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NetBSD/sys/kern/exec_elf.c

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/* $NetBSD: exec_elf.c,v 1.105 2023/08/17 06:58:26 rin Exp $ */
/*-
* Copyright (c) 1994, 2000, 2005, 2015, 2020 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Christos Zoulas and Maxime Villard.
*
* 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.
*
* 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_elf.c,v 1.105 2023/08/17 06:58:26 rin Exp $");
#ifdef _KERNEL_OPT
#include "opt_pax.h"
#endif /* _KERNEL_OPT */
#include <sys/param.h>
#include <sys/proc.h>
#include <sys/kmem.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 <sys/kauth.h>
#include <sys/bitops.h>
#include <sys/cpu.h>
#include <machine/reg.h>
#include <compat/common/compat_util.h>
#include <sys/pax.h>
#include <uvm/uvm_param.h>
#define elf_check_header ELFNAME(check_header)
#define elf_copyargs ELFNAME(copyargs)
#define elf_populate_auxv ELFNAME(populate_auxv)
#define elf_load_interp ELFNAME(load_interp)
#define elf_load_psection ELFNAME(load_psection)
#define exec_elf_makecmds ELFNAME2(exec,makecmds)
#define netbsd_elf_signature ELFNAME2(netbsd,signature)
#define netbsd_elf_note ELFNAME2(netbsd,note)
#define netbsd_elf_probe ELFNAME2(netbsd,probe)
#define coredump ELFNAMEEND(coredump)
#define elf_free_emul_arg ELFNAME(free_emul_arg)
static int
elf_load_interp(struct lwp *, struct exec_package *, char *,
struct exec_vmcmd_set *, u_long *, Elf_Addr *);
static int
elf_load_psection(struct exec_vmcmd_set *, struct vnode *, const Elf_Phdr *,
Elf_Addr *, u_long *, int);
int netbsd_elf_signature(struct lwp *, struct exec_package *, Elf_Ehdr *);
int netbsd_elf_note(struct exec_package *, const Elf_Nhdr *, const char *,
const char *);
int netbsd_elf_probe(struct lwp *, struct exec_package *, void *, char *,
vaddr_t *);
static void elf_free_emul_arg(void *);
#ifdef DEBUG_ELF
#define DPRINTF(a, ...) printf("%s: " a "\n", __func__, ##__VA_ARGS__)
#else
#define DPRINTF(a, ...)
#endif
/* 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))
static int
elf_placedynexec(struct exec_package *epp, Elf_Ehdr *eh, Elf_Phdr *ph)
{
Elf_Addr align, offset;
int i;
for (align = 1, i = 0; i < eh->e_phnum; i++)
if (ph[i].p_type == PT_LOAD && ph[i].p_align > align)
align = ph[i].p_align;
offset = (Elf_Addr)pax_aslr_exec_offset(epp, align);
if (offset < epp->ep_vm_minaddr)
offset = roundup(epp->ep_vm_minaddr, align);
if ((offset & (align - 1)) != 0) {
DPRINTF("bad offset=%#jx align=%#jx",
(uintmax_t)offset, (uintmax_t)align);
return EINVAL;
}
for (i = 0; i < eh->e_phnum; i++)
ph[i].p_vaddr += offset;
epp->ep_entryoffset = offset;
eh->e_entry += offset;
return 0;
}
int
elf_populate_auxv(struct lwp *l, struct exec_package *pack, char **stackp)
{
size_t len, vlen;
AuxInfo ai[ELF_AUX_ENTRIES], *a, *execname;
struct elf_args *ap;
char *path = l->l_proc->p_path;
int error;
execname = NULL;
a = ai;
memset(ai, 0, sizeof(ai));
/*
* Push extra arguments on the stack needed by dynamically
* linked binaries
*/
if ((ap = (struct elf_args *)pack->ep_emul_arg)) {
struct vattr *vap = pack->ep_vap;
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_STACKBASE;
a->a_v = l->l_proc->p_stackbase;
a++;
a->a_type = AT_EUID;
if (vap->va_mode & S_ISUID)
a->a_v = vap->va_uid;
else
a->a_v = kauth_cred_geteuid(l->l_cred);
a++;
a->a_type = AT_RUID;
a->a_v = kauth_cred_getuid(l->l_cred);
a++;
a->a_type = AT_EGID;
if (vap->va_mode & S_ISGID)
a->a_v = vap->va_gid;
else
a->a_v = kauth_cred_getegid(l->l_cred);
a++;
a->a_type = AT_RGID;
a->a_v = kauth_cred_getgid(l->l_cred);
a++;
/* "/" means fexecve(2) could not resolve the pathname */
if (path[0] == '/' && path[1] != '\0') {
execname = a;
a->a_type = AT_SUN_EXECNAME;
a++;
}
exec_free_emul_arg(pack);
}
a->a_type = AT_NULL;
a->a_v = 0;
a++;
vlen = (a - ai) * sizeof(ai[0]);
KASSERT(vlen <= sizeof(ai));
if (execname) {
execname->a_v = (uintptr_t)(*stackp + vlen);
len = strlen(path) + 1;
if ((error = copyout(path, (*stackp + vlen), len)) != 0)
return error;
len = ALIGN(len);
} else {
len = 0;
}
if ((error = copyout(ai, *stackp, vlen)) != 0)
return error;
*stackp += vlen + len;
return 0;
}
/*
* Copy arguments onto the stack in the normal way, but add some
* extra information in case of dynamic binding.
