[PATCH] libelf: Reject class zero (no Ehdr) in gelf_fsize

[Mark Wielaard]

An Elf descriptor has a "zero" class until the Ehdr is created.
gelf_fsize needs a valid class for the size table lookup.

        * libelf/gelf_fsize.c (gelf_fsize): Return zero and set libelf
        errno to ELF_E_WRONG_ORDER_EHDR, when class is 0.

Signed-off-by: Mark Wielaard <m...@klomp.org>
---
 libelf/gelf_fsize.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/libelf/gelf_fsize.c b/libelf/gelf_fsize.c
index 6f99d83979aa..371f08f2cc2c 100644
--- a/libelf/gelf_fsize.c
+++ b/libelf/gelf_fsize.c
@@ -100,6 +100,13 @@ gelf_fsize (Elf *elf, Elf_Type type, size_t count, 
unsigned int version)
       return 0;
     }
 
+  /* Class is set from the Ehdr.  */
+  if (elf->class == 0)
+    {
+      __libelf_seterrno (ELF_E_WRONG_ORDER_EHDR);
+      return 0;
+    }
+
   return count * __libelf_type_sizes[elf->class - 1][type];
 }
 INTDEF(gelf_fsize)
-- 
2.56.0