| // 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/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/bootmem.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 <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 |
| |
| /* An ELF note in memory */ |
| struct memelfnote |
| { |
| const char *name; |
| int type; |
| unsigned int datasz; |
| void *data; |
| }; |
| |
| static LIST_HEAD(kclist_head); |
| static DEFINE_RWLOCK(kclist_lock); |
| static int kcore_need_update = 1; |
| |
| void |
| kclist_add(struct kcore_list *new, void *addr, size_t size, int type) |
| { |
| new->addr = (unsigned long)addr; |
| new->size = size; |
| new->type = type; |
| |
| write_lock(&kclist_lock); |
| list_add_tail(&new->list, &kclist_head); |
| write_unlock(&kclist_lock); |
| } |
| |
| static size_t get_kcore_size(int *nphdr, size_t *elf_buflen) |
| { |
| 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; |
| } |
| *elf_buflen = sizeof(struct elfhdr) + |
| (*nphdr + 2)*sizeof(struct elf_phdr) + |
| 3 * ((sizeof(struct elf_note)) + |
| roundup(sizeof(CORE_STR), 4)) + |
| roundup(sizeof(struct elf_prstatus), 4) + |
| roundup(sizeof(struct elf_prpsinfo), 4) + |
| roundup(arch_task_struct_size, 4); |
| *elf_buflen = PAGE_ALIGN(*elf_buflen); |
| return size + *elf_buflen; |
| } |
| |
| static void free_kclist_ents(struct list_head *head) |
| { |
| struct kcore_list *tmp, *pos; |
| |
| list_for_each_entry_safe(pos, tmp, head, list) { |
| list_del(&pos->list); |
| kfree(pos); |
| } |
| } |
| /* |
| * Replace all KCORE_RAM/KCORE_VMEMMAP information with passed list. |
| */ |
| static void __kcore_update_ram(struct list_head *list) |
| { |
| int nphdr; |
| size_t size; |
| struct kcore_list *tmp, *pos; |
| LIST_HEAD(garbage); |
| |
| write_lock(&kclist_lock); |
| if (kcore_need_update) { |
| 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); |
| } else |
| list_splice(list, &garbage); |
| kcore_need_update = 0; |
| proc_root_kcore->size = get_kcore_size(&nphdr, &size); |
| write_unlock(&kclist_lock); |
| |
| free_kclist_ents(&garbage); |
| } |
| |
| |
| #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_update_ram(void) |
| { |
| LIST_HEAD(head); |
| struct kcore_list *ent; |
| int ret = 0; |
| |
| 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); |
| __kcore_update_ram(&head); |
| return ret; |
| } |
| |
| #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; |
| |
| ent = kmalloc(sizeof(*ent), GFP_KERNEL); |
| if (!ent) |
| return -ENOMEM; |
| ent->addr = (unsigned long)__va((pfn << PAGE_SHIFT)); |
| ent->size = nr_pages << PAGE_SHIFT; |
| |
| /* Sanity check: Can happen in 32bit arch...maybe */ |
| if (ent->addr < (unsigned long) __va(0)) |
| goto free_out; |
| |
| /* cut not-mapped area. ....from ppc-32 code. */ |
| if (ULONG_MAX - ent->addr < ent->size) |
| ent->size = ULONG_MAX - ent->addr; |
| |
| /* cut when vmalloc() area is higher than direct-map area */ |
| if (VMALLOC_START > (unsigned long)__va(0)) { |
| if (ent->addr > VMALLOC_START) |
| goto free_out; |
| 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_update_ram(void) |
| { |
| int nid, ret; |
| unsigned long end_pfn; |
| LIST_HEAD(head); |
| |
| /* 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, &head, kclist_add_private); |
| if (ret) { |
| free_kclist_ents(&head); |
| return -ENOMEM; |
| } |
| __kcore_update_ram(&head); |
| return ret; |
| } |
| #endif /* CONFIG_HIGHMEM */ |
| |
| /*****************************************************************************/ |
| /* |
| * determine size of ELF note |
| */ |
| static int notesize(struct memelfnote *en) |
| { |
| int sz; |
| |
| sz = sizeof(struct elf_note); |
| sz += roundup((strlen(en->name) + 1), 4); |
| sz += roundup(en->datasz, 4); |
| |
| return sz; |
| } /* end notesize() */ |