*/
int
elf_copyargs(struct lwp *l, struct exec_package *pack,
struct ps_strings *arginfo, char **stackp, void *argp)
{
int error;
if ((error = copyargs(l, pack, arginfo, stackp, argp)) != 0)
return error;
return elf_populate_auxv(l, pack, stackp);
}
/*
* elf_check_header():
*
* Check header for validity; return 0 if ok, ENOEXEC if error
*/
int
elf_check_header(Elf_Ehdr *eh)
{
if (memcmp(eh->e_ident, ELFMAG, SELFMAG) != 0 ||
eh->e_ident[EI_CLASS] != ELFCLASS) {
DPRINTF("bad magic e_ident[EI_MAG0,EI_MAG3] %#x%x%x%x, "
"e_ident[EI_CLASS] %#x", eh->e_ident[EI_MAG0],
eh->e_ident[EI_MAG1], eh->e_ident[EI_MAG2],
eh->e_ident[EI_MAG3], eh->e_ident[EI_CLASS]);
return ENOEXEC;
}
switch (eh->e_machine) {
ELFDEFNNAME(MACHDEP_ID_CASES)
default:
DPRINTF("bad machine %#x", eh->e_machine);
return ENOEXEC;
}
if (ELF_EHDR_FLAGS_OK(eh) == 0) {
DPRINTF("bad flags %#x", eh->e_flags);
return ENOEXEC;
}
if (eh->e_shnum > ELF_MAXSHNUM || eh->e_phnum > ELF_MAXPHNUM) {
DPRINTF("bad shnum/phnum %#x/%#x", eh->e_shnum, eh->e_phnum);
return ENOEXEC;
}
return 0;
}
/*
* elf_load_psection():
*
* Load a psection at the appropriate address
*/
static int
elf_load_psection(struct exec_vmcmd_set *vcset, struct vnode *vp,
const Elf_Phdr *ph, Elf_Addr *addr, u_long *size, int flags)
{
u_long msize, psize, rm, rf;
long diff, offset;
int vmprot = 0;
KASSERT(VOP_ISLOCKED(vp) != LK_NONE);
/*
* If the user specified an address, then we load there.
*/
if (*addr == ELFDEFNNAME(NO_ADDR))
*addr = ph->p_vaddr;
if (ph->p_align > 1) {
/*
* Make sure we are virtually aligned as we are supposed to be.
*/
diff = ph->p_vaddr - ELF_TRUNC(ph->p_vaddr, ph->p_align);
if (*addr - diff != ELF_TRUNC(*addr, ph->p_align)) {
DPRINTF("bad alignment %#jx != %#jx\n",
(uintptr_t)(*addr - diff),
(uintptr_t)ELF_TRUNC(*addr, ph->p_align));
return EINVAL;
}
/*
* But make sure to not map any pages before the start of the
* psection by limiting the difference to within a page.
*/
diff &= PAGE_MASK;
} else
diff = 0;
vmprot |= (ph->p_flags & PF_R) ? VM_PROT_READ : 0;
vmprot |= (ph->p_flags & PF_W) ? VM_PROT_WRITE : 0;
vmprot |= (ph->p_flags & PF_X) ? VM_PROT_EXECUTE : 0;
/*
* Adjust everything so it all starts on a page boundary.
