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Date:      Thu, 21 Mar 2024 10:13:04 +0000
From:      bugzilla-noreply@freebsd.org
To:        bugs@FreeBSD.org
Subject:   [Bug 277861] corrupt ELF file can crash llvm-objdump in printSymbolVersionDefinition()
Message-ID:  <bug-277861-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D277861

            Bug ID: 277861
           Summary: corrupt ELF file can crash llvm-objdump in
                    printSymbolVersionDefinition()
           Product: Base System
           Version: CURRENT
          Hardware: Any
                OS: Any
            Status: New
          Severity: Affects Some People
          Priority: ---
         Component: bin
          Assignee: bugs@FreeBSD.org
          Reporter: rtm@lcs.mit.edu

Created attachment 249368
  --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=3D249368&action=
=3Dedit
broken ELF file that crashes llvm-objdump in printSymbolVersionDefinition()

This line in printSymbolVersionDefinition() in
llvm-project/llvm/tools/llvm-objdump/ELFDump.cpp forms a pointer using
a value pulled from the ELF file (vd_aux) without a sanity check:

    const uint8_t *BufAux =3D Buf + Verdef->vd_aux;

It may be that the subsequent uses of vda_next and vd_next have a
similar problem.

I've attached an ELF file that crashes objdump due to a huge vd_aux:

# freebsd-version
15.0-CURRENT
# objdump --version
LLVM (http://llvm.org/):
  LLVM version 17.0.6
  Optimized build with assertions.
...
# objdump -p objdump2a.exe

objdump2a.exe:  file format elf32-lanai

Program Header:
objdump: warning: 'objdump2a.exe': section [index 7] has invalid sh_entsize:
expected 8, but got 5

Version definitions:
1 0x00 0x7650bc00 PLEASE submit a bug report to
https://bugs.freebsd.org/submit/ and include the crash backtrace.
Stack dump:
0.      Program arguments: objdump -p objdump2a.exe
 #0 0x0000000001230c41 PrintStackTrace
/usr/src/contrib/llvm-project/llvm/lib/Support/Unix/Signals.inc:602:13
 #1 0x000000000122f0b5 RunSignalHandlers
/usr/src/contrib/llvm-project/llvm/lib/Support/Signals.cpp:105:18
 #2 0x0000000001231365 SignalHandler
/usr/src/contrib/llvm-project/llvm/lib/Support/Unix/Signals.inc:0:3
 #3 0x00000008255ae5ff handle_signal /usr/src/lib/libthr/thread/thr_sig.c:0=
:3
 #4 0x00000008255adbbb thr_sighandler
/usr/src/lib/libthr/thread/thr_sig.c:244:1
 #5 0x00000008223cd2d3 ([vdso]+0x2d3)
 #6 0x0000000000de60d7 read<unsigned int, 1UL>
/usr/src/contrib/llvm-project/llvm/include/llvm/Support/Endian.h:66:3
 #7 0x0000000000de60d7 read<unsigned int, (llvm::support::endianness)1, 1UL>
/usr/src/contrib/llvm-project/llvm/include/llvm/Support/Endian.h:77:10
 #8 0x0000000000de60d7 operator unsigned int
/usr/src/contrib/llvm-project/llvm/include/llvm/Support/Endian.h:216:12
 #9 0x0000000000de60d7
printSymbolVersionDefinition<llvm::object::ELFType<(llvm::support::endianne=
ss)1,
false> >
/usr/src/contrib/llvm-project/llvm/tools/llvm-objdump/ELFDump.cpp:398:45
#10 0x0000000000de60d7 printSymbolVersion
/usr/src/contrib/llvm-project/llvm/tools/llvm-objdump/ELFDump.cpp:425:7
#11 0x0000000000de60d7 printPrivateHeaders
/usr/src/contrib/llvm-project/llvm/tools/llvm-objdump/ELFDump.cpp:432:3
#12 0x0000000000e6a13c dumpObject
/usr/src/contrib/llvm-project/llvm/tools/llvm-objdump/llvm-objdump.cpp:2815=
:7
#13 0x0000000000e654b0 dumpInput
/usr/src/contrib/llvm-project/llvm/tools/llvm-objdump/llvm-objdump.cpp:0:5
#14 0x0000000000e654b0
for_each<std::__1::__wrap_iter<std::__1::basic_string<char,
std::__1::char_traits<char>, std::__1::allocator<char> > *>, void
(*)(llvm::StringRef)>
/usr/obj/usr/src/amd64.amd64/tmp/usr/include/c++/v1/__algorithm/for_each.h:=
26:5
#15 0x0000000000e654b0 for_each<std::__1::vector<std::__1::basic_string<cha=
r,
std::__1::char_traits<char>, std::__1::allocator<char> >,
std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char=
>,
std::__1::allocator<char> > > > &, void (*)(llvm::StringRef)>
/usr/src/contrib/llvm-project/llvm/include/llvm/ADT/STLExtras.h:1731:10
#16 0x0000000000e654b0 main
/usr/src/contrib/llvm-project/llvm/tools/llvm-objdump/llvm-objdump.cpp:3248=
:3
#17 0x0000000828d4d0aa __libc_start1 /usr/src/lib/libc/csu/libc_start1.c:15=
7:2
Segmentation fault (core dumped)

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