d/freebsd-dev
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
9edc34f864
freebsd-dev/sys/kern/imgact_elf.c
Robert Watson 95c807cf5e When a statically linked binary is executed (or at least, one without 
an interpreter definition in its program header), set the auxiliary
ELF argument AT_BASE to 0 rather than to the address that we would
have mapped the interpreter at if there had been one.

The ELF ABI specifications appear to be ambiguous as to the desired
behavior in this situation, as they define AT_BASE as the base address
of the interpreter, but do not mention what to do if there is none.
On Solaris, AT_BASE will be set to the base address of the static
binary if there is no interpreter, and on Linux, AT_BASE is set to 0.
We go with the Linux semantics as they are of more immediate utility
and allow the early runtime environment to know that the kernel has
not mapped an interpreter, but because AT_PHDR points at the ELF
header for the running binary, it is still possible to retrieve all
required mapping information when the process starts should it be
required.  Either approach would be preferable to our current behavior
of passing a pointer to an unmapped region of user memory as AT_BASE.

MFC after:	3 weeks
2009-01-25 12:07:43 +00:00

1346 lines
36 KiB
C
Raw Blame History

/*-
* Copyright (c) 2000 David O'Brien
* Copyright (c) 1995-1996 Søren Schmidt
* Copyright (c) 1996 Peter Wemm
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer
* in this position and unchanged.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_compat.h"
#include <sys/param.h>
#include <sys/exec.h>
#include <sys/fcntl.h>
#include <sys/imgact.h>
#include <sys/imgact_elf.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/mutex.h>
#include <sys/mman.h>
#include <sys/namei.h>
#include <sys/pioctl.h>
#include <sys/proc.h>
#include <sys/procfs.h>
#include <sys/resourcevar.h>
#include <sys/sf_buf.h>
#include <sys/systm.h>
#include <sys/signalvar.h>
#include <sys/stat.h>
#include <sys/sx.h>
#include <sys/syscall.h>
#include <sys/sysctl.h>
#include <sys/sysent.h>
#include <sys/vnode.h>
#include <vm/vm.h>
#include <vm/vm_kern.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include <vm/vm_map.h>
#include <vm/vm_object.h>
#include <vm/vm_extern.h>
#include <machine/elf.h>
#include <machine/md_var.h>
#if defined(COMPAT_IA32) && __ELF_WORD_SIZE == 32
#include <machine/fpu.h>
#include <compat/ia32/ia32_reg.h>
#endif
#define OLD_EI_BRAND 8
static int __elfN(check_header)(const Elf_Ehdr *hdr);
static Elf_Brandinfo *__elfN(get_brandinfo)(const Elf_Ehdr *hdr,
const char *interp);
static int __elfN(load_file)(struct proc *p, const char *file, u_long *addr,
u_long *entry, size_t pagesize);
static int __elfN(load_section)(struct vmspace *vmspace, vm_object_t object,
vm_offset_t offset, caddr_t vmaddr, size_t memsz, size_t filsz,
vm_prot_t prot, size_t pagesize);
static int __CONCAT(exec_, __elfN(imgact))(struct image_params *imgp);
SYSCTL_NODE(_kern, OID_AUTO, __CONCAT(elf, __ELF_WORD_SIZE), CTLFLAG_RW, 0,
"");
int __elfN(fallback_brand) = -1;
SYSCTL_INT(__CONCAT(_kern_elf, __ELF_WORD_SIZE), OID_AUTO,
fallback_brand, CTLFLAG_RW, &__elfN(fallback_brand), 0,
__XSTRING(__CONCAT(ELF, __ELF_WORD_SIZE)) " brand of last resort");
TUNABLE_INT("kern.elf" __XSTRING(__ELF_WORD_SIZE) ".fallback_brand",
&__elfN(fallback_brand));
static int elf_legacy_coredump = 0;
SYSCTL_INT(_debug, OID_AUTO, __elfN(legacy_coredump), CTLFLAG_RW,
&elf_legacy_coredump, 0, "");
static Elf_Brandinfo *elf_brand_list[MAX_BRANDS];
#define trunc_page_ps(va, ps) ((va) & ~(ps - 1))
#define round_page_ps(va, ps) (((va) + (ps - 1)) & ~(ps - 1))
#define aligned(a, t) (trunc_page_ps((u_long)(a), sizeof(t)) == (u_long)(a))
int
__elfN(insert_brand_entry)(Elf_Brandinfo *entry)
{
int i;
for (i = 0; i < MAX_BRANDS; i++) {
if (elf_brand_list[i] == NULL) {
elf_brand_list[i] = entry;
break;
}
}
if (i == MAX_BRANDS)
return (-1);
return (0);
}
int
__elfN(remove_brand_entry)(Elf_Brandinfo *entry)
{
int i;
for (i = 0; i < MAX_BRANDS; i++) {
if (elf_brand_list[i] == entry) {
elf_brand_list[i] = NULL;
break;
}
}
if (i == MAX_BRANDS)
return (-1);
return (0);
}
int
__elfN(brand_inuse)(Elf_Brandinfo *entry)
{
struct proc *p;
int rval = FALSE;
sx_slock(&allproc_lock);
FOREACH_PROC_IN_SYSTEM(p) {
if (p->p_sysent == entry->sysvec) {
rval = TRUE;
break;
}
}
sx_sunlock(&allproc_lock);
return (rval);
}
static Elf_Brandinfo *
__elfN(get_brandinfo)(const Elf_Ehdr *hdr, const char *interp)
{
Elf_Brandinfo *bi;
int i;
/*
* We support three types of branding -- (1) the ELF EI_OSABI field
* that SCO added to the ELF spec, (2) FreeBSD 3.x's traditional string
* branding w/in the ELF header, and (3) path of the `interp_path'
* field. We should also look for an ".note.ABI-tag" ELF section now
* in all Linux ELF binaries, FreeBSD 4.1+, and some NetBSD ones.
