From d2b8178ca7324a21495cb71049b4e4a041ab5942 Mon Sep 17 00:00:00 2001 From: Philipp Rudo Date: Fri, 13 Apr 2018 15:36:13 -0700 Subject: [PATCH] kernel/kexec_file.c: remove checks in kexec_purgatory_load Before the purgatory is loaded several checks are done whether the ELF file in kexec_purgatory is valid or not. These checks are incomplete. For example they don't check for the total size of the sections defined in the section header table or if the entry point actually points into the purgatory. On the other hand the purgatory, although an ELF file on its own, is part of the kernel. Thus not trusting the purgatory means not trusting the kernel build itself. So remove all validity checks on the purgatory and just trust the kernel build. Link: http://lkml.kernel.org/r/20180321112751.22196-3-prudo@linux.vnet.ibm.com Signed-off-by: Philipp Rudo Acked-by: Dave Young Cc: AKASHI Takahiro Cc: Eric Biederman Cc: Heiko Carstens Cc: Ingo Molnar Cc: Martin Schwidefsky Cc: Michael Ellerman Cc: Thiago Jung Bauermann Cc: Vivek Goyal Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/kexec_file.c | 14 -------------- 1 file changed, 14 deletions(-) diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index b06b1fac5252..81ba4f782486 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -941,22 +941,8 @@ int kexec_load_purgatory(struct kimage *image, unsigned long min, if (kexec_purgatory_size <= 0) return -EINVAL; - if (kexec_purgatory_size < sizeof(Elf_Ehdr)) - return -ENOEXEC; - pi->ehdr = (Elf_Ehdr *)kexec_purgatory; - if (memcmp(pi->ehdr->e_ident, ELFMAG, SELFMAG) != 0 - || pi->ehdr->e_type != ET_REL - || !elf_check_arch(pi->ehdr) - || pi->ehdr->e_shentsize != sizeof(Elf_Shdr)) - return -ENOEXEC; - - if (pi->ehdr->e_shoff >= kexec_purgatory_size - || (pi->ehdr->e_shnum * sizeof(Elf_Shdr) > - kexec_purgatory_size - pi->ehdr->e_shoff)) - return -ENOEXEC; - ret = __kexec_load_purgatory(image, min, max, top_down); if (ret) return ret; -- 2.30.2