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Date: Sun, 30 Sep 2012 20:59:05 +0200 From: Geert Uytterhoeven <geert@...ux-m68k.org> To: Greg Kroah-Hartman <gregkh@...uxfoundation.org> Cc: Alex Williamson <alex.williamson@...com>, Alex Chiang <achiang@...com>, linux-kernel@...r.kernel.org, stable@...r.kernel.org Subject: Re: [PATCH] sysfs: sysfs_pathname/sysfs_add_one: Use strlcat() instead of strcat() Hi Greg, On Sun, Sep 30, 2012 at 4:49 PM, Greg Kroah-Hartman <gregkh@...uxfoundation.org> wrote: > On Sat, Sep 29, 2012 at 10:23:19PM +0200, Geert Uytterhoeven wrote: >> The warning check for duplicate sysfs entries can cause a buffer overflow >> when printing the warning, as strcat() doesn't check buffer sizes. >> Use strlcat() instead. > > As the comment said, we knew about this, but I have never seen it, do > you know of a way to trigger it? I expected there would be a check somewhere else in the code, so we can never overflow here. But I did manage to overflow the buffer by having a real long name (4060 characters) in a conflicting mfd_cell. There may be other ways. I don't know how likely it is to trigger in a real world scenario. Is there a limit on the depth of sysfs? Or can it go unbounded, e.g. by cascading USB hubs? >> Cc: stable@...r.kernel.org > > Given that I don't know of any way to actually hit this problem, is it > really needed for older kernel releases? That's up to you to decide... Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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