Commit 6d8c4e3b authored by David Howells's avatar David Howells Committed by Linus Torvalds
Browse files

[PATCH] FDPIC: Add coredump capability for the ELF-FDPIC binfmt



Add coredump capability for the ELF-FDPIC binfmt.
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent b4cac1a0
......@@ -371,3 +371,11 @@ int elf_check_arch(const struct elf32_hdr *hdr)
return 1;
}
int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpregs)
{
memcpy(fpregs,
&current->thread.user->f,
sizeof(current->thread.user->f));
return 1;
}
......@@ -24,7 +24,9 @@
#include <linux/file.h>
#include <linux/fcntl.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <linux/highmem.h>
#include <linux/highuid.h>
#include <linux/personality.h>
#include <linux/ptrace.h>
#include <linux/init.h>
......@@ -48,6 +50,12 @@ typedef char *elf_caddr_t;
#define kdebug(fmt, ...) do {} while(0)
#endif
#if 0
#define kdcore(fmt, ...) printk("FDPIC "fmt"\n" ,##__VA_ARGS__ )
#else
#define kdcore(fmt, ...) do {} while(0)
#endif
MODULE_LICENSE("GPL");
static int load_elf_fdpic_binary(struct linux_binprm *, struct pt_regs *);
......@@ -70,10 +78,16 @@ static int elf_fdpic_map_file_constdisp_on_uclinux(struct elf_fdpic_params *,
static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *,
struct file *, struct mm_struct *);
#if defined(USE_ELF_CORE_DUMP) && defined(CONFIG_ELF_CORE)
static int elf_fdpic_core_dump(long, struct pt_regs *, struct file *);
#endif
static struct linux_binfmt elf_fdpic_format = {
.module = THIS_MODULE,
.load_binary = load_elf_fdpic_binary,
// .core_dump = elf_fdpic_core_dump,
#if defined(USE_ELF_CORE_DUMP) && defined(CONFIG_ELF_CORE)
.core_dump = elf_fdpic_core_dump,
#endif
.min_coredump = ELF_EXEC_PAGESIZE,
};
......@@ -87,7 +101,7 @@ static void __exit exit_elf_fdpic_binfmt(void)
unregister_binfmt(&elf_fdpic_format);
}
module_init(init_elf_fdpic_binfmt);
core_initcall(init_elf_fdpic_binfmt);
module_exit(exit_elf_fdpic_binfmt);
static int is_elf_fdpic(struct elfhdr *hdr, struct file *file)
......@@ -1118,3 +1132,661 @@ static int elf_fdpic_map_file_by_direct_mmap(struct elf_fdpic_params *params,
return 0;
}
/*****************************************************************************/
/*
* ELF-FDPIC core dumper
*
* Modelled on fs/exec.c:aout_core_dump()
* Jeremy Fitzhardinge <jeremy@sw.oz.au>
*
* Modelled on fs/binfmt_elf.c core dumper
*/
#if defined(USE_ELF_CORE_DUMP) && defined(CONFIG_ELF_CORE)
/*
* These are the only things you should do on a core-file: use only these
* functions to write out all the necessary info.
*/
static int dump_write(struct file *file, const void *addr, int nr)
{
return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
}
static int dump_seek(struct file *file, loff_t off)
{
if (file->f_op->llseek) {
if (file->f_op->llseek(file, off, SEEK_SET) != off)
return 0;
} else {
file->f_pos = off;
}
return 1;
}
/*
* Decide whether a segment is worth dumping; default is yes to be
* sure (missing info is worse than too much; etc).
* Personally I'd include everything, and use the coredump limit...
*
* I think we should skip something. But I am not sure how. H.J.
*/
static int maydump(struct vm_area_struct *vma)
{
/* Do not dump I/O mapped devices or special mappings */
if (vma->vm_flags & (VM_IO | VM_RESERVED)) {
kdcore("%08lx: %08lx: no (IO)", vma->vm_start, vma->vm_flags);
return 0;
}
/* If we may not read the contents, don't allow us to dump
* them either. "dump_write()" can't handle it anyway.
