From e1553d860dc42a819fe71913d5a68a77fbf64a6e Mon Sep 17 00:00:00 2001
From: William Wilgus <wilgus.william@gmail.com>
Date: Mon, 18 Oct 2021 01:23:07 -0400
Subject: Open_Plugin add checksum on struct offsets

Adding a checksum over the struct offset will allow checking
for compatibility across machines rather than using packed structs
to ensure compability

For any file created by the user from the device  this isn't really a concern

But for files between machines, across installs (sim v device),
possibly even across compilers this at least will alert the user
rather than returning junk data

Change-Id: Id0531bbaa7013dce24dece270849f0a10ac99c20
---
 apps/plugins/open_plugins.c | 36 ++++++++++++++++++++++++++----------
 1 file changed, 26 insertions(+), 10 deletions(-)

(limited to 'apps/plugins/open_plugins.c')

diff --git a/apps/plugins/open_plugins.c b/apps/plugins/open_plugins.c
index b8d11d2ae5..3a0c34d8d6 100644
--- a/apps/plugins/open_plugins.c
+++ b/apps/plugins/open_plugins.c
@@ -49,7 +49,8 @@
 static int fd_dat;
 static struct gui_synclist lists;
 struct open_plugin_entry_t op_entry;
-const off_t op_entry_sz = sizeof(struct open_plugin_entry_t);
+static const uint32_t open_plugin_csum = OPEN_PLUGIN_CHECKSUM;
+static const off_t op_entry_sz = sizeof(struct open_plugin_entry_t);
 
 /* we only need the names for the first menu so don't bother reading paths yet */
 const off_t op_name_sz = OPEN_PLUGIN_NAMESZ + (op_entry.name - (char*)&op_entry);
@@ -101,6 +102,15 @@ static bool op_entry_read_name(int fd, int selected_item)
     return op_entry_read(fd, selected_item, op_name_sz);
 }
 
+static int op_entry_checksum(void)
+{
+    if (op_entry.checksum != open_plugin_csum)
+    {
+        return 0;
+    }
+    return 1;
+}
+
 static int op_entry_read_opx(const char *path)
 {
     int ret = -1;
@@ -112,13 +122,14 @@ static int op_entry_read_opx(const char *path)
     if(len > OP_LEN && rb->strcasecmp(&((path)[len-OP_LEN]), "." OP_EXT) == 0)
     {
         fd_opx = rb->open(path, O_RDONLY);
-        if (fd_opx)
+        if (fd_opx >= 0)
         {
             filesize = rb->filesize(fd_opx);
             ret = filesize;
             if (filesize == op_entry_sz && !op_entry_read(fd_opx, 0, op_entry_sz))
                 ret = 0;
-
+            else if (op_entry_checksum() <= 0)
+                ret = 0;
             rb->close(fd_opx);
         }
     }
@@ -131,7 +142,7 @@ static void op_entry_export(int selection)
     int fd = -1;
     char filename [MAX_PATH + 1];
 
-    if (!op_entry_read(fd_dat, selection, op_entry_sz))
+    if (!op_entry_read(fd_dat, selection, op_entry_sz) || op_entry_checksum() <= 0)
         goto failure;
 
     rb->snprintf(filename, MAX_PATH, "%s/%s", PLUGIN_APPS_DIR, op_entry.name);
@@ -161,6 +172,11 @@ failure:
 
 }
 
+static void op_entry_set_checksum(void)
+{
+        op_entry.checksum = open_plugin_csum;
+}
+
 static void op_entry_set_name(void)
 {
     char tmp_buf[OPEN_PLUGIN_NAMESZ+1];
@@ -277,12 +293,12 @@ static int op_entry_transfer(int fd, int fd_tmp,
                             void *data)
 {
     int entries = -1;
-    if (fd_tmp && fd && rb->lseek(fd, 0, SEEK_SET) == 0)
+    if (fd_tmp >= 0 && fd >= 0 && rb->lseek(fd, 0, SEEK_SET) == 0)
     {
         entries = 0;
         while (rb->read(fd, &op_entry, op_entry_sz) == op_entry_sz)
         {
-            if (compfn && compfn(&op_entry, entries, data) > 0)
+            if (compfn && compfn(&op_entry, entries, data) > 0 && op_entry_checksum() > 0)
             {
                 rb->write(fd_tmp, &op_entry, op_entry_sz);
                 entries++;
@@ -359,7 +375,7 @@ static uint32_t op_entry_add_path(const char *key, const char *plugin, const cha
                     op_entry.hash = newhash;
                 }
             }
-
+            op_entry_set_checksum();
             rb->write(fd_tmp, &op_entry, op_entry_sz); /* add new entry first */
         }
         else if(op_entry_read_opx(plugin) == op_entry_sz)
@@ -374,13 +390,13 @@ static uint32_t op_entry_add_path(const char *key, const char *plugin, const cha
                 open_plugin_get_hash(op_entry.path, &hash);
 
             op_entry.hash = hash;
-
+            op_entry_set_checksum();
             rb->write(fd_tmp, &op_entry, op_entry_sz); /* add new entry first */
         }
         else
         {
             if (op_entry.lang_id != LANG_SHORTCUTS)
-                rb->splashf(HZ / 2, rb->str(LANG_OPEN_PLUGIN_NOT_A_PLUGIN), pos);
+                rb->splashf(HZ * 2, rb->str(LANG_OPEN_PLUGIN_NOT_A_PLUGIN), pos);
             return 0;
         }
     }
@@ -845,7 +861,7 @@ reopen_datfile:
         synclist_set(MENU_ID_MAIN, selection, items, 1);
         rb->gui_synclist_draw(&lists);
 
-        while (!exit)
+        while (!exit && fd_dat >= 0)
         {
             action = rb->get_action(CONTEXT_LIST,TIMEOUT_BLOCK);
 
-- 
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