nsJSON plug-in

[maliktous]

nsJSON::Serialize crashes nsis installer with recent stable chrome default Preferences, which contain a very long (~66 KBytes) `variations_seed` string parameter.

Test case:
Fresh install of google chrome (33.0.1750.154) which contain `variations_seed` parameter.

code:
nsJSON::Set /file "$Prefs"

nsJSON::Serialize /format /file "$Prefs"

I'm using ANSI NSIS v2.46 with nsJSON 1.0.1.0.

Preferences sample:

http://pastebin.com/raw.php?i=Xs4HLBMN

deleting `variations_seed` before serializing workarounds this, but is ugly

code:
nsJSON :: Delete `variations_seed` /end

[maliktous]

nsJSON::Set /file "$Prefs"
nsJSON::Serialize /format /file "$Prefs" 

with following json:

{
   "selectfile": {
      "last_directory": "E:\\"
   },
   "session": {
      "restore_on_startup_migrated": true,
      "startup_urls_migration_time": "13037468179710507"
   }
} 

saves broken json:

{
    "selectfile": {
        "last_directory": "E:\\"
   },
   "
    }
} 

[Yathosho]

{
   "selectfile": {
      "last_directory": "E:\\"
   },
} 

It take it the plugin escapes the last quote, but wouldn't you have to escape the backslash as well?

[Anders]

It take it the plugin escapes the last quote, but wouldn't you have to escape the backslash as well?

"E:\\" should end up as "E:\", there is no escaped quote because that double backslash was already used to create a backslash

[maliktous]

It take it the plugin escapes the last quote, but wouldn't you have to escape the backslash as well?

1. It is a standart Google Chrome Preferences, so it is a valid json. I did not create it manually. I just read it, add my values, then save it.
2. Python parses it correctly:

$ cat test.json
{
   "selectfile": {
      "last_directory": "E:\\"
   },
   "session": {
      "restore_on_startup_migrated": true,
      "startup_urls_migration_time": "13037468179710507"
   }
}
>>> f=open("test.json")
>>> import json
>>> json.load(f)
{u'selectfile': {u'last_directory': u'E:\\'}, u'session': {u'restore_on_startup_migrated': True, u'startup_urls_migration_time': u'13037468179710507'}} 

[Yathosho]

"E:\\" should end up as "E:\", there is no escaped quote because that double backslash was already used to create a backslash

ah, of course. you're right

[maliktous]

nsJSON::Set /file "$Prefs"
nsJSON::Serialize /format /file "$Prefs"
with following json:
saves broken json:

workaround (should be used before Set /file ):

Push `\\"`          # text to be replaced
Push `"`            # replace with
Push all            # replace all occurrences
Push all            # replace all occurrences
Push ${PrefsFile}   # file to replace in
Call AdvReplaceInFile 

[Afrow UK]

I will try to look at the issues this weekend.

Stu

[Afrow UK]

1.0.1.1 - 29th March 2014
* Fixed incorrect handling of escape character (\).

nsJSON::Serialize crashes nsis installer with recent stable chrome default Preferences, which contain a very long (~66 KBytes) `variations_seed` string parameter.

I could not reproduce this with the new build so it may be fixed. The full output string (66224 bytes) is correctly written to the output file for both the ANSI and Unicode versions. No memory access violations were caught in the debugger either.

Stu

[CherryDT]

I can confirm that there is still a problem. The problem happens when the data is >64KB. It doesn't always crash, though, because it's corrupting the heap which might or might not result in a crash.

The source of the problem is that in the Serialize function, you allocate 65536 bytes for pszArg:

code:
PTCHAR pszArg = (PTCHAR)LocalAlloc(LPTR, sizeof(TCHAR) * 65536);

...and later you are using this buffer to store the serialized string:

code:
bOK = JSON_Serialize(g_root, pszArg, bIsFile, bAsUnicode, bFormat);

There is no length check taking place anywhere.

[Afrow UK]

I will work on a fix to automatically increase the buffer size this weekend.

Stu

[Afrow UK]

New version:

1.0.1.2 - 12th July 2014
* Fixed crash on serialization to file for node values larger than 64KB.
* Fixed crash on serialization to stack for JSON larger than NSIS_MAX_STRLEN. The JSON will now be truncated.

The file serialization doesn't use any temporary buffer any more (it just writes directly to the file) so no reallocation was necessary.

Stu

[maliktous]

1.0.1.2 crashes if JSON file starts with Byte order mark

It seems that `nsJSON::Set /file $JSON` works but the next `nsJSON::Set` crashes installer.

I don't know if json can contain BOM, so it is just for your attention, but I guess, at least, it should not crash.

--- "Bad" 2014-09-05 15:53:16.000000000 +0300
+++ "Good" 2014-09-05 15:53:16.000000000 +0300
@@ -1,4 +1,4 @@
-<U+FEFF>{
+{
"test": {

[Afrow UK]

New version:

1.0.1.3 - 18th October 2014
* Added UTF-16LE BOM, UTF-16BE BOM and UTF-8 signature detection for input files (with UTF-16BE conversion to UTF-16LE).
* Fixed formatting errors for the Serialize function.
* Fixed closing bracket or curly brace not being included on Serialize to stack when not using /format.

This should resolve the crash for files with UTF-8 signatures.

My next task is to add HTTP GET/PUT/POST support for use with REST.

Stu

[MeTaNoV]

nsJSON does not support comment

Hi,
I am trying to use nsJSON plug-in and just find out that comment '//' does disturb somehow the parser, and break the reading of any node inside the file...
I'll temporally avoid using comment until I find a proper solution!
Cheers,
Pascal