robustify: Use gelf_fsize instead of relying on shdr->sh_entsize.

Signed-off-by: Mark Wielaard <mjw@redhat.com>

4 files changed, 46 insertions, 13 deletions

diff --git a/libdwfl/ChangeLog b/libdwfl/ChangeLog
index 55980a57..e55b03b7 100644
--- a/libdwfl/ChangeLog
+++ b/libdwfl/ChangeLog
@@ -1,3 +1,8 @@
+2014-01-17  Petr Machata  <pmachata@redhat.com>
+
+	* relocate.c (relocate_section): Use gelf_fsize instead of relying
+	on shdr->sh_entsize.
+
 2014-01-05  Mark Wielaard  <mjw@redhat.com>
 
 	* frame_unwind.c (handle_cfi): Only skip resetting return register
diff --git a/libdwfl/relocate.c b/libdwfl/relocate.c
index f8a5fcfa..52b7b5eb 100644
--- a/libdwfl/relocate.c
+++ b/libdwfl/relocate.c
@@ -1,5 +1,5 @@
 /* Relocate debug information.
-   Copyright (C) 2005-2010 Red Hat, Inc.
+   Copyright (C) 2005-2011, 2014 Red Hat, Inc.
    This file is part of elfutils.
 
    This file is free software; you can redistribute it and/or modify
@@ -456,7 +456,10 @@ relocate_section (Dwfl_Module *mod, Elf *relocated, const GElf_Ehdr *ehdr,
       }
   }
 
-  size_t nrels = shdr->sh_size / shdr->sh_entsize;
+  size_t sh_entsize
+    = gelf_fsize (relocated, shdr->sh_type == SHT_REL ? ELF_T_REL : ELF_T_RELA,
+		  1, EV_CURRENT);
+  size_t nrels = shdr->sh_size / sh_entsize;
   size_t complete = 0;
   if (shdr->sh_type == SHT_REL)
     for (size_t relidx = 0; !result && relidx < nrels; ++relidx)
@@ -558,7 +561,7 @@ relocate_section (Dwfl_Module *mod, Elf *relocated, const GElf_Ehdr *ehdr,
 	  nrels = next;
 	}
 
-      shdr->sh_size = reldata->d_size = nrels * shdr->sh_entsize;
+      shdr->sh_size = reldata->d_size = nrels * sh_entsize;
       gelf_update_shdr (scn, shdr);
     }
 
diff --git a/src/ChangeLog b/src/ChangeLog
index d085d754..a3f56fb5 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,9 @@
+2014-01-17  Petr Machata  <pmachata@redhat.com>
+
+	* readelf.c (handle_dynamic, handle_relocs_rel)
+	(handle_relocs_rela, handle_versym, print_liblist):
+	Use gelf_fsize instead of relying on shdr->sh_entsize.
+
 2014-01-14  Mark Wielaard  <mjw@redhat.com>
 
 	* readelf.c (print_debug_macro_section): Clear vendor array before
diff --git a/src/readelf.c b/src/readelf.c
index 39912243..a6376087 100644
--- a/src/readelf.c
+++ b/src/readelf.c
@@ -1,5 +1,5 @@
 /* Print information from ELF file in human-readable form.
-   Copyright (C) 1999-2013 Red Hat, Inc.
+   Copyright (C) 1999-2014 Red Hat, Inc.
    This file is part of elfutils.
    Written by Ulrich Drepper <drepper@redhat.com>, 1999.
 
@@ -1532,6 +1532,7 @@ handle_dynamic (Ebl *ebl, Elf_Scn *scn, GElf_Shdr *shdr)
   Elf_Data *data;
   size_t cnt;
   size_t shstrndx;
+  size_t sh_entsize;
 
   /* Get the data of the section.  */
   data = elf_getdata (scn, NULL);
@@ -1543,12 +1544,19 @@ handle_dynamic (Ebl *ebl, Elf_Scn *scn, GElf_Shdr *shdr)
     error (EXIT_FAILURE, 0,
 	   gettext ("cannot get section header string table index"));
 
+  sh_entsize = gelf_fsize (ebl->elf, ELF_T_DYN, 1, EV_CURRENT);
+
+  glink = gelf_getshdr (elf_getscn (ebl->elf, shdr->sh_link), &glink_mem);
+  if (glink == NULL)
+    error (EXIT_FAILURE, 0, gettext ("invalid sh_link value in section %Zu"),
+	   elf_ndxscn (scn));
+
   printf (ngettext ("\
 \nDynamic segment contains %lu entry:\n Addr: %#0*" PRIx64 "  Offset: %#08" PRIx64 "  Link to section: [%2u] '%s'\n",
 		    "\
 \nDynamic segment contains %lu entries:\n Addr: %#0*" PRIx64 "  Offset: %#08" PRIx64 "  Link to section: [%2u] '%s'\n",
-		    shdr->sh_size / shdr->sh_entsize),
-	  (unsigned long int) (shdr->sh_size / shdr->sh_entsize),
+		    shdr->sh_size / sh_entsize),
+	  (unsigned long int) (shdr->sh_size / sh_entsize),
 	  class == ELFCLASS32 ? 10 : 18, shdr->sh_addr,
 	  shdr->sh_offset,
 	  (int) shdr->sh_link,
@@ -1557,7 +1565,7 @@ handle_dynamic (Ebl *ebl, Elf_Scn *scn, GElf_Shdr *shdr)
 				    &glink)->sh_name));
   fputs_unlocked (gettext ("  Type              Value\n"), stdout);
 
