[PATCH] fs: squasfs: fix a possible NULL pointer dereference in sqfs_opendir()

[Miquel Raynal <miquel.raynal@bootlin.com>]

Hi Richard,

Richard Genoud <richard.genoud@posteo.net> wrote on Mon, 21 Dec 2020
16:06:37 +0100:

> Hi Miquel,
> 
> Le 18/12/2020 ? 19:50, Miquel Raynal a ?crit?:
> > Hi Richard,
> > 
> > Richard Genoud <richard.genoud@posteo.net> wrote on Fri, 18 Dec 2020
> > 15:24:40 +0100:
> >   
> >> token_count may be != 0 and token_list not yet allocated when the out
> >> code is reached  
> > 
> > Wouldn't it be better to initialize token_count than adding an
> > (obscure) indentation level?  
> Well, token_count is initialized :
> token_count = sqfs_count_tokens(filename);
> 
> But token_list is not yet populated. It is some lines bellow:
> token_list = malloc(token_count * sizeof(char *));
> 
> 
> But I could use something like that, maybe it's clearer :
> 	for (j = 0; (token_list != NULL) && (j < token_count); j++)
> 		free(token_list[j]);

I had a look at the code, the error path is clearly not correctly
organized.

I think the right approach would be to have real labels like,
free_token_list, free_this, free_that and for each of them only do the
right cleanup. Doing so should fix the issue.

Thanks,
Miqu?l