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NetBSD/sys/kern/exec_elf32.c

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/* $NetBSD: exec_elf32.c,v 1.76 2002/10/05 22:34:05 chs Exp $ */
/*-
* Copyright (c) 1994, 2000 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Christos Zoulas.
*
* 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.
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the NetBSD
* Foundation, Inc. and its contributors.
* 4. Neither the name of The NetBSD Foundation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``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 FOUNDATION OR CONTRIBUTORS
* 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.
*/
/*
* Copyright (c) 1996 Christopher G. Demetriou
* 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.
* 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>
__KERNEL_RCSID(1, "$NetBSD: exec_elf32.c,v 1.76 2002/10/05 22:34:05 chs Exp $");
/* If not included by exec_elf64.c, ELFSIZE won't be defined. */
#ifndef ELFSIZE
#define ELFSIZE 32
#endif
#include <sys/param.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/namei.h>
#include <sys/vnode.h>
#include <sys/exec.h>
#include <sys/exec_elf.h>
#include <sys/syscall.h>
#include <sys/signalvar.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <machine/cpu.h>
#include <machine/reg.h>
extern const struct emul emul_netbsd;
int ELFNAME(check_header)(Elf_Ehdr *, int);
int ELFNAME(load_file)(struct proc *, struct exec_package *, char *,
struct exec_vmcmd_set *, u_long *, struct elf_args *, Elf_Addr *);
void ELFNAME(load_psection)(struct exec_vmcmd_set *, struct vnode *,
const Elf_Phdr *, Elf_Addr *, u_long *, int *, int);
int ELFNAME2(netbsd,signature)(struct proc *, struct exec_package *,
Elf_Ehdr *);
int ELFNAME2(netbsd,probe)(struct proc *, struct exec_package *,
void *, char *, vaddr_t *);
/* round up and down to page boundaries. */
#define ELF_ROUND(a, b) (((a) + (b) - 1) & ~((b) - 1))
#define ELF_TRUNC(a, b) ((a) & ~((b) - 1))
/*
* Copy arguments onto the stack in the normal way, but add some
* extra information in case of dynamic binding.
*/
int
ELFNAME(copyargs)(struct proc *p, struct exec_package *pack,
struct ps_strings *arginfo, char **stackp, void *argp)
{
size_t len;
AuxInfo ai[ELF_AUX_ENTRIES], *a;
struct elf_args *ap;
int error;
if ((error = copyargs(p, pack, arginfo, stackp, argp)) != 0)
return error;
a = ai;
/*
* Push extra arguments on the stack needed by dynamically
* linked binaries
*/
if ((ap = (struct elf_args *)pack->ep_emul_arg)) {
a->a_type = AT_PHDR;
a->a_v = ap->arg_phaddr;
a++;
a->a_type = AT_PHENT;
a->a_v = ap->arg_phentsize;
a++;
a->a_type = AT_PHNUM;
a->a_v = ap->arg_phnum;
a++;
a->a_type = AT_PAGESZ;
a->a_v = PAGE_SIZE;
a++;
a->a_type = AT_BASE;
a->a_v = ap->arg_interp;
a++;
a->a_type = AT_FLAGS;
a->a_v = 0;
a++;
a->a_type = AT_ENTRY;
a->a_v = ap->arg_entry;
a++;
a->a_type = AT_EUID;
a->a_v = p->p_ucred->cr_uid;
a++;
a->a_type = AT_RUID;
a->a_v = p->p_cred->p_ruid;
a++;
a->a_type = AT_EGID;
a->a_v = p->p_ucred->cr_gid;
a++;
a->a_type = AT_RGID;
a->a_v = p->p_cred->p_rgid;
a++;
free(ap, M_TEMP);
pack->ep_emul_arg = NULL;
}
a->a_type = AT_NULL;
a->a_v = 0;
a++;
len = (a - ai) * sizeof(AuxInfo);
if ((error = copyout(ai, *stackp, len)) != 0)
return error;
*stackp += len;
return 0;
}
/*
* elf_check_header():
*
* Check header for validity; return 0 of ok ENOEXEC if error
*/
int
ELFNAME(check_header)(Elf_Ehdr *eh, int type)
{
if (memcmp(eh->e_ident, ELFMAG, SELFMAG) != 0 ||
eh->e_ident[EI_CLASS] != ELFCLASS)
return (ENOEXEC);
switch (eh->e_machine) {
ELFDEFNNAME(MACHDEP_ID_CASES)
default:
return (ENOEXEC);
}
if (ELF_EHDR_FLAGS_OK(eh) == 0)
return (ENOEXEC);
if (eh->e_type != type)
return (ENOEXEC);
if (eh->e_shnum > 512 ||
eh->e_phnum > 128)
return (ENOEXEC);
return (0);
}
/*
* elf_load_psection():
*
* Load a psection at the appropriate address
*/
void
ELFNAME(load_psection)(struct exec_vmcmd_set *vcset, struct vnode *vp,
const Elf_Phdr *ph, Elf_Addr *addr, u_long *size, int *prot, int flags)
{
u_long uaddr, msize, psize, rm, rf;
long diff, offset;
/*
* If the user specified an address, then we load there.
