On 06/01/2011 06:47 AM, cedric.vinc...@st.com wrote:
> On Wed, Jun 01, 2011 at 03:26:09PM +0200, Richard Henderson wrote:
>>
>> 16 bytes, not 16 bits.
>
> You're right it's not 16 bits, it's "sizeof(uintptr_t)" actually:
No, it's not.
unsigned char k_rand_bytes[16];
elf_addr_t __user *u_rand_bytes;
...
/*
* Generate 16 random bytes for userspace PRNG seeding.
*/
get_random_bytes(k_rand_bytes, sizeof(k_rand_bytes));
u_rand_bytes = (elf_addr_t __user *)
STACK_ALLOC(p, sizeof(k_rand_bytes));
if (__copy_to_user(u_rand_bytes, k_rand_bytes, sizeof(k_rand_bytes)))
return -EFAULT;
...
NEW_AUX_ENT(AT_RANDOM, (elf_addr_t)(unsigned long)u_rand_bytes);
Frankly, it's trivial to do this right in create_elf_tables.
Grab 16 bytes at SP right at the beginning of the function,
fill it with whatever random values seem good.
I suggest at minimum a command-line argument to force a
particular AT_RANDOM value, for repeatability.
r~
