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Re: [gold][PATCH] PR gold/17619: Check PC-relative offset overflow in PLT entry
- From: "H.J. Lu" <hjl dot tools at gmail dot com>
- To: Cary Coutant <ccoutant at google dot com>
- Cc: Binutils <binutils at sourceware dot org>
- Date: Fri, 21 Nov 2014 11:29:22 -0800
- Subject: Re: [gold][PATCH] PR gold/17619: Check PC-relative offset overflow in PLT entry
- Authentication-results: sourceware.org; auth=none
- References: <20141118193634 dot GA16737 at intel dot com> <CAHACq4pASeVcQQa=iMw+WywpTEmWbnEvqp9DgcxQ1saAtYoo7Q at mail dot gmail dot com> <CAMe9rOrF2ZYJUdewPyHyK_x8uh59b9kMJi=25okGB4JFqnkMVA at mail dot gmail dot com> <CAMe9rOpKJi3sKV-BeLycbkJHD9oaVQ0ABuV6mPDYKbiLzJKJdg at mail dot gmail dot com> <CAHACq4qhg5BnGFLGrSowKA9qDB4wAy36Dudk6WSUuB32KE-UdQ at mail dot gmail dot com>
On Fri, Nov 21, 2014 at 11:12 AM, Cary Coutant <ccoutant@google.com> wrote:
> + bool gotplt_after_plt = got_address > plt_address;
> + int32_t plt_got_pcrel_offset = (got_address + got_offset
> + - (plt_address + plt_offset + 6));
> + if ((gotplt_after_plt && plt_got_pcrel_offset < 0)
> + || (!gotplt_after_plt && plt_got_pcrel_offset > 0))
>
> Please use a uint64_t for the offset, and check for overflow with
> Bits<32>::has_overflow() from reloc.h.
>
> This is OK with that change. Thanks!
This is what I checked in:
>From 9d585188889de38c7191976051d9acdd8d57cbbf Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Tue, 18 Nov 2014 11:34:11 -0800
Subject: [PATCH] Check PC-relative offset overflow in PLT entry
PR gold/17619
* x86_64.cc (Output_data_plt_x86_64_standard<size>::do_fill_plt_entry):
Check PC-relative offset overflow in PLT entry.
---
gold/ChangeLog | 6 ++++++
gold/x86_64.cc | 11 ++++++++---
2 files changed, 14 insertions(+), 3 deletions(-)
diff --git a/gold/ChangeLog b/gold/ChangeLog
index 66c7fca..73e601d 100644
--- a/gold/ChangeLog
+++ b/gold/ChangeLog
@@ -1,3 +1,9 @@
+2014-11-21 H.J. Lu <hongjiu.lu@intel.com>
+
+ PR gold/17619
+ * x86_64.cc (Output_data_plt_x86_64_standard<size>::do_fill_plt_entry):
+ Check PC-relative offset overflow in PLT entry.
+
2014-11-21 Alan Modra <amodra@gmail.com>
* powerpc.cc (Target_powerpc::Relocate::relocate): Correct test
diff --git a/gold/x86_64.cc b/gold/x86_64.cc
index 1fb601d..4baa2bf 100644
--- a/gold/x86_64.cc
+++ b/gold/x86_64.cc
@@ -1516,11 +1516,16 @@
Output_data_plt_x86_64_standard<size>::do_fill_plt_entry(
unsigned int plt_offset,
unsigned int plt_index)
{
+ // Check PC-relative offset overflow in PLT entry.
+ uint64_t plt_got_pcrel_offset = (got_address + got_offset
+ - (plt_address + plt_offset + 6));
+ if (Bits<32>::has_overflow(plt_got_pcrel_offset))
+ gold_error(_("PC-relative offset overflow in PLT entry %d"),
+ plt_index + 1);
+
memcpy(pov, plt_entry, plt_entry_size);
elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
- (got_address + got_offset
- - (plt_address + plt_offset
- + 6)));
+ plt_got_pcrel_offset);
elfcpp::Swap_unaligned<32, false>::writeval(pov + 7, plt_index);
elfcpp::Swap<32, false>::writeval(pov + 12,
--
1.9.3
Thanks.
H.J.