*/
*addr -= diff;
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, vmprot, flags);
flags &= VMCMD_RELATIVE;
}
if (psize < *size) {
NEW_VMCMD2(vcset, vmcmd_map_readvn, *size - psize,
*addr + psize, vp, offset + psize, vmprot, flags);
}
/*
* Check if we need to extend the size of the segment (does
* bss extend page the next page boundary)?
*/
rm = round_page(*addr + msize);
rf = round_page(*addr + *size);
if (rm != rf) {
NEW_VMCMD2(vcset, vmcmd_map_zero, rm - rf, rf, NULLVP,
0, vmprot, flags & VMCMD_RELATIVE);
*size = msize;
}
return 0;
}
/*
* elf_load_interp():
*
* Load an interpreter pointed to by path.
*/
static int
elf_load_interp(struct lwp *l, struct exec_package *epp, char *path,
struct exec_vmcmd_set *vcset, u_long *entryoff, Elf_Addr *last)
{
int error, i;
struct vnode *vp;
Elf_Ehdr eh;
Elf_Phdr *ph = NULL;
const Elf_Phdr *base_ph;
const Elf_Phdr *last_ph;
u_long phsize;
Elf_Addr addr = *last;
struct proc *p;
bool use_topdown;
p = l->l_proc;
KASSERT(p->p_vmspace);
KASSERT(p->p_vmspace != proc0.p_vmspace);
#ifdef __USE_TOPDOWN_VM
use_topdown = epp->ep_flags & EXEC_TOPDOWN_VM;
#else
use_topdown = false;
#endif
/*
* 1. open file
* 2. read filehdr
* 3. map text, data, and bss out of it using VM_*
*/
vp = epp->ep_interp;
if (vp == NULL) {
error = emul_find_interp(l, epp, path);
if (error != 0)
return error;
vp = epp->ep_interp;
}
/* We'll tidy this ourselves - otherwise we have locking issues */
epp->ep_interp = NULL;
vn_lock(vp, LK_SHARED | LK_RETRY);
/*
* 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 bad;
}
if ((error = VOP_ACCESS(vp, VEXEC, l->l_cred)) != 0)
goto bad;
/*
* 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 bad;
}
if (vp->v_mount->mnt_flag & MNT_NOSUID)
epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID);
error = vn_marktext(vp);
if (error)
goto bad;
error = exec_read(l, vp, 0, &eh, sizeof(eh), IO_NODELOCKED);
if (error != 0)
goto bad;
if ((error = elf_check_header(&eh)) != 0)
goto bad;
if (eh.e_type != ET_DYN || eh.e_phnum == 0) {
DPRINTF("bad interpreter type %#x", eh.e_type);
error = ENOEXEC;
goto bad;
}
phsize = eh.e_phnum * sizeof(Elf_Phdr);
ph = kmem_alloc(phsize, KM_SLEEP);
error = exec_read(l, vp, eh.e_phoff, ph, phsize, IO_NODELOCKED);
if (error != 0)
goto bad;
#ifdef ELF_INTERP_NON_RELOCATABLE
/*
* Evil hack: Only MIPS should be non-relocatable, and the
* psections should have a high address (typically 0x5ffe0000).
* If it's now relocatable, it should be linked at 0 and the
* psections should have zeros in the upper part of the address.
* Otherwise, force the load at the linked address.
*/
if (*last == ELF_LINK_ADDR && (ph->p_vaddr & 0xffff0000) == 0)
*last = ELFDEFNNAME(NO_ADDR);
#endif
/*
* 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 (*last == ELFDEFNNAME(NO_ADDR)) {
u_long limit = 0;
/*
* Find the start and ending addresses of the psections to
* be loaded. This will give us the size.
*/
for (i = 0, base_ph = NULL; i < eh.e_phnum; i++) {
if (ph[i].p_type == PT_LOAD) {
u_long psize = ph[i].p_vaddr + ph[i].p_memsz;
if (base_ph == NULL)
base_ph = &ph[i];
if (psize > limit)
limit = psize;
}
}
if (base_ph == NULL) {
DPRINTF("no interpreter loadable sections");
error = ENOEXEC;
goto bad;
}
/*
* Now compute the size and load address.
