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[PATCH] Replace unsafe alloca for baseclass type
- From: Siddhesh Poyarekar <siddhesh at redhat dot com>
- To: gdb-patches at sourceware dot org
- Date: Wed, 4 Jul 2012 16:04:23 +0530
- Subject: [PATCH] Replace unsafe alloca for baseclass type
Hi,
While working on a review for the bitpos patch[1], I found an unsafe
alloca in cp-valprint, which could result in a crash since the
baseclass size could get very large. Here's a patch based on Jan's
suggestion to fix this.
I have tested to verify that this does not introduce any regressions in
the testsuite on x86_64.
Regards,
Siddhesh
[1] http://sourceware.org/ml/gdb-patches/2012-06/msg00851.html
gdb/ChangeLog:
2012-07-04 Siddhesh Poyarekar <siddhesh@redhat.com>
Jan Kartochvil <jan.kratochvil@redhat.com>
* cp-valprint.c (cp_print_value): Replace potentially unsafe
alloca with xmalloc/xfree.
diff --git a/gdb/cp-valprint.c b/gdb/cp-valprint.c
index 2e3beea..c066aa5 100644
--- a/gdb/cp-valprint.c
+++ b/gdb/cp-valprint.c
@@ -554,9 +554,11 @@ cp_print_value (struct type *type, struct type *real_type,
if ((boffset + offset) < 0
|| (boffset + offset) >= TYPE_LENGTH (real_type))
{
- /* FIXME (alloca): unsafe if baseclass is really
- really large. */
- gdb_byte *buf = alloca (TYPE_LENGTH (baseclass));
+ gdb_byte *buf;
+ struct cleanup *back_to;
+
+ buf = xmalloc (TYPE_LENGTH (baseclass));
+ back_to = make_cleanup (xfree, buf);
if (target_read_memory (address + boffset, buf,
TYPE_LENGTH (baseclass)) != 0)
@@ -568,6 +570,7 @@ cp_print_value (struct type *type, struct type *real_type,
boffset = 0;
thistype = baseclass;
base_valaddr = value_contents_for_printing_const (base_val);
+ do_cleanups (back_to);
}
else
{