[PATCH 5/6] util/grub-module-verifierXX.c: Add e_shoff check in get_shdr()

[Alec Brown]

In util/grub-module-verifierXX.c, the function get_shdr() is used to obtain the
section header at a given index but isn't checking that there is an offset for
the section header table. To validate that there is, we can check that e_shoff
isn't 0.

Signed-off-by: Alec Brown <alec.r.brown@oracle.com>
---
 util/grub-module-verifierXX.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/util/grub-module-verifierXX.c b/util/grub-module-verifierXX.c
index 4e6cf133f..cf3ff0dfa 100644
--- a/util/grub-module-verifierXX.c
+++ b/util/grub-module-verifierXX.c
@@ -134,6 +134,9 @@ grub_target_to_host_real (const struct 
grub_module_verifier_arch *arch, grub_uin
 static Elf_Shdr *
 get_shdr (const struct grub_module_verifier_arch *arch, Elf_Ehdr *e, Elf_Word 
index)
 {
+  if (grub_target_to_host (e->e_shoff) == 0)
+    grub_util_error ("Invalid section header offset");
+
   return (Elf_Shdr *) ((char *) e + grub_target_to_host (e->e_shoff) +
                       index * grub_target_to_host16 (e->e_shentsize));
 }
-- 
2.27.0