Patch: check for invalid string offsets when linking stabs

[Richard Sandiford]

ld can segfault if a stabs entry contains an invalid string offset.
Is it OK to add a bounds check?  Patch checked for basic sanity on
mips64-elf.

Richard

	* stabs.c (_bfd_link_section_stabs): Check that the symbol offset
	is within the .stabstr section.

Index: stabs.c
===================================================================
RCS file: /cvs/src/src/bfd/stabs.c,v
retrieving revision 1.9
diff -c -d -p -r1.9 stabs.c
*** stabs.c	26 Nov 2001 19:31:27 -0000	1.9
--- stabs.c	5 Jun 2002 14:13:59 -0000
*************** _bfd_link_section_stabs (abfd, psinfo, s
*** 284,289 ****
--- 284,290 ----
         sym < symend;
         sym += STABSIZE, ++pstridx)
      {
+       bfd_size_type symstroff;
        int type;
        const char *string;
  
*************** _bfd_link_section_stabs (abfd, psinfo, s
*** 311,319 ****
  	}
  
        /* Store the string in the hash table, and record the index.  */
!       string = ((char *) stabstrbuf
! 		+ stroff
! 		+ bfd_get_32 (abfd, sym + STRDXOFF));
        *pstridx = _bfd_stringtab_add (sinfo->strings, string, true, true);
  
        /* An N_BINCL symbol indicates the start of the stabs entries
--- 312,321 ----
  	}
  
        /* Store the string in the hash table, and record the index.  */
!       symstroff = stroff + bfd_get_32 (abfd, sym + STRDXOFF);
!       if (symstroff >= stabstrsec->_raw_size)
! 	goto error_return;
!       string = (char *) stabstrbuf + symstroff;
        *pstridx = _bfd_stringtab_add (sinfo->strings, string, true, true);
  
        /* An N_BINCL symbol indicates the start of the stabs entries