A few /dev/random improvements for the v3.8 merge window.

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Merge tag 'random_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random

Pull random updates from Ted Ts'o:
 "A few /dev/random improvements for the v3.8 merge window."

* tag 'random_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random:
  random: Mix cputime from each thread that exits to the pool
  random: prime last_data value per fips requirements
  random: fix debug format strings
  random: make it possible to enable debugging without rebuild
This commit is contained in:
Linus Torvalds 2012-12-19 20:23:37 -08:00
commit 7005cd3970
2 changed files with 30 additions and 13 deletions

View file

@ -399,7 +399,6 @@ static DECLARE_WAIT_QUEUE_HEAD(random_read_wait);
static DECLARE_WAIT_QUEUE_HEAD(random_write_wait);
static struct fasync_struct *fasync;
#if 0
static bool debug;
module_param(debug, bool, 0644);
#define DEBUG_ENT(fmt, arg...) do { \
@ -410,9 +409,6 @@ module_param(debug, bool, 0644);
blocking_pool.entropy_count,\
nonblocking_pool.entropy_count,\
## arg); } while (0)
#else
#define DEBUG_ENT(fmt, arg...) do {} while (0)
#endif
/**********************************************************************
*
@ -437,6 +433,7 @@ struct entropy_store {
int entropy_count;
int entropy_total;
unsigned int initialized:1;
bool last_data_init;
__u8 last_data[EXTRACT_SIZE];
};
@ -829,7 +826,7 @@ static void xfer_secondary_pool(struct entropy_store *r, size_t nbytes)
bytes = min_t(int, bytes, sizeof(tmp));
DEBUG_ENT("going to reseed %s with %d bits "
"(%d of %d requested)\n",
"(%zu of %d requested)\n",
r->name, bytes * 8, nbytes * 8, r->entropy_count);
bytes = extract_entropy(r->pull, tmp, bytes,
@ -860,7 +857,7 @@ static size_t account(struct entropy_store *r, size_t nbytes, int min,
spin_lock_irqsave(&r->lock, flags);
BUG_ON(r->entropy_count > r->poolinfo->POOLBITS);
DEBUG_ENT("trying to extract %d bits from %s\n",
DEBUG_ENT("trying to extract %zu bits from %s\n",
nbytes * 8, r->name);
/* Can we pull enough? */
@ -882,7 +879,7 @@ static size_t account(struct entropy_store *r, size_t nbytes, int min,
}
}
DEBUG_ENT("debiting %d entropy credits from %s%s\n",
DEBUG_ENT("debiting %zu entropy credits from %s%s\n",
nbytes * 8, r->name, r->limit ? "" : " (unlimited)");
spin_unlock_irqrestore(&r->lock, flags);
@ -957,6 +954,10 @@ static ssize_t extract_entropy(struct entropy_store *r, void *buf,
ssize_t ret = 0, i;
__u8 tmp[EXTRACT_SIZE];
/* if last_data isn't primed, we need EXTRACT_SIZE extra bytes */
if (fips_enabled && !r->last_data_init)
nbytes += EXTRACT_SIZE;
trace_extract_entropy(r->name, nbytes, r->entropy_count, _RET_IP_);
xfer_secondary_pool(r, nbytes);
nbytes = account(r, nbytes, min, reserved);
@ -967,6 +968,17 @@ static ssize_t extract_entropy(struct entropy_store *r, void *buf,
if (fips_enabled) {
unsigned long flags;
/* prime last_data value if need be, per fips 140-2 */
if (!r->last_data_init) {
spin_lock_irqsave(&r->lock, flags);
memcpy(r->last_data, tmp, EXTRACT_SIZE);
r->last_data_init = true;
nbytes -= EXTRACT_SIZE;
spin_unlock_irqrestore(&r->lock, flags);
extract_buf(r, tmp);
}
spin_lock_irqsave(&r->lock, flags);
if (!memcmp(tmp, r->last_data, EXTRACT_SIZE))
panic("Hardware RNG duplicated output!\n");
@ -1086,6 +1098,7 @@ static void init_std_data(struct entropy_store *r)
r->entropy_count = 0;
r->entropy_total = 0;
r->last_data_init = false;
mix_pool_bytes(r, &now, sizeof(now), NULL);
for (i = r->poolinfo->POOLBYTES; i > 0; i -= sizeof(rv)) {
if (!arch_get_random_long(&rv))
@ -1142,11 +1155,16 @@ random_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
if (n > SEC_XFER_SIZE)
n = SEC_XFER_SIZE;
DEBUG_ENT("reading %d bits\n", n*8);
DEBUG_ENT("reading %zu bits\n", n*8);
n = extract_entropy_user(&blocking_pool, buf, n);
DEBUG_ENT("read got %d bits (%d still needed)\n",
if (n < 0) {
retval = n;
break;
}
DEBUG_ENT("read got %zd bits (%zd still needed)\n",
n*8, (nbytes-n)*8);
if (n == 0) {
@ -1171,10 +1189,6 @@ random_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
continue;
}
if (n < 0) {
retval = n;
break;
}
count += n;
buf += n;
nbytes -= n;

View file

@ -9,6 +9,7 @@
#include <asm/uaccess.h>
#include <linux/kernel_stat.h>
#include <trace/events/timer.h>
#include <linux/random.h>
/*
* Called after updating RLIMIT_CPU to run cpu timer and update
@ -470,6 +471,8 @@ static void cleanup_timers(struct list_head *head,
*/
void posix_cpu_timers_exit(struct task_struct *tsk)
{
add_device_randomness((const void*) &tsk->se.sum_exec_runtime,
sizeof(unsigned long long));
cleanup_timers(tsk->cpu_timers,
tsk->utime, tsk->stime, tsk->se.sum_exec_runtime);