*/
/* If the executable has a brand, search for it in the brand list. */
for (i = 0; i < MAX_BRANDS; i++) {
bi = elf_brand_list[i];
if (bi != NULL && hdr->e_machine == bi->machine &&
(hdr->e_ident[EI_OSABI] == bi->brand ||
strncmp((const char *)&hdr->e_ident[OLD_EI_BRAND],
bi->compat_3_brand, strlen(bi->compat_3_brand)) == 0))
return (bi);
}
/* Lacking a known brand, search for a recognized interpreter. */
if (interp != NULL) {
for (i = 0; i < MAX_BRANDS; i++) {
bi = elf_brand_list[i];
if (bi != NULL && hdr->e_machine == bi->machine &&
strcmp(interp, bi->interp_path) == 0)
return (bi);
}
}
/* Lacking a recognized interpreter, try the default brand */
for (i = 0; i < MAX_BRANDS; i++) {
bi = elf_brand_list[i];
if (bi != NULL && hdr->e_machine == bi->machine &&
__elfN(fallback_brand) == bi->brand)
return (bi);
}
return (NULL);
}
static int
__elfN(check_header)(const Elf_Ehdr *hdr)
{
Elf_Brandinfo *bi;
int i;
if (!IS_ELF(*hdr) ||
hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS ||
hdr->e_ident[EI_DATA] != ELF_TARG_DATA ||
hdr->e_ident[EI_VERSION] != EV_CURRENT ||
hdr->e_phentsize != sizeof(Elf_Phdr) ||
hdr->e_version != ELF_TARG_VER)
return (ENOEXEC);
/*
* Make sure we have at least one brand for this machine.
*/
for (i = 0; i < MAX_BRANDS; i++) {
bi = elf_brand_list[i];
if (bi != NULL && bi->machine == hdr->e_machine)
break;
}
if (i == MAX_BRANDS)
return (ENOEXEC);
return (0);
}
static int
__elfN(map_partial)(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
vm_offset_t start, vm_offset_t end, vm_prot_t prot)
{
struct sf_buf *sf;
int error;
vm_offset_t off;
/*
* Create the page if it doesn't exist yet. Ignore errors.
*/
vm_map_lock(map);
vm_map_insert(map, NULL, 0, trunc_page(start), round_page(end),
VM_PROT_ALL, VM_PROT_ALL, 0);
vm_map_unlock(map);
/*
* Find the page from the underlying object.
*/
if (object) {
sf = vm_imgact_map_page(object, offset);
if (sf == NULL)
return (KERN_FAILURE);
off = offset - trunc_page(offset);
error = copyout((caddr_t)sf_buf_kva(sf) + off, (caddr_t)start,
end - start);
vm_imgact_unmap_page(sf);
if (error) {
return (KERN_FAILURE);
}
}
return (KERN_SUCCESS);
}
static int
__elfN(map_insert)(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
vm_offset_t start, vm_offset_t end, vm_prot_t prot, int cow)
{
struct sf_buf *sf;
vm_offset_t off;
vm_size_t sz;
int error, rv;
if (start != trunc_page(start)) {
rv = __elfN(map_partial)(map, object, offset, start,
round_page(start), prot);
if (rv)
return (rv);
offset += round_page(start) - start;
start = round_page(start);
}
if (end != round_page(end)) {
rv = __elfN(map_partial)(map, object, offset +
trunc_page(end) - start, trunc_page(end), end, prot);
if (rv)
return (rv);
end = trunc_page(end);
}
if (end > start) {
if (offset & PAGE_MASK) {
/*
* The mapping is not page aligned. This means we have
* to copy the data. Sigh.
*/
rv = vm_map_find(map, NULL, 0, &start, end - start,
FALSE, prot | VM_PROT_WRITE, VM_PROT_ALL, 0);
if (rv)
return (rv);
if (object == NULL)
return (KERN_SUCCESS);
for (; start < end; start += sz) {
sf = vm_imgact_map_page(object, offset);
if (sf == NULL)
return (KERN_FAILURE);
off = offset - trunc_page(offset);
sz = end - start;
if (sz > PAGE_SIZE - off)
sz = PAGE_SIZE - off;
error = copyout((caddr_t)sf_buf_kva(sf) + off,
(caddr_t)start, sz);
vm_imgact_unmap_page(sf);
if (error) {
return (KERN_FAILURE);
}
offset += sz;
}
rv = KERN_SUCCESS;
} else {
vm_object_reference(object);
vm_map_lock(map);
rv = vm_map_insert(map, object, offset, start, end,
prot, VM_PROT_ALL, cow);
vm_map_unlock(map);
if (rv != KERN_SUCCESS)
vm_object_deallocate(object);
}
return (rv);
} else {
return (KERN_SUCCESS);
}
}
static int
__elfN(load_section)(struct vmspace *vmspace,
vm_object_t object, vm_offset_t offset,
caddr_t vmaddr, size_t memsz, size_t filsz, vm_prot_t prot,
size_t pagesize)
{
struct sf_buf *sf;
size_t map_len;
vm_offset_t map_addr;
int error, rv, cow;
size_t copy_len;
vm_offset_t file_addr;
/*
* It's necessary to fail if the filsz + offset taken from the
* header is greater than the actual file pager object's size.
