From: Xi Ruoyao <xry111@xry111.site>
To: liuzhensong <liuzhensong@loongson.cn>, binutils@sourceware.org
Cc: Lulu Cheng <chenglulu@loongson.cn>, Wang Xuerui <i@xen0n.name>,
Chenghua Xu <xuchenghua@loongson.cn>,
mengqinggang@loongson.cn
Subject: Re: [PATCH 1/2] LoongArch: Avoid heap-buffer-overflow in loongarch_elf_relocate_section
Date: Wed, 14 Sep 2022 18:15:57 +0800 [thread overview]
Message-ID: <a07e9df509c6171f004741fd4f9c943079585557.camel@xry111.site> (raw)
In-Reply-To: <b4d228b5-2742-a75f-432b-431feb815c14@loongson.cn>
On Wed, 2022-09-14 at 16:57 +0800, liuzhensong wrote:
> 在 2022/9/13 下午11:44, Xi Ruoyao 写道:
>
> > If a and b are different sections, we cannot access something in b
> > with
> > "a->contents + (offset from a)" because "a->contents" and "b-
> > >contents"
> > are heap buffers allocated separately, not slices of a large buffer.
> >
> > The issue was found during an attempt to add static-pie support to
> > the
> > toolchain with ASAN.
> Can you provide compile parameters?
To reproduce it easily, add a check to detect the heap buffer overflow:
diff --git a/bfd/elfnn-loongarch.c b/bfd/elfnn-loongarch.c
index a9bb66a1e04..716e3d5a246 100644
--- a/bfd/elfnn-loongarch.c
+++ b/bfd/elfnn-loongarch.c
@@ -3202,6 +3202,7 @@ loongarch_elf_relocate_section (bfd *output_bfd, struct bfd_link_info *info,
}
}
+ BFD_ASSERT (got_off < got->size);
bfd_put_NN (output_bfd, relocation, got->contents + got_off);
relocation = got_off + sec_addr (got);
Then
$ cat test.S
.text
.align 2
.local ifunc
.type ifunc, @gnu_indirect_function
.set ifunc, resolver
resolver:
la.local $a0, impl
jr $ra
impl:
li.w $a0, 42
jr $ra
.global test
.type test, @function
test:
move $s0, $ra
la.got $t0, ifunc
jirl $ra, $t0, 0
xori $a0, $a0, 42
jr $s0
$ cc test.S -c
$ ld/ld-new test.o -shared
ld/ld-new: BFD (GNU Binutils) 2.39.50.20220914 assertion fail elfnn-loongarch.c:3205
And if GDB is used with a breakpoint at bfd_assert, we can see got_off
is "18446744073709551608" (-8).
> Shouldn't write to got table when using hidden ifunc.
Perhaps it's true, using RELA to resolve a GOT entry should not depend
on any "initial" value of the entry...
--
Xi Ruoyao <xry111@xry111.site>
School of Aerospace Science and Technology, Xidian University
next prev parent reply other threads:[~2022-09-14 10:16 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-13 15:44 [PATCH 0/2] LoongArch: Fix two bugs breaking IFUNC in static PIE Xi Ruoyao
2022-09-13 15:44 ` [PATCH 1/2] LoongArch: Avoid heap-buffer-overflow in loongarch_elf_relocate_section Xi Ruoyao
2022-09-14 8:57 ` liuzhensong
2022-09-14 10:15 ` Xi Ruoyao [this message]
2022-09-14 11:15 ` Xi Ruoyao
2022-09-15 1:47 ` liuzhensong
2022-09-15 2:56 ` Xi Ruoyao
2022-09-15 3:54 ` liuzhensong
2022-09-15 6:13 ` Xi Ruoyao
2022-09-13 15:44 ` [PATCH 2/2] LoongArch: Fix R_LARCH_IRELATIVE insertion after elf_link_sort_relocs Xi Ruoyao
2022-09-15 13:03 ` liuzhensong
2022-09-16 20:11 ` Xi Ruoyao
2022-09-18 9:58 ` Xi Ruoyao
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=a07e9df509c6171f004741fd4f9c943079585557.camel@xry111.site \
--to=xry111@xry111.site \
--cc=binutils@sourceware.org \
--cc=chenglulu@loongson.cn \
--cc=i@xen0n.name \
--cc=liuzhensong@loongson.cn \
--cc=mengqinggang@loongson.cn \
--cc=xuchenghua@loongson.cn \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).