[PATCH] Fix readelf versioning handling

[Jakub Jelinek <jakub at redhat dot com>]

Hi!

readelf is reading from VERNEED/VERDEF sections even if they are not present
at all. This results either in slightly wrong output (it may e.g. print
different symbol versions for the same VERSYM value) or crash (especially if
virtual base address is non-zero).
The following patch fixes this (and in addition to that saves nearly 2K of
redundant code.
Ok to commit?

2000-12-30  Jakub Jelinek  <jakub@redhat.com>

	* readelf.c (process_version_sections): Check if VERDEF or VERNEED
	sections are present before using them.  Remove code duplication.
	(process_symbol_table): Check if VERDEF or VERNEED sections are
	present before using them.

--- binutils/readelf.c.jj	Fri Dec 29 18:12:12 2000
+++ binutils/readelf.c	Sat Dec 30 00:30:25 2000
@@ -3996,6 +3996,7 @@ process_version_sections (file)
 	    for (cnt = 0; cnt < total; cnt += 4)
 	      {
 		int j, nn;
+		int check_def, check_need;
 		char * name;
 
 		printf ("  %03x:", cnt);
@@ -4015,111 +4016,20 @@ process_version_sections (file)
 		      nn = printf ("%4x%c", data [cnt + j] & 0x7fff,
 				   data [cnt + j] & 0x8000 ? 'h' : ' ');
 
-		      if (symbols [cnt + j].st_shndx < SHN_LORESERVE
-			  && section_headers[symbols [cnt + j].st_shndx].sh_type
-			  == SHT_NOBITS)
+		      check_def = 1;
+		      check_need = 1;
+		      if (symbols [cnt + j].st_shndx >= SHN_LORESERVE
+			  || section_headers[symbols [cnt + j].st_shndx].sh_type
+			  != SHT_NOBITS)
 			{
-			  /* We must test both.  */
-			  Elf_Internal_Verneed     ivn;
-			  unsigned long            offset;
-
-			  offset = version_info [DT_VERSIONTAGIDX (DT_VERNEED)]
-			    - loadaddr;
-
-			  do
-			    {
-			      Elf_External_Verneed   evn;
-			      Elf_External_Vernaux   evna;
-			      Elf_Internal_Vernaux   ivna;
-			      unsigned long          vna_off;
-
-			      GET_DATA (offset, evn, "version need");
-
-			      ivn.vn_aux  = BYTE_GET (evn.vn_aux);
-			      ivn.vn_next = BYTE_GET (evn.vn_next);
-
-			      vna_off = offset + ivn.vn_aux;
-
-			      do
-				{
-				  GET_DATA (vna_off, evna,
-					    "version need aux (1)");
-
-				  ivna.vna_next  = BYTE_GET (evna.vna_next);
-				  ivna.vna_other = BYTE_GET (evna.vna_other);
-
-				  vna_off += ivna.vna_next;
-				}
-			      while (ivna.vna_other != data [cnt + j]
-				     && ivna.vna_next != 0);
-
-			      if (ivna.vna_other == data [cnt + j])
-				{
-				  ivna.vna_name = BYTE_GET (evna.vna_name);
-
-				  name = strtab + ivna.vna_name;
-				  nn += printf ("(%s%-*s",
-						name,
-						12 - (int) strlen (name),
-						")");
-				  break;
-				}
-			      else if (ivn.vn_next == 0)
-				{
-				  if (data [cnt + j] != 0x8001)
-				    {
-				      Elf_Internal_Verdef  ivd;
-				      Elf_External_Verdef  evd;
-
-				      offset = version_info
-					[DT_VERSIONTAGIDX (DT_VERDEF)]
-					- loadaddr;
-
-				      do
-					{
-					  GET_DATA (offset, evd,
-						    "version definition");
-
-					  ivd.vd_next = BYTE_GET (evd.vd_next);
-					  ivd.vd_ndx  = BYTE_GET (evd.vd_ndx);
-
-					  offset += ivd.vd_next;
-					}
-				      while (ivd.vd_ndx
-					     != (data [cnt + j] & 0x7fff)
-					     && ivd.vd_next != 0);
-
-				      if (ivd.vd_ndx
-					  == (data [cnt + j] & 0x7fff))
-					{
-					  Elf_External_Verdaux  evda;
-					  Elf_Internal_Verdaux  ivda;
-
-					  ivd.vd_aux = BYTE_GET (evd.vd_aux);
-
-					  GET_DATA (offset + ivd.vd_aux, evda,
-						    "version definition aux");
-
-					  ivda.vda_name =
-					    BYTE_GET (evda.vda_name);
-
-					  name = strtab + ivda.vda_name;
-					  nn +=
-					    printf ("(%s%-*s",
-						    name,
-						    12 - (int) strlen (name),
-						    ")");
-					}
-				    }
-
-				  break;
-				}
-			      else
-				offset += ivn.vn_next;
-			    }
-			  while (ivn.vn_next);
+			  if (symbols [cnt + j].st_shndx == SHN_UNDEF)
+			    check_def = 0;
+			  else
+			    check_need = 0;
 			}
-		      else if (symbols [cnt + j].st_shndx == SHN_UNDEF)
+
+		      if (check_need
+			  && version_info [DT_VERSIONTAGIDX (DT_VERNEED)])
 			{
 			  Elf_Internal_Verneed     ivn;
 			  unsigned long            offset;
@@ -4163,6 +4073,7 @@ process_version_sections (file)
 						name,
 						12 - (int) strlen (name),
 						")");
+				  check_def = 0;
 				  break;
 				}
 
@@ -4170,7 +4081,9 @@ process_version_sections (file)
 			    }
 			  while (ivn.vn_next);
 			}
-		      else if (data [cnt + j] != 0x8001)
+
+		      if (check_def && data [cnt + j] != 0x8001
+			  && version_info [DT_VERSIONTAGIDX (DT_VERDEF)])
 			{
 			  Elf_Internal_Verdef  ivd;
 			  Elf_External_Verdef  evd;
@@ -4547,7 +4460,8 @@ process_symbol_table (file)
 
 		  if ((vers_data & 0x8000) || vers_data > 1)
 		    {
-		      if (is_nobits || ! check_def)
+		      if (version_info [DT_VERSIONTAGIDX (DT_VERNEED)]
+			  && (is_nobits || ! check_def))
 			{
 			  Elf_External_Verneed  evn;
 			  Elf_Internal_Verneed  ivn;
@@ -4605,7 +4519,8 @@ process_symbol_table (file)
 
 		      if (check_def)
 			{
-			  if (vers_data != 0x8001)
+			  if (vers_data != 0x8001
+			      && version_info [DT_VERSIONTAGIDX (DT_VERDEF)])
 			    {
 			      Elf_Internal_Verdef     ivd;
 			      Elf_Internal_Verdaux    ivda;

	Jakub