*/
addr = (*epp->ep_esch->es_emul->e_vm_default_addr)(p,
epp->ep_daddr,
round_page(limit) - trunc_page(base_ph->p_vaddr),
use_topdown);
addr += (Elf_Addr)pax_aslr_rtld_offset(epp, base_ph->p_align,
use_topdown);
} else {
addr = *last; /* may be ELF_LINK_ADDR */
}
/*
* Load all the necessary sections
*/
for (i = 0, base_ph = NULL, last_ph = NULL; i < eh.e_phnum; i++) {
switch (ph[i].p_type) {
case PT_LOAD: {
u_long size;
int flags;
if (base_ph == NULL) {
/*
* First encountered psection is always the
* base psection. Make sure it's aligned
* properly (align down for topdown and align
* upwards for not topdown).
*/
base_ph = &ph[i];
flags = VMCMD_BASE;
if (addr == ELF_LINK_ADDR)
addr = ph[i].p_vaddr;
if (use_topdown)
addr = ELF_TRUNC(addr, ph[i].p_align);
else
addr = ELF_ROUND(addr, ph[i].p_align);
} else {
u_long limit = round_page(last_ph->p_vaddr
+ last_ph->p_memsz);
u_long base = trunc_page(ph[i].p_vaddr);
/*
* If there is a gap in between the psections,
* map it as inaccessible so nothing else
* mmap'ed will be placed there.
*/
if (limit != base) {
NEW_VMCMD2(vcset, vmcmd_map_zero,
base - limit,
limit - base_ph->p_vaddr, NULLVP,
0, VM_PROT_NONE, VMCMD_RELATIVE);
}
addr = ph[i].p_vaddr - base_ph->p_vaddr;
flags = VMCMD_RELATIVE;
}
last_ph = &ph[i];
if ((error = elf_load_psection(vcset, vp, &ph[i], &addr,
&size, flags)) != 0)
goto bad;
/*
* If entry is within this psection then this
* must contain the .text section. *entryoff is
* relative to the base psection.
*/
if (eh.e_entry >= ph[i].p_vaddr &&
eh.e_entry < (ph[i].p_vaddr + size)) {
*entryoff = eh.e_entry - base_ph->p_vaddr;
}
addr += size;
break;
}
default:
break;
}
}
kmem_free(ph, phsize);
/*
* This value is ignored if TOPDOWN.
*/
*last = addr;
vput(vp);
return 0;
bad:
if (ph != NULL)
kmem_free(ph, phsize);
vput(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
exec_elf_makecmds(struct lwp *l, struct exec_package *epp)
{
Elf_Ehdr *eh = epp->ep_hdr;
Elf_Phdr *ph, *pp;
Elf_Addr phdr = 0, computed_phdr = 0, pos = 0, end_text = 0;
int error, i;
char *interp = NULL;
u_long phsize;
struct elf_args *ap;
bool is_dyn = false;
if (epp->ep_hdrvalid < sizeof(Elf_Ehdr)) {
DPRINTF("small header %#x", epp->ep_hdrvalid);
return ENOEXEC;
}
if ((error = elf_check_header(eh)) != 0)
return error;
if (eh->e_type == ET_DYN)
/* PIE, and some libs have an entry point */
is_dyn = true;
else if (eh->e_type != ET_EXEC) {
DPRINTF("bad type %#x", eh->e_type);
return ENOEXEC;
}
if (eh->e_phnum == 0) {
DPRINTF("no program headers");
return ENOEXEC;
}
/* XXX only LK_EXCLUSIVE to match all others - allow spinning */
vn_lock(epp->ep_vp, LK_EXCLUSIVE | LK_RETRY);
error = vn_marktext(epp->ep_vp);
if (error) {
VOP_UNLOCK(epp->ep_vp);
return error;
}
/*
* Allocate space to hold all the program headers, and read them
* from the file
*/
phsize = eh->e_phnum * sizeof(Elf_Phdr);
ph = kmem_alloc(phsize, KM_SLEEP);
error = exec_read(l, epp->ep_vp, eh->e_phoff, ph, phsize,
IO_NODELOCKED);
if (error != 0) {
VOP_UNLOCK(epp->ep_vp);
goto bad;
}
epp->ep_taddr = epp->ep_tsize = ELFDEFNNAME(NO_ADDR);
epp->ep_daddr = epp->ep_dsize = ELFDEFNNAME(NO_ADDR);
for (i = 0; i < eh->e_phnum; i++) {
pp = &ph[i];
if (pp->p_type == PT_INTERP) {
if (pp->p_filesz < 2 || pp->p_filesz > MAXPATHLEN) {
DPRINTF("bad interpreter namelen %#jx",
(uintmax_t)pp->p_filesz);
error = ENOEXEC;
VOP_UNLOCK(epp->ep_vp);
goto bad;
}
interp = PNBUF_GET();
error = exec_read(l, epp->ep_vp, pp->p_offset, interp,
pp->p_filesz, IO_NODELOCKED);
if (error != 0) {
VOP_UNLOCK(epp->ep_vp);
goto bad;
}
/* Ensure interp is NUL-terminated and of the expected length */
if (strnlen(interp, pp->p_filesz) != pp->p_filesz - 1) {
DPRINTF("bad interpreter name");
error = ENOEXEC;
VOP_UNLOCK(epp->ep_vp);
goto bad;
}
break;
}
}
/*
* On the same architecture, we may be emulating different systems.
