linux-kernel - Re: [PATCH] scripts/kallsyms: fix memory corruption caused by write over-run

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Message-ID: <CAK7LNARV34onaXiZA-UAvKZdwnfX_D3g=k0a8EJkD4HzEWRo-Q@mail.gmail.com>
Date:   Tue, 11 Feb 2020 23:46:38 +0900
From:   Masahiro Yamada <masahiroy@...nel.org>
To:     Justin Capella <justincapella@...il.com>
Cc:     Linux Kbuild mailing list <linux-kbuild@...r.kernel.org>,
        youling257 <youling257@...il.com>, Pavel Machek <pavel@....cz>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] scripts/kallsyms: fix memory corruption caused by write over-run

Hi.

On Tue, Feb 11, 2020 at 11:36 AM Justin Capella <justincapella@...il.com> wrote:
>
> Looks like len is already +1, maybe it shouldn't be?

This increment is for storing one more character, 'type'.

        sym->sym[0] = type;



> >         len = strlen(name) + 1;
> >
> > -       sym = malloc(sizeof(*sym) + len);
> > +       sym = malloc(sizeof(*sym) + len + 1);


This increment is for the '\0' termination.



So, malloc() needs to allocate:
sizeof(*sym) + strlen(name) + 2.





>
>
> Maybe strlcpy or if len wasn't incremented?
>
> >
> > -       memcpy(sym_name(sym), name, len);
> > +       strcpy(sym_name(sym), name);
> >



-- 
Best Regards
Masahiro Yamada