*/
if (*addr != ELFDEFNNAME(NO_ADDR)) {
if (ph->p_align > 1) {
*addr = ELF_TRUNC(*addr, ph->p_align);
uaddr = ELF_TRUNC(ph->p_vaddr, ph->p_align);
} else
uaddr = ph->p_vaddr;
diff = ph->p_vaddr - uaddr;
} else {
*addr = uaddr = ph->p_vaddr;
if (ph->p_align > 1)
*addr = ELF_TRUNC(uaddr, ph->p_align);
diff = uaddr - *addr;
}
*prot |= (ph->p_flags & PF_R) ? VM_PROT_READ : 0;
*prot |= (ph->p_flags & PF_W) ? VM_PROT_WRITE : 0;
*prot |= (ph->p_flags & PF_X) ? VM_PROT_EXECUTE : 0;
offset = ph->p_offset - diff;
*size = ph->p_filesz + diff;
msize = ph->p_memsz + diff;
if (ph->p_align >= PAGE_SIZE) {
if ((ph->p_flags & PF_W) != 0) {
/*
* Because the pagedvn pager can't handle zero fill
* of the last data page if it's not page aligned we
* map the last page readvn.
*/
psize = trunc_page(*size);
} else {
psize = round_page(*size);
}
} else {
psize = *size;
}
if (psize > 0) {
NEW_VMCMD2(vcset, ph->p_align < PAGE_SIZE ?
vmcmd_map_readvn : vmcmd_map_pagedvn, psize, *addr, vp,
offset, *prot, flags);
}
if (psize < *size) {
NEW_VMCMD2(vcset, vmcmd_map_readvn, *size - psize,
*addr + psize, vp, offset + psize, *prot,
psize > 0 ? flags & VMCMD_RELATIVE : flags);
}
/*
* Check if we need to extend the size of the segment
*/
rm = round_page(*addr + msize);
rf = round_page(*addr + *size);
if (rm != rf) {
NEW_VMCMD2(vcset, vmcmd_map_zero, rm - rf, rf, NULLVP,
0, *prot, flags & VMCMD_RELATIVE);
*size = msize;
}
}
/*
* elf_load_file():
*
* Load a file (interpreter/library) pointed to by path
* [stolen from coff_load_shlib()]. Made slightly generic
* so it might be used externally.
*/
int
ELFNAME(load_file)(struct proc *p, struct exec_package *epp, char *path,
struct exec_vmcmd_set *vcset, u_long *entry, struct elf_args *ap,
Elf_Addr *last)
{
int error, i;
struct nameidata nd;
struct vnode *vp;
struct vattr attr;
Elf_Ehdr eh;
Elf_Phdr *ph = NULL;
Elf_Phdr *base_ph = NULL;
u_long phsize;
char *bp = NULL;
Elf_Addr addr = *last;
bp = path;
/*
* 1. open file
* 2. read filehdr
* 3. map text, data, and bss out of it using VM_*
*/
NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, path, p);
if ((error = namei(&nd)) != 0)
return error;
vp = nd.ni_vp;
/*
* Similarly, if it's not marked as executable, or it's not a regular
* file, we don't allow it to be used.
*/
if (vp->v_type != VREG) {
error = EACCES;
goto badunlock;
}
if ((error = VOP_ACCESS(vp, VEXEC, p->p_ucred, p)) != 0)
goto badunlock;
/* get attributes */
if ((error = VOP_GETATTR(vp, &attr, p->p_ucred, p)) != 0)
goto badunlock;
/*
* Check mount point. Though we're not trying to exec this binary,
* we will be executing code from it, so if the mount point
* disallows execution or set-id-ness, we punt or kill the set-id.
*/
if (vp->v_mount->mnt_flag & MNT_NOEXEC) {
error = EACCES;
goto badunlock;
}
if (vp->v_mount->mnt_flag & MNT_NOSUID)
epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID);
#ifdef notyet /* XXX cgd 960926 */
XXX cgd 960926: (maybe) VOP_OPEN it (and VOP_CLOSE in copyargs?)
