elflint: Fix sh_entsize check when comparing SHT_HASH and SHT_GNU_HASH.

GCC6 -Wduplicated-cond found the following issue:

elflint.c: In function ‘compare_hash_gnu_hash’:
elflint.c:2483:34: error: duplicated ‘if’ condition [-Werror=duplicated-cond]
   else if (hash_shdr->sh_entsize == sizeof (Elf64_Word))
            ~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
elflint.c:2448:29: note: previously used here
   if (hash_shdr->sh_entsize == sizeof (Elf32_Word))
       ~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

Which is correct, a Word in both Elf32 and Elf64 files is 4 bytes.
We meant to check for sizeof (Elf64_Xword) which is 8 bytes.

Also fix the section index and name in the error message.

The reason we probably didn't see this issue before is that SHT_HASH
sections really always should have sh_entsize of 4 even on 64bit arches.
There are however a couple of arches with mistakes in their sysv ABI.
See libelf/common.h. This also would only be triggered if on such an
architectures when the ELF file would have both a SHT_HASH and SHT_GNU_HASH
section and elflint would try to compare those sections.

Add an example testfile-s390x-hash-both to run-elflint-test.sh.

Signed-off-by: Mark Wielaard <[email protected]>

1 files changed, 6 insertions, 0 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 707c2717..e4b17d62 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,9 @@
+2016-02-09  Mark Wielaard  <[email protected]>
+
+	* elflint.c (compare_hash_gnu_hash): Check hash sh_entsize against
+	sizeof (Elf64_Xword). Correct invalid sh_entsize error message
+	section idx and name.
+
 2016-01-13  Mark Wielaard  <[email protected]>
 
 	* elflint.c (check_elf_header): Recognize ELFOSABI_FREEBSD.