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Commit 961d921a authored by Philipp Rudo's avatar Philipp Rudo Committed by Linus Torvalds
Browse files

kernel/kexec_file.c: search symbols in read-only kexec_purgatory 

The stripped purgatory does not contain a symtab.  So when looking for
symbols this is done in read-only kexec_purgatory.  Highlight this by
marking the corresponding variables as 'const'.

Link: http://lkml.kernel.org/r/20180321112751.22196-5-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 65c225d3

kernel/kexec_file.c

+22 −16
Original line number Diff line number Diff line
@@ -962,20 +962,27 @@ int kexec_load_purgatory(struct kimage *image, unsigned long min, 
	return ret;

}



static Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,

/*

 * kexec_purgatory_find_symbol - find a symbol in the purgatory

 * @pi:		Purgatory to search in.

 * @name:	Name of the symbol.

 *

 * Return: pointer to symbol in read-only symtab on success, NULL on error.

 */

static const Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi,

						  const char *name)

{

	const Elf_Shdr *sechdrs;

	const Elf_Ehdr *ehdr;

	Elf_Sym *syms;

	Elf_Shdr *sechdrs;

	int i, k;

	const Elf_Sym *syms;

	const char *strtab;

	int i, k;



	if (!pi->sechdrs || !pi->ehdr)

	if (!pi->ehdr)

		return NULL;



	sechdrs = pi->sechdrs;

	ehdr = pi->ehdr;

	sechdrs = (void *)ehdr + ehdr->e_shoff;



	for (i = 0; i < ehdr->e_shnum; i++) {

		if (sechdrs[i].sh_type != SHT_SYMTAB)
@@ -984,8 +991,8 @@ static Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi, 
		if (sechdrs[i].sh_link >= ehdr->e_shnum)

			/* Invalid strtab section number */

			continue;

		strtab = (char *)sechdrs[sechdrs[i].sh_link].sh_offset;

		syms = (Elf_Sym *)sechdrs[i].sh_offset;

		strtab = (void *)ehdr + sechdrs[sechdrs[i].sh_link].sh_offset;

		syms = (void *)ehdr + sechdrs[i].sh_offset;



		/* Go through symbols for a match */

		for (k = 0; k < sechdrs[i].sh_size/sizeof(Elf_Sym); k++) {
@@ -1013,7 +1020,7 @@ static Elf_Sym *kexec_purgatory_find_symbol(struct purgatory_info *pi, 
void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name)

{

	struct purgatory_info *pi = &image->purgatory_info;

	Elf_Sym *sym;

	const Elf_Sym *sym;

	Elf_Shdr *sechdr;



	sym = kexec_purgatory_find_symbol(pi, name);
@@ -1036,9 +1043,9 @@ void *kexec_purgatory_get_symbol_addr(struct kimage *image, const char *name) 
int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name,

				   void *buf, unsigned int size, bool get_value)

{

	Elf_Sym *sym;

	Elf_Shdr *sechdrs;

	struct purgatory_info *pi = &image->purgatory_info;

	const Elf_Sym *sym;

	Elf_Shdr *sec;

	char *sym_buf;



	sym = kexec_purgatory_find_symbol(pi, name);
@@ -1051,16 +1058,15 @@ int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name, 
		return -EINVAL;

	}



	sechdrs = pi->sechdrs;

	sec = pi->sechdrs + sym->st_shndx;



	if (sechdrs[sym->st_shndx].sh_type == SHT_NOBITS) {

	if (sec->sh_type == SHT_NOBITS) {

		pr_err("symbol %s is in a bss section. Cannot %s\n", name,

		       get_value ? "get" : "set");

		return -EINVAL;

	}



	sym_buf = (unsigned char *)sechdrs[sym->st_shndx].sh_offset +

					sym->st_value;

	sym_buf = (char *)sec->sh_offset + sym->st_value;



	if (get_value)

		memcpy((void *)buf, sym_buf, size);