libblock: PR2145: Limit maximum read-ahead blocks

This helps to prevent stack overflows due to configuration errors.

8 files changed, 103 insertions, 3 deletions

diff --git a/cpukit/libblock/include/rtems/bdbuf.h b/cpukit/libblock/include/rtems/bdbuf.h
index cde32d7c4c..2794af7300 100644
--- a/cpukit/libblock/include/rtems/bdbuf.h
+++ b/cpukit/libblock/include/rtems/bdbuf.h
@@ -460,7 +460,7 @@ extern const rtems_bdbuf_config rtems_bdbuf_configuration;
  * @retval RTEMS_SUCCESSFUL Successful operation. 
  * @retval RTEMS_CALLED_FROM_ISR Called from an interrupt context.
  * @retval RTEMS_INVALID_NUMBER The buffer maximum is not an integral multiple
- * of the buffer minimum.
+ * of the buffer minimum.  The maximum read-ahead blocks count is too large.
  * @retval RTEMS_RESOURCE_IN_USE Already initialized.
  * @retval RTEMS_UNSATISFIED Not enough resources.
  */
diff --git a/cpukit/libblock/src/bdbuf.c b/cpukit/libblock/src/bdbuf.c
index b7663f1408..9f5274c024 100644
--- a/cpukit/libblock/src/bdbuf.c
+++ b/cpukit/libblock/src/bdbuf.c
@@ -1378,6 +1378,13 @@ rtems_bdbuf_swapout_workers_create (void)
   return sc;
 }
 
+static size_t
+rtems_bdbuf_read_request_size (uint32_t transfer_count)
+{
+  return sizeof (rtems_blkdev_request)
+    + sizeof (rtems_blkdev_sg_buffer) * transfer_count;
+}
+
 /**
  * Initialise the cache.
  *
@@ -1403,9 +1410,14 @@ rtems_bdbuf_init (void)
   /*
    * Check the configuration table values.
    */
+
   if ((bdbuf_config.buffer_max % bdbuf_config.buffer_min) != 0)
     return RTEMS_INVALID_NUMBER;
 
+  if (rtems_bdbuf_read_request_size (bdbuf_config.max_read_ahead_blocks)
+      > RTEMS_MINIMUM_STACK_SIZE / 8U)
+    return RTEMS_INVALID_NUMBER;
+
   /*
    * We use a special variable to manage the initialisation incase we have
    * completing threads doing this. You may get errors if the another thread
@@ -2077,8 +2089,7 @@ rtems_bdbuf_execute_read_request (rtems_disk_device  *dd,
    */
 #define bdbuf_alloc(size) __builtin_alloca (size)
 
-  req = bdbuf_alloc (sizeof (rtems_blkdev_request) +
-                     sizeof (rtems_blkdev_sg_buffer) * transfer_count);
+  req = bdbuf_alloc (rtems_bdbuf_read_request_size (transfer_count));
 
   req->req = RTEMS_BLKDEV_REQ_READ;
   req->done = rtems_bdbuf_transfer_done;
diff --git a/testsuites/libtests/Makefile.am b/testsuites/libtests/Makefile.am
index d1ffabc980..f05f12b10a 100644
--- a/testsuites/libtests/Makefile.am
+++ b/testsuites/libtests/Makefile.am
@@ -1,6 +1,7 @@
 ACLOCAL_AMFLAGS = -I ../aclocal
 
