diff --git a/src/testcurl/test_digestauth.c b/src/testcurl/test_digestauth.c
index 47d4f5d0..a2b38b2e 100644
--- a/src/testcurl/test_digestauth.c
+++ b/src/testcurl/test_digestauth.c
@@ -423,8 +423,8 @@ testDigestAuth ()
   while (off < 8)
   {
     len = read (fd,
-                rnd,
-                8);
+                rnd + off,
+                8 - off);
     if (len == (size_t) -1)
       externalErrorExitDesc ("Failed to read '/dev/urandom'");
     off += len;
diff --git a/src/testcurl/test_digestauth_sha256.c b/src/testcurl/test_digestauth_sha256.c
index f6df664e..bb0e786c 100644
--- a/src/testcurl/test_digestauth_sha256.c
+++ b/src/testcurl/test_digestauth_sha256.c
@@ -198,8 +198,8 @@ testDigestAuth ()
   while (off < 8)
   {
     len = read (fd,
-                rnd,
-                8);
+                rnd + off,
+                8 - off);
     if (len == (size_t) -1)
     {
       fprintf (stderr,
diff --git a/src/testcurl/test_digestauth_with_arguments.c b/src/testcurl/test_digestauth_with_arguments.c
index ac1aed56..602c1180 100644
--- a/src/testcurl/test_digestauth_with_arguments.c
+++ b/src/testcurl/test_digestauth_with_arguments.c
@@ -181,7 +181,7 @@ testDigestAuth ()
   }
   while (off < 8)
   {
-    len = read (fd, rnd, 8);
+    len = read (fd, rnd + off, 8 - off);
     if (len == (size_t) -1)
     {
       fprintf (stderr,