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HardenedBSD/sys/kern/imgact_elf.c
Dmitry Chagin cd899aad76 Fix KBI breakage by r190520 which affects older linux.ko binaries: 
1) Move the new field (brand_note) to the end of the Brandinfo structure.
2) Add a new flag BI_BRAND_NOTE that indicates that the brand_note pointer
   is valid.
3) Use the brand_note field if the flag BI_BRAND_NOTE is set and as old
   modules won't have the flag set, so the new field brand_note would be
   ignored.

Suggested by:	jhb
Reviewed by:	jhb
Approved by:	kib (mentor)
MFC after:	6 days
2009-04-05 09:27:19 +00:00

1398 lines
37 KiB
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/*-
* 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)(struct image_params *imgp,
const char *interp, int32_t *osrel);
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);
static boolean_t __elfN(check_note)(struct image_params *imgp,
Elf_Brandnote *checknote, int32_t *osrel);
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))
static const char FREEBSD_ABI_VENDOR[] = "FreeBSD";
Elf_Brandnote __elfN(freebsd_brandnote) = {
.hdr.n_namesz = sizeof(FREEBSD_ABI_VENDOR),
.hdr.n_descsz = sizeof(int32_t),
.hdr.n_type = 1,
.vendor = FREEBSD_ABI_VENDOR,
.flags = BN_CAN_FETCH_OSREL
};
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)(struct image_params *imgp, const char *interp,
int32_t *osrel)
{
const Elf_Ehdr *hdr = (const Elf_Ehdr *)imgp->image_header;
Elf_Brandinfo *bi;
boolean_t ret;
int i;
/*
* We support four 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, (3) path of the `interp_path'
* field, and (4) the ".note.ABI-tag" ELF section.
*/
/* Look for an ".note.ABI-tag" ELF section */
for (i = 0; i < MAX_BRANDS; i++) {
bi = elf_brand_list[i];
if (bi != NULL && hdr->e_machine == bi->machine &&
(bi->flags & BI_BRAND_NOTE) != 0) {
ret = __elfN(check_note)(imgp, bi->brand_note, osrel);
if (ret)
return (bi);
}
}
/* 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 int
__CONCAT(exec_, __elfN(imgact))(struct image_params *imgp)
{
const Elf_Ehdr *hdr = (const Elf_Ehdr *)imgp->image_header;
const Elf_Phdr *phdr;
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;
int32_t osrel = 0;
int error = 0, i;
const char *interp = NULL, *newinterp = NULL;
Elf_Brandinfo *brand_info;
char *path;
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)(imgp, interp, &osrel);
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;
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;
imgp->proc->p_osrel = osrel;
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);
if (imgp->execpathp != 0)
AUXARGS_ENTRY(pos, AT_EXECPATH, imgp->execpathp);
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));
}
/*
* Try to find the appropriate ABI-note section for checknote,
* fetch the osreldate for binary from the ELF OSABI-note. Only the
* first page of the image is searched, the same as for headers.
*/
static boolean_t
__elfN(check_note)(struct image_params *imgp, Elf_Brandnote *checknote,
int32_t *osrel)
{
const Elf_Note *note, *note0, *note_end;
const Elf_Phdr *phdr, *pnote;
const Elf_Ehdr *hdr;
const char *note_name;
int i;
pnote = NULL;
hdr = (const Elf_Ehdr *)imgp->image_header;
phdr = (const Elf_Phdr *)(imgp->image_header + hdr->e_phoff);
for (i = 0; i < hdr->e_phnum; i++) {
if (phdr[i].p_type == PT_NOTE) {
pnote = &phdr[i];
break;
}
}
if (pnote == NULL || pnote->p_offset >= PAGE_SIZE ||
pnote->p_offset + pnote->p_filesz >= PAGE_SIZE)
return (FALSE);
note = note0 = (const Elf_Note *)(imgp->image_header + pnote->p_offset);
note_end = (const Elf_Note *)(imgp->image_header +
pnote->p_offset + pnote->p_filesz);
for (i = 0; i < 100 && note >= note0 && note < note_end; i++) {
if (!aligned(note, Elf32_Addr))
return (FALSE);
if (note->n_namesz != checknote->hdr.n_namesz ||
note->n_descsz != checknote->hdr.n_descsz ||
note->n_type != checknote->hdr.n_type)
goto nextnote;
note_name = (const char *)(note + 1);
if (strncmp(checknote->vendor, note_name,
checknote->hdr.n_namesz) != 0)
goto nextnote;
/*
* Fetch the osreldate for binary
* from the ELF OSABI-note if necessary.
*/
if ((checknote->flags & BN_CAN_FETCH_OSREL) != 0 &&
osrel != NULL)
*osrel = *(const int32_t *) (note_name +
roundup2(checknote->hdr.n_namesz,
sizeof(Elf32_Addr)));
return (TRUE);
nextnote:
note = (const Elf_Note *)((const char *)(note + 1) +
roundup2(note->n_namesz, sizeof(Elf32_Addr)) +
roundup2(note->n_descsz, sizeof(Elf32_Addr)));
}
return (FALSE);
}
/*
* 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));
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