From: Philipp Rudo <prudo@xxxxxxxxxxxxxxxxxx> Subject: 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@xxxxxxxxxxxxxxxxxx Signed-off-by: Philipp Rudo <prudo@xxxxxxxxxxxxxxxxxx> Acked-by: Dave Young <dyoung@xxxxxxxxxx> Cc: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx> Cc: Eric Biederman <ebiederm@xxxxxxxxxxxx> Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Cc: Thiago Jung Bauermann <bauerman@xxxxxxxxxxxxxxxxxx> Cc: Vivek Goyal <vgoyal@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/kexec.h | 17 +++++++++++------ kernel/kexec_file.c | 4 ++-- 2 files changed, 13 insertions(+), 8 deletions(-) diff -puN include/linux/kexec.h~kexec_file-make-purgatory_info-ehdr-const include/linux/kexec.h --- a/include/linux/kexec.h~kexec_file-make-purgatory_info-ehdr-const +++ a/include/linux/kexec.h @@ -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; diff -puN kernel/kexec_file.c~kexec_file-make-purgatory_info-ehdr-const kernel/kexec_file.c --- a/kernel/kexec_file.c~kexec_file-make-purgatory_info-ehdr-const +++ a/kernel/kexec_file.c @@ -941,7 +941,7 @@ int kexec_load_purgatory(struct kimage * 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 @@ out: 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; _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