* If we were to allow this, then the vm_map_find() below would
* walk right off the end of the file object and into the ether.
*
* While I'm here, might as well check for something else that
* is invalid: filsz cannot be greater than memsz.
*/
if ((off_t)filsz + offset > object->un_pager.vnp.vnp_size ||
filsz > memsz) {
uprintf("elf_load_section: truncated ELF file\n");
return (ENOEXEC);
}
map_addr = trunc_page_ps((vm_offset_t)vmaddr, pagesize);
file_addr = trunc_page_ps(offset, pagesize);
/*
* We have two choices. We can either clear the data in the last page
* of an oversized mapping, or we can start the anon mapping a page
* early and copy the initialized data into that first page. We
* choose the second..
*/
if (memsz > filsz)
map_len = trunc_page_ps(offset + filsz, pagesize) - file_addr;
else
map_len = round_page_ps(offset + filsz, pagesize) - file_addr;
if (map_len != 0) {
/* cow flags: don't dump readonly sections in core */
cow = MAP_COPY_ON_WRITE | MAP_PREFAULT |
(prot & VM_PROT_WRITE ? 0 : MAP_DISABLE_COREDUMP);
rv = __elfN(map_insert)(&vmspace->vm_map,
object,
file_addr, /* file offset */
map_addr, /* virtual start */
map_addr + map_len,/* virtual end */
prot,
cow);
if (rv != KERN_SUCCESS)
return (EINVAL);
/* we can stop now if we've covered it all */
if (memsz == filsz) {
return (0);
}
}
/*
* We have to get the remaining bit of the file into the first part
* of the oversized map segment. This is normally because the .data
* segment in the file is extended to provide bss. It's a neat idea
* to try and save a page, but it's a pain in the behind to implement.
*/
copy_len = (offset + filsz) - trunc_page_ps(offset + filsz, pagesize);
map_addr = trunc_page_ps((vm_offset_t)vmaddr + filsz, pagesize);
map_len = round_page_ps((vm_offset_t)vmaddr + memsz, pagesize) -
map_addr;
/* This had damn well better be true! */
if (map_len != 0) {
rv = __elfN(map_insert)(&vmspace->vm_map, NULL, 0, map_addr,
map_addr + map_len, VM_PROT_ALL, 0);
if (rv != KERN_SUCCESS) {
return (EINVAL);
}
}
if (copy_len != 0) {
vm_offset_t off;
sf = vm_imgact_map_page(object, offset + filsz);
if (sf == NULL)
return (EIO);
/* send the page fragment to user space */
off = trunc_page_ps(offset + filsz, pagesize) -
trunc_page(offset + filsz);
error = copyout((caddr_t)sf_buf_kva(sf) + off,
(caddr_t)map_addr, copy_len);
vm_imgact_unmap_page(sf);
if (error) {
return (error);
}
}
/*
* set it to the specified protection.
* XXX had better undo the damage from pasting over the cracks here!
*/
vm_map_protect(&vmspace->vm_map, trunc_page(map_addr),
round_page(map_addr + map_len), prot, FALSE);
return (0);
}
/*
* Load the file "file" into memory. It may be either a shared object
* or an executable.
*
* The "addr" reference parameter is in/out. On entry, it specifies
* the address where a shared object should be loaded. If the file is
* an executable, this value is ignored. On exit, "addr" specifies
* where the file was actually loaded.
*
* The "entry" reference parameter is out only. On exit, it specifies
* the entry point for the loaded file.
*/
static int
__elfN(load_file)(struct proc *p, const char *file, u_long *addr,
u_long *entry, size_t pagesize)
{
struct {
struct nameidata nd;
struct vattr attr;
struct image_params image_params;
} *tempdata;
const Elf_Ehdr *hdr = NULL;
const Elf_Phdr *phdr = NULL;
struct nameidata *nd;
struct vmspace *vmspace = p->p_vmspace;
struct vattr *attr;
struct image_params *imgp;
vm_prot_t prot;
u_long rbase;
u_long base_addr = 0;
int vfslocked, error, i, numsegs;
tempdata = malloc(sizeof(*tempdata), M_TEMP, M_WAITOK);
nd = &tempdata->nd;
attr = &tempdata->attr;
imgp = &tempdata->image_params;
/*
* Initialize part of the common data
*/
imgp->proc = p;
imgp->attr = attr;
imgp->firstpage = NULL;
imgp->image_header = NULL;
imgp->object = NULL;
imgp->execlabel = NULL;
NDINIT(nd, LOOKUP, MPSAFE|LOCKLEAF|FOLLOW, UIO_SYSSPACE, file,
curthread);
vfslocked = 0;
if ((error = namei(nd)) != 0) {
nd->ni_vp = NULL;
goto fail;
}
vfslocked = NDHASGIANT(nd);
NDFREE(nd, NDF_ONLY_PNBUF);
imgp->vp = nd->ni_vp;
/*
* Check permissions, modes, uid, etc on the file, and "open" it.
*/
error = exec_check_permissions(imgp);
if (error)
goto fail;
error = exec_map_first_page(imgp);
if (error)
goto fail;
/*
* Also make certain that the interpreter stays the same, so set
* its VV_TEXT flag, too.
