system/freebsd-src
system/freebsd-src
1
0
Fork 0
mirror of https://github.com/freebsd/freebsd-src synced 2024-11-05 18:22:52 +00:00
Code Issues Projects Releases Packages Wiki Activity

Fixed arg order in an outb() call. add_timer_randomness() clobbered

Browse source 
part of the DMA channel 0 address and wasn't random in the intended
way.
Submitted by:	KATO Takenori <kato@eclogite.eps.nagoya-u.ac.jp>

Disable interrupts while reading the clock.  This probably isn't
important (allowing interrupts probably increased randomness in
the usual case).

Removed __i386__ ifdef.  This file is in an i386 directory and has
other i386 dependencies.
This commit is contained in:
Bruce Evans 1995-12-22 15:20:50 +00:00
parent 526d7a354a
commit aa67202b2b
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=12963
1 changed files with 9 additions and 6 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

15
sys/i386/isa/random.c
View file

@ -1,7 +1,7 @@
/*
* random.c -- A strong random number generator
*
* $Id: random.c,v 1.2 1995/11/04 16:00:50 markm Exp $
* $Id: random.c,v 1.3 1995/11/20 12:12:02 phk Exp $
*
* Version 0.92, last modified 21-Sep-95
*
@ -303,6 +303,7 @@ add_timer_randomness(struct random_bucket *r, struct timer_rand_state *state,
{
int delta, delta2;
int nbits;
u_int8_t timer_high, timer_low;
/*
* Calculate number of bits of randomness we probably
@ -321,19 +322,21 @@ add_timer_randomness(struct random_bucket *r, struct timer_rand_state *state,
add_entropy(r, (u_int8_t *) &ticks, sizeof(ticks), nbits, delay);
#if defined (__i386__)
/*
* On a 386, read the high resolution timer. We assume that
* this gives us 2 bits of randomness. XXX This needs
* investigation.
*/
outb(TIMER_LATCH|TIMER_SEL0, TIMER_MODE); /* latch the count ASAP */
add_entropy_byte(r, inb(TIMER_CNTR0), 1);
add_entropy_byte(r, inb(TIMER_CNTR0), 1);
disable_intr();
outb(TIMER_MODE, TIMER_SEL0 | TIMER_LATCH);
timer_low = inb(TIMER_CNTR0);
timer_high = inb(TIMER_CNTR0);
enable_intr();
add_entropy_byte(r, timer_low, 1);
add_entropy_byte(r, timer_high, 1);
r->entropy_count += 2;
if (r->entropy_count > r->bit_length)
r->entropy_count = r->bit_length;
#endif
}
void