diff options
Diffstat (limited to 'source4/lib/util/genrand.c')
| -rw-r--r-- | source4/lib/util/genrand.c | 68 |
1 files changed, 50 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) |