mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-21 16:29:59 +00:00
413 lines
10 KiB
C
413 lines
10 KiB
C
/*
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* fs/proc/kcore.c kernel ELF core dumper
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*
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* Modelled on fs/exec.c:aout_core_dump()
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* Jeremy Fitzhardinge <jeremy@sw.oz.au>
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* ELF version written by David Howells <David.Howells@nexor.co.uk>
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* Modified and incorporated into 2.3.x by Tigran Aivazian <tigran@veritas.com>
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* Support to dump vmalloc'd areas (ELF only), Tigran Aivazian <tigran@veritas.com>
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* Safe accesses to vmalloc/direct-mapped discontiguous areas, Kanoj Sarcar <kanoj@sgi.com>
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*/
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#include <linux/mm.h>
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#include <linux/proc_fs.h>
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#include <linux/user.h>
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#include <linux/capability.h>
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#include <linux/elf.h>
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#include <linux/elfcore.h>
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#include <linux/vmalloc.h>
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#include <linux/highmem.h>
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#include <linux/init.h>
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#include <asm/uaccess.h>
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#include <asm/io.h>
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#define CORE_STR "CORE"
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#ifndef ELF_CORE_EFLAGS
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#define ELF_CORE_EFLAGS 0
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#endif
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static struct proc_dir_entry *proc_root_kcore;
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static int open_kcore(struct inode * inode, struct file * filp)
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{
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return capable(CAP_SYS_RAWIO) ? 0 : -EPERM;
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}
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static ssize_t read_kcore(struct file *, char __user *, size_t, loff_t *);
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static const struct file_operations proc_kcore_operations = {
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.read = read_kcore,
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.open = open_kcore,
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};
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#ifndef kc_vaddr_to_offset
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#define kc_vaddr_to_offset(v) ((v) - PAGE_OFFSET)
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#endif
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#ifndef kc_offset_to_vaddr
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#define kc_offset_to_vaddr(o) ((o) + PAGE_OFFSET)
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#endif
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/* An ELF note in memory */
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struct memelfnote
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{
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const char *name;
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int type;
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unsigned int datasz;
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void *data;
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};
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static struct kcore_list *kclist;
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static DEFINE_RWLOCK(kclist_lock);
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void
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kclist_add(struct kcore_list *new, void *addr, size_t size)
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{
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new->addr = (unsigned long)addr;
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new->size = size;
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write_lock(&kclist_lock);
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new->next = kclist;
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kclist = new;
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write_unlock(&kclist_lock);
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}
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static size_t get_kcore_size(int *nphdr, size_t *elf_buflen)
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{
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size_t try, size;
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struct kcore_list *m;
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*nphdr = 1; /* PT_NOTE */
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size = 0;
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for (m=kclist; m; m=m->next) {
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try = kc_vaddr_to_offset((size_t)m->addr + m->size);
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if (try > size)
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size = try;
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*nphdr = *nphdr + 1;
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}
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*elf_buflen = sizeof(struct elfhdr) +
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(*nphdr + 2)*sizeof(struct elf_phdr) +
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3 * ((sizeof(struct elf_note)) +
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roundup(sizeof(CORE_STR), 4)) +
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roundup(sizeof(struct elf_prstatus), 4) +
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roundup(sizeof(struct elf_prpsinfo), 4) +
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roundup(sizeof(struct task_struct), 4);
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*elf_buflen = PAGE_ALIGN(*elf_buflen);
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return size + *elf_buflen;
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}
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/*****************************************************************************/
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/*
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* determine size of ELF note
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*/
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static int notesize(struct memelfnote *en)
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{
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int sz;
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sz = sizeof(struct elf_note);
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sz += roundup((strlen(en->name) + 1), 4);
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sz += roundup(en->datasz, 4);
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return sz;
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} /* end notesize() */
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/*****************************************************************************/
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/*
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* store a note in the header buffer
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*/
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static char *storenote(struct memelfnote *men, char *bufp)
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{
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struct elf_note en;
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#define DUMP_WRITE(addr,nr) do { memcpy(bufp,addr,nr); bufp += nr; } while(0)
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en.n_namesz = strlen(men->name) + 1;
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en.n_descsz = men->datasz;
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en.n_type = men->type;
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DUMP_WRITE(&en, sizeof(en));
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DUMP_WRITE(men->name, en.n_namesz);
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/* XXX - cast from long long to long to avoid need for libgcc.a */
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bufp = (char*) roundup((unsigned long)bufp,4);
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DUMP_WRITE(men->data, men->datasz);
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bufp = (char*) roundup((unsigned long)bufp,4);
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#undef DUMP_WRITE
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return bufp;
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} /* end storenote() */
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/*
