[Elftoolchain-developers] Error in section '.dynamic' to segment 'DYNAMIC' assignment

[Frank T. <fra...@ts...>]

Dear all,

I am facing an issue while adding a new section to an existing ELF
binary for the ARM platform.

For some reason the already contained dynamic section of the ELF binary
is somehow assigned to the wrong segment after updating the ELF binary
(elf_update).

If the command "readelf -l" is used on the unmodified ELF binary (shared
object), it results in the following output:

---------------------
readelf -l mylib.so

Header:
  Typ            Offset   VirtAdr    PhysAdr    DateiGr SpeiGr  Flg Ausr.
  EXIDX          0x127b3c 0x00127b3c 0x00127b3c 0x01490 0x01490 R   0x4
  PHDR           0x000034 0x00000034 0x00000034 0x00140 0x00140 R E 0x4
  INTERP         0x126e2c 0x00126e2c 0x00126e2c 0x00014 0x00014 R   0x4
  LOAD           0x000000 0x00000000 0x00000000 0x12c23c 0x12c23c R E 0x8000
  LOAD           0x12c6cc 0x001346cc 0x001346cc 0x02748 0x04ecc RW  0x8000
  DYNAMIC        0x12df28 0x00135f28 0x00135f28 0x000d8 0x000d8 RW  0x4
  NOTE           0x000174 0x00000174 0x00000174 0x00020 0x00020 R   0x4
  TLS            0x12c6cc 0x001346cc 0x001346cc 0x00008 0x0004c R   0x4
  GNU_STACK      0x000000 0x00000000 0x00000000 0x00000 0x00000 RW  0x4
  GNU_RELRO      0x12c6cc 0x001346cc 0x001346cc 0x01934 0x01934 R   0x1

...
   00     .ARM.exidx
   01
   02     .interp
   03     .note.ABI-tag .gnu.hash .dynsym .dynstr .gnu.version
.gnu.version_d .gnu.version_r .rel.dyn .rel.plt .plt .text
__libc_freeres_fn __libc_thread_freeres_fn .rodata .interp .ARM.extab
.ARM.exidx .eh_frame .hash
   04     .tdata __libc_subfreeres __libc_atexit
__libc_thread_subfreeres .data.rel.ro .dynamic .got .data .bss
   05     .dynamic
   06     .note.ABI-tag
   07     .tdata .tbss
   08
   09     .tdata __libc_subfreeres __libc_atexit
__libc_thread_subfreeres .data.rel.ro .dynamic

---------------------

After adding the new section and updating the ELF binary, the command
raises the warning '.dynamic section is not contained within the dynamic
segment' and the output is as follows:

---------------------
readelf -l mylib.so

Header:
  Typ            Offset   VirtAdr    PhysAdr    DateiGr SpeiGr  Flg Ausr.
  EXIDX          0x127b3c 0x00127b3c 0x00127b3c 0x01490 0x01490 R   0x4
  PHDR           0x000034 0x00000034 0x00000034 0x00140 0x00140 R E 0x4
  INTERP         0x126e2c 0x00126e2c 0x00126e2c 0x00014 0x00014 R   0x4
  LOAD           0x000000 0x00000000 0x00000000 0x12c23c 0x12c23c R E 0x8000
  LOAD           0x12c6cc 0x001346cc 0x001346cc 0x02748 0x04ecc RW  0x8000
  DYNAMIC        0x12df28 0x00135f28 0x00135f28 0x000d8 0x000d8 RW
0x4readelf: Warning: the .dynamic section is not contained within the
dynamic segment

  NOTE           0x000174 0x00000174 0x00000174 0x00020 0x00020 R   0x4
  TLS            0x12c6cc 0x001346cc 0x001346cc 0x00008 0x0004c R   0x4
  GNU_STACK      0x000000 0x00000000 0x00000000 0x00000 0x00000 RW  0x4
  GNU_RELRO      0x12c6cc 0x001346cc 0x001346cc 0x01934 0x01934 R   0x1

...
   00     .ARM.exidx
   01
   02     .interp
   03     .note.ABI-tag .gnu.hash .dynsym .dynstr .gnu.version
.gnu.version_d .gnu.version_r .rel.dyn .rel.plt .plt .text
__libc_freeres_fn __libc_thread_freeres_fn .rodata .interp .ARM.extab
.ARM.exidx .eh_frame .hash
   04     .dynamic .got .data .bss .ARM.attributes .shstrtab
   05
   06     .note.ABI-tag
   07     .tbss
   08
   09     .dynamic

---------------------

In contrast to the original file the ELF section '.dynamic', which
should be contained within segment no 5 (DYNAMIC), is contained within
segment no 4 (LOAD). Some other sections even seem to be mixed up or
missing compared to the original ELF binary.

As a result all programs using this library are crashing.

Any hints?

Regards,

Frank