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Only read /dev/random once when the program starts

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rather than for every connection, to "conserve entropy".

--HG--
extra : convert_revision : 21df240b71c0af8454725dec9abb428dd4bb97a2
This commit is contained in:
Matt Johnston
2006-02-11 15:15:37 +00:00
parent fcba907998
commit 1eb9209afe
6 changed files with 39 additions and 13 deletions
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31
random.c
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@@ -30,8 +30,8 @@
static int donerandinit = 0;
/* this is used to generate unique output from the same hashpool */
static unsigned int counter = 0;
#define MAX_COUNTER 1000000/* the max value for the counter, so it won't loop */
static uint32_t counter = 0;
#define MAX_COUNTER 1<<31 /* the max value for the counter, so it won't loop */
static unsigned char hashpool[SHA1_HASH_SIZE];
@@ -132,7 +132,8 @@ void seedrandom() {
hash_state hs;
/* initialise so compilers will be happy about hashing it */
/* initialise so that things won't warn about
* hashing an undefined buffer */
if (!donerandinit) {
m_burn(hashpool, sizeof(hashpool));
}
@@ -150,6 +151,30 @@ void seedrandom() {
donerandinit = 1;
}
/* hash the current random pool with some unique identifiers
* for this process and point-in-time. this is used to separate
* the random pools for fork()ed processes. */
void reseedrandom() {
pid_t pid;
struct timeval tv;
if (!donerandinit) {
dropbear_exit("seedrandom not done");
}
pid = getpid();
gettimeofday(&tv, NULL);
hash_state hs;
unsigned char hash[SHA1_HASH_SIZE];
sha1_init(&hs);
sha1_process(&hs, (void*)hashpool, sizeof(hashpool));
sha1_process(&hs, (void*)&pid, sizeof(pid));
sha1_process(&hs, (void*)&tv, sizeof(tv));
sha1_done(&hs, hashpool);
}
/* return len bytes of pseudo-random data */
void genrandom(unsigned char* buf, unsigned int len) {