// SPDX-License-Identifier: GPL-2.0/* *	fs/proc/kcore.c kernel ELF core dumper * *	Modelled on fs/exec.c:aout_core_dump() *	Jeremy Fitzhardinge <jeremy@sw.oz.au> *	ELF version written by David Howells <David.Howells@nexor.co.uk> *	Modified and incorporated into 2.3.x by Tigran Aivazian <tigran@veritas.com> *	Support to dump vmalloc'd areas (ELF only), Tigran Aivazian <tigran@veritas.com> *	Safe accesses to vmalloc/direct-mapped discontiguous areas, Kanoj Sarcar <kanoj@sgi.com> */ #include <linux/crash_core.h>#include <linux/mm.h>#include <linux/proc_fs.h>#include <linux/kcore.h>#include <linux/user.h>#include <linux/capability.h>#include <linux/elf.h>#include <linux/elfcore.h>#include <linux/notifier.h>#include <linux/vmalloc.h>#include <linux/highmem.h>#include <linux/printk.h>#include <linux/memblock.h>#include <linux/init.h>#include <linux/slab.h>#include <linux/uaccess.h>#include <asm/io.h>#include <linux/list.h>#include <linux/ioport.h>#include <linux/memory.h>#include <linux/sched/task.h>#include <linux/security.h>#include <asm/sections.h>#include "internal.h" #define CORE_STR "CORE" #ifndef ELF_CORE_EFLAGS#define ELF_CORE_EFLAGS	0#endif static struct proc_dir_entry *proc_root_kcore;  #ifndef kc_vaddr_to_offset#define	kc_vaddr_to_offset(v) ((v) - PAGE_OFFSET)#endif#ifndef	kc_offset_to_vaddr#define	kc_offset_to_vaddr(o) ((o) + PAGE_OFFSET)#endif static LIST_HEAD(kclist_head);static DECLARE_RWSEM(kclist_lock);static int kcore_need_update = 1; /* * Returns > 0 for RAM pages, 0 for non-RAM pages, < 0 on error * Same as oldmem_pfn_is_ram in vmcore */static int (*mem_pfn_is_ram)(unsigned long pfn); int __init register_mem_pfn_is_ram(int (*fn)(unsigned long pfn)){	if (mem_pfn_is_ram)		return -EBUSY;	mem_pfn_is_ram = fn;	return 0;} static int pfn_is_ram(unsigned long pfn){	if (mem_pfn_is_ram)		return mem_pfn_is_ram(pfn);	else		return 1;} /* This doesn't grab kclist_lock, so it should only be used at init time. */void __init kclist_add(struct kcore_list *new, void *addr, size_t size,		       int type){	new->addr = (unsigned long)addr;	new->size = size;	new->type = type; 	list_add_tail(&new->list, &kclist_head);} static size_t get_kcore_size(int *nphdr, size_t *phdrs_len, size_t *notes_len,			     size_t *data_offset){	size_t try, size;	struct kcore_list *m; 	*nphdr = 1; /* PT_NOTE */	size = 0; 	list_for_each_entry(m, &kclist_head, list) {		try = kc_vaddr_to_offset((size_t)m->addr + m->size);		if (try > size)			size = try;		*nphdr = *nphdr + 1;	} 	*phdrs_len = *nphdr * sizeof(struct elf_phdr);	*notes_len = (4 * sizeof(struct elf_note) +		      3 * ALIGN(sizeof(CORE_STR), 4) +		      VMCOREINFO_NOTE_NAME_BYTES +		      ALIGN(sizeof(struct elf_prstatus), 4) +		      ALIGN(sizeof(struct elf_prpsinfo), 4) +		      ALIGN(arch_task_struct_size, 4) +		      ALIGN(vmcoreinfo_size, 4));	*data_offset = PAGE_ALIGN(sizeof(struct elfhdr) + *phdrs_len +				  *notes_len);	return *data_offset + size;} #ifdef CONFIG_HIGHMEM/* * If no highmem, we can assume [0...max_low_pfn) continuous