* See which one will accept this executable.
*
* 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>).
*/
pos = ELFDEFNNAME(NO_ADDR);
if (epp->ep_esch->u.elf_probe_func) {
vaddr_t startp = (vaddr_t)pos;
error = (*epp->ep_esch->u.elf_probe_func)(l, epp, eh, interp,
&startp);
if (error) {
VOP_UNLOCK(epp->ep_vp);
goto bad;
}
pos = (Elf_Addr)startp;
}
if (is_dyn && (error = elf_placedynexec(epp, eh, ph)) != 0) {
VOP_UNLOCK(epp->ep_vp);
goto bad;
}
/*
* Load all the necessary sections
*/
for (i = 0; i < eh->e_phnum; i++) {
Elf_Addr addr = ELFDEFNNAME(NO_ADDR);
u_long size = 0;
switch (ph[i].p_type) {
case PT_LOAD:
if ((error = elf_load_psection(&epp->ep_vmcmds,
epp->ep_vp, &ph[i], &addr, &size, VMCMD_FIXED))
!= 0) {
VOP_UNLOCK(epp->ep_vp);
goto bad;
}
/*
* Consider this as text segment, if it is executable.
* If there is more than one text segment, pick the
* largest.
*/
if (ph[i].p_flags & PF_X) {
if (epp->ep_taddr == ELFDEFNNAME(NO_ADDR) ||
size > epp->ep_tsize) {
epp->ep_taddr = addr;
epp->ep_tsize = size;
}
end_text = addr + size;
} else {
epp->ep_daddr = addr;
epp->ep_dsize = size;
}
if (ph[i].p_offset == 0) {
computed_phdr = ph[i].p_vaddr + eh->e_phoff;
}
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 = ph[i].p_vaddr;
break;
default:
/*
* Not fatal; we don't need to understand everything.
*/
break;
}
}
/* Now done with the vnode. */
VOP_UNLOCK(epp->ep_vp);
if (epp->ep_vmcmds.evs_used == 0) {
/* No VMCMD; there was no PT_LOAD section, or those
* sections were empty */
DPRINTF("no vmcommands");
error = ENOEXEC;
goto bad;
}
if (epp->ep_daddr == ELFDEFNNAME(NO_ADDR)) {
epp->ep_daddr = round_page(end_text);
epp->ep_dsize = 0;
}
/*
* Check if we found a dynamically linked binary and arrange to load
* its interpreter
*/
if (interp) {
u_int nused = epp->ep_vmcmds.evs_used;
u_long interp_offset = 0;
if ((error = elf_load_interp(l, epp, interp,
&epp->ep_vmcmds, &interp_offset, &pos)) != 0) {
goto bad;
}
if (epp->ep_vmcmds.evs_used == nused) {
/* elf_load_interp() has not set up any new VMCMD */
DPRINTF("no vmcommands for interpreter");
error = ENOEXEC;
goto bad;
}
ap = kmem_alloc(sizeof(*ap), KM_SLEEP);
ap->arg_interp = epp->ep_vmcmds.evs_cmds[nused].ev_addr;
epp->ep_entryoffset = interp_offset;
epp->ep_entry = ap->arg_interp + interp_offset;
PNBUF_PUT(interp);
interp = NULL;
} else {
epp->ep_entry = eh->e_entry;
if (epp->ep_flags & EXEC_FORCEAUX) {
ap = kmem_zalloc(sizeof(*ap), KM_SLEEP);
ap->arg_interp = (vaddr_t)NULL;
} else {
ap = NULL;
}
}
if (ap) {
ap->arg_phaddr = phdr ? phdr : computed_phdr;
