[Bug libelf/24387] New: Invalid address Deference in elf32_xlatetom function in libelf/elf32_xlatetom.c

[Bug libelf/24387] New: Invalid address Deference in elf32_xlatetom function in libelf/elf32_xlatetom.c

[wcventure at 126 dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=24387

            Bug ID: 24387
           Summary: Invalid address Deference in elf32_xlatetom function
                    in libelf/elf32_xlatetom.c
           Product: elfutils
           Version: unspecified
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: libelf
          Assignee: unassigned at sourceware dot org
          Reporter: wcventure at 126 dot com
                CC: elfutils-devel at sourceware dot org
  Target Milestone: ---

Created attachment 11701
  --> https://sourceware.org/bugzilla/attachment.cgi?id=11701&action=edit
POC1

Similar to Bug 24103. But this bug happened in elf32_xlatetom function, and can
still reproduce on elfutils 0.176.
So the Fixed is Incomplete.
Need to check the root cause.

Here are the POC file. Please use the "eu-stack --core=$POC"to reproduce the
bug.

ASAN backtrace:

> =================================================================
> ==6345==ERROR: AddressSanitizer: unknown-crash on address 0x7f79e8976000 at pc 0x7f79e7886df8 bp 0x7ffd4529cf30 sp 0x7ffd4529c6d8
> READ of size 3104 at 0x7f79e8976000 thread T0
>     #0 0x7f79e7886df7 in __asan_memmove (/usr/lib/x86_64-linux-gnu/libasan.so.2+0x8cdf7)
>     #1 0x7f79e756ac2b in memmove /usr/include/x86_64-linux-gnu/bits/string3.h:59
>     #2 0x7f79e756ac2b in elf32_xlatetom /Regression/elfutils-0.176/libelf/elf32_xlatetom.c:100
>     #3 0x7f79e72c29c8 in dwfl_segment_report_module /Regression/elfutils-0.176/libdwfl/dwfl_segment_report_module.c:607
>     #4 0x7f79e72d51b9 in dwfl_core_file_report /Regression/elfutils-0.176/libdwfl/core-file.c:543
>     #5 0x40322d in parse_opt /Regression/elfutils-0.176/src/stack.c:590
>     #6 0x7f79e6b2a847 in argp_parse (/lib/x86_64-linux-gnu/libc.so.6+0x114847)
>     #7 0x40271b in main /Regression/elfutils-0.176/src/stack.c:690
>     #8 0x7f79e6a3682f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2082f)
>     #9 0x402ef8 in _start (/Regression/elfutils-0.176_ASAN/build/bin/eu-stack+0x402ef8)
> 
> AddressSanitizer can not describe address in more detail (wild memory access suspected).
> SUMMARY: AddressSanitizer: unknown-crash ??:0 __asan_memmove
> Shadow bytes around the buggy address:
>   0x0fefbd126bb0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>   0x0fefbd126bc0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>   0x0fefbd126bd0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>   0x0fefbd126be0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>   0x0fefbd126bf0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> =>0x0fefbd126c00:[fe]fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
>   0x0fefbd126c10: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
>   0x0fefbd126c20: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
>   0x0fefbd126c30: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
>   0x0fefbd126c40: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
>   0x0fefbd126c50: fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe fe
> Shadow byte legend (one shadow byte represents 8 application bytes):
>   Addressable:           00
>   Partially addressable: 01 02 03 04 05 06 07 
>   Heap left redzone:       fa
>   Heap right redzone:      fb
>   Freed heap region:       fd
>   Stack left redzone:      f1
>   Stack mid redzone:       f2
>   Stack right redzone:     f3
>   Stack partial redzone:   f4
>   Stack after return:      f5
>   Stack use after scope:   f8
>   Global redzone:          f9
>   Global init order:       f6
>   Poisoned by user:        f7
>   Container overflow:      fc
>   Array cookie:            ac
>   Intra object redzone:    bb
>   ASan internal:           fe
> ==6345==ABORTING

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[Bug libelf/24387] Invalid address Deference in elf32_xlatetom function in libelf/elf32_xlatetom.c

[wcventure at 126 dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=24387

--- Comment #1 from wcventure <wcventure at 126 dot com> ---
Created attachment 11702
  --> https://sourceware.org/bugzilla/attachment.cgi?id=11702&action=edit
POC2

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[Bug libelf/24387] dwfl_segment_report_module doesn't check whether the phdrs data read from core file is truncated

[mark at klomp dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=24387

Mark Wielaard <mark at klomp dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
                 CC|                            |mark at klomp dot org
         Resolution|---                         |FIXED
            Summary|Invalid address Deference   |dwfl_segment_report_module
                   |in elf32_xlatetom function  |doesn't check whether the
                   |in libelf/elf32_xlatetom.c  |phdrs data read from core
                   |                            |file is truncated

--- Comment #2 from Mark Wielaard <mark at klomp dot org> ---
Can be replicated with valgrind.

It is indeed similar to bug #24103. Both of which aren't bugs in
elf(64|32)_xlatetom, but dwfl_segment_report_module should also check that the
core file isn't truncated so that not all of the phdrs can be read.

Fix is similar:

diff --git a/libdwfl/dwfl_segment_report_module.c
b/libdwfl/dwfl_segment_report_
index f6ad39b..76ba150 100644
--- a/libdwfl/dwfl_segment_report_module.c
+++ b/libdwfl/dwfl_segment_report_module.c
@@ -412,6 +412,12 @@ dwfl_segment_report_module (Dwfl *dwfl, int ndx, const
char
                    start + phoff, xlatefrom.d_size))
     return finish ();

+  /* ph_buffer_size will be zero if we got everything from the initial
+     buffer, otherwise it will be the size of the new buffer that
+     could be read.  */
+  if (ph_buffer_size != 0)
+    xlatefrom.d_size = ph_buffer_size;
+
   xlatefrom.d_buf = ph_buffer;

   bool class32 = ei_class == ELFCLASS32;

commit e1f353b785b5cdb20d8004b6c4070c3e2a783e8b
Author: Mark Wielaard <mark@klomp.org>
Date:   Wed Mar 27 22:32:21 2019 +0100

    libdwfl: Sanity check partial core file phdrs data read.

    When reading the phdrs data from the core file check if we got everything,
    or just part of the data.

    https://sourceware.org/bugzilla/show_bug.cgi?id=24387

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

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