Document that lhash isn't thread safe under any circumstances and

indicate the level of locking required for various operations.

Remove the lock and atomics from the lhash code.  These we're not complete
or adequate.

Refer to #4418 and #4427 for details.

Reviewed-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Ben Kaduk <kaduk@mit.edu>
Reviewed-by: Andy Polyakov <appro@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/4429)

1 files changed, 14 insertions, 20 deletions

diff --git a/crypto/lhash/lhash.c b/crypto/lhash/lhash.c
index 8f28c48c4d..28528817a1 100644
--- a/crypto/lhash/lhash.c
+++ b/crypto/lhash/lhash.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 1995-2017 The OpenSSL Project Authors. All Rights Reserved.
  *
  * Licensed under the OpenSSL license (the "License").  You may not use
  * this file except in compliance with the License.  You can obtain a copy
@@ -32,8 +32,6 @@ OPENSSL_LHASH *OPENSSL_LH_new(OPENSSL_LH_HASHFUNC h, OPENSSL_LH_COMPFUNC c)
         return NULL;
     if ((ret->b = OPENSSL_zalloc(sizeof(*ret->b) * MIN_NODES)) == NULL)
         goto err;
-    if ((ret->retrieve_stats_lock = CRYPTO_THREAD_lock_new()) == NULL)
-        goto err;
     ret->comp = ((c == NULL) ? (OPENSSL_LH_COMPFUNC)strcmp : c);
     ret->hash = ((h == NULL) ? (OPENSSL_LH_HASHFUNC)OPENSSL_LH_strhash : h);
     ret->num_nodes = MIN_NODES / 2;
@@ -41,7 +39,7 @@ OPENSSL_LHASH *OPENSSL_LH_new(OPENSSL_LH_HASHFUNC h, OPENSSL_LH_COMPFUNC c)
     ret->pmax = MIN_NODES / 2;
     ret->up_load = UP_LOAD;
     ret->down_load = DOWN_LOAD;
-    return (ret);
+    return ret;
 
 err:
     OPENSSL_free(ret->b);
@@ -65,7 +63,6 @@ void OPENSSL_LH_free(OPENSSL_LHASH *lh)
             n = nn;
         }
     }
-    CRYPTO_THREAD_lock_free(lh->retrieve_stats_lock);
     OPENSSL_free(lh->b);
     OPENSSL_free(lh);
 }
@@ -85,7 +82,7 @@ void *OPENSSL_LH_insert(OPENSSL_LHASH *lh, void *data)
     if (*rn == NULL) {
         if ((nn = OPENSSL_malloc(sizeof(*nn))) == NULL) {
             lh->error++;
-            return (NULL);
+            return NULL;
         }
         nn->data = data;
         nn->next = NULL;
@@ -95,12 +92,11 @@ void *OPENSSL_LH_insert(OPENSSL_LHASH *lh, void *data)
         lh->num_insert++;
         lh->num_items++;
     } else {                    /* replace same key */
-
         ret = (*rn)->data;
         (*rn)->data = data;
         lh->num_replace++;
     }
-    return (ret);
+    return ret;
 }
 
 void *OPENSSL_LH_delete(OPENSSL_LHASH *lh, const void *data)
@@ -114,7 +110,7 @@ void *OPENSSL_LH_delete(OPENSSL_LHASH *lh, const void *data)
 
     if (*rn == NULL) {
         lh->num_no_delete++;
-        return (NULL);
+        return NULL;
     } else {
         nn = *rn;
         *rn = nn->next;
@@ -128,7 +124,7 @@ void *OPENSSL_LH_delete(OPENSSL_LHASH *lh, const void *data)
         (lh->down_load >= (lh->num_items * LH_LOAD_MULT / lh->num_nodes)))
         contract(lh);
 
-    return (ret);
+    return ret;
 }
 
 void *OPENSSL_LH_retrieve(OPENSSL_LHASH *lh, const void *data)
@@ -136,17 +132,16 @@ void *OPENSSL_LH_retrieve(OPENSSL_LHASH *lh, const void *data)
     unsigned long hash;
     OPENSSL_LH_NODE **rn;
     void *ret;
-    int scratch;
 
     lh->error = 0;
     rn = getrn(lh, data, &hash);
 
     if (*rn == NULL) {
-        CRYPTO_atomic_add(&lh->num_retrieve_miss, 1, &scratch, lh->retrieve_stats_lock);
+        lh->num_retrieve_miss++;
         return NULL;
     } else {
         ret = (*rn)->data;
-        CRYPTO_atomic_add(&lh->num_retrieve, 1, &scratch, lh->retrieve_stats_lock);
+        lh->num_retrieve++;
     }
     return ret;
 }
@@ -274,10 +269,9 @@ static OPENSSL_LH_NODE **getrn(OPENSSL_LHASH *lh,
     OPENSSL_LH_NODE **ret, *n1;
     unsigned long hash, nn;
     OPENSSL_LH_COMPFUNC cf;
-    int scratch;
 
     hash = (*(lh->hash)) (data);
-    CRYPTO_atomic_add(&lh->num_hash_calls, 1, &scratch, lh->retrieve_stats_lock);
+    lh->num_hash_calls++;
     *rhash = hash;
 
     nn = hash % lh->pmax;
@@ -287,17 +281,17 @@ static OPENSSL_LH_NODE **getrn(OPENSSL_LHASH *lh,
     cf = lh->comp;
     ret = &(lh->b[(int)nn]);
     for (n1 = *ret; n1 != NULL; n1 = n1->next) {
-        CRYPTO_atomic_add(&lh->num_hash_comps, 1, &scratch, lh->retrieve_stats_lock);
+        lh->num_hash_comps++;
         if (n1->hash != hash) {
             ret = &(n1->next);
             continue;
         }
-        CRYPTO_atomic_add(&lh->num_comp_calls, 1, &scratch, lh->retrieve_stats_lock);
+        lh->num_comp_calls++;
         if (cf(n1->data, data) == 0)
             break;
         ret = &(n1->next);
     }
-    return (ret);
+    return ret;
 }
 
 /*
@@ -313,7 +307,7 @@ unsigned long OPENSSL_LH_strhash(const char *c)
     int r;
 
     if ((c == NULL) || (*c == '\0'))
-        return (ret);
+        return ret;
 
     n = 0x100;
     while (*c) {
@@ -325,7 +319,7 @@ unsigned long OPENSSL_LH_strhash(const char *c)
         ret ^= v * v;
         c++;
     }
-    return ((ret >> 16) ^ ret);
+    return (ret >> 16) ^ ret;
 }
 
 unsigned long OPENSSL_LH_num_items(const OPENSSL_LHASH *lh)