From 3304f8be45c377f912c8beb19d02dc83aee12d86 Mon Sep 17 00:00:00 2001
From: Sean Gillies <sean@mapbox.com>
Date: Thu, 5 Nov 2015 16:59:37 -0700
Subject: [PATCH] Closes #520

---
 rasterio/_io.pyx      |  8 ++++++++
 tests/test_blocks.py  |  4 ++--
 tests/test_profile.py | 31 +++++++++++++++++++++++--------
 3 files changed, 33 insertions(+), 10 deletions(-)

diff --git a/rasterio/_io.pyx b/rasterio/_io.pyx
index 44afff77..9af954f0 100644
--- a/rasterio/_io.pyx
+++ b/rasterio/_io.pyx
@@ -1298,6 +1298,13 @@ cdef class RasterUpdater(RasterReader):
                     continue
                 kwds.append((k.lower(), v))
                 k, v = k.upper(), str(v).upper()
+
+                # Guard against block size that exceed image size.
+                if k == 'BLOCKXSIZE' and int(v) > self.width:
+                    raise ValueError("blockxsize exceeds raster width.")
+                if k == 'BLOCKYSIZE' and int(v) > self.height:
+                    raise ValueError("blockysize exceeds raster height.")
+
                 key_b = k.encode('utf-8')
                 val_b = v.encode('utf-8')
                 key_c = key_b
@@ -1310,6 +1317,7 @@ cdef class RasterUpdater(RasterReader):
             self._hds = _gdal.GDALCreate(
                 drv, fname, self.width, self.height, self._count,
                 gdal_dtype, options)
+
             if self._hds == NULL:
                 raise ValueError("NULL dataset")
 
diff --git a/tests/test_blocks.py b/tests/test_blocks.py
index 912baf5a..4ca99bec 100644
--- a/tests/test_blocks.py
+++ b/tests/test_blocks.py
@@ -1,15 +1,16 @@
 import logging
 import os.path
-import unittest
 import shutil
 import subprocess
 import sys
 import tempfile
+import unittest
 
 import numpy
 
 import rasterio
 
+
 logging.basicConfig(stream=sys.stderr, level=logging.DEBUG)
 
 class WindowTest(unittest.TestCase):
@@ -120,4 +121,3 @@ class WindowWriteTest(unittest.TestCase):
             "Minimum=0.000, Maximum=127.000, "
             "Mean=31.750, StdDev=54.993" in info.decode('utf-8'),
             info)
-
diff --git a/tests/test_profile.py b/tests/test_profile.py
index 07cc2cf3..b85b885f 100644
--- a/tests/test_profile.py
+++ b/tests/test_profile.py
@@ -60,14 +60,29 @@ def test_gtiff_profile_protected_driver():
 
 
 def test_open_with_profile(tmpdir):
-        tiffname = str(tmpdir.join('foo.tif'))
-        with rasterio.open(
-                tiffname,
-                'w',
-                **default_gtiff_profile(
-                    count=1, width=1, height=1)) as dst:
-            data = dst.read()
-            assert data.flatten().tolist() == [0]
+    tiffname = str(tmpdir.join('foo.tif'))
+    with rasterio.open(
+            tiffname,
+            'w',
+            **default_gtiff_profile(
+                count=1, width=256, height=256)) as dst:
+        data = dst.read()
+
+
+def test_blockxsize_guard(tmpdir):
+    """blockxsize can't be greater than image width."""
+    tiffname = str(tmpdir.join('foo.tif'))
+    with pytest.raises(ValueError):
+        _ = rasterio.open(tiffname, 'w', **default_gtiff_profile(
+                count=1, width=128, height=256))
+
+
+def test_blockysize_guard(tmpdir):
+    """blockysize can't be greater than image height."""
+    tiffname = str(tmpdir.join('foo.tif'))
+    with pytest.raises(ValueError):
+        _ = rasterio.open(tiffname, 'w', **default_gtiff_profile(
+                count=1, width=256, height=128))
 
 
 def test_profile_overlay():