*/
nd->ni_vp->v_vflag |= VV_TEXT;
imgp->object = nd->ni_vp->v_object;
hdr = (const Elf_Ehdr *)imgp->image_header;
if ((error = __elfN(check_header)(hdr)) != 0)
goto fail;
if (hdr->e_type == ET_DYN)
rbase = *addr;
else if (hdr->e_type == ET_EXEC)
rbase = 0;
else {
error = ENOEXEC;
goto fail;
}
/* Only support headers that fit within first page for now */
/* (multiplication of two Elf_Half fields will not overflow) */
if ((hdr->e_phoff > PAGE_SIZE) ||
(hdr->e_phentsize * hdr->e_phnum) > PAGE_SIZE - hdr->e_phoff) {
error = ENOEXEC;
goto fail;
}
phdr = (const Elf_Phdr *)(imgp->image_header + hdr->e_phoff);
if (!aligned(phdr, Elf_Addr)) {
error = ENOEXEC;
goto fail;
}
for (i = 0, numsegs = 0; i < hdr->e_phnum; i++) {
if (phdr[i].p_type == PT_LOAD) { /* Loadable segment */
prot = 0;
if (phdr[i].p_flags & PF_X)
prot |= VM_PROT_EXECUTE;
if (phdr[i].p_flags & PF_W)
prot |= VM_PROT_WRITE;
if (phdr[i].p_flags & PF_R)
prot |= VM_PROT_READ;
if ((error = __elfN(load_section)(vmspace,
imgp->object, phdr[i].p_offset,
(caddr_t)(uintptr_t)phdr[i].p_vaddr + rbase,
phdr[i].p_memsz, phdr[i].p_filesz, prot,
pagesize)) != 0)
goto fail;
/*
* Establish the base address if this is the
* first segment.
*/
if (numsegs == 0)
base_addr = trunc_page(phdr[i].p_vaddr +
rbase);
numsegs++;
}
}
*addr = base_addr;
*entry = (unsigned long)hdr->e_entry + rbase;
fail:
if (imgp->firstpage)
exec_unmap_first_page(imgp);
if (nd->ni_vp)
vput(nd->ni_vp);
VFS_UNLOCK_GIANT(vfslocked);
free(tempdata, M_TEMP);
return (error);
}
static const char FREEBSD_ABI_VENDOR[] = "FreeBSD";
static int
__CONCAT(exec_, __elfN(imgact))(struct image_params *imgp)
{
const Elf_Ehdr *hdr = (const Elf_Ehdr *)imgp->image_header;
const Elf_Phdr *phdr, *pnote = NULL;
Elf_Auxargs *elf_auxargs;
struct vmspace *vmspace;
vm_prot_t prot;
u_long text_size = 0, data_size = 0, total_size = 0;
u_long text_addr = 0, data_addr = 0;
u_long seg_size, seg_addr;
u_long addr, entry = 0, proghdr = 0;
int error = 0, i;
const char *interp = NULL, *newinterp = NULL;
Elf_Brandinfo *brand_info;
const Elf_Note *note, *note_end;
char *path;
const char *note_name;
struct sysentvec *sv;
/*
* Do we have a valid ELF header ?
*
* Only allow ET_EXEC & ET_DYN here, reject ET_DYN later
* if particular brand doesn't support it.
*/
if (__elfN(check_header)(hdr) != 0 ||
(hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN))
return (-1);
/*
* From here on down, we return an errno, not -1, as we've
* detected an ELF file.
*/
if ((hdr->e_phoff > PAGE_SIZE) ||
(hdr->e_phoff + hdr->e_phentsize * hdr->e_phnum) > PAGE_SIZE) {
/* Only support headers in first page for now */
return (ENOEXEC);
}
phdr = (const Elf_Phdr *)(imgp->image_header + hdr->e_phoff);
if (!aligned(phdr, Elf_Addr))
return (ENOEXEC);
for (i = 0; i < hdr->e_phnum; i++) {
if (phdr[i].p_type == PT_INTERP) {
/* Path to interpreter */
if (phdr[i].p_filesz > MAXPATHLEN ||
phdr[i].p_offset + phdr[i].p_filesz > PAGE_SIZE)
return (ENOEXEC);
interp = imgp->image_header + phdr[i].p_offset;
break;
}
}
brand_info = __elfN(get_brandinfo)(hdr, interp);
if (brand_info == NULL) {
uprintf("ELF binary type \"%u\" not known.\n",
hdr->e_ident[EI_OSABI]);
return (ENOEXEC);
}
if (hdr->e_type == ET_DYN &&
(brand_info->flags & BI_CAN_EXEC_DYN) == 0)
return (ENOEXEC);
sv = brand_info->sysvec;
if (interp != NULL && brand_info->interp_newpath != NULL)
newinterp = brand_info->interp_newpath;
/*
* Avoid a possible deadlock if the current address space is destroyed
* and that address space maps the locked vnode. In the common case,
* the locked vnode's v_usecount is decremented but remains greater
* than zero. Consequently, the vnode lock is not needed by vrele().
* However, in cases where the vnode lock is external, such as nullfs,
* v_usecount may become zero.
*/
VOP_UNLOCK(imgp->vp, 0);
error = exec_new_vmspace(imgp, sv);
imgp->proc->p_sysent = sv;
vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY);
if (error)
return (error);
vmspace = imgp->proc->p_vmspace;
for (i = 0; i < hdr->e_phnum; i++) {
switch (phdr[i].p_type) {
case PT_LOAD: /* Loadable segment */
prot = 0;
if (phdr[i].p_flags & PF_X)
prot |= VM_PROT_EXECUTE;
if (phdr[i].p_flags & PF_W)
prot |= VM_PROT_WRITE;
if (phdr[i].p_flags & PF_R)
prot |= VM_PROT_READ;
#if defined(__ia64__) && __ELF_WORD_SIZE == 32 && defined(IA32_ME_HARDER)
/*
* Some x86 binaries assume read == executable,
* notably the M3 runtime and therefore cvsup
*/
if (prot & VM_PROT_READ)
prot |= VM_PROT_EXECUTE;
#endif
if ((error = __elfN(load_section)(vmspace,
imgp->object, phdr[i].p_offset,
(caddr_t)(uintptr_t)phdr[i].p_vaddr,
phdr[i].p_memsz, phdr[i].p_filesz, prot,
sv->sv_pagesize)) != 0)
return (error);
/*
* If this segment contains the program headers,
* remember their virtual address for the AT_PHDR
* aux entry. Static binaries don't usually include
* a PT_PHDR entry.
