On Thu, Jul 10, 2014 at 10:28:35AM -0700, Matthew Dempsky wrote:
> +/*
> + * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX
> + * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW
> + */
> +#define MUL_NO_OVERFLOW (1UL << (sizeof(size_t) * 4))
> +
> +void *
> +mallocarray(unsigned long nmemb, unsigned long size, int type, int flags)
> +{
> + if ((nmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
> + nmemb > 0 && SIZE_MAX / nmemb < size) {
> + if (flags & M_CANFAIL)
> + return (NULL);
> + panic("overflow");
> + }
> + return (malloc(size * nmemb, type, flags));
> +}
Oops, didn't fully convert size_t -> unsigned long to match malloc(9).
(size_t *is* unsigned long currently on all of our architectures, but
technically that's supposed to be opaque.)
Fixed kern_mallocarray.c below.
/* $OpenBSD$ */
/*
* Copyright (c) 2008 Otto Moerbeek <[email protected]>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/param.h>
#include <sys/limits.h>
#include <sys/malloc.h>
#include <sys/systm.h>
/*
* This is sqrt(ULONG_MAX+1), as s1*s2 <= ULONG_MAX
* if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW
*/
#define MUL_NO_OVERFLOW (1UL << (sizeof(unsigned long) * 4))
void *
mallocarray(unsigned long nmemb, unsigned long size, int type, int flags)
{
if ((nmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
nmemb > 0 && ULONG_MAX / nmemb < size) {
if (flags & M_CANFAIL)
return (NULL);
panic("overflow");
}
return (malloc(size * nmemb, type, flags));
}
