This is the mail archive of the
elfutils-devel@sourceware.org
mailing list for the elfutils project.
Re: [PATCH] readelf: Fix cie_offset calculation comparison on 32bit.
- From: Mark Wielaard <mjw at redhat dot com>
- To: elfutils-devel at lists dot fedorahosted dot org
- Date: Tue, 28 Apr 2015 14:15:08 +0200
- Subject: Re: [PATCH] readelf: Fix cie_offset calculation comparison on 32bit.
On Wed, 2015-04-22 at 12:50 +0200, Mark Wielaard wrote:
> gcc -fsanitize=undefined pointed out that on 32bit systems the calculation
> to match the cie_offset to the cie_id could be undefined because a cie_id
> could be an unsigned 64bit value while ptrdiff_t is only 32bits. Correct
> the calculation to use 64bit values.
>
> 2015-03-22 Mark Wielaard <mjw@redhat.com>
>
> + * readelf.c (print_debug_frame_section): Cast start to Dwarf_Off
> + before subtracting cie_id.
That wasn't completely correct on 64bit. We also need to explicitly cast
cie_offset to Dwarf_Off. Pushed with that fixed as attached.
From 32d5b6f61a90b3c0c777b73eee973d6816a21294 Mon Sep 17 00:00:00 2001
From: Mark Wielaard <mjw@redhat.com>
Date: Wed, 22 Apr 2015 12:47:46 +0200
Subject: [PATCH] readelf: Fix cie_offset calculation comparison on 32bit.
gcc -fsanitize=undefined pointed out that on 32bit systems the calculation
to match the cie_offset to the cie_id could be undefined because a cie_id
could be an unsigned 64bit value while ptrdiff_t is only 32bits. Correct
the calculation to use 64bit values.
Signed-off-by: Mark Wielaard <mjw@redhat.com>
---
src/ChangeLog | 6 ++++++
src/readelf.c | 4 ++--
2 files changed, 8 insertions(+), 2 deletions(-)
diff --git a/src/ChangeLog b/src/ChangeLog
index 40a0e6f..a4ac4e4 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,11 @@
2015-03-22 Mark Wielaard <mjw@redhat.com>
+ * readelf.c (print_debug_frame_section): Cast start to Dwarf_Off
+ before subtracting cie_id. And cast cie_offset to Dwarf_Off before
+ comparison.
+
+2015-03-22 Mark Wielaard <mjw@redhat.com>
+
* readelf.c (print_gdb_index_section): Check all offsets used
against section d_size.
diff --git a/src/readelf.c b/src/readelf.c
index 26c7eed..b4cb3a8 100644
--- a/src/readelf.c
+++ b/src/readelf.c
@@ -5619,8 +5619,8 @@ print_debug_frame_section (Dwfl_Module *dwflmod, Ebl *ebl, GElf_Ehdr *ehdr,
struct cieinfo *cie = cies;
while (cie != NULL)
if (is_eh_frame
- ? start - (ptrdiff_t) cie_id == cie->cie_offset
- : (ptrdiff_t) cie_id == cie->cie_offset)
+ ? ((Dwarf_Off) start - cie_id) == (Dwarf_Off) cie->cie_offset
+ : cie_id == (Dwarf_Off) cie->cie_offset)
break;
else
cie = cie->next;
--
1.8.3.1