* [including the GNU Public Licence.]
*/
+#ifndef MD_RAND_DEBUG
+# ifndef NDEBUG
+# define NDEBUG
+# endif
+#endif
+
+#include <assert.h>
#include <stdio.h>
#include <time.h>
#include <string.h>
static void ssleay_rand_seed(const void *buf, int num)
{
- int i,j,k,st_idx,st_num;
+ int i,j,k,st_idx;
+ long md_c[2];
+ unsigned char local_md[MD_DIGEST_LENGTH];
MD_CTX m;
#ifdef NORAND
return;
#endif
+ /*
+ * (Based on doc/ssleay.txt, section rand.doc:)
+ *
+ * The input is chopped up into units of 16 bytes (or less for
+ * the last block). Each of these blocks is run through the MD5
+ * message digest as follow: The data passed to the MD5 digest
+ * is the current 'md', the same number of bytes from the 'state'
+ * (the location determined by in incremented looping index) as
+ * the current 'block', the new key data 'block', and 'count'
+ * (which is incremented after each use).
+ * The result of this is kept in 'md' and also xored into the
+ * 'state' at the same locations that were used as input into the MD5.
+ */
+
CRYPTO_w_lock(CRYPTO_LOCK_RAND);
st_idx=state_index;
- st_num=state_num;
- state_index=(state_index+num);
+ /* use our own copies of the counters so that even
+ * if a concurrent thread seeds with exactly the
+ * same data and uses the same subarray there's _some_
+ * difference */
+ md_c[0] = md_count[0];
+ md_c[1] = md_count[1];
+
+ memcpy(local_md, md, sizeof md);
+
+ /* state_index <= state_num <= STATE_SIZE */
+ state_index += num;
if (state_index >= STATE_SIZE)
{
state_index%=STATE_SIZE;
if (state_index > state_num)
state_num=state_index;
}
+ /* state_index <= state_num <= STATE_SIZE */
+
+ /* state[st_idx], ..., state[(st_idx + num - 1) % STATE_SIZE]
+ * are what we will use now, but other threads may use them
+ * as well */
+
+ md_count[1] += (num / MD_DIGEST_LENGTH) + (num % MD_DIGEST_LENGTH > 0);
+
CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
for (i=0; i<num; i+=MD_DIGEST_LENGTH)
j=(j > MD_DIGEST_LENGTH)?MD_DIGEST_LENGTH:j;
MD_Init(&m);
- MD_Update(&m,md,MD_DIGEST_LENGTH);
+ MD_Update(&m,local_md,MD_DIGEST_LENGTH);
k=(st_idx+j)-STATE_SIZE;
if (k > 0)
{
MD_Update(&m,&(state[st_idx]),j);
MD_Update(&m,buf,j);
- MD_Update(&m,(unsigned char *)&(md_count[0]),sizeof(md_count));
- MD_Final(md,&m);
- md_count[1]++;
+ MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c));
+ MD_Final(local_md,&m);
+ md_c[1]++;
buf=(const char *)buf + j;
for (k=0; k<j; k++)
{
- state[st_idx++]^=md[k];
+ /* Parallel threads may interfere with this,
+ * but always each byte of the new state is
+ * the XOR of some previous value of its
+ * and local_md (itermediate values may be lost).
+ * Alway using locking could hurt performance more
+ * than necessary given that conflicts occur only
+ * when the total seeding is longer than the random
+ * state. */
+ state[st_idx++]^=local_md[k];
if (st_idx >= STATE_SIZE)
- {
st_idx=0;
- st_num=STATE_SIZE;
- }
}
}
memset((char *)&m,0,sizeof(m));
+
+ CRYPTO_w_lock(CRYPTO_LOCK_RAND);
+ /* Don't just copy back local_md into md -- this could mean that
+ * other thread's seeding remains without effect (except for
+ * the incremented counter). By XORing it we keep at least as
+ * much entropy as fits into md. */
+ for (k = 0; k < sizeof md; k++)
+ {
+ md[k] ^= local_md[k];
+ }
+ CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
+
+#ifndef THREADS
+ assert(md_c[1] == md_count[1]);
+#endif
}
static void ssleay_rand_bytes(unsigned char *buf, int num)
{
int i,j,k,st_num,st_idx;
+ long md_c[2];
+ unsigned char local_md[MD_DIGEST_LENGTH];
MD_CTX m;
static int init=1;
unsigned long l;
+#ifndef MSDOS
+ pid_t curr_pid = getpid();
+#endif
#ifdef DEVRANDOM
FILE *fh;
#endif
}
#endif
+ /*
+ * (Based on doc/ssleay.txt, section rand.doc:)
+ *
+ * For each group of 8 bytes (or less), we do the following,
+ *
+ * Input into MD5, the top 8 bytes from 'md', the byte that are
+ * to be overwritten by the random bytes and bytes from the
+ * 'state' (incrementing looping index). From this digest output
+ * (which is kept in 'md'), the top (upto) 8 bytes are
+ * returned to the caller and the bottom (upto) 8 bytes are xored
+ * into the 'state'.
+ * Finally, after we have finished 'num' random bytes for the
+ * caller, 'count' (which is incremented) and the local and globl 'md'
+ * are fed into MD5 and the results are kept in the global 'md'.
+ */
+
CRYPTO_w_lock(CRYPTO_LOCK_RAND);
if (init)
* just this */
RAND_seed(&m,sizeof(m));
#ifndef MSDOS
- l=getpid();
+ l=curr_pid;
RAND_seed(&l,sizeof(l));
l=getuid();
RAND_seed(&l,sizeof(l));
st_idx=state_index;
st_num=state_num;
+ md_c[0] = md_count[0];
+ md_c[1] = md_count[1];
+ memcpy(local_md, md, sizeof md);
+
state_index+=num;
if (state_index > state_num)
- state_index=(state_index%state_num);
+ state_index %= state_num;
+
+ /* state[st_idx], ..., state[(st_idx + num - 1) % st_num]
+ * are now ours (but other threads may use them too) */
+ md_count[0] += 1;
CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
while (num > 0)
j=(num >= MD_DIGEST_LENGTH/2)?MD_DIGEST_LENGTH/2:num;
num-=j;
MD_Init(&m);
- MD_Update(&m,&(md[MD_DIGEST_LENGTH/2]),MD_DIGEST_LENGTH/2);
- MD_Update(&m,(unsigned char *)&(md_count[0]),sizeof(md_count));
+#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
MD_Update(&m,buf,j); /* purify complains */
#endif
}
else
MD_Update(&m,&(state[st_idx]),j);
- MD_Final(md,&m);
+ MD_Final(local_md,&m);
for (i=0; i<j; i++)
{
+ state[st_idx++]^=local_md[i]; /* may compete with other threads */
+ *(buf++)=local_md[i+MD_DIGEST_LENGTH/2];
if (st_idx >= st_num)
st_idx=0;
- state[st_idx++]^=md[i];
- *(buf++)=md[i+MD_DIGEST_LENGTH/2];
}
}
MD_Init(&m);
- MD_Update(&m,(unsigned char *)&(md_count[0]),sizeof(md_count));
- md_count[0]++;
+ MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c));
+ MD_Update(&m,local_md,MD_DIGEST_LENGTH);
+ CRYPTO_w_lock(CRYPTO_LOCK_RAND);
MD_Update(&m,md,MD_DIGEST_LENGTH);
MD_Final(md,&m);
+ CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
+
memset(&m,0,sizeof(m));
}
projects / openssl.git / blobdiff