diff options
Diffstat (limited to 'source3/lib/genrand.c')
| -rw-r--r-- | source3/lib/genrand.c | 61 |
1 files changed, 39 insertions, 22 deletions
diff --git a/source3/lib/genrand.c b/source3/lib/genrand.c index 5808206f6b..78d19da00a 100644 --- a/source3/lib/genrand.c +++ b/source3/lib/genrand.c @@ -26,6 +26,30 @@ 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. +*****************************************************************/ +static void do_filehash(char *fname, unsigned char *hash) +{ + unsigned char buf[1011]; /* deliberate weird size */ + unsigned char tmp_md4[16]; + int fd, n; + + fd = open(fname,O_RDONLY); + if (fd == -1) return; + + while ((n = read(fd, (char *)buf, sizeof(buf))) > 0) { + mdfour(tmp_md4, buf, n); + for (n=0;n<16;n++) + hash[n] ^= tmp_md4[n]; + } + close(fd); +} + + + /**************************************************************** Try and get a seed by looking at the atimes of files in a given directory. XOR them into the buf array. @@ -81,14 +105,15 @@ static void do_dirrand(char *name, unsigned char *buf, int buf_len) XOR all the file timestamps. If this fails then just use 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 uint32 do_reseed(void) +static void do_reseed(unsigned char *md4_outbuf) { - unsigned char md4_outbuf[16]; unsigned char md4_inbuf[40]; BOOL got_random = False; - uint32 v1, v2, ret; + uint32 v1, v2; int fd; struct timeval tval; pid_t mypid; @@ -115,6 +140,10 @@ static uint32 do_reseed(void) do_dirrand("/dev", md4_inbuf, sizeof(md4_inbuf)); } + /* possibly add in some secret file contents */ + do_filehash("/etc/shadow", &md4_inbuf[0]); + do_filehash(SMB_PASSWD_FILE, &md4_inbuf[16]); + /* * Finally add the counter, time of day, and pid. */ @@ -124,19 +153,9 @@ static uint32 do_reseed(void) v2 = (counter++) * mypid + tval.tv_usec; SIVAL(md4_inbuf, 32, v1 ^ IVAL(md4_inbuf, 32)); - SIVAL(md4_inbuf, 36, v1 ^ IVAL(md4_inbuf, 36)); + SIVAL(md4_inbuf, 36, v2 ^ IVAL(md4_inbuf, 36)); mdfour(md4_outbuf, md4_inbuf, sizeof(md4_inbuf)); - - /* XOR everything togther in blocks of 4 bytes. */ - ret = IVAL(md4_outbuf,0); - ret ^= IVAL(md4_outbuf,4); - ret ^= IVAL(md4_outbuf,8); - ret ^= IVAL(md4_outbuf,12); - - DEBUG(10,("do_reseed: returning seed %lu\n", ret)); - - return ret; } /******************************************************************* @@ -146,13 +165,13 @@ static uint32 do_reseed(void) void generate_random_buffer( unsigned char *out, int len, BOOL re_seed) { static BOOL done_reseed = False; - unsigned char tmp_buf[64]; + unsigned char tmp_buf[16]; unsigned char md4_buf[16]; unsigned char *p; if(!done_reseed || re_seed) { - srandom(do_reseed()); - done_reseed = True; + do_reseed(md4_buf); + done_reseed = True; } /* @@ -162,12 +181,10 @@ void generate_random_buffer( unsigned char *out, int len, BOOL re_seed) p = out; while(len > 0) { - int i; int copy_len = len > 16 ? 16 : len; - for( i = 0; i < 16; i++) - SIVAL(tmp_buf, i*4, random()); - mdfour(md4_buf, tmp_buf, sizeof(tmp_buf)); - memcpy(p, md4_buf, copy_len); + mdfour(tmp_buf, md4_buf, sizeof(md4_buf)); + memcpy(md4_buf, tmp_buf, sizeof(md4_buf)); + memcpy(p, tmp_buf, copy_len); p += copy_len; len -= copy_len; } |