#endif
error = vn_marktext(vp);
if (error)
goto badunlock;
VOP_UNLOCK(vp, 0);
if ((error = exec_read_from(p, vp, 0, &eh, sizeof(eh))) != 0)
goto bad;
if ((error = ELFNAME(check_header)(&eh, ET_DYN)) != 0)
goto bad;
phsize = eh.e_phnum * sizeof(Elf_Phdr);
ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK);
if ((error = exec_read_from(p, vp, eh.e_phoff, ph, phsize)) != 0)
goto bad;
/*
* Load all the necessary sections
*/
for (i = 0; i < eh.e_phnum; i++) {
u_long size = 0;
int prot = 0;
int flags;
switch (ph[i].p_type) {
case PT_LOAD:
if (base_ph == NULL) {
addr = *last;
flags = VMCMD_BASE;
} else {
addr = ph[i].p_vaddr - base_ph->p_vaddr;
flags = VMCMD_RELATIVE;
}
ELFNAME(load_psection)(vcset, vp, &ph[i], &addr,
&size, &prot, flags);
/* If entry is within this section it must be text */
if (eh.e_entry >= ph[i].p_vaddr &&
eh.e_entry < (ph[i].p_vaddr + size)) {
*entry = addr + eh.e_entry - ph[i].p_vaddr;
ap->arg_interp = addr;
}
if (base_ph == NULL)
base_ph = &ph[i];
addr += size;
break;
case PT_DYNAMIC:
case PT_PHDR:
case PT_NOTE:
break;
default:
break;
}
}
free(ph, M_TEMP);
*last = addr;
vrele(vp);
return 0;
badunlock:
VOP_UNLOCK(vp, 0);
bad:
if (ph != NULL)
free(ph, M_TEMP);
#ifdef notyet /* XXX cgd 960926 */
(maybe) VOP_CLOSE it
#endif
vrele(vp);
return error;
}
/*
* exec_elf_makecmds(): Prepare an Elf binary's exec package
*
* First, set of the various offsets/lengths in the exec package.
*
* Then, mark the text image busy (so it can be demand paged) or error
* out if this is not possible. Finally, set up vmcmds for the
* text, data, bss, and stack segments.
*/
int
ELFNAME2(exec,makecmds)(struct proc *p, struct exec_package *epp)
{
Elf_Ehdr *eh = epp->ep_hdr;
Elf_Phdr *ph, *pp;
Elf_Addr phdr = 0, pos = 0;
int error, i, nload;
char *interp = NULL;
u_long phsize;
if (epp->ep_hdrvalid < sizeof(Elf_Ehdr))
return ENOEXEC;
/*
* XXX allow for executing shared objects. It seems silly
* but other ELF-based systems allow it as well.
*/
if (ELFNAME(check_header)(eh, ET_EXEC) != 0 &&
ELFNAME(check_header)(eh, ET_DYN) != 0)
return ENOEXEC;
error = vn_marktext(epp->ep_vp);
if (error)
return (error);
/*
* Allocate space to hold all the program headers, and read them
* from the file
*/
phsize = eh->e_phnum * sizeof(Elf_Phdr);
ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK);
if ((error = exec_read_from(p, epp->ep_vp, eh->e_phoff, ph, phsize)) !=
0)
goto bad;
epp->ep_taddr = epp->ep_tsize = ELFDEFNNAME(NO_ADDR);
epp->ep_daddr = epp->ep_dsize = ELFDEFNNAME(NO_ADDR);
MALLOC(interp, char *, MAXPATHLEN, M_TEMP, M_WAITOK);
interp[0] = '\0';
for (i = 0; i < eh->e_phnum; i++) {
pp = &ph[i];
if (pp->p_type == PT_INTERP) {
if (pp->p_filesz >= MAXPATHLEN)
goto bad;
if ((error = exec_read_from(p, epp->ep_vp,
pp->p_offset, interp, pp->p_filesz)) != 0)
goto bad;
break;
}
}
/*
* On the same architecture, we may be emulating different systems.
* See which one will accept this executable. This currently only
* applies to SVR4, and IBCS2 on the i386 and Linux on the i386
* and the Alpha.
*
* Probe functions would normally see if the interpreter (if any)
* exists. Emulation packages may possibly replace the interpreter in
* interp[] with a changed path (/emul/xxx/<path>).
*/
if (!epp->ep_esch->u.elf_probe_func) {
pos = ELFDEFNNAME(NO_ADDR);
} else {
vaddr_t startp = 0;
error = (*epp->ep_esch->u.elf_probe_func)(p, epp, eh, interp,
&startp);
pos = (Elf_Addr)startp;
if (error)
goto bad;
}
/*
* Load all the necessary sections
*/
for (i = nload = 0; i < eh->e_phnum; i++) {
Elf_Addr addr = ELFDEFNNAME(NO_ADDR);
u_long size = 0;
int prot = 0;
pp = &ph[i];
switch (ph[i].p_type) {
case PT_LOAD:
/*
* XXX
* Can handle only 2 sections: text and data
*/
if (nload++ == 2)
goto bad;
ELFNAME(load_psection)(&epp->ep_vmcmds, epp->ep_vp,
&ph[i], &addr, &size, &prot, 0);
/*
* Decide whether it's text or data by looking
* at the entry point.
