[Bug general/24385] New: Regression lead to Invalid Address Deference, in handle_elf function in /src/strip.c

[Bug general/24385] New: Regression lead to Invalid Address Deference, in handle_elf function in /src/strip.c

[wcventure at 126 dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=24385

            Bug ID: 24385
           Summary: Regression lead to Invalid Address Deference, in
                    handle_elf function in /src/strip.c
           Product: elfutils
           Version: unspecified
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: general
          Assignee: unassigned at sourceware dot org
          Reporter: wcventure at 126 dot com
                CC: elfutils-devel at sourceware dot org
  Target Milestone: ---

Created attachment 11698
  --> https://sourceware.org/bugzilla/attachment.cgi?id=11698&action=edit
POC1

Hi,

I found some a regression bug.

This is anInvalid Address Deference bug, in handle_elf function in
/src/strip.c.

This problem exists in elfutils-0.176, but cannot reproduce in elfutils-0.175.
Thus this is a regression bug. elfutils 0.175 is right.

Here are the POC files. Please use " ./eu-strip $POC " to reproduce this 



ASAN bt:

> ASAN:SIGSEGV
> =================================================================
> ==10044==ERROR: AddressSanitizer: SEGV on unknown address 0x7ffce19d97b0 (pc 0x00000041339d bp 0x7ffce1978410 sp 0x7ffce1976750 T0)
>     #0 0x41339c in handle_elf elfutils-0.176/src/strip.c:1978
>     #1 0x41a2d1 in process_file elfutils-0.176/src/strip.c:769
>     #2 0x403b4b in main elfutils-0.176/src/strip.c:272
>     #3 0x7f505ec0382f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
>     #4 0x4046d8 in _start (elfutils-0.176_ASAN/build/bin/eu-strip+0x4046d8)
> 
> AddressSanitizer can not provide additional info.
> SUMMARY: AddressSanitizer: SEGV elfutils-0.176/src/strip.c:1978 handle_elf
> ==10044==ABORTING

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[Bug general/24385] Regression lead to Invalid Address Deference, in handle_elf function in /src/strip.c

[wcventure at 126 dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=24385

--- Comment #1 from wcventure <wcventure at 126 dot com> ---
Created attachment 11699
  --> https://sourceware.org/bugzilla/attachment.cgi?id=11699&action=edit
POC2

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[Bug general/24385] Regression lead to Invalid Address Deference, in handle_elf function in /src/strip.c

[mark at klomp dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=24385

Mark Wielaard <mark at klomp dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
                 CC|                            |mark at klomp dot org
         Resolution|---                         |FIXED

--- Comment #2 from Mark Wielaard <mark at klomp dot org> ---
This code is only triggered when stripping into a new file with -o. With that
it can be replicated under valgrind:

==1008== Command: src/strip -o POC1.stripped ./POC1
==1008== 
==1008== Invalid read of size 4
==1008==    at 0x804EB0A: handle_elf.constprop.2 (strip.c:1978)
==1008==    by 0x804F2F7: process_file (strip.c:769)
==1008==    by 0x8049AFF: main (strip.c:272)
==1008==  Address 0xfec3c840 is not stack'd, malloc'd or (recently) free'd
==1008== 
==1008== 
==1008== Process terminating with default action of signal 11 (SIGSEGV)
==1008==  Access not within mapped region at address 0xFEC3C840

The file is obviously illformed because the symbol refers to a non-existing
section. The fix is simple:

diff --git a/src/strip.c b/src/strip.c
index a73009d..4cd8750 100644
--- a/src/strip.c
+++ b/src/strip.c
@@ -1975,6 +1975,7 @@ handle_elf (int fd, Elf *elf, const char *prefix, const
ch
                                  && shndxdata->d_buf != NULL);
                    size_t sidx = (sym->st_shndx != SHN_XINDEX
                                   ? sym->st_shndx : xshndx);
+                   elf_assert (sidx < shnum);
                    sec = shdr_info[sidx].idx;

                    if (sec != 0)

commit f03ac75239e0981deaf4aa18f66f423bcc5ce051
Author: Mark Wielaard <mark@klomp.org>
Date:   Wed Mar 27 21:54:06 2019 +0100

    strip: Files with symbols referring to non-existing sections are illformed

    The check added in commit 4540ea98c "strip: Fix check test for SHN_XINDEX
    symbol" was not complete. The (extended) section index should also exist.
    If it doesn't exist, mark the file as illformed.

    https://sourceware.org/bugzilla/show_bug.cgi?id=24385

    Signed-off-by: Mark Wielaard <mark@klomp.org>

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[Bug general/24385] Check symbols only refer to existing sections in eu-strip handle_elf

[mark at klomp dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=24385

Mark Wielaard <mark at klomp dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|Regression lead to Invalid  |Check symbols only refer to
                   |Address Deference, in       |existing sections in
                   |handle_elf function in      |eu-strip handle_elf
                   |/src/strip.c                |

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