BB#110 secure the hashmaps by adding a seed

Based on a patch provided by gpernot@praksys.org on bugzilla.

Signed-off-by: Michael Adam <obnox@samba.org>

2 files changed, 9 insertions, 6 deletions

diff --git a/src/child.c b/src/child.c
index fefffa6..2c4dc22 100644
--- a/src/child.c
+++ b/src/child.c
@@ -200,6 +200,7 @@ static void child_main (struct child_s *ptr)
         }
 
         ptr->connects = 0;
+        srand(time(NULL));
 
         /*
          * We have to wait for connections on multiple fds,
diff --git a/src/hashmap.c b/src/hashmap.c
index 0c911a8..b99f838 100644
--- a/src/hashmap.c
+++ b/src/hashmap.c
@@ -50,6 +50,7 @@ struct hashbucket_s {
 };
 
 struct hashmap_s {
+        uint32_t seed;
         unsigned int size;
         hashmap_iter end_iterator;
 
@@ -68,7 +69,7 @@ struct hashmap_s {
  *
  * If any of the arguments are invalid a negative number is returned.
  */
-static int hashfunc (const char *key, unsigned int size)
+static int hashfunc (const char *key, unsigned int size, uint32_t seed)
 {
         uint32_t hash;
 
@@ -77,7 +78,7 @@ static int hashfunc (const char *key, unsigned int size)
         if (size == 0)
                 return -ERANGE;
 
-        for (hash = 5381; *key != '\0'; key++) {
+        for (hash = seed; *key != '\0'; key++) {
                 hash = ((hash << 5) + hash) ^ tolower (*key);
         }
 
@@ -103,6 +104,7 @@ hashmap_t hashmap_create (unsigned int nbuckets)
         if (!ptr)
                 return NULL;
 
+        ptr->seed = (uint32_t)rand();
         ptr->size = nbuckets;
         ptr->buckets = (struct hashbucket_s *) safecalloc (nbuckets,
                                                            sizeof (struct
@@ -200,7 +202,7 @@ hashmap_insert (hashmap_t map, const char *key, const void *data, size_t len)
         if (!data || len < 1)
                 return -ERANGE;
 
-        hash = hashfunc (key, map->size);
+        hash = hashfunc (key, map->size, map->seed);
         if (hash < 0)
                 return hash;
 
@@ -381,7 +383,7 @@ ssize_t hashmap_search (hashmap_t map, const char *key)
         if (map == NULL || key == NULL)
                 return -EINVAL;
 
-        hash = hashfunc (key, map->size);
+        hash = hashfunc (key, map->size, map->seed);
         if (hash < 0)
                 return hash;
 
@@ -415,7 +417,7 @@ ssize_t hashmap_entry_by_key (hashmap_t map, const char *key, void **data)
         if (!map || !key || !data)
                 return -EINVAL;
 
-        hash = hashfunc (key, map->size);
+        hash = hashfunc (key, map->size, map->seed);
         if (hash < 0)
                 return hash;
 
@@ -450,7 +452,7 @@ ssize_t hashmap_remove (hashmap_t map, const char *key)
         if (map == NULL || key == NULL)
                 return -EINVAL;
 
-        hash = hashfunc (key, map->size);
+        hash = hashfunc (key, map->size, map->seed);
         if (hash < 0)
                 return hash;