*/
if (!(vma->vm_flags & VM_READ)) {
kdcore("%08lx: %08lx: no (!read)", vma->vm_start, vma->vm_flags);
return 0;
}
/* Dump shared memory only if mapped from an anonymous file. */
if (vma->vm_flags & VM_SHARED) {
if (vma->vm_file->f_dentry->d_inode->i_nlink == 0) {
kdcore("%08lx: %08lx: no (share)", vma->vm_start, vma->vm_flags);
return 1;
}
kdcore("%08lx: %08lx: no (share)", vma->vm_start, vma->vm_flags);
return 0;
}
#ifdef CONFIG_MMU
/* If it hasn't been written to, don't write it out */
if (!vma->anon_vma) {
kdcore("%08lx: %08lx: no (!anon)", vma->vm_start, vma->vm_flags);
return 0;
}
#endif
kdcore("%08lx: %08lx: yes", vma->vm_start, vma->vm_flags);
return 1;
}
/* An ELF note in memory */
struct memelfnote
{
const char *name;
int type;
unsigned int datasz;
void *data;
};
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;
}
/* #define DEBUG */
#define DUMP_WRITE(addr, nr) \
do { if (!dump_write(file, (addr), (nr))) return 0; } while(0)
#define DUMP_SEEK(off) \
do { if (!dump_seek(file, (off))) return 0; } while(0)
static int writenote(struct memelfnote *men, struct file *file)
{
struct elf_note en;
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 */
DUMP_SEEK(roundup((unsigned long)file->f_pos, 4)); /* XXX */
DUMP_WRITE(men->data, men->datasz);
DUMP_SEEK(roundup((unsigned long)file->f_pos, 4)); /* XXX */
return 1;
}
#undef DUMP_WRITE
#undef DUMP_SEEK
#define DUMP_WRITE(addr, nr) \
if ((size += (nr)) > limit || !dump_write(file, (addr), (nr))) \
goto end_coredump;
#define DUMP_SEEK(off) \
if (!dump_seek(file, (off))) \
goto end_coredump;
static inline void fill_elf_fdpic_header(struct elfhdr *elf, int segs)
{
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_FDPIC_CORE_EFLAGS;
elf->e_ehsize = sizeof(struct elfhdr);
elf->e_phentsize = sizeof(struct elf_phdr);
elf->e_phnum = segs;
elf->e_shentsize = 0;
elf->e_shnum = 0;
elf->e_shstrndx = 0;
return;
}
static inline void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offset)
{
phdr->p_type = PT_NOTE;
phdr->p_offset = offset;
phdr->p_vaddr = 0;
phdr->p_paddr = 0;
phdr->p_filesz = sz;
phdr->p_memsz = 0;
phdr->p_flags = 0;
phdr->p_align = 0;
return;
}
static inline void fill_note(struct memelfnote *note, const char *name, int type,
unsigned int sz, void *data)
{
note->name = name;
note->type = type;
note->datasz = sz;
note->data = data;
return;
}
/*
* fill up all the fields in prstatus from the given task struct, except
* registers which need to be filled up seperately.
*/
static void fill_prstatus(struct elf_prstatus *prstatus,
struct task_struct *p, long signr)
{
prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
prstatus->pr_sigpend = p->pending.signal.sig[0];
prstatus->pr_sighold = p->blocked.sig[0];
prstatus->pr_pid = p->pid;
prstatus->pr_ppid = p->parent->pid;
prstatus->pr_pgrp = process_group(p);
prstatus->pr_sid = p->signal->session;
if (thread_group_leader(p)) {
/*
* This is the record for the group leader. Add in the
* cumulative times of previous dead threads. This total
* won't include the time of each live thread whose state
* is included in the core dump. The final total reported
* to our parent process when it calls wait4 will include
* those sums as well as the little bit more time it takes
* this and each other thread to finish dying after the
* core dump synchronization phase.
*/
cputime_to_timeval(cputime_add(p->utime, p->signal->utime),
&prstatus->pr_utime);
cputime_to_timeval(cputime_add(p->stime, p->signal->stime),
&prstatus->pr_stime);
} else {
cputime_to_timeval(p->utime, &prstatus->pr_utime);
cputime_to_timeval(p->stime, &prstatus->pr_stime);
}
cputime_to_timeval(p->signal->cutime, &prstatus->pr_cutime);
cputime_to_timeval(p->signal->cstime, &prstatus->pr_cstime);
prstatus->pr_exec_fdpic_loadmap = p->mm->context.exec_fdpic_loadmap;
prstatus->pr_interp_fdpic_loadmap = p->mm->context.interp_fdpic_loadmap;
}
static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
struct mm_struct *mm)
{
unsigned int i, len;
/* first copy the parameters from user space */
memset(psinfo, 0, sizeof(struct elf_prpsinfo));
len = mm->arg_end - mm->arg_start;
if (len >= ELF_PRARGSZ)
len = ELF_PRARGSZ - 1;
if (copy_from_user(&psinfo->pr_psargs,
(const char __user *) mm->arg_start, len))
return -EFAULT;
for (i = 0; i < len; i++)
if (psinfo->pr_psargs[i] == 0)
psinfo->pr_psargs[i] = ' ';
psinfo->pr_psargs[len] = 0;
psinfo->pr_pid = p->pid;
psinfo->pr_ppid = p->parent->pid;
psinfo->pr_pgrp = process_group(p);
psinfo->pr_sid = p->signal->session;
i = p->state ? ffz(~p->state) + 1 : 0;
psinfo->pr_state = i;
psinfo->pr_sname = (i > 5) ? '.' : "RSDTZW"[i];
psinfo->pr_zomb = psinfo->pr_sname == 'Z';
psinfo->pr_nice = task_nice(p);
psinfo->pr_flag = p->flags;
SET_UID(psinfo->pr_uid, p->uid);
SET_GID(psinfo->pr_gid, p->gid);
strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname));
return 0;
}
/* Here is the structure in which status of each thread is captured. */
struct elf_thread_status
{
struct list_head list;
struct elf_prstatus prstatus; /* NT_PRSTATUS */
elf_fpregset_t fpu; /* NT_PRFPREG */
struct task_struct *thread;
#ifdef ELF_CORE_COPY_XFPREGS
elf_fpxregset_t xfpu; /* NT_PRXFPREG */
#endif
struct memelfnote notes[3];
int num_notes;
};
/*
* In order to add the specific thread information for the elf file format,
* we need to keep a linked list of every thread's pr_status and then create
* a single section for them in the final core file.
