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From: Ruslan Kabatsayev <b7.10110111@gmail.com>
To: gdb-patches@sourceware.org
Cc: Ruslan Kabatsayev <b7.10110111@gmail.com>
Subject: [PATCH] Avoid indexing std::vector past the end
Date: Sat, 30 Dec 2017 19:31:00 -0000	[thread overview]
Message-ID: <1514662273-27858-1-git-send-email-b7.10110111@gmail.com> (raw)

The code here wants to find address of an element, and often this
element is one past the end of std::vector. Dereferencing that element
leads to undefined behavior, so it's better to simply use pointer
arithmetic instead of taking address of invalid dereference.

gdb/ChangeLog:

	* psymtab.c (recursively_search_psymtabs): Use pointer arithmetic
	instead of dereferencing std::vector past the end.
---
 gdb/psymtab.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/gdb/psymtab.c b/gdb/psymtab.c
index c87ef25..c622f4c 100644
--- a/gdb/psymtab.c
+++ b/gdb/psymtab.c
@@ -1337,21 +1337,21 @@ recursively_search_psymtabs
     }
 
   partial_symbol **gbound
-    = &objfile->global_psymbols[ps->globals_offset + ps->n_global_syms];
+    = objfile->global_psymbols.data() + ps->globals_offset + ps->n_global_syms;
   partial_symbol **sbound
-    = &objfile->static_psymbols[ps->statics_offset + ps->n_static_syms];
+    = objfile->static_psymbols.data() + ps->statics_offset + ps->n_static_syms;
   partial_symbol **bound = gbound;
 
   /* Go through all of the symbols stored in a partial
      symtab in one loop.  */
-  partial_symbol **psym = &objfile->global_psymbols[ps->globals_offset];
+  partial_symbol **psym = objfile->global_psymbols.data() + ps->globals_offset;
   while (keep_going)
     {
       if (psym >= bound)
 	{
 	  if (bound == gbound && ps->n_static_syms != 0)
 	    {
-	      psym = &objfile->static_psymbols[ps->statics_offset];
+	      psym = objfile->static_psymbols.data() + ps->statics_offset;
 	      bound = sbound;
 	    }
 	  else
-- 
1.7.10.2

             reply	other threads:[~2017-12-30 19:31 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-12-30 19:31 Ruslan Kabatsayev [this message]
2017-12-31  1:31 ` Simon Marchi

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