[Geany-Devel] CodeAi Fixes a Null Pointer Dereference

[Lex Trotman]

On 11 May 2017 at 08:10, Benjamin Bales <benjamin.bales at qbitlogic.com>
wrote:

> CodeAi (https://github.com/C0deAi), an automated repair tool developed at
> QbitLogic (www.qbitlogic.com), suggested the following fix. Could I
> submit it as a patch if it looks alright?
>
> plugins/saveactions.c: “doc->file_type” pointer might be dereferenced when
> null on line 283.  Initialization may be provided by “doc” passed in as a
> function argument, but a null check would be prudent just in case. The fix
> checks “doc->file_type” for null before allowing a dereference on the
> following line.  A snapshot of the bug report generated by CodeAi is
> attached.  A full report is available upon request.
>

This function is called (via the signal framework) by the function that
created `doc` and as such cannot be null.  The design of the application
uses the signal framework to decouple caller and callee and this is likely
to confuse your tool since it cannot see where functions are called.
Whilst any contributions are welcome, a report with a lot of similar false
positives may end up being ignored and be a bad advertisement for your tool.

Cheers
Lex



>
> diff --git a/plugins/saveactions.c b/plugins/saveactions.c
>
> @@ -280,8 +280,10 @@ static void instantsave_document_new_cb(GObject
> *obj, GeanyDocument *doc, gpoint
>
>
>
>   doc->file_name = new_filename;
>
>
>
> - if (doc->file_type->id == GEANY_FILETYPES_NONE)
>
> + if(doc->file_type) {
>
> +    if (doc->file_type->id == GEANY_FILETYPES_NONE)
>
>   document_set_filetype(doc, filetypes_lookup_by_name(
> instantsave_default_ft));
>
> + }
>
>
>
>   /* force saving the file to enable all the related actions(tab name,
> filetype, etc.) */
>
>   document_save_file(doc, TRUE);
>
> /* force saving the file to enable all the related actions(tab name,
> filetype, etc.) */
>
> document_save_file(doc, TRUE);
>
>     }
>
> }
>
> Base-commit: 84253714771f48dbc7fab02f7de43f253734dee2
>
> Please let me know if you are interested in seeing more fixes from our
> tool. Thanks!
>
> Sincerely,
> --
> Benjamin Bales
> Chief Technology Officer
> [image: QbitLogic]
> 1050 Crown Pointe Pkwy, Ste. 840
> Atlanta, GA 30338
> 470-554-2690
>
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