add firmware validity sanity check

user/cgiflash.c

@@ -13,11 +13,21 @@ Some flash handling cgi routines. Used for reading the existing flash and updati
 
 
 #include <esp8266.h>
+#include <osapi.h>
 #include "cgiflash.h"
 #include "espfs.h"
 
+// Check that the header of the firmware blob looks like actual firmware...
+static char* ICACHE_FLASH_ATTR check_header(void *buf) {
+	uint8_t *cd = (uint8_t *)buf;
+	if (cd[0] != 0xEA) return "IROM magic missing";
+	if (cd[1] != 4 || cd[2] > 3 || cd[3] > 0x40) return "bad flash header";
+	if (((uint16_t *)buf)[3] != 0x4010) return "Invalid entry addr";
+	if (((uint32_t *)buf)[2] != 0) return "Invalid start offset";
+	return NULL;
+}
 
-//Cgi that reads the SPI flash. Assumes 512KByte flash.
+//===== Cgi that reads the SPI flash. Assumes 512KByte flash.
 int ICACHE_FLASH_ATTR cgiReadFlash(HttpdConnData *connData) {
 	int *pos=(int *)&connData->cgiData;
 	if (connData->conn==NULL) {
@@ -39,7 +49,7 @@ int ICACHE_FLASH_ATTR cgiReadFlash(HttpdConnData *connData) {
 	if (*pos>=0x40200000+(512*1024)) return HTTPD_CGI_DONE; else return HTTPD_CGI_MORE;
 }
 
-// Return which firmware needs to be uploaded next
+//===== Cgi to query which firmware needs to be uploaded next
 int ICACHE_FLASH_ATTR cgiGetFirmwareNext(HttpdConnData *connData) {
 	if (connData->conn==NULL) {
 		//Connection aborted. Clean up.
@@ -49,43 +59,67 @@ int ICACHE_FLASH_ATTR cgiGetFirmwareNext(HttpdConnData *connData) {
 	uint8 id = system_upgrade_userbin_check();
 	httpdStartResponse(connData, 200);
 	httpdHeader(connData, "Content-Type", "text/plain");
+	httpdHeader(connData, "Content-Length", "9");
 	httpdEndHeaders(connData);
-	httpdSend(connData, (id == 1 ? "user1.bin" : "user2.bin"), -1);
-	os_printf("Next firmware: user%d.bin\n", 1-id);
+	char *next = id == 1 ? "user1.bin" : "user2.bin";
+	httpdSend(connData, next, -1);
+	os_printf("Next firmware: %s (got %d)\n", next, id);
 
 	return HTTPD_CGI_DONE;
 }
 
-//Cgi that allows the firmware to be replaced via http POST
+//===== Cgi that allows the firmware to be replaced via http POST
 int ICACHE_FLASH_ATTR cgiUploadFirmware(HttpdConnData *connData) {
 	if (connData->conn==NULL) {
 		//Connection aborted. Clean up.
 		return HTTPD_CGI_DONE;
 	}
 
-	if(connData->post->len > FIRMWARE_SIZE){
-		// The uploaded file is too large
-		os_printf("Firmware image too large\n");
-		httpdStartResponse(connData, 400);
+	int offset = connData->post->received - connData->post->buffLen;
+	if (offset == 0) {
+		connData->cgiPrivData = NULL;
+	} else if (connData->cgiPrivData != NULL) {
+		// we have an error condition, do nothing
+		return HTTPD_CGI_DONE;
+	}
+
+	// assume no error yet...
+	char *err = NULL;
+	int code = 400;
+
+	// check overall size
+	if (connData->post->len > FIRMWARE_SIZE) err = "Firmware image too large";
+
+	// check that data starts with an appropriate header
+	if (err == NULL && offset == 0) err = check_header(connData->post->buff);
+
+	// make sure we're buffering in 1024 byte chunks
+	if (err == NULL && offset % 1024 != 0) {
+		err = "Buffering problem";
+		code = 500;
+	}
+
+	// return an error if there is one
+	if (err != NULL) {
+		os_printf("Error %d: %s\n", code, err);
+		httpdStartResponse(connData, code);
 		httpdHeader(connData, "Content-Type", "text/plain");
+		//httpdHeader(connData, "Content-Length", strlen(err)+2);
 		httpdEndHeaders(connData);
-		httpdSend(connData, "Firmware image loo large.\r\n", -1);
+		httpdSend(connData, err, -1);
+		httpdSend(connData, "\r\n", -1);
+		connData->cgiPrivData = (void *)1;
 		return HTTPD_CGI_DONE;
 	}
 