*/
if (phdr[i].p_offset == 0 &&
hdr->e_phoff + hdr->e_phnum * hdr->e_phentsize
<= phdr[i].p_filesz)
proghdr = phdr[i].p_vaddr + hdr->e_phoff;
seg_addr = trunc_page(phdr[i].p_vaddr);
seg_size = round_page(phdr[i].p_memsz +
phdr[i].p_vaddr - seg_addr);
/*
* Is this .text or .data? We can't use
* VM_PROT_WRITE or VM_PROT_EXEC, it breaks the
* alpha terribly and possibly does other bad
* things so we stick to the old way of figuring
* it out: If the segment contains the program
* entry point, it's a text segment, otherwise it
* is a data segment.
*
* Note that obreak() assumes that data_addr +
* data_size == end of data load area, and the ELF
* file format expects segments to be sorted by
* address. If multiple data segments exist, the
* last one will be used.
*/
if (hdr->e_entry >= phdr[i].p_vaddr &&
hdr->e_entry < (phdr[i].p_vaddr +
phdr[i].p_memsz)) {
text_size = seg_size;
text_addr = seg_addr;
entry = (u_long)hdr->e_entry;
} else {
data_size = seg_size;
data_addr = seg_addr;
}
total_size += seg_size;
break;
case PT_PHDR: /* Program header table info */
proghdr = phdr[i].p_vaddr;
break;
case PT_NOTE:
pnote = &phdr[i];
break;
default:
break;
}
}
if (data_addr == 0 && data_size == 0) {
data_addr = text_addr;
data_size = text_size;
}
/*
* Check limits. It should be safe to check the
* limits after loading the segments since we do
* not actually fault in all the segments pages.
*/
PROC_LOCK(imgp->proc);
if (data_size > lim_cur(imgp->proc, RLIMIT_DATA) ||
text_size > maxtsiz ||
total_size > lim_cur(imgp->proc, RLIMIT_VMEM)) {
PROC_UNLOCK(imgp->proc);
return (ENOMEM);
}
vmspace->vm_tsize = text_size >> PAGE_SHIFT;
vmspace->vm_taddr = (caddr_t)(uintptr_t)text_addr;
vmspace->vm_dsize = data_size >> PAGE_SHIFT;
vmspace->vm_daddr = (caddr_t)(uintptr_t)data_addr;
/*
* We load the dynamic linker where a userland call
* to mmap(0, ...) would put it. The rationale behind this
* calculation is that it leaves room for the heap to grow to
* its maximum allowed size.
*/
addr = round_page((vm_offset_t)imgp->proc->p_vmspace->vm_daddr +
lim_max(imgp->proc, RLIMIT_DATA));
PROC_UNLOCK(imgp->proc);
imgp->entry_addr = entry;
if (interp != NULL) {
int have_interp = FALSE;
VOP_UNLOCK(imgp->vp, 0);
if (brand_info->emul_path != NULL &&
brand_info->emul_path[0] != '\0') {
path = malloc(MAXPATHLEN, M_TEMP, M_WAITOK);
snprintf(path, MAXPATHLEN, "%s%s",
brand_info->emul_path, interp);
error = __elfN(load_file)(imgp->proc, path, &addr,
&imgp->entry_addr, sv->sv_pagesize);
free(path, M_TEMP);
if (error == 0)
have_interp = TRUE;
}
if (!have_interp && newinterp != NULL) {
error = __elfN(load_file)(imgp->proc, newinterp, &addr,
&imgp->entry_addr, sv->sv_pagesize);
if (error == 0)
have_interp = TRUE;
}
if (!have_interp) {
error = __elfN(load_file)(imgp->proc, interp, &addr,
&imgp->entry_addr, sv->sv_pagesize);
}
vn_lock(imgp->vp, LK_EXCLUSIVE | LK_RETRY);
if (error != 0) {
uprintf("ELF interpreter %s not found\n", interp);
return (error);
}
} else
addr = 0;
/*
* Construct auxargs table (used by the fixup routine)
*/
elf_auxargs = malloc(sizeof(Elf_Auxargs), M_TEMP, M_WAITOK);
elf_auxargs->execfd = -1;
elf_auxargs->phdr = proghdr;
elf_auxargs->phent = hdr->e_phentsize;
elf_auxargs->phnum = hdr->e_phnum;
elf_auxargs->pagesz = PAGE_SIZE;
elf_auxargs->base = addr;
elf_auxargs->flags = 0;
elf_auxargs->entry = entry;
imgp->auxargs = elf_auxargs;
imgp->interpreted = 0;
/*
* Try to fetch the osreldate for FreeBSD binary from the ELF
* OSABI-note. Only the first page of the image is searched,
* the same as for headers.