ap->arg_phentsize = eh->e_phentsize;
ap->arg_phnum = eh->e_phnum;
ap->arg_entry = eh->e_entry;
epp->ep_emul_arg = ap;
epp->ep_emul_arg_free = elf_free_emul_arg;
}
#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
error = (*epp->ep_esch->es_setup_stack)(l, epp);
if (error)
goto bad;
kmem_free(ph, phsize);
return 0;
bad:
if (interp)
PNBUF_PUT(interp);
exec_free_emul_arg(epp);
kmem_free(ph, phsize);
kill_vmcmds(&epp->ep_vmcmds);
return error;
}
int
netbsd_elf_signature(struct lwp *l, struct exec_package *epp,
Elf_Ehdr *eh)
{
size_t i;
Elf_Phdr *ph;
size_t phsize;
char *nbuf;
int error;
int isnetbsd = 0;
epp->ep_pax_flags = 0;
if (eh->e_phnum > ELF_MAXPHNUM || eh->e_phnum == 0) {
DPRINTF("no signature %#x", eh->e_phnum);
return ENOEXEC;
}
phsize = eh->e_phnum * sizeof(Elf_Phdr);
ph = kmem_alloc(phsize, KM_SLEEP);
error = exec_read(l, epp->ep_vp, eh->e_phoff, ph, phsize,
IO_NODELOCKED);
if (error)
goto out;
nbuf = kmem_alloc(ELF_MAXNOTESIZE, KM_SLEEP);
for (i = 0; i < eh->e_phnum; i++) {
const char *nptr;
size_t nlen;
if (ph[i].p_type != PT_NOTE ||
ph[i].p_filesz > ELF_MAXNOTESIZE)
continue;
nlen = ph[i].p_filesz;
error = exec_read(l, epp->ep_vp, ph[i].p_offset, nbuf, nlen,
IO_NODELOCKED);
if (error)
continue;
nptr = nbuf;
while (nlen > 0) {
const Elf_Nhdr *np;
const char *ndata, *ndesc;
/* note header */
np = (const Elf_Nhdr *)nptr;
if (nlen < sizeof(*np)) {
break;
}
nptr += sizeof(*np);
nlen -= sizeof(*np);
/* note name */
ndata = nptr;
if (nlen < roundup(np->n_namesz, 4)) {
break;
}
nptr += roundup(np->n_namesz, 4);
nlen -= roundup(np->n_namesz, 4);
/* note description */
ndesc = nptr;
if (nlen < roundup(np->n_descsz, 4)) {
break;
}
nptr += roundup(np->n_descsz, 4);
nlen -= roundup(np->n_descsz, 4);
isnetbsd |= netbsd_elf_note(epp, np, ndata, ndesc);
}
}
kmem_free(nbuf, ELF_MAXNOTESIZE);
error = isnetbsd ? 0 : ENOEXEC;
#ifdef DEBUG_ELF
if (error)
DPRINTF("not netbsd");
#endif
out:
kmem_free(ph, phsize);
return error;
}
int
netbsd_elf_note(struct exec_package *epp,
const Elf_Nhdr *np, const char *ndata, const char *ndesc)
{
int isnetbsd = 0;
#ifdef DIAGNOSTIC
const char *badnote;
#define BADNOTE(n) badnote = (n)
#else
#define BADNOTE(n)
#endif
switch (np->n_type) {
case ELF_NOTE_TYPE_NETBSD_TAG:
/* It is us */
if (np->n_namesz == ELF_NOTE_NETBSD_NAMESZ &&
np->n_descsz == ELF_NOTE_NETBSD_DESCSZ &&
memcmp(ndata, ELF_NOTE_NETBSD_NAME,
ELF_NOTE_NETBSD_NAMESZ) == 0) {
memcpy(&epp->ep_osversion, ndesc,
ELF_NOTE_NETBSD_DESCSZ);
isnetbsd = 1;
break;
}
/*
* Ignore SuSE tags; SuSE's n_type is the same the
* NetBSD one.