+	// let's see which partition we need to flash and what flash address that puts us at
 	uint8 id = system_upgrade_userbin_check();
+	int address = id == 1 ? 4*1024                   // either start after 4KB boot partition
+	    : 4*1024 + FIRMWARE_SIZE + 16*1024 + 4*1024; // 4KB boot, fw1, 16KB user param, 4KB reserved
+	address += offset;
 
-	int address;
-	if (id == 1) {
-		address = 4*1024; // start after 4KB boot partition
-	} else {
-		// 4KB boot, firmware1, 16KB user param, 4KB reserved
-		address = 4*1024 + FIRMWARE_SIZE + 16*1024 + 4*1024;
-	}
-	address += connData->post->received - connData->post->buffLen;
-
-	if(address % SPI_FLASH_SEC_SIZE == 0){
-		// We need to erase this block
+	// erase next flash block if necessary
+	if (address % SPI_FLASH_SEC_SIZE == 0){
 		os_printf("Erasing flash at 0x%05x (id=%d)\n", address, 2-id);
 		spi_flash_erase_sector(address/SPI_FLASH_SEC_SIZE);
 	}
@@ -96,7 +130,6 @@ int ICACHE_FLASH_ATTR cgiUploadFirmware(HttpdConnData *connData) {
 	spi_flash_write(address, (uint32 *)connData->post->buff, connData->post->buffLen);
 
 	if (connData->post->received == connData->post->len){
-		// TODO: verify the firmware (is there a checksum or something???)
 		httpdStartResponse(connData, 200);
 		httpdEndHeaders(connData);
 		return HTTPD_CGI_DONE;
@@ -105,6 +138,8 @@ int ICACHE_FLASH_ATTR cgiUploadFirmware(HttpdConnData *connData) {
 	}
 }
 
+static ETSTimer flash_reboot_timer;
+
 // Handle request to reboot into the new firmware
 int ICACHE_FLASH_ATTR cgiRebootFirmware(HttpdConnData *connData) {
 	if (connData->conn==NULL) {
@@ -112,16 +147,33 @@ int ICACHE_FLASH_ATTR cgiRebootFirmware(HttpdConnData *connData) {
 		return HTTPD_CGI_DONE;
 	}
 
-	// TODO: sanity-check that the 'next' partition actually contains something that looks like
+	// sanity-check that the 'next' partition actually contains something that looks like
 	// valid firmware
+	uint8 id = system_upgrade_userbin_check();
+	int address = id == 1 ? 4*1024                   // either start after 4KB boot partition
+	    : 4*1024 + FIRMWARE_SIZE + 16*1024 + 4*1024; // 4KB boot, fw1, 16KB user param, 4KB reserved
+	uint32 buf[8];
+	spi_flash_read(address, buf, sizeof(buf));
+	char *err = check_header(buf);
+	if (err != NULL) {
+		os_printf("Error %d: %s\n", 400, err);
+		httpdStartResponse(connData, 400);
+		httpdHeader(connData, "Content-Type", "text/plain");
+		//httpdHeader(connData, "Content-Length", strlen(err)+2);
+		httpdEndHeaders(connData);
+		httpdSend(connData, err, -1);
+		httpdSend(connData, "\r\n", -1);
+		return HTTPD_CGI_DONE;
+	}
 
-	// This hsould probably be forked into a separate task that waits a second to let the
-	// current HTTP request finish...
-	system_upgrade_flag_set(UPGRADE_FLAG_FINISH);
-	system_upgrade_reboot();
 	httpdStartResponse(connData, 200);
+	httpdHeader(connData, "Content-Length", "0");
 	httpdEndHeaders(connData);
+
+	// Schedule a reboot
+	system_upgrade_flag_set(UPGRADE_FLAG_FINISH);
+	os_timer_disarm(&flash_reboot_timer);
+	os_timer_setfn(&flash_reboot_timer, (os_timer_func_t *)system_upgrade_reboot, NULL);
+	os_timer_arm(&flash_reboot_timer, 2000, 1);
 	return HTTPD_CGI_DONE;
 }
-
-