| |
| /*****************************************************************************/ |
| /* |
| * store a note in the header buffer |
| */ |
| static char *storenote(struct memelfnote *men, char *bufp) |
| { |
| struct elf_note en; |
| |
| #define DUMP_WRITE(addr,nr) do { memcpy(bufp,addr,nr); bufp += nr; } while(0) |
| |
| en.n_namesz = strlen(men->name) + 1; |
| en.n_descsz = men->datasz; |
| en.n_type = men->type; |
| |
| DUMP_WRITE(&en, sizeof(en)); |
| DUMP_WRITE(men->name, en.n_namesz); |
| |
| /* XXX - cast from long long to long to avoid need for libgcc.a */ |
| bufp = (char*) roundup((unsigned long)bufp,4); |
| DUMP_WRITE(men->data, men->datasz); |
| bufp = (char*) roundup((unsigned long)bufp,4); |
| |
| #undef DUMP_WRITE |
| |
| return bufp; |
| } /* end storenote() */ |
| |
| /* |
| * store an ELF coredump header in the supplied buffer |
| * nphdr is the number of elf_phdr to insert |
| */ |
| static void elf_kcore_store_hdr(char *bufp, int nphdr, int dataoff) |
| { |
| struct elf_prstatus prstatus; /* NT_PRSTATUS */ |
| struct elf_prpsinfo prpsinfo; /* NT_PRPSINFO */ |
| struct elf_phdr *nhdr, *phdr; |
| struct elfhdr *elf; |
| struct memelfnote notes[3]; |
| off_t offset = 0; |
| struct kcore_list *m; |
| |
| /* setup ELF header */ |
| elf = (struct elfhdr *) bufp; |
| bufp += sizeof(struct elfhdr); |
| offset += sizeof(struct elfhdr); |
| memcpy(elf->e_ident, ELFMAG, SELFMAG); |
| elf->e_ident[EI_CLASS] = ELF_CLASS; |
| elf->e_ident[EI_DATA] = ELF_DATA; |
| elf->e_ident[EI_VERSION]= EV_CURRENT; |
| elf->e_ident[EI_OSABI] = ELF_OSABI; |
| memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD); |
| elf->e_type = ET_CORE; |
| elf->e_machine = ELF_ARCH; |
| elf->e_version = EV_CURRENT; |
| elf->e_entry = 0; |
| elf->e_phoff = sizeof(struct elfhdr); |
| elf->e_shoff = 0; |
| elf->e_flags = ELF_CORE_EFLAGS; |
| elf->e_ehsize = sizeof(struct elfhdr); |
| elf->e_phentsize= sizeof(struct elf_phdr); |
| elf->e_phnum = nphdr; |
| elf->e_shentsize= 0; |
| elf->e_shnum = 0; |
| elf->e_shstrndx = 0; |
| |
| /* setup ELF PT_NOTE program header */ |
| nhdr = (struct elf_phdr *) bufp; |
| bufp += sizeof(struct elf_phdr); |
| offset += sizeof(struct elf_phdr); |
| nhdr->p_type = PT_NOTE; |
| nhdr->p_offset = 0; |
| nhdr->p_vaddr = 0; |
| nhdr->p_paddr = 0; |
| nhdr->p_filesz = 0; |
| nhdr->p_memsz = 0; |
| nhdr->p_flags = 0; |
| nhdr->p_align = 0; |
| |
| /* setup ELF PT_LOAD program header for every area */ |
| list_for_each_entry(m, &kclist_head, list) { |
| phdr = (struct elf_phdr *) bufp; |
| bufp += sizeof(struct elf_phdr); |
| offset += sizeof(struct elf_phdr); |
| |
| phdr->p_type = PT_LOAD; |
| phdr->p_flags = PF_R|PF_W|PF_X; |
| phdr->p_offset = kc_vaddr_to_offset(m->addr) + dataoff; |
| phdr->p_vaddr = (size_t)m->addr; |
| if (m->type == KCORE_RAM || m->type == KCORE_TEXT) |
| phdr->p_paddr = __pa(m->addr); |
| else |
| phdr->p_paddr = (elf_addr_t)-1; |
| phdr->p_filesz = phdr->p_memsz = m->size; |
| phdr->p_align = PAGE_SIZE; |
| } |
| |
| /* |
| * Set up the notes in similar form to SVR4 core dumps made |
| * with info from their /proc. |
| */ |
| nhdr->p_offset = offset; |
| |
| /* set up the process status */ |
| notes[0].name = CORE_STR; |
| notes[0].type = NT_PRSTATUS; |
| notes[0].datasz = sizeof(struct elf_prstatus); |
| notes[0].data = &prstatus; |
| |
| memset(&prstatus, 0, sizeof(struct elf_prstatus)); |
| |
| nhdr->p_filesz = notesize(¬es[0]); |
| bufp = storenote(¬es[0], bufp); |
| |
| /* set up the process info */ |
| notes[1].name = CORE_STR; |
| notes[1].type = NT_PRPSINFO; |
| notes[1].datasz = sizeof(struct elf_prpsinfo); |
| notes[1].data = &prpsinfo; |
| |
| memset(&prpsinfo, 0, sizeof(struct elf_prpsinfo)); |
| prpsinfo.pr_state = 0; |
| prpsinfo.pr_sname = 'R'; |
