RISC OS: fix up use of strncpy

Ensure that strings copied using strncpy are NUL terminated.

Additionally, replace use of strncpy entirely where we are writing
into non-indirected OS icon blocks (where an unterminated 12
character long string is perfectly valid).

4 files changed, 20 insertions, 13 deletions

diff --git a/frontends/riscos/download.c b/frontends/riscos/download.c
index bdc705426..216f5750c 100644
--- a/frontends/riscos/download.c
+++ b/frontends/riscos/download.c
@@ -313,8 +313,8 @@ gui_download_window_create(download_context *ctx, struct gui_window *gui)
 	/** @todo change this to take a reference to the nsurl and use
 	 * that value directly rather than using a fixed buffer.
 	 */
-	strncpy(dw->url, nsurl_access(url), sizeof dw->url);
-	dw->url[sizeof dw->url - 1] = 0;
+	strncpy(dw->url, nsurl_access(url), sizeof(dw->url) - 1);
+	dw->url[sizeof(dw->url) - 1] = 0;
 
 	dw->status[0] = 0;
 	gettimeofday(&dw->start_time, 0);
@@ -414,7 +414,8 @@ gui_download_window_create(download_context *ctx, struct gui_window *gui)
 		return 0;
 	}
 	else {
-		strncpy(dw->path, local_path, sizeof dw->path);
+		strncpy(dw->path, local_path, sizeof(dw->path) - 1);
+		dw->path[sizeof(dw->path)-1] = 0;
 		free(local_path);
 	}
 
@@ -484,7 +485,8 @@ static void gui_download_window_error(struct gui_download_window *dw,
 	riscos_schedule(-1, ro_gui_download_update_status_wrapper, dw);
 
 	/* place error message in status icon in red */
-	strncpy(dw->status, error_msg, sizeof dw->status);
+	strncpy(dw->status, error_msg, sizeof(dw->status) - 1);
+	dw->status[sizeof(dw->status)-1] = 0;
 	error = xwimp_set_icon_state(dw->window,
 			ICON_DOWNLOAD_STATUS,
 			wimp_COLOUR_RED << wimp_ICON_FG_COLOUR_SHIFT,
@@ -872,11 +874,11 @@ bool ro_gui_download_click(wimp_pointer *pointer)
 		ro_gui_drag_icon(x, y, sprite);
 
 	} else if (pointer->i == ICON_DOWNLOAD_DESTINATION) {
-		char command[256] = "Filer_OpenDir ";
+		char command[sizeof(dw->path) + 14 + 1] = "Filer_OpenDir ";
 		char *dot;
 
-		strncpy(command + 14, dw->path, 242);
-		command[255] = 0;
+		strncpy(command + 14, dw->path, sizeof(command) - 14 - 1);
+		command[sizeof(command) - 1] = 0;
 		dot = strrchr(command, '.');
 		if (dot) {
 			os_error *error;
@@ -1384,7 +1386,8 @@ bool ro_gui_download_save(struct gui_download_window *dw,
 	}
 
 	dw->saved = true;
-	strncpy(dw->path, file_name, sizeof dw->path);
+	strncpy(dw->path, file_name, sizeof(dw->path) - 1);
+	dw->path[sizeof(dw->path)-1] = 0;
 
 	if (!dw->send_dataload || dw->save_message.data.data_xfer.est_size != -1)
 		ro_gui_download_remember_dir(file_name);
diff --git a/frontends/riscos/gui/button_bar.c b/frontends/riscos/gui/button_bar.c
index 34ae39ae5..50e1de3c1 100644
--- a/frontends/riscos/gui/button_bar.c
+++ b/frontends/riscos/gui/button_bar.c
@@ -189,7 +189,8 @@ struct button_bar *ro_gui_button_bar_create(struct theme_descriptor *theme,
 		icon->bar_next = NULL;
 
 		strncpy(icon->sprite, buttons[def].icon,
-				BUTTONBAR_SPRITE_NAME_LENGTH);
+				BUTTONBAR_SPRITE_NAME_LENGTH - 1);
+		icon->sprite[BUTTONBAR_SPRITE_NAME_LENGTH-1] = 0;
 		snprintf(icon->validation, BUTTONBAR_VALIDATION_LENGTH,
 				"R5;S%s,p%s", icon->sprite, icon->sprite);
 
diff --git a/frontends/riscos/save.c b/frontends/riscos/save.c
index 325bccc51..e6b43f1a3 100644
--- a/frontends/riscos/save.c
+++ b/frontends/riscos/save.c
@@ -40,8 +40,10 @@
 #include "utils/config.h"
 #include "utils/log.h"
 #include "utils/messages.h"
-#include "utils/utf8.h"
+#include "utils/nsoption.h"
 #include "utils/nsurl.h"
+#include "utils/utf8.h"
+#include "utils/utils.h"
 #include "netsurf/browser_window.h"
 #include "netsurf/window.h"
 #include "netsurf/bitmap.h"
@@ -60,7 +62,6 @@
 #include "riscos/menus.h"
 #include "riscos/message.h"
 #include "riscos/mouse.h"
-#include "utils/nsoption.h"
 #include "riscos/query.h"
 #include "riscos/save.h"
 #include "riscos/save_draw.h"
@@ -257,7 +258,8 @@ ro_gui_save_create_thumbnail(struct hlcache_handle *h, const char *name)
 	}
 
 	sprite_header = (osspriteop_header *)(area + 1);
-	strncpy(sprite_header->name, name, 12);
+	memset(sprite_header->name, 0, 12);
+	memcpy(sprite_header->name, name, min(strlen(name), 12));
 
 
 	/* we can't resize the saveas sprite area because it may move
diff --git a/frontends/riscos/window.c b/frontends/riscos/window.c
index 2c442ab2c..2b51c2fb9 100644
--- a/frontends/riscos/window.c
+++ b/frontends/riscos/window.c
@@ -3594,7 +3594,8 @@ static void gui_window_set_title(struct gui_window *g, const char *title)
 					title, scale_disp);
 		}
 	} else {
-		strncpy(g->title, title, sizeof(g->title));
+		strncpy(g->title, title, sizeof(g->title) - 1);
+		g->title[sizeof(g->title)-1] = 0;
 	}
 
 	ro_gui_set_window_title(g->window, g->title);