*/
if (eh->e_entry >= addr &&
eh->e_entry < (addr + size)) {
epp->ep_taddr = addr;
epp->ep_tsize = size;
if (epp->ep_daddr == ELFDEFNNAME(NO_ADDR)) {
epp->ep_daddr = addr;
epp->ep_dsize = size;
}
} else {
epp->ep_daddr = addr;
epp->ep_dsize = size;
}
break;
case PT_SHLIB:
/* SCO has these sections. */
case PT_INTERP:
/* Already did this one. */
case PT_DYNAMIC:
case PT_NOTE:
break;
case PT_PHDR:
/* Note address of program headers (in text segment) */
phdr = pp->p_vaddr;
break;
default:
/*
* Not fatal; we don't need to understand everything.
*/
break;
}
}
/* this breaks on, e.g., OpenBSD-compatible mips shared binaries. */
#ifndef ELF_INTERP_NON_RELOCATABLE
/*
* If no position to load the interpreter was set by a probe
* function, pick the same address that a non-fixed mmap(0, ..)
* would (i.e. something safely out of the way).
*/
if (pos == ELFDEFNNAME(NO_ADDR))
pos = round_page(epp->ep_daddr + MAXDSIZ);
#endif /* !ELF_INTERP_NON_RELOCATABLE */
/*
* Check if we found a dynamically linked binary and arrange to load
* it's interpreter
*/
if (interp[0]) {
struct elf_args *ap;
MALLOC(ap, struct elf_args *, sizeof(struct elf_args),
M_TEMP, M_WAITOK);
if ((error = ELFNAME(load_file)(p, epp, interp,
&epp->ep_vmcmds, &epp->ep_entry, ap, &pos)) != 0) {
FREE(ap, M_TEMP);
goto bad;
}
ap->arg_phaddr = phdr;
ap->arg_phentsize = eh->e_phentsize;
ap->arg_phnum = eh->e_phnum;
ap->arg_entry = eh->e_entry;
epp->ep_emul_arg = ap;
} else
epp->ep_entry = eh->e_entry;
#ifdef ELF_MAP_PAGE_ZERO
/* Dell SVR4 maps page zero, yeuch! */
NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, PAGE_SIZE, 0,
epp->ep_vp, 0, VM_PROT_READ);
#endif
FREE(interp, M_TEMP);
free(ph, M_TEMP);
return exec_elf_setup_stack(p, epp);
bad:
if (interp)
FREE(interp, M_TEMP);
free(ph, M_TEMP);
kill_vmcmds(&epp->ep_vmcmds);
return ENOEXEC;
}
int
ELFNAME2(netbsd,signature)(struct proc *p, struct exec_package *epp,
Elf_Ehdr *eh)
{
size_t i;
Elf_Phdr *ph;
size_t phsize;
int error;
phsize = eh->e_phnum * sizeof(Elf_Phdr);
ph = (Elf_Phdr *)malloc(phsize, M_TEMP, M_WAITOK);
error = exec_read_from(p, epp->ep_vp, eh->e_phoff, ph, phsize);
if (error)
goto out;
for (i = 0; i < eh->e_phnum; i++) {
Elf_Phdr *ephp = &ph[i];
Elf_Nhdr *np;
if (ephp->p_type != PT_NOTE ||
ephp->p_filesz > 1024 ||
ephp->p_filesz < sizeof(Elf_Nhdr) + ELF_NOTE_NETBSD_NAMESZ)
continue;
np = (Elf_Nhdr *)malloc(ephp->p_filesz, M_TEMP, M_WAITOK);
error = exec_read_from(p, epp->ep_vp, ephp->p_offset, np,
ephp->p_filesz);
if (error)
goto next;
if (np->n_type != ELF_NOTE_TYPE_NETBSD_TAG ||
np->n_namesz != ELF_NOTE_NETBSD_NAMESZ ||
np->n_descsz != ELF_NOTE_NETBSD_DESCSZ ||
memcmp((caddr_t)(np + 1), ELF_NOTE_NETBSD_NAME,
ELF_NOTE_NETBSD_NAMESZ))
goto next;
error = 0;
free(np, M_TEMP);
goto out;
next:
free(np, M_TEMP);
continue;
}
error = ENOEXEC;
out:
free(ph, M_TEMP);
return (error);
}
int
ELFNAME2(netbsd,probe)(struct proc *p, struct exec_package *epp,
void *eh, char *itp, vaddr_t *pos)
{
int error;
if ((error = ELFNAME2(netbsd,signature)(p, epp, eh)) != 0)
return error;
*pos = ELFDEFNNAME(NO_ADDR);
return 0;
}
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