Fix malloc allocation size sanity check

During debugging of PR26362, it was noticed that the malloc size check
in check_type_length_before_alloc wasn't detecting an allocation attempt
of a huge amount of bytes, making GDB run into an internal error.

This happens because we're using an int to store a type's length. When the
type length is large enough, the int will overflow and the max_value_size
check won't work anymore.

The following patch fixes this by making the length variable a ULONGEST.

Printing statements were also updated to show the correct number of bytes.

gdb/ChangeLog:

2020-08-12  Luis Machado  <luis.machado@linaro.org>

	* value.c (check_type_length_before_alloc): Use ULONGEST to store a
	type's length.
	Use %s and pulongest to print the length.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 4abc47dab42975db92a0a8dbf44342a2c26200db..27c6849cd6ae182b7ebebfe1bf260a1549721799 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@
+2020-08-12  Luis Machado  <luis.machado@linaro.org>
+
+       * value.c (check_type_length_before_alloc): Use ULONGEST to store a
+       type's length.
+       Use %s and pulongest to print the length.
+
 2020-08-12  Pedro Alves  <palves@redhat.com>
 
        * NEWS: Move "Multi-target debugging support" item to the

diff --git a/gdb/value.c b/gdb/value.c
index aac9baaaf5652969ce6e6c4ff999217aec04a052..a6e21309f857086db69f9c615839457bd3cac0c4 100644 (file)
--- a/gdb/value.c
+++ b/gdb/value.c
@@ -997,16 +997,16 @@ show_max_value_size (struct ui_file *file, int from_tty,
 static void
 check_type_length_before_alloc (const struct type *type)
 {
-  unsigned int length = TYPE_LENGTH (type);
+  ULONGEST length = TYPE_LENGTH (type);
 
   if (max_value_size > -1 && length > max_value_size)
     {
       if (type->name () != NULL)
-       error (_("value of type `%s' requires %u bytes, which is more "
-                "than max-value-size"), type->name (), length);
+       error (_("value of type `%s' requires %s bytes, which is more "
+                "than max-value-size"), type->name (), pulongest (length));
       else
-       error (_("value requires %u bytes, which is more than "
-                "max-value-size"), length);
+       error (_("value requires %s bytes, which is more than "
+                "max-value-size"), pulongest (length));
     }
 }