-  for (cnt = 0; cnt < shdr->sh_size / shdr->sh_entsize; ++cnt)
+  for (cnt = 0; cnt < shdr->sh_size / sh_entsize; ++cnt)
     {
       GElf_Dyn dynmem;
       GElf_Dyn *dyn = gelf_getdyn (data, cnt, &dynmem);
@@ -1706,7 +1714,8 @@ static void
 handle_relocs_rel (Ebl *ebl, GElf_Ehdr *ehdr, Elf_Scn *scn, GElf_Shdr *shdr)
 {
   int class = gelf_getclass (ebl->elf);
-  int nentries = shdr->sh_size / shdr->sh_entsize;
+  size_t sh_entsize = gelf_fsize (ebl->elf, ELF_T_REL, 1, EV_CURRENT);
+  int nentries = shdr->sh_size / sh_entsize;
 
   /* Get the data of the section.  */
   Elf_Data *data = elf_getdata (scn, NULL);
@@ -1892,7 +1901,8 @@ static void
 handle_relocs_rela (Ebl *ebl, GElf_Ehdr *ehdr, Elf_Scn *scn, GElf_Shdr *shdr)
 {
   int class = gelf_getclass (ebl->elf);
-  int nentries = shdr->sh_size / shdr->sh_entsize;
+  size_t sh_entsize = gelf_fsize (ebl->elf, ELF_T_RELA, 1, EV_CURRENT);
+  int nentries = shdr->sh_size / sh_entsize;
 
   /* Get the data of the section.  */
   Elf_Data *data = elf_getdata (scn, NULL);
@@ -2736,16 +2746,24 @@ handle_versym (Ebl *ebl, Elf_Scn *scn, GElf_Shdr *shdr)
       filename = NULL;
     }
 
+  GElf_Shdr glink_mem;
+  GElf_Shdr *glink = gelf_getshdr (elf_getscn (ebl->elf, shdr->sh_link),
+				   &glink_mem);
+  size_t sh_entsize = gelf_fsize (ebl->elf, ELF_T_HALF, 1, EV_CURRENT);
+  if (glink == NULL)
+    error (EXIT_FAILURE, 0, gettext ("invalid sh_link value in section %Zu"),
+	   elf_ndxscn (scn));
+
   /* Print the header.  */
   GElf_Shdr glink;
   printf (ngettext ("\
 \nVersion symbols section [%2u] '%s' contains %d entry:\n Addr: %#0*" PRIx64 "  Offset: %#08" PRIx64 "  Link to section: [%2u] '%s'",
 		    "\
 \nVersion symbols section [%2u] '%s' contains %d entries:\n Addr: %#0*" PRIx64 "  Offset: %#08" PRIx64 "  Link to section: [%2u] '%s'",
-		    shdr->sh_size / shdr->sh_entsize),
+		    shdr->sh_size / sh_entsize),
 	  (unsigned int) elf_ndxscn (scn),
 	  elf_strptr (ebl->elf, shstrndx, shdr->sh_name),
-	  (int) (shdr->sh_size / shdr->sh_entsize),
+	  (int) (shdr->sh_size / sh_entsize),
 	  class == ELFCLASS32 ? 10 : 18, shdr->sh_addr,
 	  shdr->sh_offset,
 	  (unsigned int) shdr->sh_link,
@@ -2754,7 +2772,7 @@ handle_versym (Ebl *ebl, Elf_Scn *scn, GElf_Shdr *shdr)
 				    &glink)->sh_name));
 
   /* Now we can finally look at the actual contents of this section.  */
-  for (unsigned int cnt = 0; cnt < shdr->sh_size / shdr->sh_entsize; ++cnt)
+  for (unsigned int cnt = 0; cnt < shdr->sh_size / sh_entsize; ++cnt)
     {
       if (cnt % 2 == 0)
 	printf ("\n %4d:", cnt);
@@ -3078,7 +3096,8 @@ print_liblist (Ebl *ebl)
 
       if (shdr != NULL && shdr->sh_type == SHT_GNU_LIBLIST)
 	{
-	  int nentries = shdr->sh_size / shdr->sh_entsize;
+	  size_t sh_entsize = gelf_fsize (ebl->elf, ELF_T_LIB, 1, EV_CURRENT);
+	  int nentries = shdr->sh_size / sh_entsize;
 	  printf (ngettext ("\
 \nLibrary list section [%2zu] '%s' at offset %#0" PRIx64 " contains %d entry:\n",
 			    "\