Re: [PATCH] 2.4 vsnprintf fix.

Crutcher Dunnavant (crutcher@datastacks.com)
Fri, 21 Sep 2001 15:26:26 -0400

++ 20/09/01 21:29 +1000 - Rusty Russell:
> Following patch fixes calling vsnprintf with (NULL, 0) to get the
> length of the string. The problem is that the end ptr is set to
> 0xFFFFFFFF in this case, causing a write into address 0 as start <
> end.

Doh! Egg on face. Between this and the sysrq bugs, I'm thinking of going
into dance instead of hacking anymore. Sorry about this, it is a basic
mistake (right up there with going up against a scicilian when death is
on the line.)

>
> Cheers,
> Rusty.
> --
> Premature optmztion is rt of all evl. --DK
>
> --- working-pmac-module/lib/vsprintf.c.~1~ Mon Sep 17 08:53:56 2001
> +++ working-pmac-module/lib/vsprintf.c Thu Sep 20 21:26:05 2001
> @@ -246,6 +246,8 @@
> /* 'z' support added 23/7/1999 S.H. */
> /* 'z' changed to 'Z' --davidm 1/25/99 */
>
> + /* buf = NULL, size = 0 is common for getting length */
> + if (size == 0) buf = (void *)1;
> str = buf;
> end = buf + size - 1;
> -
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-- 
Crutcher        <crutcher@datastacks.com>
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