*/
if (pnote != NULL && pnote->p_offset < PAGE_SIZE &&
pnote->p_offset + pnote->p_filesz < PAGE_SIZE ) {
note = (const Elf_Note *)(imgp->image_header + pnote->p_offset);
if (!aligned(note, Elf32_Addr)) {
free(imgp->auxargs, M_TEMP);
imgp->auxargs = NULL;
return (ENOEXEC);
}
note_end = (const Elf_Note *)(imgp->image_header + pnote->p_offset +
pnote->p_filesz);
while (note < note_end) {
if (note->n_namesz == sizeof(FREEBSD_ABI_VENDOR) &&
note->n_descsz == sizeof(int32_t) &&
note->n_type == 1 /* ABI_NOTETYPE */) {
note_name = (const char *)(note + 1);
if (strncmp(FREEBSD_ABI_VENDOR, note_name,
sizeof(FREEBSD_ABI_VENDOR)) == 0) {
imgp->proc->p_osrel = *(const int32_t *)
(note_name +
round_page_ps(sizeof(FREEBSD_ABI_VENDOR),
sizeof(Elf32_Addr)));
break;
}
}
note = (const Elf_Note *)((const char *)(note + 1) +
round_page_ps(note->n_namesz, sizeof(Elf32_Addr)) +
round_page_ps(note->n_descsz, sizeof(Elf32_Addr)));
}
}
return (error);
}
#define suword __CONCAT(suword, __ELF_WORD_SIZE)
int
__elfN(freebsd_fixup)(register_t **stack_base, struct image_params *imgp)
{
Elf_Auxargs *args = (Elf_Auxargs *)imgp->auxargs;
Elf_Addr *base;
Elf_Addr *pos;
base = (Elf_Addr *)*stack_base;
pos = base + (imgp->args->argc + imgp->args->envc + 2);
if (args->execfd != -1)
AUXARGS_ENTRY(pos, AT_EXECFD, args->execfd);
AUXARGS_ENTRY(pos, AT_PHDR, args->phdr);
AUXARGS_ENTRY(pos, AT_PHENT, args->phent);
AUXARGS_ENTRY(pos, AT_PHNUM, args->phnum);
AUXARGS_ENTRY(pos, AT_PAGESZ, args->pagesz);
AUXARGS_ENTRY(pos, AT_FLAGS, args->flags);
AUXARGS_ENTRY(pos, AT_ENTRY, args->entry);
AUXARGS_ENTRY(pos, AT_BASE, args->base);
AUXARGS_ENTRY(pos, AT_NULL, 0);
free(imgp->auxargs, M_TEMP);
imgp->auxargs = NULL;
base--;
suword(base, (long)imgp->args->argc);
*stack_base = (register_t *)base;
return (0);
}
/*
* Code for generating ELF core dumps.
*/
typedef void (*segment_callback)(vm_map_entry_t, void *);
/* Closure for cb_put_phdr(). */
struct phdr_closure {
Elf_Phdr *phdr; /* Program header to fill in */
Elf_Off offset; /* Offset of segment in core file */
};
/* Closure for cb_size_segment(). */
struct sseg_closure {
int count; /* Count of writable segments. */
size_t size; /* Total size of all writable segments. */
};
static void cb_put_phdr(vm_map_entry_t, void *);
static void cb_size_segment(vm_map_entry_t, void *);
static void each_writable_segment(struct thread *, segment_callback, void *);
static int __elfN(corehdr)(struct thread *, struct vnode *, struct ucred *,
int, void *, size_t);
static void __elfN(puthdr)(struct thread *, void *, size_t *, int);
static void __elfN(putnote)(void *, size_t *, const char *, int,
const void *, size_t);
int
__elfN(coredump)(td, vp, limit)
struct thread *td;
struct vnode *vp;
off_t limit;
{
struct ucred *cred = td->td_ucred;
int error = 0;
struct sseg_closure seginfo;
void *hdr;
size_t hdrsize;
/* Size the program segments. */
seginfo.count = 0;
seginfo.size = 0;
each_writable_segment(td, cb_size_segment, &seginfo);
/*
* Calculate the size of the core file header area by making
* a dry run of generating it. Nothing is written, but the
* size is calculated.
*/
hdrsize = 0;
__elfN(puthdr)(td, (void *)NULL, &hdrsize, seginfo.count);
if (hdrsize + seginfo.size >= limit)
return (EFAULT);
/*
* Allocate memory for building the header, fill it up,
* and write it out.
*/
hdr = malloc(hdrsize, M_TEMP, M_WAITOK);
if (hdr == NULL) {
return (EINVAL);
}
error = __elfN(corehdr)(td, vp, cred, seginfo.count, hdr, hdrsize);
/* Write the contents of all of the writable segments. */
if (error == 0) {
Elf_Phdr *php;
off_t offset;
int i;
php = (Elf_Phdr *)((char *)hdr + sizeof(Elf_Ehdr)) + 1;
offset = hdrsize;
for (i = 0; i < seginfo.count; i++) {
error = vn_rdwr_inchunks(UIO_WRITE, vp,
(caddr_t)(uintptr_t)php->p_vaddr,
php->p_filesz, offset, UIO_USERSPACE,
IO_UNIT | IO_DIRECT, cred, NOCRED, NULL,
curthread);
if (error != 0)
break;
offset += php->p_filesz;
php++;
}
}
free(hdr, M_TEMP);
return (error);
}
/*
* A callback for each_writable_segment() to write out the segment's
* program header entry.