| prpsinfo.pr_zomb = 0; |
| |
| strcpy(prpsinfo.pr_fname, "vmlinux"); |
| strlcpy(prpsinfo.pr_psargs, saved_command_line, sizeof(prpsinfo.pr_psargs)); |
| |
| nhdr->p_filesz += notesize(¬es[1]); |
| bufp = storenote(¬es[1], bufp); |
| |
| /* set up the task structure */ |
| notes[2].name = CORE_STR; |
| notes[2].type = NT_TASKSTRUCT; |
| notes[2].datasz = arch_task_struct_size; |
| notes[2].data = current; |
| |
| nhdr->p_filesz += notesize(¬es[2]); |
| bufp = storenote(¬es[2], bufp); |
| |
| } /* end elf_kcore_store_hdr() */ |
| |
| /*****************************************************************************/ |
| /* |
| * read from the ELF header and then kernel memory |
| */ |
| static ssize_t |
| read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos) |
| { |
| char *buf = file->private_data; |
| ssize_t acc = 0; |
| size_t size, tsz; |
| size_t elf_buflen; |
| int nphdr; |
| unsigned long start; |
| |
| read_lock(&kclist_lock); |
| size = get_kcore_size(&nphdr, &elf_buflen); |
| |
| if (buflen == 0 || *fpos >= size) { |
| read_unlock(&kclist_lock); |
| return 0; |
| } |
| |
| /* trim buflen to not go beyond EOF */ |
| if (buflen > size - *fpos) |
| buflen = size - *fpos; |
| |
| /* construct an ELF core header if we'll need some of it */ |
| if (*fpos < elf_buflen) { |
| char * elf_buf; |
| |
| tsz = elf_buflen - *fpos; |
| if (buflen < tsz) |
| tsz = buflen; |
| elf_buf = kzalloc(elf_buflen, GFP_ATOMIC); |
| if (!elf_buf) { |
| read_unlock(&kclist_lock); |
| return -ENOMEM; |
| } |
| elf_kcore_store_hdr(elf_buf, nphdr, elf_buflen); |
| read_unlock(&kclist_lock); |
| if (copy_to_user(buffer, elf_buf + *fpos, tsz)) { |
| kfree(elf_buf); |
| return -EFAULT; |
| } |
| kfree(elf_buf); |
| buflen -= tsz; |
| *fpos += tsz; |
| buffer += tsz; |
| acc += tsz; |
| |
| /* leave now if filled buffer already */ |
| if (buflen == 0) |
| return acc; |
| } else |
| read_unlock(&kclist_lock); |
| |
| /* |
| * 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 - elf_buflen); |
| if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen) |
| tsz = buflen; |
| |
| while (buflen) { |
| struct kcore_list *m; |
| |
| read_lock(&kclist_lock); |
| list_for_each_entry(m, &kclist_head, list) { |
| if (start >= m->addr && start < (m->addr+m->size)) |
| break; |
| } |
| read_unlock(&kclist_lock); |
| |
| if (&m->list == &kclist_head) { |
| if (clear_user(buffer, tsz)) |
| return -EFAULT; |
| } 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)) |
| return -EFAULT; |
| } else { |
| if (kern_addr_valid(start)) { |
| /* |
| * Using bounce buffer to bypass the |
| * hardened user copy kernel text checks. |
| */ |
| if (probe_kernel_read(buf, (void *) start, tsz)) { |
| if (clear_user(buffer, tsz)) |
| return -EFAULT; |
| } else { |
| if (copy_to_user(buffer, buf, tsz)) |
| return -EFAULT; |
| } |
| } else { |
| if (clear_user(buffer, tsz)) |
| return -EFAULT; |
| } |
| } |
| buflen -= tsz; |
| *fpos += tsz; |
| buffer += tsz; |
| acc += tsz; |
| start += tsz; |
| tsz = (buflen > PAGE_SIZE ? PAGE_SIZE : buflen); |
| } |
| |
| return acc; |
| } |
| |
| |
| static int open_kcore(struct inode *inode, struct file *filp) |
| { |
| if (!capable(CAP_SYS_RAWIO)) |
| return -EPERM; |
| |
| 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 file_operations proc_kcore_operations = { |
| .read = read_kcore, |
| .open = open_kcore, |
| .release = release_kcore, |
| .llseek = 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: |
| write_lock(&kclist_lock); |
| kcore_need_update = 1; |
| write_unlock(&kclist_lock); |
| } |
| 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. |
| */ |
| 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, |
| &proc_kcore_operations); |
| 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); |