range of memory * because memory hole is not as big as !HIGHMEM case. * (HIGHMEM is special because part of memory is _invisible_ from the kernel.) */static int kcore_ram_list(struct list_head *head){	struct kcore_list *ent; 	ent = kmalloc(sizeof(*ent), GFP_KERNEL);	if (!ent)		return -ENOMEM;	ent->addr = (unsigned long)__va(0);	ent->size = max_low_pfn << PAGE_SHIFT;	ent->type = KCORE_RAM;	list_add(&ent->list, head);	return 0;} #else /* !CONFIG_HIGHMEM */ #ifdef CONFIG_SPARSEMEM_VMEMMAP/* calculate vmemmap's address from given system ram pfn and register it */static intget_sparsemem_vmemmap_info(struct kcore_list *ent, struct list_head *head){	unsigned long pfn = __pa(ent->addr) >> PAGE_SHIFT;	unsigned long nr_pages = ent->size >> PAGE_SHIFT;	unsigned long start, end;	struct kcore_list *vmm, *tmp;  	start = ((unsigned long)pfn_to_page(pfn)) & PAGE_MASK;	end = ((unsigned long)pfn_to_page(pfn + nr_pages)) - 1;	end = PAGE_ALIGN(end);	/* overlap check (because we have to align page */	list_for_each_entry(tmp, head, list) {		if (tmp->type != KCORE_VMEMMAP)			continue;		if (start < tmp->addr + tmp->size)			if (end > tmp->addr)				end = tmp->addr;	}	if (start < end) {		vmm = kmalloc(sizeof(*vmm), GFP_KERNEL);		if (!vmm)			return 0;		vmm->addr = start;		vmm->size = end - start;		vmm->type = KCORE_VMEMMAP;		list_add_tail(&vmm->list, head);	}	return 1; }#elsestatic intget_sparsemem_vmemmap_info(struct kcore_list *ent, struct list_head *head){	return 1;} #endif static intkclist_add_private(unsigned long pfn, unsigned long nr_pages, void *arg){	struct list_head *head = (struct list_head *)arg;	struct kcore_list *ent;	struct page *p; 	if (!pfn_valid(pfn))		return 1; 	p = pfn_to_page(pfn); 	ent = kmalloc(sizeof(*ent), GFP_KERNEL);	if (!ent)		return -ENOMEM;	ent->addr = (unsigned long)page_to_virt(p);	ent->size = nr_pages << PAGE_SHIFT; 	if (!virt_addr_valid(ent->addr))		goto free_out; 	/* cut not-mapped area. ....from ppc-32 code. */	if (ULONG_MAX - ent->addr < ent->size)		ent->size = ULONG_MAX - ent->addr; 	/*	 * We've already checked virt_addr_valid so we know this address	 * is a valid pointer, therefore we can check against it to determine	 * if we need to trim	 */	if (VMALLOC_START > ent->addr) {		if (VMALLOC_START - ent->addr < ent->size)			ent->size = VMALLOC_START - ent->addr;	} 	ent->type = KCORE_RAM;	list_add_tail(&ent->list, head); 	if (!get_sparsemem_vmemmap_info(ent, head)) {		list_del(&ent->list);		goto free_out;	} 	return 0;free_out:	kfree(ent);	return 1;} static int kcore_ram_list(struct list_head *list){	int nid, ret;	unsigned long end_pfn; 	/* Not inialized....update now */	/* find out "max pfn" */	end_pfn = 0;	for_each_node_state(nid, N_MEMORY) {		unsigned long node_end;		node_end = node_end_pfn(nid);		if (end_pfn < node_end)			end_pfn = node_end;	}	/* scan 0 to max_pfn */	ret = walk_system_ram_range(0, end_pfn, list, kclist_add_private);	if (ret)		return -ENOMEM;	return 0;}#endif /* CONFIG_HIGHMEM */ static int kcore_update_ram(void){	LIST_HEAD(list);	