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-rw-r--r--source4/lib/util/genrand.c68
-rw-r--r--source4/lib/util/util.h8
2 files changed, 58 insertions, 18 deletions
diff --git a/source4/lib/util/genrand.c b/source4/lib/util/genrand.c
index 4d976cecf8..31c0fce633 100644
--- a/source4/lib/util/genrand.c
+++ b/source4/lib/util/genrand.c
@@ -33,6 +33,10 @@ static unsigned char hash[258];
static uint32_t counter;
static bool done_reseed = false;
+static unsigned int bytes_since_reseed = 0;
+
+static int urand_fd = -1;
+
static void (*reseed_callback)(int *newseed);
/**
@@ -51,6 +55,7 @@ _PUBLIC_ void set_rand_reseed_callback(void (*fn)(int *))
_PUBLIC_ void set_need_random_reseed(void)
{
done_reseed = false;
+ bytes_since_reseed = 0;
}
static void get_rand_reseed_data(int *reseed_data)
@@ -163,12 +168,16 @@ static int do_reseed(bool use_fd, int fd)
int reseed_data = 0;
if (use_fd) {
- if (fd != -1)
- return fd;
-
- fd = open( "/dev/urandom", O_RDONLY,0);
- if(fd >= 0)
+ if (fd == -1) {
+ fd = open( "/dev/urandom", O_RDONLY,0);
+ }
+ if (fd != -1
+ && (read(fd, seed_inbuf, sizeof(seed_inbuf)) == sizeof(seed_inbuf))) {
+ DEBUG(0, ("do_reseed: need %d\n", sizeof(seed_inbuf)));
+ call_backtrace();
+ seed_random_stream(seed_inbuf, sizeof(seed_inbuf));
return fd;
+ }
}
/* Add in some secret file contents */
@@ -205,28 +214,33 @@ static int do_reseed(bool use_fd, int fd)
/**
Interface to the (hopefully) good crypto random number generator.
+ Will use our internal PRNG if more than 40 bytes of random generation
+ has been requested, otherwise tries to read from /dev/random
**/
_PUBLIC_ void generate_random_buffer(uint8_t *out, int len)
{
- static int urand_fd = -1;
unsigned char md4_buf[64];
unsigned char tmp_buf[16];
unsigned char *p;
if(!done_reseed) {
- urand_fd = do_reseed(true, urand_fd);
- done_reseed = true;
- }
-
- if (urand_fd != -1 && len > 0) {
-
- if (read(urand_fd, out, len) == len)
- return; /* len bytes of random data read from urandom. */
+ bytes_since_reseed += len;
+
+ /* Magic constant to try and avoid reading 40 bytes
+ * and setting up the PRNG if the app only ever wants
+ * a few bytes */
+ if (bytes_since_reseed < 40) {
+ if (urand_fd == -1) {
+ urand_fd = open( "/dev/urandom", O_RDONLY,0);
+ }
+ DEBUG(0, ("generate_random_buffer: need %d\n", len));
+ call_backtrace();
+ if(urand_fd != -1 && (read(urand_fd, out, len) == len)) {
+ return;
+ }
+ }
- /* Read of urand error, drop back to non urand method. */
- close(urand_fd);
- urand_fd = -1;
- do_reseed(false, -1);
+ urand_fd = do_reseed(true, urand_fd);
done_reseed = true;
}
@@ -250,6 +264,24 @@ _PUBLIC_ void generate_random_buffer(uint8_t *out, int len)
}
/**
+ Interface to the (hopefully) good crypto random number generator.
+ Will always use /dev/urandom if available.
+**/
+_PUBLIC_ void generate_secret_buffer(uint8_t *out, int len)
+{
+ if (urand_fd == -1) {
+ urand_fd = open( "/dev/urandom", O_RDONLY,0);
+ }
+ DEBUG(0, ("generate_random_buffer: need %d\n", len));
+ call_backtrace();
+ if(urand_fd != -1 && (read(urand_fd, out, len) == len)) {
+ return;
+ }
+
+ generate_random_buffer(out, len);
+}
+
+/**
generate a single random uint32_t
**/
_PUBLIC_ uint32_t generate_random(void)
diff --git a/source4/lib/util/util.h b/source4/lib/util/util.h
index 42dde70a44..fc9cb1e57a 100644
--- a/source4/lib/util/util.h
+++ b/source4/lib/util/util.h
@@ -226,10 +226,18 @@ _PUBLIC_ void set_need_random_reseed(void);
/**
Interface to the (hopefully) good crypto random number generator.
+ Will use our internal PRNG if more than 40 bytes of random generation
+ has been requested, otherwise tries to read from /dev/random
**/
_PUBLIC_ void generate_random_buffer(uint8_t *out, int len);
/**
+ Interface to the (hopefully) good crypto random number generator.
+ Will always use /dev/urandom if available.
+**/
+_PUBLIC_ void generate_secret_buffer(uint8_t *out, int len);
+
+/**
generate a single random uint32_t
**/
_PUBLIC_ uint32_t generate_random(void);