRODUCTVERSION 3,2,1325,0
  FILEFLAGSMASK 0x3fL
 #ifdef _DEBUG
  FILEFLAGS 0x1L
@@ -407,13 +407,13 @@ BEGIN
         BEGIN
             VALUE "CompanyName", "Akeo Consulting (http://akeo.ie)"
             VALUE "FileDescription", "Rufus"
-            VALUE "FileVersion", "3.2.1324"
+            VALUE "FileVersion", "3.2.1325"
             VALUE "InternalName", "Rufus"
             VALUE "LegalCopyright", "© 2011-2018 Pete Batard (GPL v3)"
             VALUE "LegalTrademarks", "http://www.gnu.org/copyleft/gpl.html"
             VALUE "OriginalFilename", "rufus.exe"
             VALUE "ProductName", "Rufus"
-            VALUE "ProductVersion", "3.2.1324"
+            VALUE "ProductVersion", "3.2.1325"
         END
     END
     BLOCK "VarFileInfo"

src/stdlg.c

@@ -1630,7 +1630,7 @@ INT_PTR CALLBACK NewVersionCallback(HWND hDlg, UINT message, WPARAM wParam, LPAR
 				si.cb = sizeof(si);
 				if (!CreateProcessU(filepath, cmdline, NULL, NULL, FALSE, 0, NULL, NULL, &si, &pi)) {
 					PrintInfo(0, MSG_214);
-					uprintf("Failed to launch new application: %s\n", WindowsErrorString());
+					uprintf("Failed to launch new application: %s", WindowsErrorString());
 				} else {
 					PrintInfo(0, MSG_213);
 					PostMessage(hDlg, WM_COMMAND, (WPARAM)IDCLOSE, 0);
@@ -1639,19 +1639,19 @@ INT_PTR CALLBACK NewVersionCallback(HWND hDlg, UINT message, WPARAM wParam, LPAR
 				break;
 			default:	// Download
 				if (update.download_url == NULL) {
-					uprintf("Could not get download URL\n");
+					uprintf("Could not get download URL");
 					break;
 				}
 				for (i=(int)strlen(update.download_url); (i>0)&&(update.download_url[i]!='/'); i--);
 				dl_ext.filename = &update.download_url[i+1];
 				filepath = FileDialog(TRUE, app_dir, &dl_ext, OFN_NOCHANGEDIR);
 				if (filepath == NULL) {
-					uprintf("Could not get save path\n");
+					uprintf("Could not get save path");
 					break;
 				}
 				// Opening the File Dialog will make us lose tabbing focus - set it back
 				SendMessage(hDlg, WM_NEXTDLGCTL, (WPARAM)GetDlgItem(hDlg, IDC_DOWNLOAD), TRUE);
-				DownloadFileThreaded(update.download_url, filepath, hDlg);
+				DownloadSignedFileThreaded(update.download_url, filepath, hDlg);
 				break;
 			}
 			return (INT_PTR)TRUE;