Commit 62ac2938 authored by Bodo Möller's avatar Bodo Möller
Browse files

Always hash the pid in the first iteration in ssleay_rand_bytes, 

don't try to detect fork()s by looking at getpid().
The reason is that threads sharing the same memory can have different
PIDs; it's inefficient to run RAND_seed each time a different thread
calls RAND_bytes.
parent c1e744b9

CHANGES

+1 −1
Original line number Diff line number Diff line
@@ -5,7 +5,7 @@ 
 Changes between 0.9.4 and 0.9.5  [xx XXX 1999]



  *) Make crypto/rand/md_rand.c more robust:

     - Detect fork() and assure unique random states.

     - Assure unique random numbers after fork().

     - Make sure that concurrent threads access the global counter and

       md serializably so that we never lose entropy in them

       or use exactly the same state in multiple threads.

crypto/rand/md_rand.c

+9 −18
Original line number Diff line number Diff line
@@ -287,8 +287,7 @@ static void ssleay_rand_bytes(unsigned char *buf, int num) 
	static int init=1;

	unsigned long l;

#ifndef MSDOS

	static pid_t prev_pid = 0;

	pid_t curr_pid;

	pid_t curr_pid = getpid();

#endif

#ifdef DEVRANDOM

	FILE *fh;
@@ -329,8 +328,7 @@ static void ssleay_rand_bytes(unsigned char *buf, int num) 
		 * just this */

		RAND_seed(&m,sizeof(m));

#ifndef MSDOS

		prev_pid = getpid();

		l=prev_pid;

		l=curr_pid;

		RAND_seed(&l,sizeof(l));

		l=getuid();

		RAND_seed(&l,sizeof(l));
@@ -367,20 +365,6 @@ static void ssleay_rand_bytes(unsigned char *buf, int num) 
		init=0;

		}



#ifndef MSDOS

	/* make sure we have unique states when a program forks

	 * (new with OpenSSL 0.9.5; for earlier versions, applications

	 * must take care of this) */

	curr_pid = getpid();

	if (prev_pid != curr_pid)

		{

		prev_pid = curr_pid;

		CRYPTO_w_unlock(CRYPTO_LOCK_RAND);

		RAND_seed(&curr_pid, sizeof curr_pid);

		CRYPTO_w_lock(CRYPTO_LOCK_RAND);

		}

#endif



	st_idx=state_index;

	st_num=state_num;

	md_c[0] = md_count[0];
@@ -402,6 +386,13 @@ static void ssleay_rand_bytes(unsigned char *buf, int num) 
		j=(num >= MD_DIGEST_LENGTH/2)?MD_DIGEST_LENGTH/2:num;

		num-=j;

		MD_Init(&m);

#ifndef MSDOS

		if (curr_pid) /* just in the first iteration to save time */

			{

			MD_Update(&m,(unsigned char*)&curr_pid,sizeof curr_pid);

			curr_pid = 0;

			}

#endif

		MD_Update(&m,&(local_md[MD_DIGEST_LENGTH/2]),MD_DIGEST_LENGTH/2);

		MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c));

#ifndef PURIFY