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-rw-r--r--fs/proc/kcore.c701
1 files changed, 701 insertions, 0 deletions
diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c
new file mode 100644
index 000000000..dff921f7c
--- /dev/null
+++ b/fs/proc/kcore.c
@@ -0,0 +1,701 @@
+// 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 page_offline_frozen = 1;
+ 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);
+ /*
+ * Don't race against drivers that set PageOffline() and expect no
+ * further page access.
+ */
+ page_offline_freeze();
+
+ 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;
+ phdr->p_vaddr = (size_t)m->addr;
+ if (m->type == KCORE_RAM)
+ 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) {
+ struct page *page;
+ unsigned long pfn;
+
+ /*
+ * 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) {
+ struct kcore_list *iter;
+
+ m = NULL;
+ list_for_each_entry(iter, &kclist_head, list) {
+ if (start >= iter->addr &&
+ start < iter->addr + iter->size) {
+ m = iter;
+ break;
+ }
+ }
+ }
+
+ if (page_offline_frozen++ % MAX_ORDER_NR_PAGES == 0) {
+ page_offline_thaw();
+ cond_resched();
+ page_offline_freeze();
+ }
+
+ if (!m) {
+ if (clear_user(buffer, tsz)) {
+ ret = -EFAULT;
+ goto out;
+ }
+ goto skip;
+ }
+
+ switch (m->type) {
+ case 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;
+ }
+ break;
+ case KCORE_USER:
+ /* User page is handled prior to normal kernel page: */
+ if (copy_to_user(buffer, (char *)start, tsz)) {
+ ret = -EFAULT;
+ goto out;
+ }
+ break;
+ case KCORE_RAM:
+ pfn = __pa(start) >> PAGE_SHIFT;
+ page = pfn_to_online_page(pfn);
+
+ /*
+ * Don't read offline sections, logically offline pages
+ * (e.g., inflated in a balloon), hwpoisoned pages,
+ * and explicitly excluded physical ranges.
+ */
+ if (!page || PageOffline(page) ||
+ is_page_hwpoison(page) || !pfn_is_ram(pfn)) {
+ if (clear_user(buffer, tsz)) {
+ ret = -EFAULT;
+ goto out;
+ }
+ break;
+ }
+ fallthrough;
+ case KCORE_VMEMMAP:
+ case KCORE_TEXT:
+ 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;
+ }
+ }
+ break;
+ default:
+ pr_warn_once("Unhandled KCORE type: %d\n", m->type);
+ if (clear_user(buffer, tsz)) {
+ ret = -EFAULT;
+ goto out;
+ }
+ }
+skip:
+ buflen -= tsz;
+ *fpos += tsz;
+ buffer += tsz;
+ start += tsz;
+ tsz = (buflen > PAGE_SIZE ? PAGE_SIZE : buflen);
+ }
+
+out:
+ page_offline_thaw();
+ 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);
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-08 16:58:04 +0000