LIST_HEAD(garbage);	int nphdr;	size_t phdrs_len, notes_len, data_offset;	struct kcore_list *tmp, *pos;	int ret = 0; 	down_write(&kclist_lock);	if (!xchg(&kcore_need_update, 0))		goto out; 	ret = kcore_ram_list(&list);	if (ret) {		/* Couldn't get the RAM list, try again next time. */		WRITE_ONCE(kcore_need_update, 1);		list_splice_tail(&list, &garbage);		goto out;	} 	list_for_each_entry_safe(pos, tmp, &kclist_head, list) {		if (pos->type == KCORE_RAM || pos->type == KCORE_VMEMMAP)			list_move(&pos->list, &garbage);	}	list_splice_tail(&list, &kclist_head); 	proc_root_kcore->size = get_kcore_size(&nphdr, &phdrs_len, &notes_len,					       &data_offset); out:	up_write(&kclist_lock);	list_for_each_entry_safe(pos, tmp, &garbage, list) {		list_del(&pos->list);		kfree(pos);	}	return ret;} static void append_kcore_note(char *notes, size_t *i, const char *name,			      unsigned int type, const void *desc,			      size_t descsz){	struct elf_note *note = (struct elf_note *)&notes[*i]; 	note->n_namesz = strlen(name) + 1;	note->n_descsz = descsz;	note->n_type = type;	*i += sizeof(*note);	memcpy(&notes[*i], name, note->n_namesz);	*i = ALIGN(*i + note->n_namesz, 4);	memcpy(&notes[*i], desc, descsz);	*i = ALIGN(*i + descsz, 4);} static ssize_tread_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos){	char *buf = file->private_data;	size_t phdrs_offset, notes_offset, data_offset;	size_t phdrs_len, notes_len;	struct kcore_list *m;	size_t tsz;	int nphdr;	unsigned long start;	size_t orig_buflen = buflen;	int ret = 0; 	down_read(&kclist_lock); 	get_kcore_size(&nphdr, &phdrs_len, &notes_len, &data_offset);	phdrs_offset = sizeof(struct elfhdr);	notes_offset = phdrs_offset + phdrs_len; 	/* ELF file header. */	if (buflen && *fpos < sizeof(struct elfhdr)) {		struct elfhdr ehdr = {			.e_ident = {				[EI_MAG0] = ELFMAG0,				[EI_MAG1] = ELFMAG1,				[EI_MAG2] = ELFMAG2,				[EI_MAG3] = ELFMAG3,				[EI_CLASS] = ELF_CLASS,				[EI_DATA] = ELF_DATA,				[EI_VERSION] = EV_CURRENT,				[EI_OSABI] = ELF_OSABI,			},			.e_type = ET_CORE,			.e_machine = ELF_ARCH,			.e_version = EV_CURRENT,			.e_phoff = sizeof(struct elfhdr),			.e_flags = ELF_CORE_EFLAGS,			.e_ehsize = sizeof(struct elfhdr),			.e_phentsize = sizeof(struct elf_phdr),			.e_phnum = nphdr,		}; 		tsz = min_t(size_t, buflen, sizeof(struct elfhdr) - *fpos);		if (copy_to_user(buffer, (char *)&ehdr + *fpos, tsz)) {			ret = -EFAULT;			goto out;		} 		buffer += tsz;		buflen -= tsz;		*fpos += tsz;	} 	/* ELF program headers. */	if (buflen && *fpos < phdrs_offset + phdrs_len) {		struct elf_phdr *phdrs, *phdr; 		phdrs = kzalloc(phdrs_len, GFP_KERNEL);		if (!phdrs) {			ret = -ENOMEM;			goto out;		} 		phdrs[0].p_type = PT_NOTE;		phdrs[0].p_offset = notes_offset;		phdrs[0].p_filesz = notes_len; 		phdr = &phdrs[1];		list_for_each_entry(m, &kclist_head, list) {			phdr->p_type = PT_LOAD;			phdr->p_flags = PF_R | PF_W | PF_X;			phdr->p_offset = kc_vaddr_to_offset(m->addr) + data_offset;			if (m->type == KCORE_REMAP)				phdr->p_vaddr = (size_t)m->vaddr;			