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>

configure.ac

@@ -205,6 +205,8 @@ AC_CHECK_FUNCS([gethostname inet_ntoa memchr memset select socket strcasecmp \
 AC_CHECK_FUNCS([isascii memcpy memmove setrlimit ftruncate regcomp regexec])
 AC_CHECK_FUNCS([strlcpy strlcat setgroups])
 
+AC_CHECK_FUNCS([time rand srand])
+
 
 dnl Enable extra warnings
 DESIRED_FLAGS="-fdiagnostics-show-option -Wall -Wextra -Wno-unused-parameter -Wmissing-prototypes -Wstrict-prototypes -Wmissing-declarations -Wfloat-equal -Wundef -Wformat=2 -Wlogical-op -Wmissing-include-dirs -Wformat-nonliteral -Wold-style-definition -Wpointer-arith -Waggregate-return -Winit-self -Wpacked --std=c89 -ansi -pedantic -Wno-overlength-strings -Wc++-compat -Wno-long-long -Wno-overlength-strings -Wdeclaration-after-statement -Wredundant-decls -Wmissing-noreturn -Wshadow -Wendif-labels -Wcast-qual -Wcast-align -Wwrite-strings -Wp,-D_FORTIFY_SOURCE=2 -fno-common"

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,

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;