kernel/kexec_file.c: use read-only sections in arch_kexec_apply_relocations* (8aec395b) · Commits · e / devices / android_kernel_fairphone_FP5

arch/x86/kernel/machine_kexec_64.c

+20 −36

Original line number	Original line	Diff line number	Diff line
	@@ -382,52 +382,36 @@ void arch_kexec_kernel_image_load(struct kimage image)
	/*		/*
	* Apply purgatory relocations.		* Apply purgatory relocations.
	*		*
	* ehdr: Pointer to elf headers		* @pi: Purgatory to be relocated.
	* sechdrs: Pointer to section headers.		* @section: Section relocations applying to.
	* relsec: section index of SHT_RELA section.		* @relsec: Section containing RELAs.
			* @symtabsec: Corresponding symtab.
	*		*
	* TODO: Some of the code belongs to generic code. Move that in kexec.c.		* TODO: Some of the code belongs to generic code. Move that in kexec.c.
	*/		*/
	int arch_kexec_apply_relocations_add(const Elf64_Ehdr *ehdr,		int arch_kexec_apply_relocations_add(struct purgatory_info *pi,
	Elf64_Shdr *sechdrs, unsigned int relsec)		Elf_Shdr section, const Elf_Shdr relsec,
			const Elf_Shdr *symtabsec)
	{		{
	unsigned int i;		unsigned int i;
	Elf64_Rela *rel;		Elf64_Rela *rel;
	Elf64_Sym *sym;		Elf64_Sym *sym;
	void *location;		void *location;
	Elf64_Shdr section, symtabsec;
	unsigned long address, sec_base, value;		unsigned long address, sec_base, value;
	const char strtab, name, *shstrtab;		const char strtab, name, *shstrtab;
			const Elf_Shdr *sechdrs;

	/*		/* String & section header string table */
	* ->sh_offset has been modified to keep the pointer to section		sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
	* contents in memory		strtab = (char *)pi->ehdr + sechdrs[symtabsec->sh_link].sh_offset;
	*/		shstrtab = (char *)pi->ehdr + sechdrs[pi->ehdr->e_shstrndx].sh_offset;
	rel = (void *)sechdrs[relsec].sh_offset;

	/* Section to which relocations apply */
	section = &sechdrs[sechdrs[relsec].sh_info];

	pr_debug("Applying relocate section %u to %u\n", relsec,
	sechdrs[relsec].sh_info);

	/* Associated symbol table */
	symtabsec = &sechdrs[sechdrs[relsec].sh_link];

	/* String table */
	if (symtabsec->sh_link >= ehdr->e_shnum) {
	/* Invalid strtab section number */
	pr_err("Invalid string table section index %d\n",
	symtabsec->sh_link);
	return -ENOEXEC;
	}

	strtab = (char *)sechdrs[symtabsec->sh_link].sh_offset;		rel = (void *)pi->ehdr + relsec->sh_offset;

	/* section header string table */		pr_debug("Applying relocate section %s to %u\n",
	shstrtab = (char *)sechdrs[ehdr->e_shstrndx].sh_offset;		shstrtab + relsec->sh_name, relsec->sh_info);

	for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {		for (i = 0; i < relsec->sh_size / sizeof(*rel); i++) {

	/*		/*
	* rel[i].r_offset contains byte offset from beginning		* rel[i].r_offset contains byte offset from beginning
	@@ -450,8 +434,8 @@ int arch_kexec_apply_relocations_add(const Elf64_Ehdr *ehdr,
	* to apply. ELF64_R_SYM() and ELF64_R_TYPE() macros get		* to apply. ELF64_R_SYM() and ELF64_R_TYPE() macros get
	* these respectively.		* these respectively.
	*/		*/
	sym = (Elf64_Sym *)symtabsec->sh_offset +		sym = (void *)pi->ehdr + symtabsec->sh_offset;
	ELF64_R_SYM(rel[i].r_info);		sym += ELF64_R_SYM(rel[i].r_info);

