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-rw-r--r--source3/lib/genrand.c41
1 files changed, 32 insertions, 9 deletions
diff --git a/source3/lib/genrand.c b/source3/lib/genrand.c
index 8d7084d9f6..e20f054504 100644
--- a/source3/lib/genrand.c
+++ b/source3/lib/genrand.c
@@ -26,7 +26,6 @@
extern int DEBUGLEVEL;
static uint32 counter = 0;
-
/****************************************************************
get a 16 byte hash from the contents of a file
Note that the hash is not initialised.
@@ -102,18 +101,19 @@ static void do_dirrand(char *name, unsigned char *buf, int buf_len)
Try and get a good random number seed. Try a number of
different factors. Firstly, try /dev/random and try and
read from this. If this fails iterate through /tmp and
- XOR all the file timestamps. If this fails then just use
- a combination of pid and time of day (yes I know this
+ /dev and XOR all the file timestamps. Next add in
+ a hash of the contents of /etc/shadow and the smb passwd
+ file and a combination of pid and time of day (yes I know this
sucks :-). Finally md4 the result.
The result goes in a 16 byte buffer passed from the caller
**************************************************************/
-static void do_reseed(unsigned char *md4_outbuf)
+static uint32 do_reseed(unsigned char *md4_outbuf)
{
unsigned char md4_inbuf[40];
BOOL got_random = False;
- uint32 v1, v2;
+ uint32 v1, v2, ret;
int fd;
struct timeval tval;
pid_t mypid;
@@ -135,7 +135,7 @@ static void do_reseed(unsigned char *md4_outbuf)
if(!got_random) {
/*
- * /dev/random failed - try /tmp/ for timestamps.
+ * /dev/random failed - try /tmp and /dev for timestamps.
*/
do_dirrand("/tmp", md4_inbuf, sizeof(md4_inbuf));
do_dirrand("/dev", md4_inbuf, sizeof(md4_inbuf));
@@ -148,7 +148,7 @@ static void do_reseed(unsigned char *md4_outbuf)
/* add in the root encrypted password. On any system where security is taken
seriously this will be secret */
pw = getpwnam("root");
- if (pw) {
+ if (pw && pw->pw_passwd) {
int i;
unsigned char md4_tmp[16];
mdfour(md4_tmp, pw->pw_passwd, strlen(pw->pw_passwd));
@@ -168,6 +168,16 @@ static void do_reseed(unsigned char *md4_outbuf)
SIVAL(md4_inbuf, 36, v2 ^ IVAL(md4_inbuf, 36));
mdfour(md4_outbuf, md4_inbuf, sizeof(md4_inbuf));
+
+ /*
+ * Return a 32 bit int created from XORing the
+ * 16 bit return buffer.
+ */
+
+ ret = IVAL(md4_outbuf, 0);
+ ret ^= IVAL(md4_outbuf, 4);
+ ret ^= IVAL(md4_outbuf, 8);
+ return (ret ^ IVAL(md4_outbuf, 12));
}
/*******************************************************************
@@ -177,25 +187,38 @@ static void do_reseed(unsigned char *md4_outbuf)
void generate_random_buffer( unsigned char *out, int len, BOOL re_seed)
{
static BOOL done_reseed = False;
+ static unsigned char md4_buf[16];
unsigned char tmp_buf[16];
- unsigned char md4_buf[16];
unsigned char *p;
if(!done_reseed || re_seed) {
- do_reseed(md4_buf);
+ srandom(do_reseed(md4_buf));
done_reseed = True;
}
/*
* Generate random numbers in chunks of 64 bytes,
* then md4 them & copy to the output buffer.
+ * Added XOR with output from random, seeded
+ * by the original md4_buf. This is to stop the
+ * output from this function being the previous
+ * md4_buf md4'ed. The output from this function
+ * is often output onto the wire, and so it should
+ * not be possible to guess the next output from
+ * this function based on the previous output.
+ * XORing in the output from random(), seeded by
+ * the original md4 hash should stop this. JRA.
*/
p = out;
while(len > 0) {
+ int i;
int copy_len = len > 16 ? 16 : len;
mdfour(tmp_buf, md4_buf, sizeof(md4_buf));
memcpy(md4_buf, tmp_buf, sizeof(md4_buf));
+ /* XOR in output from random(). */
+ for(i = 0; i < 4; i++)
+ SIVAL(tmp_buf, i*4, (IVAL(tmp_buf, i*4) ^ (uint32)random()));
memcpy(p, tmp_buf, copy_len);
p += copy_len;
len -= copy_len;