[klibc] [PATCH] add mkstemp(3) using entropy from ELF aux vector AT_RANDOM

[H. Peter Anvin]

On 01/28/2012 01:15 PM, Thorsten Glaser wrote:
> --- a/usr/klibc/libc_init.c
> +++ b/usr/klibc/libc_init.c
> @@ -34,6 +34,9 @@
>  char **environ;
>  unsigned int __page_size, __page_shift;
>  
> +/* for use with jrand48() and friends */
> +unsigned short __klibc_rand48[3];
> +
>  struct auxentry {
>  	uintptr_t type;
>  	uintptr_t v;
> @@ -85,6 +88,10 @@ __noreturn __libc_init(uintptr_t * elfdata, void (*onexit) (void))
>  		case AT_PAGESZ:
>  			page_size = (unsigned int)(auxentry->v);
>  			break;
> +		case AT_RANDOM:
> +			memcpy(__klibc_rand48, (void *)(auxentry->v),
> +			    sizeof(__klibc_rand48));
> +			break;
>  		}
>  		auxentry++;
>  	}

I suspect this kind of automatic seeding violates the POSIX definitions
of these functions.  Not 100% sure though.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.