	if (sym->st_name)		if (sym->st_name)
	name = strtab + sym->st_name;		name = strtab + sym->st_name;
	@@ -474,12 +458,12 @@ int arch_kexec_apply_relocations_add(const Elf64_Ehdr *ehdr,

	if (sym->st_shndx == SHN_ABS)		if (sym->st_shndx == SHN_ABS)
	sec_base = 0;		sec_base = 0;
	else if (sym->st_shndx >= ehdr->e_shnum) {		else if (sym->st_shndx >= pi->ehdr->e_shnum) {
	pr_err("Invalid section %d for symbol %s\n",		pr_err("Invalid section %d for symbol %s\n",
	sym->st_shndx, name);		sym->st_shndx, name);
	return -ENOEXEC;		return -ENOEXEC;
	} else		} else
	sec_base = sechdrs[sym->st_shndx].sh_addr;		sec_base = pi->sechdrs[sym->st_shndx].sh_addr;

	value = sym->st_value;		value = sym->st_value;
	value += sec_base;		value += sec_base;

include/linux/kexec.h

+9 −4

Original line number	Original line	Diff line number	Diff line
	@@ -171,6 +171,15 @@ struct kexec_buf {
	bool top_down;		bool top_down;
	};		};

			int __weak arch_kexec_apply_relocations_add(struct purgatory_info *pi,
			Elf_Shdr *section,
			const Elf_Shdr *relsec,
			const Elf_Shdr *symtab);
			int __weak arch_kexec_apply_relocations(struct purgatory_info *pi,
			Elf_Shdr *section,
			const Elf_Shdr *relsec,
			const Elf_Shdr *symtab);

	int __weak arch_kexec_walk_mem(struct kexec_buf *kbuf,		int __weak arch_kexec_walk_mem(struct kexec_buf *kbuf,
	int (func)(struct resource , void *));		int (func)(struct resource , void *));
	extern int kexec_add_buffer(struct kexec_buf *kbuf);		extern int kexec_add_buffer(struct kexec_buf *kbuf);
	@@ -304,10 +313,6 @@ int crash_shrink_memory(unsigned long new_size);
	size_t crash_get_memory_size(void);		size_t crash_get_memory_size(void);
	void crash_free_reserved_phys_range(unsigned long begin, unsigned long end);		void crash_free_reserved_phys_range(unsigned long begin, unsigned long end);

	int __weak arch_kexec_apply_relocations_add(const Elf_Ehdr *ehdr,
	Elf_Shdr *sechdrs, unsigned int relsec);
	int __weak arch_kexec_apply_relocations(const Elf_Ehdr ehdr, Elf_Shdr sechdrs,
	unsigned int relsec);
	void arch_kexec_protect_crashkres(void);		void arch_kexec_protect_crashkres(void);
	void arch_kexec_unprotect_crashkres(void);		void arch_kexec_unprotect_crashkres(void);

kernel/kexec_file.c

+42 −21

Original line number	Original line	Diff line number	Diff line
	@@ -110,19 +110,35 @@ int __weak arch_kexec_kernel_verify_sig(struct kimage image, void buf,
	}		}
	#endif		#endif

	/* Apply relocations of type RELA */		/*
			* arch_kexec_apply_relocations_add - apply relocations of type RELA
			* @pi: Purgatory to be relocated.
			* @section: Section relocations applying to.
			* @relsec: Section containing RELAs.
			* @symtab: Corresponding symtab.
			*
			* Return: 0 on success, negative errno on error.
			*/
	int __weak		int __weak
	arch_kexec_apply_relocations_add(const Elf_Ehdr ehdr, Elf_Shdr sechdrs,		arch_kexec_apply_relocations_add(struct purgatory_info pi, Elf_Shdr section,
	unsigned int relsec)		const Elf_Shdr relsec, const Elf_Shdr symtab)
	{		{
	pr_err("RELA relocation unsupported.\n");		pr_err("RELA relocation unsupported.\n");
	return -ENOEXEC;		return -ENOEXEC;
	}		}

