Messages in this thread | | | From | Geert Uytterhoeven <> | Date | Mon, 19 Jul 2021 09:53:29 +0200 | Subject | Re: [PATCH] staging/fbtft: Remove all strcpy() uses |
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On Sun, Jul 18, 2021 at 9:43 PM Andy Shevchenko <andy.shevchenko@gmail.com> wrote: > On Sun, Jul 18, 2021 at 4:43 PM Len Baker <len.baker@gmx.com> wrote: > > strcpy() performs no bounds checking on the destination buffer. This > > could result in linear overflows beyond the end of the buffer, leading > > to all kinds of misbehaviors. The safe replacement is strscpy() but in > > this case it is simpler to add NULL to the first position since we want
"NULL" is a pointer value, "NUL" is the character with value zero.
> > to empty the string. > > > This is a previous step in the path to remove the strcpy() function. > > Any document behind this (something to read on the site(s) more or > less affiliated with what is going to happen in the kernel) to read > background? > > ... > > > case -1: > > i++; > > /* make debug message */ > > - strcpy(msg, "");
While this strcpy() is provably safe at compile-time, and will probably be replaced by an assignment to zero by the compiler...
> > + msg[0] = 0; > > Strictly speaking it should be '\0'. > > > j = i + 1; > > while (par->init_sequence[j] >= 0) { > > sprintf(str, "0x%02X ", par->init_sequence[j]);
... the real danger is the
strcat(msg, str);
on the next line. Fortunately this whole debug printing block (including the strcpy) can (and should) be rewritten to just use "%*ph".
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-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
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