From 27e53de2fdb317514a0dc1d2836106e30fa863bd Mon Sep 17 00:00:00 2001 From: Alec Brown Date: Thu, 26 May 2022 15:29:51 -0400 Subject: [PATCH] util/grub-module-verifierXX: Add e_shoff check in get_shdr() 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 Reviewed-by: Daniel Kiper Reviewed-by: Darren Kenny --- 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)); }