Re: [RFA] dwarf2read.c: Add complaint for out of bounds DW_AT_ranges attribute

[Jim Blandy <jimb@redhat.com>]

Looks good.

Kevin Buettner <kevinb@redhat.com> writes:

> This one's almost obvious...
> 
> GDB for the FR-V target was segfaulting when issued the "maint
> check-symtabs" command.  Clearly this is an indication that something
> is wrong with the toolchain elsewhere, but GDB should not segfault
> when it encounters bad debug info.
> 
> Okay?
> 
> 	* dwarf2read.c (dwarf2_get_pc_bounds): Complain if offset
> 	associated with DW_AT_ranges attribute is out of bounds.
> 
> Index: dwarf2read.c
> ===================================================================
> RCS file: /cvs/src/src/gdb/dwarf2read.c,v
> retrieving revision 1.101
> diff -u -p -r1.101 dwarf2read.c
> --- dwarf2read.c	9 Sep 2003 23:23:05 -0000	1.101
> +++ dwarf2read.c	10 Sep 2003 21:11:27 -0000
> @@ -2253,7 +2253,7 @@ dwarf2_get_pc_bounds (struct die_info *d
>  	  unsigned int addr_size = cu_header->addr_size;
>  	  CORE_ADDR mask = ~(~(CORE_ADDR)1 << (addr_size * 8 - 1));
>  	  /* Value of the DW_AT_ranges attribute is the offset in the
> -	     .debug_renges section.  */
> +	     .debug_ranges section.  */
>  	  unsigned int offset = DW_UNSND (attr);
>  	  /* Base address selection entry.  */
>  	  CORE_ADDR base;
> @@ -2266,6 +2266,14 @@ dwarf2_get_pc_bounds (struct die_info *d
>   
>  	  found_base = cu_header->base_known;
>  	  base = cu_header->base_address;
> +
> +	  if (offset >= dwarf_ranges_size)
> +	    {
> +	      complaint (&symfile_complaints,
> +	                 "Offset %d out of bounds for DW_AT_ranges attribute",
> +			 offset);
> +	      return 0;
> +	    }
>  	  buffer = dwarf_ranges_buffer + offset;
>  
>  	  /* Read in the largest possible address.  */