Prevent uafs_readdir/closedir segfault

Check for the NULL case in uafs_readdir/closedir, so we don't blindly
dereference the given pointer.

Change-Id: Iaefce9bf2e5135a60e9739f866a1f27333f06e28
Reviewed-on: http://gerrit.openafs.org/1715
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>

diff --git a/src/afs/UKERNEL/afs_usrops.c b/src/afs/UKERNEL/afs_usrops.c
index 1480c42..4f1edc3 100644 (file)
--- a/src/afs/UKERNEL/afs_usrops.c
+++ b/src/afs/UKERNEL/afs_usrops.c
@@ -3958,6 +3958,11 @@ uafs_readdir_r(usr_DIR * dirp)
     struct usr_dirent *direntP;
     struct min_direct *directP;
 
+    if (!dirp) {
+       errno = EBADF;
+       return NULL;
+    }
+
     /*
      * Make sure this is an open file
      */
@@ -4045,6 +4050,11 @@ uafs_closedir_r(usr_DIR * dirp)
     int fd;
     int rc;
 
+    if (!dirp) {
+       errno = EBADF;
+       return -1;
+    }
+
     fd = dirp->dd_fd;
     afs_osi_Free((char *)dirp,
                 sizeof(usr_DIR) + USR_DIRSIZE + sizeof(struct usr_dirent));