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* store an ELF coredump header in the supplied buffer
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* nphdr is the number of elf_phdr to insert
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*/
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static void elf_kcore_store_hdr(char *bufp, int nphdr, int dataoff)
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{
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struct elf_prstatus prstatus; /* NT_PRSTATUS */
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struct elf_prpsinfo prpsinfo; /* NT_PRPSINFO */
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struct elf_phdr *nhdr, *phdr;
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struct elfhdr *elf;
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struct memelfnote notes[3];
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off_t offset = 0;
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struct kcore_list *m;
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/* setup ELF header */
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elf = (struct elfhdr *) bufp;
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bufp += sizeof(struct elfhdr);
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offset += sizeof(struct elfhdr);
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memcpy(elf->e_ident, ELFMAG, SELFMAG);
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elf->e_ident[EI_CLASS] = ELF_CLASS;
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elf->e_ident[EI_DATA] = ELF_DATA;
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elf->e_ident[EI_VERSION]= EV_CURRENT;
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elf->e_ident[EI_OSABI] = ELF_OSABI;
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memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);
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elf->e_type = ET_CORE;
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elf->e_machine = ELF_ARCH;
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elf->e_version = EV_CURRENT;
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elf->e_entry = 0;
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elf->e_phoff = sizeof(struct elfhdr);
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elf->e_shoff = 0;
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elf->e_flags = ELF_CORE_EFLAGS;
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elf->e_ehsize = sizeof(struct elfhdr);
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elf->e_phentsize= sizeof(struct elf_phdr);
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elf->e_phnum = nphdr;
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elf->e_shentsize= 0;
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elf->e_shnum = 0;
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elf->e_shstrndx = 0;
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/* setup ELF PT_NOTE program header */
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nhdr = (struct elf_phdr *) bufp;
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bufp += sizeof(struct elf_phdr);
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offset += sizeof(struct elf_phdr);
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nhdr->p_type = PT_NOTE;
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nhdr->p_offset = 0;
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nhdr->p_vaddr = 0;
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nhdr->p_paddr = 0;
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nhdr->p_filesz = 0;
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nhdr->p_memsz = 0;
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nhdr->p_flags = 0;
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nhdr->p_align = 0;
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/* setup ELF PT_LOAD program header for every area */
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for (m=kclist; m; m=m->next) {
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phdr = (struct elf_phdr *) bufp;
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bufp += sizeof(struct elf_phdr);
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offset += sizeof(struct elf_phdr);
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phdr->p_type = PT_LOAD;
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phdr->p_flags = PF_R|PF_W|PF_X;
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phdr->p_offset = kc_vaddr_to_offset(m->addr) + dataoff;
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phdr->p_vaddr = (size_t)m->addr;
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phdr->p_paddr = 0;
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phdr->p_filesz = phdr->p_memsz = m->size;
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phdr->p_align = PAGE_SIZE;
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}
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/*
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* Set up the notes in similar form to SVR4 core dumps made
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* with info from their /proc.
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*/
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nhdr->p_offset = offset;
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/* set up the process status */
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notes[0].name = CORE_STR;
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notes[0].type = NT_PRSTATUS;
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notes[0].datasz = sizeof(struct elf_prstatus);
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notes[0].data = &prstatus;
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memset(&prstatus, 0, sizeof(struct elf_prstatus));
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nhdr->p_filesz = notesize(¬es[0]);
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bufp = storenote(¬es[0], bufp);
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/* set up the process info */
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notes[1].name = CORE_STR;
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notes[1].type = NT_PRPSINFO;
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notes[1].datasz = sizeof(struct elf_prpsinfo);
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notes[1].data = &prpsinfo;
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memset(&prpsinfo, 0, sizeof(struct elf_prpsinfo));
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prpsinfo.pr_state = 0;
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prpsinfo.pr_sname = 'R';
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prpsinfo.pr_zomb = 0;
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strcpy(prpsinfo.pr_fname, "vmlinux");
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strncpy(prpsinfo.pr_psargs, saved_command_line, ELF_PRARGSZ);
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nhdr->p_filesz += notesize(¬es[1]);
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bufp = storenote(¬es[1], bufp);
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/* set up the task structure */
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notes[2].name = CORE_STR;
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notes[2].type = NT_TASKSTRUCT;
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notes[2].datasz = sizeof(struct task_struct);
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notes[2].data = current;
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nhdr->p_filesz += notesize(¬es[2]);
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bufp = storenote(¬es[2], bufp);
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} /* end elf_kcore_store_hdr() */
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/*****************************************************************************/
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/*
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* read from the ELF header and then kernel memory
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*/
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static ssize_t
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read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos)
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{
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ssize_t acc = 0;
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size_t size, tsz;
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size_t elf_buflen;
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int nphdr;
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unsigned long start;
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read_lock(&kclist_lock);
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proc_root_kcore->size = size = get_kcore_size(&nphdr, &elf_buflen);
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if (buflen == 0 || *fpos >= size) {
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read_unlock(&kclist_lock);
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return 0;
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}
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/* trim buflen to not go beyond EOF */
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if (buflen > size - *fpos)
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buflen = size - *fpos;
