PR5900: corrupt e_shstrndx

PR5900: corrupt e_shstrndx

[Ryan Mansfield]

After the change to handle >65536 sections[1], readelf now reports a 
file with no section headers as having a corrupt section header table 
index. The gABI says if the file has no section name string table that 
e_shstrndx will hold the value SHN_UNDEF. The proposed patch re-adds 
part of the original test for whether the string table exists.

ELF Header:
   Magic:   7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
   Class:                             ELF32
   Data:                              2's complement, little endian
   Version:                           1 (current)
   OS/ABI:                            UNIX - System V
   ABI Version:                       0
   Type:                              CORE (Core file)
   Machine:                           Renesas / SuperH SH
   Version:                           0x1
   Entry point address:               0x0
   Start of program headers:          52 (bytes into file)
   Start of section headers:          0 (bytes into file)
   Flags:                             0x0
   Size of this header:               52 (bytes)
   Size of program headers:           32 (bytes)
   Number of program headers:         65
   Size of section headers:           0 (bytes)
   Number of section headers:         0
   Section header string table index: 0 <corrupt: out of range>


Index: readelf.c
===================================================================
RCS file: /cvs/src/src/binutils/readelf.c,v
retrieving revision 1.441
diff -c -3 -p -r1.441 readelf.c
*** readelf.c   19 Mar 2009 14:42:52 -0000      1.441
--- readelf.c   24 Mar 2009 18:43:13 -0000
*************** process_file_header (void)
*** 3205,3211 ****
         if (section_headers != NULL
           && elf_header.e_shstrndx == (SHN_XINDEX & 0xffff))
         printf (" (%u)", section_headers[0].sh_link);
!       else if (elf_header.e_shstrndx >= elf_header.e_shnum)
         printf (" <corrupt: out of range>");
         putc ('\n', stdout);
       }
--- 3205,3212 ----
         if (section_headers != NULL
           && elf_header.e_shstrndx == (SHN_XINDEX & 0xffff))
         printf (" (%u)", section_headers[0].sh_link);
!       else if (elf_header.e_shstrndx != SHN_UNDEF
!                && elf_header.e_shstrndx >= elf_header.e_shnum)
         printf (" <corrupt: out of range>");
         putc ('\n', stdout);
       }

[1] http://sourceware.org/ml/binutils/2008-03/msg00070.html

Regards,

Ryan Mansfield

Re: PR5900: corrupt e_shstrndx

[Alan Modra]

On Tue, Mar 24, 2009 at 03:15:15PM -0400, Ryan Mansfield wrote:
> Index: readelf.c
> ===================================================================
> RCS file: /cvs/src/src/binutils/readelf.c,v
> retrieving revision 1.441
> diff -c -3 -p -r1.441 readelf.c
> *** readelf.c   19 Mar 2009 14:42:52 -0000      1.441
> --- readelf.c   24 Mar 2009 18:43:13 -0000
> *************** process_file_header (void)
> *** 3205,3211 ****
>         if (section_headers != NULL
>           && elf_header.e_shstrndx == (SHN_XINDEX & 0xffff))
>         printf (" (%u)", section_headers[0].sh_link);
> !       else if (elf_header.e_shstrndx >= elf_header.e_shnum)
>         printf (" <corrupt: out of range>");
>         putc ('\n', stdout);
>       }
> --- 3205,3212 ----
>         if (section_headers != NULL
>           && elf_header.e_shstrndx == (SHN_XINDEX & 0xffff))
>         printf (" (%u)", section_headers[0].sh_link);
> !       else if (elf_header.e_shstrndx != SHN_UNDEF
> !                && elf_header.e_shstrndx >= elf_header.e_shnum)
>         printf (" <corrupt: out of range>");
>         putc ('\n', stdout);
>       }

Applied with this changelog

2009-03-25  Ryan Mansfield  <rmansfield@qnx.com>

	* readelf.c (process_file_header): Don't report a corrupt string
	table index if it is zero.

-- 
Alan Modra
Australia Development Lab, IBM