nm: Guard against divide by zero in error check.

Also add section index number in error message.

https://bugzilla.redhat.com/show_bug.cgi?id=1170810

Reported-by: Alexander Cherepanov <cherepan@mccme.ru>
Signed-off-by: Mark Wielaard <mjw@redhat.com>

diff --git a/src/ChangeLog b/src/ChangeLog
index 9da2853..904b3c9 100644 (file)
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,10 @@
 2014-12-26  Mark Wielaard  <mjw@redhat.com>
 
+       * nm.c (show_symbols): Guard against divide by zero in error check.
+       Add section index number in error message.
+
+2014-12-26  Mark Wielaard  <mjw@redhat.com>
+
        * nm.c (handle_ar): Skip over /SYM64/ entries.
 
 2014-12-26  Mark Wielaard  <mjw@redhat.com>

diff --git a/src/nm.c b/src/nm.c
index be91459..915153f 100644 (file)
--- a/src/nm.c
+++ b/src/nm.c
@@ -1169,14 +1169,17 @@ show_symbols (Ebl *ebl, GElf_Ehdr *ehdr, Elf_Scn *scn, Elf_Scn *xndxscn,
   size_t entsize = shdr->sh_entsize;
 
   /* Consistency checks.  */
-  if (entsize != gelf_fsize (ebl->elf, ELF_T_SYM, 1, ehdr->e_version))
+  if (entsize == 0
+      || entsize != gelf_fsize (ebl->elf, ELF_T_SYM, 1, ehdr->e_version))
     error (0, 0,
-          gettext ("%s: entry size in section `%s' is not what we expect"),
-          fullname, elf_strptr (ebl->elf, shstrndx, shdr->sh_name));
+          gettext ("%s: entry size in section %zd `%s' is not what we expect"),
+          fullname, elf_ndxscn (scn),
+          elf_strptr (ebl->elf, shstrndx, shdr->sh_name));
   else if (size % entsize != 0)
     error (0, 0,
-          gettext ("%s: size of section `%s' is not multiple of entry size"),
-          fullname, elf_strptr (ebl->elf, shstrndx, shdr->sh_name));
+          gettext ("%s: size of section %zd `%s' is not multiple of entry size"),
+          fullname, elf_ndxscn (scn),
+          elf_strptr (ebl->elf, shstrndx, shdr->sh_name));
 
   /* Compute number of entries.  Handle buggy entsize values.  */
   size_t nentries = size / (entsize ?: 1);