Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 656 insertions, 0 deletions

diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c
new file mode 100644
index 000000000..4d2e64e90
--- /dev/null
+++ b/fs/proc/kcore.c
@@ -0,0 +1,656 @@
+// 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 int
+get_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;
+
+}
+#else
+static int
+get_sparsemem_vmemmap_info(struct kcore_list *ent, struct list_head *head)
+{
+	return 1;
+}
+
+#endif
+
+static int
+kclist_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_t
+read_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;
+			}
+		} else if (m->type == KCORE_USER) {
+			/* User page is handled prior to normal kernel page: */
+			if (copy_to_user(buffer, (char *)start, tsz)) {
+				ret = -EFAULT;
+				goto out;
+			}
+		} else {
+			if (kern_addr_valid(start)) {
+				/*
+				 * Using bounce buffer to bypass the
+				 * hardened user copy kernel text checks.
+				 */
+				if (copy_from_kernel_nofault(buf, (void *)start,
+						tsz)) {
+					if (clear_user(buffer, tsz)) {
+						ret = -EFAULT;
+						goto out;
+					}
+				} else {
+					if (copy_to_user(buffer, buf, tsz)) {
+						ret = -EFAULT;
+						goto out;
+					}
+				}
+			} else {
+				if (clear_user(buffer, tsz)) {
+					ret = -EFAULT;
+					goto out;
+				}
+			}
+		}
+		buflen -= tsz;
+		*fpos += tsz;
+		buffer += tsz;
+		start += tsz;
+		tsz = (buflen > PAGE_SIZE ? PAGE_SIZE : buflen);
+	}
+
+out:
+	up_read(&kclist_lock);
+	if (ret)
+		return ret;
+	return orig_buflen - buflen;
+}
+
+static int open_kcore(struct inode *inode, struct file *filp)
+{
+	int ret = security_locked_down(LOCKDOWN_KCORE);
+
+	if (!capable(CAP_SYS_RAWIO))
+		return -EPERM;
+
+	if (ret)
+		return ret;
+
+	filp->private_data = kmalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!filp->private_data)
+		return -ENOMEM;
+
+	if (kcore_need_update)
+		kcore_update_ram();
+	if (i_size_read(inode) != proc_root_kcore->size) {
+		inode_lock(inode);
+		i_size_write(inode, proc_root_kcore->size);
+		inode_unlock(inode);
+	}
+	return 0;
+}
+
+static int release_kcore(struct inode *inode, struct file *file)
+{
+	kfree(file->private_data);
+	return 0;
+}
+
+static const struct proc_ops kcore_proc_ops = {
+	.proc_read	= read_kcore,
+	.proc_open	= open_kcore,
+	.proc_release	= release_kcore,
+	.proc_lseek	= default_llseek,
+};
+
+/* just remember that we have to update kcore */
+static int __meminit kcore_callback(struct notifier_block *self,
+				    unsigned long action, void *arg)
+{
+	switch (action) {
+	case MEM_ONLINE:
+	case MEM_OFFLINE:
+		kcore_need_update = 1;
+		break;
+	}
+	return NOTIFY_OK;
+}
+
+static struct notifier_block kcore_callback_nb __meminitdata = {
+	.notifier_call = kcore_callback,
+	.priority = 0,
+};
+
+static struct kcore_list kcore_vmalloc;
+
+#ifdef CONFIG_ARCH_PROC_KCORE_TEXT
+static struct kcore_list kcore_text;
+/*
+ * If defined, special segment is used for mapping kernel text instead of
+ * direct-map area. We need to create special TEXT section.
+ */
+static void __init proc_kcore_text_init(void)
+{
+	kclist_add(&kcore_text, _text, _end - _text, KCORE_TEXT);
+}
+#else
+static void __init proc_kcore_text_init(void)
+{
+}
+#endif
+
+#if defined(CONFIG_MODULES) && defined(MODULES_VADDR)
+/*
+ * MODULES_VADDR has no intersection with VMALLOC_ADDR.
+ */
+static struct kcore_list kcore_modules;
+static void __init add_modules_range(void)
+{
+	if (MODULES_VADDR != VMALLOC_START && MODULES_END != VMALLOC_END) {
+		kclist_add(&kcore_modules, (void *)MODULES_VADDR,
+			MODULES_END - MODULES_VADDR, KCORE_VMALLOC);
+	}
+}
+#else
+static void __init add_modules_range(void)
+{
+}
+#endif
+
+static int __init proc_kcore_init(void)
+{
+	proc_root_kcore = proc_create("kcore", S_IRUSR, NULL, &kcore_proc_ops);
+	if (!proc_root_kcore) {
+		pr_err("couldn't create /proc/kcore\n");
+		return 0; /* Always returns 0. */
+	}
+	/* Store text area if it's special */
+	proc_kcore_text_init();
+	/* Store vmalloc area */
+	kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
+		VMALLOC_END - VMALLOC_START, KCORE_VMALLOC);
+	add_modules_range();
+	/* Store direct-map area from physical memory map */
+	kcore_update_ram();
+	register_hotmemory_notifier(&kcore_callback_nb);
+
+	return 0;
+}
+fs_initcall(proc_kcore_init);