*/
static void
cb_put_phdr(entry, closure)
vm_map_entry_t entry;
void *closure;
{
struct phdr_closure *phc = (struct phdr_closure *)closure;
Elf_Phdr *phdr = phc->phdr;
phc->offset = round_page(phc->offset);
phdr->p_type = PT_LOAD;
phdr->p_offset = phc->offset;
phdr->p_vaddr = entry->start;
phdr->p_paddr = 0;
phdr->p_filesz = phdr->p_memsz = entry->end - entry->start;
phdr->p_align = PAGE_SIZE;
phdr->p_flags = 0;
if (entry->protection & VM_PROT_READ)
phdr->p_flags |= PF_R;
if (entry->protection & VM_PROT_WRITE)
phdr->p_flags |= PF_W;
if (entry->protection & VM_PROT_EXECUTE)
phdr->p_flags |= PF_X;
phc->offset += phdr->p_filesz;
phc->phdr++;
}
/*
* A callback for each_writable_segment() to gather information about
* the number of segments and their total size.
*/
static void
cb_size_segment(entry, closure)
vm_map_entry_t entry;
void *closure;
{
struct sseg_closure *ssc = (struct sseg_closure *)closure;
ssc->count++;
ssc->size += entry->end - entry->start;
}
/*
* For each writable segment in the process's memory map, call the given
* function with a pointer to the map entry and some arbitrary
* caller-supplied data.
*/
static void
each_writable_segment(td, func, closure)
struct thread *td;
segment_callback func;
void *closure;
{
struct proc *p = td->td_proc;
vm_map_t map = &p->p_vmspace->vm_map;
vm_map_entry_t entry;
vm_object_t backing_object, object;
boolean_t ignore_entry;
vm_map_lock_read(map);
for (entry = map->header.next; entry != &map->header;
entry = entry->next) {
/*
* Don't dump inaccessible mappings, deal with legacy
* coredump mode.
*
* Note that read-only segments related to the elf binary
* are marked MAP_ENTRY_NOCOREDUMP now so we no longer
* need to arbitrarily ignore such segments.
*/
if (elf_legacy_coredump) {
if ((entry->protection & VM_PROT_RW) != VM_PROT_RW)
continue;
} else {
if ((entry->protection & VM_PROT_ALL) == 0)
continue;
}
/*
* Dont include memory segment in the coredump if
* MAP_NOCORE is set in mmap(2) or MADV_NOCORE in
* madvise(2). Do not dump submaps (i.e. parts of the
* kernel map).
*/
if (entry->eflags & (MAP_ENTRY_NOCOREDUMP|MAP_ENTRY_IS_SUB_MAP))
continue;
if ((object = entry->object.vm_object) == NULL)
continue;
/* Ignore memory-mapped devices and such things. */
VM_OBJECT_LOCK(object);
while ((backing_object = object->backing_object) != NULL) {
VM_OBJECT_LOCK(backing_object);
VM_OBJECT_UNLOCK(object);
object = backing_object;
}
ignore_entry = object->type != OBJT_DEFAULT &&
object->type != OBJT_SWAP && object->type != OBJT_VNODE;
VM_OBJECT_UNLOCK(object);
if (ignore_entry)
continue;
(*func)(entry, closure);
}
vm_map_unlock_read(map);
}
/*
* Write the core file header to the file, including padding up to
* the page boundary.
*/
static int
__elfN(corehdr)(td, vp, cred, numsegs, hdr, hdrsize)
struct thread *td;
struct vnode *vp;
struct ucred *cred;
int numsegs;
size_t hdrsize;
void *hdr;
{
size_t off;
/* Fill in the header. */
bzero(hdr, hdrsize);
off = 0;
__elfN(puthdr)(td, hdr, &off, numsegs);
/* Write it to the core file. */
return (vn_rdwr_inchunks(UIO_WRITE, vp, hdr, hdrsize, (off_t)0,
UIO_SYSSPACE, IO_UNIT | IO_DIRECT, cred, NOCRED, NULL,
td));
}
#if defined(COMPAT_IA32) && __ELF_WORD_SIZE == 32
typedef struct prstatus32 elf_prstatus_t;
typedef struct prpsinfo32 elf_prpsinfo_t;
typedef struct fpreg32 elf_prfpregset_t;
typedef struct fpreg32 elf_fpregset_t;
typedef struct reg32 elf_gregset_t;
#else
typedef prstatus_t elf_prstatus_t;
typedef prpsinfo_t elf_prpsinfo_t;
typedef prfpregset_t elf_prfpregset_t;
typedef prfpregset_t elf_fpregset_t;
typedef gregset_t elf_gregset_t;
#endif
static void
__elfN(puthdr)(struct thread *td, void *dst, size_t *off, int numsegs)
{
struct {
elf_prstatus_t status;
elf_prfpregset_t fpregset;
elf_prpsinfo_t psinfo;
} *tempdata;
elf_prstatus_t *status;
elf_prfpregset_t *fpregset;
elf_prpsinfo_t *psinfo;
struct proc *p;
struct thread *thr;
size_t ehoff, noteoff, notesz, phoff;
p = td->td_proc;
ehoff = *off;
*off += sizeof(Elf_Ehdr);
phoff = *off;
*off += (numsegs + 1) * sizeof(Elf_Phdr);
noteoff = *off;
/*
* Don't allocate space for the notes if we're just calculating
* the size of the header. We also don't collect the data.
*/
if (dst != NULL) {
tempdata = malloc(sizeof(*tempdata), M_TEMP, M_ZERO|M_WAITOK);
status = &tempdata->status;
fpregset = &tempdata->fpregset;
psinfo = &tempdata->psinfo;
} else {
tempdata = NULL;
status = NULL;
fpregset = NULL;
psinfo = NULL;
}
if (dst != NULL) {
psinfo->pr_version = PRPSINFO_VERSION;
psinfo->pr_psinfosz = sizeof(elf_prpsinfo_t);
strlcpy(psinfo->pr_fname, p->p_comm, sizeof(psinfo->pr_fname));
/*
* XXX - We don't fill in the command line arguments properly
* yet.
