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Commit 65c225d3 authored by Philipp Rudo's avatar Philipp Rudo Committed by Linus Torvalds
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kernel/kexec_file.c: make purgatory_info->ehdr const 

The kexec_purgatory buffer is read-only.  Thus all pointers into
kexec_purgatory are read-only, too.  Point this out by explicitly
marking purgatory_info->ehdr as 'const' and update the comments in
purgatory_info.

Link: http://lkml.kernel.org/r/20180321112751.22196-4-prudo@linux.vnet.ibm.com


Signed-off-by: default avatarPhilipp Rudo <prudo@linux.vnet.ibm.com>
Acked-by: default avatarDave Young <dyoung@redhat.com>
Cc: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d2b8178c

include/linux/kexec.h

+11 −6
Original line number Diff line number Diff line
@@ -99,14 +99,19 @@ struct compat_kexec_segment { 


#ifdef CONFIG_KEXEC_FILE

struct purgatory_info {

	/* Pointer to elf header of read only purgatory */

	Elf_Ehdr *ehdr;



	/* Pointer to purgatory sechdrs which are modifiable */

	/*

	 * Pointer to elf header at the beginning of kexec_purgatory.

	 * Note: kexec_purgatory is read only

	 */

	const Elf_Ehdr *ehdr;

	/*

	 * Temporary, modifiable buffer for sechdrs used for relocation.

	 * This memory can be freed post image load.

	 */

	Elf_Shdr *sechdrs;

	/*

	 * Temporary buffer location where purgatory is loaded and relocated

	 * This memory can be freed post image load

	 * Temporary, modifiable buffer for stripped purgatory used for

	 * relocation. This memory can be freed post image load.

	 */

	void *purgatory_buf;

kernel/kexec_file.c

+2 −2
Original line number Diff line number Diff line
@@ -941,7 +941,7 @@ int kexec_load_purgatory(struct kimage *image, unsigned long min, 
	if (kexec_purgatory_size <= 0)

		return -EINVAL;



	pi->ehdr = (Elf_Ehdr *)kexec_purgatory;

	pi->ehdr = (const Elf_Ehdr *)kexec_purgatory;



	ret = __kexec_load_purgatory(image, min, max, top_down);

	if (ret)
@@ -965,9 +965,9 @@ int kexec_load_purgatory(struct kimage *image, unsigned long min, 
static Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,

					    const char *name)

{

	const Elf_Ehdr *ehdr;

	Elf_Sym *syms;

	Elf_Shdr *sechdrs;

	Elf_Ehdr *ehdr;

	int i, k;

	const char *strtab;