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From: Mark Wielaard <mark@klomp.org>
To: Ben Woodard <woodard@redhat.com>
Cc: Ben Woodard via Libabigail <libabigail@sourceware.org>
Subject: Re: libabigail 2.1 trunk testing where are we?
Date: Fri, 29 Jul 2022 22:57:09 +0200	[thread overview]
Message-ID: <YuRJpWXXz+I/BI08@wildebeest.org> (raw)
In-Reply-To: <5BA0C098-9E22-4604-8C13-1D0624B2489F@redhat.com>

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On Fri, Jul 29, 2022 at 11:28:18AM -0700, Ben Woodard via Libabigail wrote:
> 1 crash due to incorrect ELF in that shows up in a small number of
> packages https://sourceware.org/bugzilla/show_bug.cgi?id=29346

I have a patch that should work around that on:
https://code.wildebeest.org/git/user/mjw/libabigail/commit/?h=pr29346
Also attached. Maybe someone with commit access could push it to a
users try branch for testing?

Thanks,

Mark

[-- Attachment #2: 0001-Handle-zero-sh_entsize-in-get_soname_of_elf_file.patch --]
[-- Type: text/x-diff, Size: 1651 bytes --]

From 05c53fcbdbccd8b08dfabd22caa9c7b4625596e8 Mon Sep 17 00:00:00 2001
From: Mark Wielaard <mark@klomp.org>
Date: Wed, 20 Jul 2022 01:01:14 +0200
Subject: [PATCH] Handle zero sh_entsize in get_soname_of_elf_file

Apparently guile produced ELF files don't set sh_entsize for the
dynamic section. Which would cause a divide by zero. Luckily we do
know how big an dynamic entry should be. So use gelf_fsize for
ELF_T_DYN if sh_entsize is zero.

	  * src/abg-dwarf-reader.cc (get_soname_of_elf_file):
	  Make sure entsize is non-zero before use.

https://sourceware.org/bugzilla/show_bug.cgi?id=29346

Signed-off-by: Mark Wielaard <mark@klomp.org>
---
 src/abg-dwarf-reader.cc | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/abg-dwarf-reader.cc b/src/abg-dwarf-reader.cc
index e5159c89..288a56b8 100644
--- a/src/abg-dwarf-reader.cc
+++ b/src/abg-dwarf-reader.cc
@@ -16629,8 +16629,11 @@ get_soname_of_elf_file(const string& path, string &soname)
           Elf_Scn* scn = gelf_offscn (elf, phdr->p_offset);
           GElf_Shdr shdr_mem;
           GElf_Shdr* shdr = gelf_getshdr (scn, &shdr_mem);
+          size_t entsize = (shdr != NULL && shdr->sh_entsize != 0
+                            ? shdr->sh_entsize
+                            : gelf_fsize (elf, ELF_T_DYN, 1, EV_CURRENT));
           int maxcnt = (shdr != NULL
-                        ? shdr->sh_size / shdr->sh_entsize : INT_MAX);
+                        ? shdr->sh_size / entsize : INT_MAX);
           ABG_ASSERT (shdr == NULL || shdr->sh_type == SHT_DYNAMIC);
           Elf_Data* data = elf_getdata (scn, NULL);
           if (data == NULL)
-- 
2.30.2


  reply	other threads:[~2022-07-29 20:57 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-29 18:28 Ben Woodard
2022-07-29 20:57 ` Mark Wielaard [this message]
2022-07-29 22:48   ` Ben Woodard
2022-09-20  8:47   ` Dodji Seketeli
2022-09-20 15:05     ` Mark Wielaard
2022-09-25  7:06       ` Dodji Seketeli

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