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/* construct an ELF core header if we'll need some of it */
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if (*fpos < elf_buflen) {
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char * elf_buf;
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tsz = elf_buflen - *fpos;
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if (buflen < tsz)
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tsz = buflen;
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elf_buf = kzalloc(elf_buflen, GFP_ATOMIC);
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if (!elf_buf) {
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read_unlock(&kclist_lock);
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return -ENOMEM;
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}
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elf_kcore_store_hdr(elf_buf, nphdr, elf_buflen);
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read_unlock(&kclist_lock);
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if (copy_to_user(buffer, elf_buf + *fpos, tsz)) {
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kfree(elf_buf);
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return -EFAULT;
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}
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kfree(elf_buf);
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buflen -= tsz;
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*fpos += tsz;
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buffer += tsz;
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acc += tsz;
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/* leave now if filled buffer already */
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if (buflen == 0)
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return acc;
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} else
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read_unlock(&kclist_lock);
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/*
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* Check to see if our file offset matches with any of
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* the addresses in the elf_phdr on our list.
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*/
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start = kc_offset_to_vaddr(*fpos - elf_buflen);
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if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen)
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tsz = buflen;
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while (buflen) {
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struct kcore_list *m;
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read_lock(&kclist_lock);
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for (m=kclist; m; m=m->next) {
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if (start >= m->addr && start < (m->addr+m->size))
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break;
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}
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read_unlock(&kclist_lock);
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if (m == NULL) {
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if (clear_user(buffer, tsz))
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return -EFAULT;
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} else if (is_vmalloc_addr((void *)start)) {
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char * elf_buf;
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struct vm_struct *m;
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unsigned long curstart = start;
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unsigned long cursize = tsz;
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elf_buf = kzalloc(tsz, GFP_KERNEL);
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if (!elf_buf)
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return -ENOMEM;
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read_lock(&vmlist_lock);
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for (m=vmlist; m && cursize; m=m->next) {
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unsigned long vmstart;
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unsigned long vmsize;
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unsigned long msize = m->size - PAGE_SIZE;
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if (((unsigned long)m->addr + msize) <
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curstart)
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continue;
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if ((unsigned long)m->addr > (curstart +
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cursize))
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break;
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vmstart = (curstart < (unsigned long)m->addr ?
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(unsigned long)m->addr : curstart);
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if (((unsigned long)m->addr + msize) >
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(curstart + cursize))
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vmsize = curstart + cursize - vmstart;
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else
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vmsize = (unsigned long)m->addr +
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msize - vmstart;
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curstart = vmstart + vmsize;
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cursize -= vmsize;
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/* don't dump ioremap'd stuff! (TA) */
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if (m->flags & VM_IOREMAP)
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continue;
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memcpy(elf_buf + (vmstart - start),
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(char *)vmstart, vmsize);
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}
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read_unlock(&vmlist_lock);
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if (copy_to_user(buffer, elf_buf, tsz)) {
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kfree(elf_buf);
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return -EFAULT;
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}
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kfree(elf_buf);
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} else {
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if (kern_addr_valid(start)) {
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unsigned long n;
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n = copy_to_user(buffer, (char *)start, tsz);
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/*
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* We cannot distingush between fault on source
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* and fault on destination. When this happens
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* we clear too and hope it will trigger the
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* EFAULT again.
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*/
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if (n) {
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if (clear_user(buffer + tsz - n,
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n))
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return -EFAULT;
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}
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} else {
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if (clear_user(buffer, tsz))
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return -EFAULT;
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}
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}
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buflen -= tsz;
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*fpos += tsz;
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buffer += tsz;
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acc += tsz;
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start += tsz;
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tsz = (buflen > PAGE_SIZE ? PAGE_SIZE : buflen);
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}
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return acc;
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}
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static int __init proc_kcore_init(void)
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{
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proc_root_kcore = proc_create("kcore", S_IRUSR, NULL, &proc_kcore_operations);
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if (proc_root_kcore)
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proc_root_kcore->size =
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(size_t)high_memory - PAGE_OFFSET + PAGE_SIZE;
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return 0;
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}
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module_init(proc_kcore_init);
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