else				phdr->p_vaddr = (size_t)m->addr;			if (m->type == KCORE_RAM || m->type == KCORE_REMAP)				phdr->p_paddr = __pa(m->addr);			else if (m->type == KCORE_TEXT)				phdr->p_paddr = __pa_symbol(m->addr);			else				phdr->p_paddr = (elf_addr_t)-1;			phdr->p_filesz = phdr->p_memsz = m->size;			phdr->p_align = PAGE_SIZE;			phdr++;		} 		tsz = min_t(size_t, buflen, phdrs_offset + phdrs_len - *fpos);		if (copy_to_user(buffer, (char *)phdrs + *fpos - phdrs_offset,				 tsz)) {			kfree(phdrs);			ret = -EFAULT;			goto out;		}		kfree(phdrs); 		buffer += tsz;		buflen -= tsz;		*fpos += tsz;	} 	/* ELF note segment. */	if (buflen && *fpos < notes_offset + notes_len) {		struct elf_prstatus prstatus = {};		struct elf_prpsinfo prpsinfo = {			.pr_sname = 'R',			.pr_fname = "vmlinux",		};		char *notes;		size_t i = 0; 		strlcpy(prpsinfo.pr_psargs, saved_command_line,			sizeof(prpsinfo.pr_psargs)); 		notes = kzalloc(notes_len, GFP_KERNEL);		if (!notes) {			ret = -ENOMEM;			goto out;		} 		append_kcore_note(notes, &i, CORE_STR, NT_PRSTATUS, &prstatus,				  sizeof(prstatus));		append_kcore_note(notes, &i, CORE_STR, NT_PRPSINFO, &prpsinfo,				  sizeof(prpsinfo));		append_kcore_note(notes, &i, CORE_STR, NT_TASKSTRUCT, current,				  arch_task_struct_size);		/*		 * vmcoreinfo_size is mostly constant after init time, but it		 * can be changed by crash_save_vmcoreinfo(). Racing here with a		 * panic on another CPU before the machine goes down is insanely		 * unlikely, but it's better to not leave potential buffer		 * overflows lying around, regardless.		 */		append_kcore_note(notes, &i, VMCOREINFO_NOTE_NAME, 0,				  vmcoreinfo_data,				  min(vmcoreinfo_size, notes_len - i)); 		tsz = min_t(size_t, buflen, notes_offset + notes_len - *fpos);		if (copy_to_user(buffer, notes + *fpos - notes_offset, tsz)) {			kfree(notes);			ret = -EFAULT;			goto out;		}		kfree(notes); 		buffer += tsz;		buflen -= tsz;		*fpos += tsz;	} 	/*	 * Check to see if our file offset matches with any of	 * the addresses in the elf_phdr on our list.	 */	start = kc_offset_to_vaddr(*fpos - data_offset);	if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)		tsz = buflen; 	m = NULL;	while (buflen) {		/*		 * If this is the first iteration or the address is not within		 * the previous entry, search for a matching entry.		 */		if (!m || start < m->addr || start >= m->addr + m->size) {			list_for_each_entry(m, &kclist_head, list) {				if (start >= m->addr &&				    start < m->addr + m->size)					break;			}		} 		if (&m->list == &kclist_head) {			if (clear_user(buffer, tsz)) {				ret = -EFAULT;				goto out;			}			m = NULL;	/* skip the list anchor */		} else if (!pfn_is_ram(__pa(start) >> PAGE_SHIFT)) {			if (clear_user(buffer, tsz)) {				ret = -EFAULT;				goto out;			}		} else if (m->type == KCORE_VMALLOC) {			vread(buf, (char *)start, tsz);			/* we have to zero-fill user buffer even if no read */			if (copy_to_user(buffer, buf, tsz)) {				ret = -EFAULT;				goto out;			}

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