*/
if (np->n_namesz == ELF_NOTE_SUSE_NAMESZ &&
memcmp(ndata, ELF_NOTE_SUSE_NAME,
ELF_NOTE_SUSE_NAMESZ) == 0)
break;
/*
* Ignore old GCC
*/
if (np->n_namesz == ELF_NOTE_OGCC_NAMESZ &&
memcmp(ndata, ELF_NOTE_OGCC_NAME,
ELF_NOTE_OGCC_NAMESZ) == 0)
break;
BADNOTE("NetBSD tag");
goto bad;
case ELF_NOTE_TYPE_PAX_TAG:
if (np->n_namesz == ELF_NOTE_PAX_NAMESZ &&
np->n_descsz == ELF_NOTE_PAX_DESCSZ &&
memcmp(ndata, ELF_NOTE_PAX_NAME,
ELF_NOTE_PAX_NAMESZ) == 0) {
uint32_t flags;
memcpy(&flags, ndesc, sizeof(flags));
/* Convert the flags and insert them into
* the exec package. */
pax_setup_elf_flags(epp, flags);
break;
}
BADNOTE("PaX tag");
goto bad;
case ELF_NOTE_TYPE_MARCH_TAG:
/* Copy the machine arch into the package. */
if (np->n_namesz == ELF_NOTE_MARCH_NAMESZ
&& memcmp(ndata, ELF_NOTE_MARCH_NAME,
ELF_NOTE_MARCH_NAMESZ) == 0) {
/* Do not truncate the buffer */
if (np->n_descsz > sizeof(epp->ep_machine_arch)) {
BADNOTE("description size limit");
goto bad;
}
/*
* Ensure ndesc is NUL-terminated and of the
* expected length.
*/
if (strnlen(ndesc, np->n_descsz) + 1 !=
np->n_descsz) {
BADNOTE("description size");
goto bad;
}
strlcpy(epp->ep_machine_arch, ndesc,
sizeof(epp->ep_machine_arch));
break;
}
BADNOTE("march tag");
goto bad;
case ELF_NOTE_TYPE_MCMODEL_TAG:
/* arch specific check for code model */
#ifdef ELF_MD_MCMODEL_CHECK
if (np->n_namesz == ELF_NOTE_MCMODEL_NAMESZ
&& memcmp(ndata, ELF_NOTE_MCMODEL_NAME,
ELF_NOTE_MCMODEL_NAMESZ) == 0) {
ELF_MD_MCMODEL_CHECK(epp, ndesc, np->n_descsz);
break;
}
BADNOTE("mcmodel tag");
goto bad;
#endif
break;
case ELF_NOTE_TYPE_SUSE_VERSION_TAG:
break;
case ELF_NOTE_TYPE_GO_BUILDID_TAG:
break;
case ELF_NOTE_TYPE_FDO_PACKAGING_METADATA:
break;
case ELF_NOTE_TYPE_NETBSD_EMUL_TAG:
/* Ancient NetBSD version tag */
break;
default:
BADNOTE("unknown tag");
bad:
#ifdef DIAGNOSTIC
/* Ignore GNU tags */
if (np->n_namesz == ELF_NOTE_GNU_NAMESZ &&
memcmp(ndata, ELF_NOTE_GNU_NAME,
ELF_NOTE_GNU_NAMESZ) == 0)
break;
int ns = (int)np->n_namesz;
printf("%s: Unknown elf note type %d (%s): "
"[namesz=%d, descsz=%d name=%-*.*s]\n",
epp->ep_kname, np->n_type, badnote, np->n_namesz,
np->n_descsz, ns, ns, ndata);
#endif
break;
}
return isnetbsd;
}
int
netbsd_elf_probe(struct lwp *l, struct exec_package *epp, void *eh, char *itp,
vaddr_t *pos)
{
int error;
if ((error = netbsd_elf_signature(l, epp, eh)) != 0)
return error;
#ifdef ELF_MD_PROBE_FUNC
if ((error = ELF_MD_PROBE_FUNC(l, epp, eh, itp, pos)) != 0)
return error;
#elif defined(ELF_INTERP_NON_RELOCATABLE)
*pos = ELF_LINK_ADDR;
#endif
epp->ep_flags |= EXEC_FORCEAUX;
return 0;
}
void
elf_free_emul_arg(void *arg)
{
struct elf_args *ap = arg;
KASSERT(ap != NULL);
kmem_free(ap, sizeof(*ap));
}
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