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Restored from previous backing out (because that is OpenBSD way, so

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assumed to be reviewd by them):
Stir directly from the kernel PRNG, without taking less random pid & time
bytes too (when it is possible).

The difference with OpenBSD code is that they have KERN_ARND sysctl for
that task, while we need to read /dev/random
This commit is contained in:
Andrey A. Chernov 2008-08-03 20:15:22 +00:00
parent 1f696cd2bc
commit 89538e75d6
1 changed files with 16 additions and 12 deletions
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22
lib/libc/gen/arc4random.c
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@ -55,6 +55,7 @@ struct arc4_stream {
static pthread_mutex_t arc4random_mtx = PTHREAD_MUTEX_INITIALIZER;
#define RANDOMDEV "/dev/urandom"
#define KEYSIZE 128
#define THREAD_LOCK() \
do { \
if (__isthreaded) \
@ -106,24 +107,27 @@ arc4_addrandom(u_char *dat, int datlen)
static void
arc4_stir(void)
{
int fd, n;
int done, fd, n;
struct {
struct timeval tv;
pid_t pid;
u_int8_t rnd[128 - sizeof(struct timeval) - sizeof(pid_t)];
u_int8_t rnd[KEYSIZE];
} rdat;
gettimeofday(&rdat.tv, NULL);
rdat.pid = getpid();
fd = _open(RANDOMDEV, O_RDONLY, 0);
done = 0;
if (fd >= 0) {
(void) _read(fd, rdat.rnd, sizeof(rdat.rnd));
_close(fd);
if (_read(fd, &rdat, KEYSIZE) == KEYSIZE)
done = 1;
(void)_close(fd);
}
if (!done) {
(void)gettimeofday(&rdat.tv, NULL);
rdat.pid = getpid();
/* We'll just take whatever was on the stack too... */
}
/* fd < 0? Ah, what the heck. We'll just take whatever was on the
* stack... */
arc4_addrandom((void *) &rdat, sizeof(rdat));
arc4_addrandom((u_char *)&rdat, KEYSIZE);
/*
* Throw away the first N bytes of output, as suggested in the