Break checkpath_setids into separate functions which work properly even

[checkpath] / checkpath.c

diff --git a/checkpath.c b/checkpath.c
index 2047800..e594201 100644 (file)
--- a/checkpath.c
+++ b/checkpath.c
@@ -43,6 +43,7 @@
 
 #include <mLib/alloc.h>
 #include <mLib/dstr.h>
+#include <mLib/macros.h>
 
 #include "checkpath.h"
 
@@ -488,30 +489,95 @@ unsigned checkpath(const char *p, const struct checkpath *cp)
   return (bad);
 }
 
-/* --- @checkpath_setids@ --- *
+/* --- @checkpath_addgid@ --- *
  *
  * Arguments:  @struct checkpath *cp@ = pointer to block to fill in
+ *             @gid_t g@ = group id to add
  *
- * Returns:    ---
+ * Returns:    Zero if successful, nonzero if the array is full.
  *
- * Use:                Fills in the user ids and things in the structure.
+ * Use:                Adds the group @g@ to the structure.
  */
 
-void checkpath_setids(struct checkpath *cp)
+int checkpath_addgid(struct checkpath *cp, gid_t g)
 {
-  int n, i;
-  gid_t g = getgid();
+  int i;
+
+  for (i = 0; i < cp->cp_gids; i++) {
+    if (cp->cp_gid[i] == g)
+      return (0);
+  }
+  if (cp->cp_gids >= N(cp->cp_gid))
+    return (-1);
+  cp->cp_gid[cp->cp_gids++] = g;
+  return (0);
+}
+
+/* --- @checkpath_setuid@ --- *
+ *
+ * Arguments:  @struct checkpath *cp@ = pointer to block to fill in
+ *
+ * Returns:    ---
+ *
+ * Use:                Fills in the @cp_uid@ slot of the structure with the real uid
+ *             of the current process.
+ */
+
+void checkpath_setuid(struct checkpath *cp) { cp->cp_uid = getuid(); }
+
+/* --- @checkpath_setgid@ --- *
+ *
+ * Arguments:  @struct checkpath *cp@ = pointer to block to fill in
+ *
+ * Returns:    Zero if successful, nonzero if the array is full.
+ *
+ * Use:                Adds the real gid of the current process to the @cp_gid@
+ *             array.
+ */
 
-  cp->cp_uid = getuid();
-  n = getgroups(sizeof(cp->cp_gid) / sizeof(cp->cp_gid[0]), cp->cp_gid);
+int checkpath_setgid(struct checkpath *cp)
+  { return (checkpath_addgid(cp, getgid())); }
 
+/* --- @checkpath_setgroups@ --- *
+ *
+ * Arguments:  @struct checkpath *cp@ = pointer to block to fill in
+ *
+ * Returns:    Zero if successful, nonzero if the array is full.
+ *
+ * Use:                Adds the current process's supplementary groups to the
+ *             @cp_gid@ table.
+ */
+
+int checkpath_setgroups(struct checkpath *cp)
+{
+  int i, n;
+  gid_t gg[NGROUPS_MAX];
+
+  n = getgroups(N(gg), gg);
   for (i = 0; i < n; i++) {
-    if (cp->cp_gid[i] == g)
-      goto gid_ok;
+    if (checkpath_addgid(cp, gg[i]))
+      return (-1);
   }
-  cp->cp_gid[n++] = g;
-gid_ok:
-  cp->cp_gids = n;
+  return (0);
+}
+
+/* --- @checkpath_setids@ --- *
+ *
+ * Arguments:  @struct checkpath *cp@ = pointer to block to fill in
+ *
+ * Returns:    ---
+ *
+ * Use:                Fills in the user ids and things in the structure.  This is
+ *             equivalent to setting @cp_gids = 0@ and then calling
+ *             @_setuid@, @_setgid@ and @_setgroups@.  It can't fail.
+ */
+
+void checkpath_setids(struct checkpath *cp)
+{
+  cp->cp_gids = 0;
+  checkpath_setuid(cp);
+  checkpath_setgid(cp);
+  checkpath_setgroups(cp);
 }
 
 /*----- That's all, folks -------------------------------------------------*/