 SUBDIRS = POSIX
+SUBDIRS += block17
 SUBDIRS += exit02
 SUBDIRS += exit01
 SUBDIRS += utf8proc01
diff --git a/testsuites/libtests/block17/Makefile.am b/testsuites/libtests/block17/Makefile.am
new file mode 100644
index 0000000000..b61d38d9e3
--- /dev/null
+++ b/testsuites/libtests/block17/Makefile.am
@@ -0,0 +1,19 @@
+rtems_tests_PROGRAMS = block17
+block17_SOURCES = init.c
+
+dist_rtems_tests_DATA = block17.scn block17.doc
+
+include $(RTEMS_ROOT)/make/custom/@RTEMS_BSP@.cfg
+include $(top_srcdir)/../automake/compile.am
+include $(top_srcdir)/../automake/leaf.am
+
+AM_CPPFLAGS += -I$(top_srcdir)/../support/include
+
+LINK_OBJS = $(block17_OBJECTS)
+LINK_LIBS = $(block17_LDLIBS)
+
+block17$(EXEEXT): $(block17_OBJECTS) $(block17_DEPENDENCIES)
+	@rm -f block17$(EXEEXT)
+	$(make-exe)
+
+include $(top_srcdir)/../automake/local.am
diff --git a/testsuites/libtests/block17/block17.doc b/testsuites/libtests/block17/block17.doc
new file mode 100644
index 0000000000..cf6d17d814
--- /dev/null
+++ b/testsuites/libtests/block17/block17.doc
@@ -0,0 +1,12 @@
+This file describes the directives and concepts tested by this test set.
+
+test set name: block17
+
+directives:
+
+  - rtems_bdbuf_init()
+
+concepts:
+
+  - Ensure that maximum read-ahead blocks count configuration error gets
+    detected.
diff --git a/testsuites/libtests/block17/block17.scn b/testsuites/libtests/block17/block17.scn
new file mode 100644
index 0000000000..d5f97c879d
--- /dev/null
+++ b/testsuites/libtests/block17/block17.scn
@@ -0,0 +1,2 @@
+*** TEST BLOCK 17 ***
+*** END OF TEST BLOCK 17 ***
diff --git a/testsuites/libtests/block17/init.c b/testsuites/libtests/block17/init.c
new file mode 100644
index 0000000000..cb656bf493
--- /dev/null
+++ b/testsuites/libtests/block17/init.c
@@ -0,0 +1,54 @@
+/*
+ * Copyright (c) 2013 embedded brains GmbH.  All rights reserved.
+ *
+ *  embedded brains GmbH
+ *  Dornierstr. 4
+ *  82178 Puchheim
+ *  Germany
+ *  <rtems@embedded-brains.de>
+ *
+ * The license and distribution terms for this file may be
+ * found in the file LICENSE in this distribution or at
+ * http://www.rtems.com/license/LICENSE.
+ */
+
+#ifdef HAVE_CONFIG_H
+  #include "config.h"
+#endif
+
+#include <rtems/bdbuf.h>
+
+#include "tmacros.h"
+
+static void test(void)
+{
+  rtems_status_code sc = rtems_bdbuf_init();
+  rtems_test_assert(sc == RTEMS_INVALID_NUMBER);
+}
+
+static void Init(rtems_task_argument arg)
+{
+  puts("\n\n*** TEST BLOCK 17 ***");
+
+  test();
+
+  puts("*** END OF TEST BLOCK 17 ***");
+
+  rtems_test_exit(0);
+}
+
+#define CONFIGURE_APPLICATION_NEEDS_CLOCK_DRIVER
+#define CONFIGURE_APPLICATION_NEEDS_CONSOLE_DRIVER
+
+#define CONFIGURE_APPLICATION_NEEDS_LIBBLOCK
+#define CONFIGURE_BDBUF_MAX_READ_AHEAD_BLOCKS (64UL * 1024UL)
+
+#define CONFIGURE_USE_IMFS_AS_BASE_FILESYSTEM
+
+#define CONFIGURE_MAXIMUM_TASKS 1
+
+#define CONFIGURE_RTEMS_INIT_TASKS_TABLE
+
+#define CONFIGURE_INIT
+
+#include <rtems/confdefs.h>
diff --git a/testsuites/libtests/configure.ac b/testsuites/libtests/configure.ac
index 741c6034df..ebe8a0ac6f 100644
--- a/testsuites/libtests/configure.ac
+++ b/testsuites/libtests/configure.ac
@@ -43,6 +43,7 @@ AM_CONDITIONAL(HAS_POSIX,test x"${rtems_cv_RTEMS_POSIX_API}" = x"yes")
 
 # Explicitly list all Makefiles here
 AC_CONFIG_FILES([Makefile
+block17/Makefile
 exit02/Makefile
 exit01/Makefile
 utf8proc01/Makefile