Created attachment 249216 [details]
a corrupt ELF file that causes llvm-objdump to crash

This line in llvm-project/llvm/lib/Object/ELF.cpp dynamicEntries()
forms a pointer from p_offset without checking whether it's too large:

      Dyn = ArrayRef(reinterpret_cast<const Elf_Dyn *>(base() + Phdr.p_offset),
                     Phdr.p_filesz / sizeof(Elf_Dyn));

As a result a corrupt ELF file can cause objdump to crash. I've
attached a demo.

# uname -a
FreeBSD stock14 15.0-CURRENT FreeBSD 15.0-CURRENT #19 main-n268743-a58813fd701e: Sat Mar  9 07:18:21 AST 2024     root@stock14:/usr/obj/usr/src/amd64.amd64/sys/GENERIC amd64
# objdump --version
LLVM (http://llvm.org/):
  LLVM version 17.0.6
  Optimized build with assertions.
...
# objdump -p ldd1b.exe 
...
PLEASE submit a bug report to https://bugs.freebsd.org/submit/ and include the crash backtrace.
Stack dump:
0.      Program arguments: objdump -p ldd1b.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 0x00000008249cf5ff handle_signal /usr/src/lib/libthr/thread/thr_sig.c:0:3
 #4 0x00000008249cebbb thr_sighandler /usr/src/lib/libthr/thread/thr_sig.c:244:1
 #5 0x000000082270d2d3 ([vdso]+0x2d3)
 #6 0x0000000000f96641 dynamicEntries /usr/src/contrib/llvm-project/llvm/lib/Object/ELF.cpp:590:24
 #7 0x0000000000df2268 operator bool /usr/src/contrib/llvm-project/llvm/include/llvm/Support/Error.h:559:17
 #8 0x0000000000df2268 printDynamicSection /usr/src/contrib/llvm-project/llvm/tools/llvm-objdump/ELFDump.cpp:205:8
 #9 0x0000000000df2268 printPrivateHeaders /usr/src/contrib/llvm-project/llvm/tools/llvm-objdump/ELFDump.cpp:431:3
#10 0x0000000000e6a13c dumpObject /usr/src/contrib/llvm-project/llvm/tools/llvm-objdump/llvm-objdump.cpp:2815:7
#11 0x0000000000e654b0 dumpInput /usr/src/contrib/llvm-project/llvm/tools/llvm-objdump/llvm-objdump.cpp:0:5
#12 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
#13 0x0000000000e654b0 for_each<std::__1::vector<std::__1::basic_string<char, 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
#14 0x0000000000e654b0 main /usr/src/contrib/llvm-project/llvm/tools/llvm-objdump/llvm-objdump.cpp:3248:3
#15 0x0000000828a2d0aa __libc_start1 /usr/src/lib/libc/csu/libc_start1.c:157:2
Bus error (core dumped)