*/
static int elf_dump_thread_status(long signr, struct elf_thread_status *t)
{
struct task_struct *p = t->thread;
int sz = 0;
t->num_notes = 0;
fill_prstatus(&t->prstatus, p, signr);
elf_core_copy_task_regs(p, &t->prstatus.pr_reg);
fill_note(&t->notes[0], "CORE", NT_PRSTATUS, sizeof(t->prstatus),
&t->prstatus);
t->num_notes++;
sz += notesize(&t->notes[0]);
t->prstatus.pr_fpvalid = elf_core_copy_task_fpregs(p, NULL, &t->fpu);
if (t->prstatus.pr_fpvalid) {
fill_note(&t->notes[1], "CORE", NT_PRFPREG, sizeof(t->fpu),
&t->fpu);
t->num_notes++;
sz += notesize(&t->notes[1]);
}
#ifdef ELF_CORE_COPY_XFPREGS
if (elf_core_copy_task_xfpregs(p, &t->xfpu)) {
fill_note(&t->notes[2], "LINUX", NT_PRXFPREG, sizeof(t->xfpu),
&t->xfpu);
t->num_notes++;
sz += notesize(&t->notes[2]);
}
#endif
return sz;
}
/*
* dump the segments for an MMU process
*/
#ifdef CONFIG_MMU
static int elf_fdpic_dump_segments(struct file *file, struct mm_struct *mm,
size_t *size, unsigned long *limit)
{
struct vm_area_struct *vma;
for (vma = current->mm->mmap; vma; vma = vma->vm_next) {
unsigned long addr;
if (!maydump(vma))
continue;
for (addr = vma->vm_start;
addr < vma->vm_end;
addr += PAGE_SIZE
) {
struct vm_area_struct *vma;
struct page *page;
if (get_user_pages(current, current->mm, addr, 1, 0, 1,
&page, &vma) <= 0) {
DUMP_SEEK(file->f_pos + PAGE_SIZE);
}
else if (page == ZERO_PAGE(addr)) {
DUMP_SEEK(file->f_pos + PAGE_SIZE);
page_cache_release(page);
}
else {
void *kaddr;
flush_cache_page(vma, addr, page_to_pfn(page));
kaddr = kmap(page);
if ((*size += PAGE_SIZE) > *limit ||
!dump_write(file, kaddr, PAGE_SIZE)
) {
kunmap(page);
page_cache_release(page);
return -EIO;
}
kunmap(page);
page_cache_release(page);
}
}
}
return 0;
end_coredump:
return -EFBIG;
}
#endif
/*
* dump the segments for a NOMMU process
*/
#ifndef CONFIG_MMU
static int elf_fdpic_dump_segments(struct file *file, struct mm_struct *mm,
size_t *size, unsigned long *limit)
{
struct vm_list_struct *vml;
for (vml = current->mm->context.vmlist; vml; vml = vml->next) {
struct vm_area_struct *vma = vml->vma;
if (!maydump(vma))
continue;
if ((*size += PAGE_SIZE) > *limit)
return -EFBIG;
if (!dump_write(file, (void *) vma->vm_start,
vma->vm_end - vma->vm_start))
return -EIO;
}
return 0;
}
#endif
/*
* Actual dumper
*
* This is a two-pass process; first we find the offsets of the bits,
* and then they are actually written out. If we run out of core limit
* we just truncate.