	/* Apply relocations of type REL */		/*
			* arch_kexec_apply_relocations - apply relocations of type REL
			* @pi: Purgatory to be relocated.
			* @section: Section relocations applying to.
			* @relsec: Section containing RELs.
			* @symtab: Corresponding symtab.
			*
			* Return: 0 on success, negative errno on error.
			*/
	int __weak		int __weak
	arch_kexec_apply_relocations(const Elf_Ehdr ehdr, Elf_Shdr sechdrs,		arch_kexec_apply_relocations(struct purgatory_info pi, Elf_Shdr section,
	unsigned int relsec)		const Elf_Shdr relsec, const Elf_Shdr symtab)
	{		{
	pr_err("REL relocation unsupported.\n");		pr_err("REL relocation unsupported.\n");
	return -ENOEXEC;		return -ENOEXEC;
	@@ -879,14 +895,19 @@ static int kexec_apply_relocations(struct kimage *image)
	{		{
	int i, ret;		int i, ret;
	struct purgatory_info *pi = &image->purgatory_info;		struct purgatory_info *pi = &image->purgatory_info;
	Elf_Shdr *sechdrs = pi->sechdrs;		const Elf_Shdr *sechdrs;

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

	/* Apply relocations */
	for (i = 0; i < pi->ehdr->e_shnum; i++) {		for (i = 0; i < pi->ehdr->e_shnum; i++) {
	Elf_Shdr section, symtab;		const Elf_Shdr *relsec;
			const Elf_Shdr *symtab;
			Elf_Shdr *section;

			relsec = sechdrs + i;

	if (sechdrs[i].sh_type != SHT_RELA &&		if (relsec->sh_type != SHT_RELA &&
	sechdrs[i].sh_type != SHT_REL)		relsec->sh_type != SHT_REL)
	continue;		continue;

	/*		/*
	@@ -895,12 +916,12 @@ static int kexec_apply_relocations(struct kimage *image)
	* symbol table. And ->sh_info contains section header		* symbol table. And ->sh_info contains section header
	* index of section to which relocations apply.		* index of section to which relocations apply.
	*/		*/
	if (sechdrs[i].sh_info >= pi->ehdr->e_shnum \|\|		if (relsec->sh_info >= pi->ehdr->e_shnum \|\|
	sechdrs[i].sh_link >= pi->ehdr->e_shnum)		relsec->sh_link >= pi->ehdr->e_shnum)
	return -ENOEXEC;		return -ENOEXEC;

	section = &sechdrs[sechdrs[i].sh_info];		section = pi->sechdrs + relsec->sh_info;
	symtab = &sechdrs[sechdrs[i].sh_link];		symtab = sechdrs + relsec->sh_link;

	if (!(section->sh_flags & SHF_ALLOC))		if (!(section->sh_flags & SHF_ALLOC))
	continue;		continue;
	@@ -917,12 +938,12 @@ static int kexec_apply_relocations(struct kimage *image)
	* Respective architecture needs to provide support for applying		* Respective architecture needs to provide support for applying
	* relocations of type SHT_RELA/SHT_REL.		* relocations of type SHT_RELA/SHT_REL.
	*/		*/
	if (sechdrs[i].sh_type == SHT_RELA)		if (relsec->sh_type == SHT_RELA)
	ret = arch_kexec_apply_relocations_add(pi->ehdr,		ret = arch_kexec_apply_relocations_add(pi, section,
	sechdrs, i);		relsec, symtab);
	else if (sechdrs[i].sh_type == SHT_REL)		else if (relsec->sh_type == SHT_REL)
	ret = arch_kexec_apply_relocations(pi->ehdr,		ret = arch_kexec_apply_relocations(pi, section,
	sechdrs, i);		relsec, symtab);
	if (ret)		if (ret)
	return ret;		return ret;
	}		}