*/
strlcpy(psinfo->pr_psargs, p->p_comm,
sizeof(psinfo->pr_psargs));
}
__elfN(putnote)(dst, off, "FreeBSD", NT_PRPSINFO, psinfo,
sizeof *psinfo);
/*
* To have the debugger select the right thread (LWP) as the initial
* thread, we dump the state of the thread passed to us in td first.
* This is the thread that causes the core dump and thus likely to
* be the right thread one wants to have selected in the debugger.
*/
thr = td;
while (thr != NULL) {
if (dst != NULL) {
status->pr_version = PRSTATUS_VERSION;
status->pr_statussz = sizeof(elf_prstatus_t);
status->pr_gregsetsz = sizeof(elf_gregset_t);
status->pr_fpregsetsz = sizeof(elf_fpregset_t);
status->pr_osreldate = osreldate;
status->pr_cursig = p->p_sig;
status->pr_pid = thr->td_tid;
#if defined(COMPAT_IA32) && __ELF_WORD_SIZE == 32
fill_regs32(thr, &status->pr_reg);
fill_fpregs32(thr, fpregset);
#else
fill_regs(thr, &status->pr_reg);
fill_fpregs(thr, fpregset);
#endif
}
__elfN(putnote)(dst, off, "FreeBSD", NT_PRSTATUS, status,
sizeof *status);
__elfN(putnote)(dst, off, "FreeBSD", NT_FPREGSET, fpregset,
sizeof *fpregset);
/*
* Allow for MD specific notes, as well as any MD
* specific preparations for writing MI notes.
*/
__elfN(dump_thread)(thr, dst, off);
thr = (thr == td) ? TAILQ_FIRST(&p->p_threads) :
TAILQ_NEXT(thr, td_plist);
if (thr == td)
thr = TAILQ_NEXT(thr, td_plist);
}
notesz = *off - noteoff;
if (dst != NULL)
free(tempdata, M_TEMP);
/* Align up to a page boundary for the program segments. */
*off = round_page(*off);
if (dst != NULL) {
Elf_Ehdr *ehdr;
Elf_Phdr *phdr;
struct phdr_closure phc;
/*
* Fill in the ELF header.
*/
ehdr = (Elf_Ehdr *)((char *)dst + ehoff);
ehdr->e_ident[EI_MAG0] = ELFMAG0;
ehdr->e_ident[EI_MAG1] = ELFMAG1;
ehdr->e_ident[EI_MAG2] = ELFMAG2;
ehdr->e_ident[EI_MAG3] = ELFMAG3;
ehdr->e_ident[EI_CLASS] = ELF_CLASS;
ehdr->e_ident[EI_DATA] = ELF_DATA;
ehdr->e_ident[EI_VERSION] = EV_CURRENT;
ehdr->e_ident[EI_OSABI] = ELFOSABI_FREEBSD;
ehdr->e_ident[EI_ABIVERSION] = 0;
ehdr->e_ident[EI_PAD] = 0;
ehdr->e_type = ET_CORE;
#if defined(COMPAT_IA32) && __ELF_WORD_SIZE == 32
ehdr->e_machine = EM_386;
#else
ehdr->e_machine = ELF_ARCH;
#endif
ehdr->e_version = EV_CURRENT;
ehdr->e_entry = 0;
ehdr->e_phoff = phoff;
ehdr->e_flags = 0;
ehdr->e_ehsize = sizeof(Elf_Ehdr);
ehdr->e_phentsize = sizeof(Elf_Phdr);
ehdr->e_phnum = numsegs + 1;
ehdr->e_shentsize = sizeof(Elf_Shdr);
ehdr->e_shnum = 0;
ehdr->e_shstrndx = SHN_UNDEF;
/*
* Fill in the program header entries.
*/
phdr = (Elf_Phdr *)((char *)dst + phoff);
/* The note segement. */
phdr->p_type = PT_NOTE;
phdr->p_offset = noteoff;
phdr->p_vaddr = 0;
phdr->p_paddr = 0;
phdr->p_filesz = notesz;
phdr->p_memsz = 0;
phdr->p_flags = 0;
phdr->p_align = 0;
phdr++;
/* All the writable segments from the program. */
phc.phdr = phdr;
phc.offset = *off;
each_writable_segment(td, cb_put_phdr, &phc);
}
}
static void
__elfN(putnote)(void *dst, size_t *off, const char *name, int type,
const void *desc, size_t descsz)
{
Elf_Note note;
note.n_namesz = strlen(name) + 1;
note.n_descsz = descsz;
note.n_type = type;
if (dst != NULL)
bcopy(&note, (char *)dst + *off, sizeof note);
*off += sizeof note;
if (dst != NULL)
bcopy(name, (char *)dst + *off, note.n_namesz);
*off += roundup2(note.n_namesz, sizeof(Elf_Size));
if (dst != NULL)
bcopy(desc, (char *)dst + *off, note.n_descsz);
*off += roundup2(note.n_descsz, sizeof(Elf_Size));
}
/*
* Tell kern_execve.c about it, with a little help from the linker.
*/
static struct execsw __elfN(execsw) = {
__CONCAT(exec_, __elfN(imgact)),
__XSTRING(__CONCAT(ELF, __ELF_WORD_SIZE))
};
EXEC_SET(__CONCAT(elf, __ELF_WORD_SIZE), __elfN(execsw));
Reference in New Issue View Git Blame Copy Permalink