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.

diff --git a/CHANGES b/CHANGES
index 54457c7ae12f911eaff73169213010e9c9c0ef35..474319de06d4e20ae3a9bf9ad0cb584b393c9ddb 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -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.

diff --git a/crypto/rand/md_rand.c b/crypto/rand/md_rand.c
index 26bb1244d06f3af1405debd5b85813b8ca5a0892..729484fe9275b20d7dd8bee5d9fadf595b69b908 100644 (file)
--- a/crypto/rand/md_rand.c
+++ b/crypto/rand/md_rand.c
@@ -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