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Re: wprintf/vfprintf.c vs. large precision: allocates far too much memory
- From: Wolfram Gloger <wmglo at dent dot med dot uni-muenchen dot de>
- To: libc-alpha at sourceware dot org
- Date: 5 May 2007 17:23:26 -0000
- Subject: Re: wprintf/vfprintf.c vs. large precision: allocates far too much memory
- References: <firstname.lastname@example.org>
> Here's an untested patch to protect against an inordinately large
> precision. However, if the string itself has length SIZE_MAX / 4
> or greater, the expressions still overflow.
> diff --git a/stdio-common/vfprintf.c b/stdio-common/vfprintf.c
> index 20c07ce..1e2d928 100644
> --- a/stdio-common/vfprintf.c
> +++ b/stdio-common/vfprintf.c
> @@ -1026,7 +1026,9 @@ vfprintf (FILE *s, const CHAR_T *format, va_list ap)
> const char *mbs = (const char *) string; \
> mbstate_t mbstate; \
> - len = prec != -1 ? (size_t) prec : strlen (mbs); \
> + len = strlen (mbs); \
> + if (prec != -1) \
> + len = (size_t) prec; \
I've stared at this patch for 4 minutes now, and even accounting for
potential traps with arithmetic conversion I can't see any effect..