*/
static int elf_fdpic_core_dump(long signr, struct pt_regs *regs,
struct file *file)
{
#define NUM_NOTES 6
int has_dumped = 0;
mm_segment_t fs;
int segs;
size_t size = 0;
int i;
struct vm_area_struct *vma;
struct elfhdr *elf = NULL;
loff_t offset = 0, dataoff;
unsigned long limit = current->signal->rlim[RLIMIT_CORE].rlim_cur;
int numnote;
struct memelfnote *notes = NULL;
struct elf_prstatus *prstatus = NULL; /* NT_PRSTATUS */
struct elf_prpsinfo *psinfo = NULL; /* NT_PRPSINFO */
struct task_struct *g, *p;
LIST_HEAD(thread_list);
struct list_head *t;
elf_fpregset_t *fpu = NULL;
#ifdef ELF_CORE_COPY_XFPREGS
elf_fpxregset_t *xfpu = NULL;
#endif
int thread_status_size = 0;
#ifndef CONFIG_MMU
struct vm_list_struct *vml;
#endif
elf_addr_t *auxv;
/*
* We no longer stop all VM operations.
*
* This is because those proceses that could possibly change map_count
* or the mmap / vma pages are now blocked in do_exit on current
* finishing this core dump.
*
* Only ptrace can touch these memory addresses, but it doesn't change
* the map_count or the pages allocated. So no possibility of crashing
* exists while dumping the mm->vm_next areas to the core file.
*/
/* alloc memory for large data structures: too large to be on stack */
elf = kmalloc(sizeof(*elf), GFP_KERNEL);
if (!elf)
goto cleanup;
prstatus = kzalloc(sizeof(*prstatus), GFP_KERNEL);
if (!prstatus)
goto cleanup;
psinfo = kmalloc(sizeof(*psinfo), GFP_KERNEL);
if (!psinfo)
goto cleanup;
notes = kmalloc(NUM_NOTES * sizeof(struct memelfnote), GFP_KERNEL);
if (!notes)
goto cleanup;
fpu = kmalloc(sizeof(*fpu), GFP_KERNEL);
if (!fpu)
goto cleanup;
#ifdef ELF_CORE_COPY_XFPREGS
xfpu = kmalloc(sizeof(*xfpu), GFP_KERNEL);
if (!xfpu)
goto cleanup;
#endif
if (signr) {
struct elf_thread_status *tmp;
read_lock(&tasklist_lock);
do_each_thread(g,p)
if (current->mm == p->mm && current != p) {
tmp = kzalloc(sizeof(*tmp), GFP_ATOMIC);
if (!tmp) {
read_unlock(&tasklist_lock);
goto cleanup;
}
INIT_LIST_HEAD(&tmp->list);
tmp->thread = p;
list_add(&tmp->list, &thread_list);
}
while_each_thread(g,p);
read_unlock(&tasklist_lock);
list_for_each(t, &thread_list) {
struct elf_thread_status *tmp;
int sz;
tmp = list_entry(t, struct elf_thread_status, list);
sz = elf_dump_thread_status(signr, tmp);
thread_status_size += sz;
}
}
/* now collect the dump for the current */
fill_prstatus(prstatus, current, signr);
elf_core_copy_regs(&prstatus->pr_reg, regs);
#ifdef CONFIG_MMU
segs = current->mm->map_count;
#else
segs = 0;
for (vml = current->mm->context.vmlist; vml; vml = vml->next)
segs++;
#endif
#ifdef ELF_CORE_EXTRA_PHDRS
segs += ELF_CORE_EXTRA_PHDRS;
#endif
/* Set up header */
fill_elf_fdpic_header(elf, segs + 1); /* including notes section */
has_dumped = 1;
current->flags |= PF_DUMPCORE;
/*
* Set up the notes in similar form to SVR4 core dumps made
* with info from their /proc.
*/
fill_note(notes + 0, "CORE", NT_PRSTATUS, sizeof(*prstatus), prstatus);
fill_psinfo(psinfo, current->group_leader, current->mm);
fill_note(notes + 1, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo);
numnote = 2;
auxv = (elf_addr_t *) current->mm->saved_auxv;
i = 0;
do
i += 2;
while (auxv[i - 2] != AT_NULL);
fill_note(&notes[numnote++], "CORE", NT_AUXV,
i * sizeof(elf_addr_t), auxv);
/* Try to dump the FPU. */
if ((prstatus->pr_fpvalid =
elf_core_copy_task_fpregs(current, regs, fpu)))
fill_note(notes + numnote++,
"CORE", NT_PRFPREG, sizeof(*fpu), fpu);
#ifdef ELF_CORE_COPY_XFPREGS
if (elf_core_copy_task_xfpregs(current, xfpu))
fill_note(notes + numnote++,
"LINUX", NT_PRXFPREG, sizeof(*xfpu), xfpu);
#endif
fs = get_fs();
set_fs(KERNEL_DS);
DUMP_WRITE(elf, sizeof(*elf));
offset += sizeof(*elf); /* Elf header */
offset += (segs+1) * sizeof(struct elf_phdr); /* Program headers */
/* Write notes phdr entry */
{
struct elf_phdr phdr;
int sz = 0;