From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- fs/proc/kcore.c | 701 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 701 insertions(+) create mode 100644 fs/proc/kcore.c (limited to 'fs/proc/kcore.c') 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 + * ELF version written by David Howells + * Modified and incorporated into 2.3.x by Tigran Aivazian + * Support to dump vmalloc'd areas (ELF only), Tigran Aivazian + * Safe accesses to vmalloc/direct-mapped discontiguous areas, Kanoj Sarcar + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#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, ¬es_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 *)¬es[*i]; + + note->n_namesz = strlen(name) + 1; + note->n_descsz = descsz; + note->n_type = type; + *i += sizeof(*note); + memcpy(¬es[*i], name, note->n_namesz); + *i = ALIGN(*i + note->n_namesz, 4); + memcpy(¬es[*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, ¬es_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); -- cgit v1.2.3