445 lines
12 KiB
C
445 lines
12 KiB
C
/* $OpenBSD: exec_subr.c,v 1.67 2024/04/02 08:39:16 deraadt Exp $ */
|
|
/* $NetBSD: exec_subr.c,v 1.9 1994/12/04 03:10:42 mycroft Exp $ */
|
|
|
|
/*
|
|
* Copyright (c) 1993, 1994 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. All advertising materials mentioning features or use of this software
|
|
* must display the following acknowledgement:
|
|
* This product includes software developed by Christopher G. Demetriou.
|
|
* 4. 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/param.h>
|
|
#include <sys/systm.h>
|
|
#include <sys/proc.h>
|
|
#include <sys/malloc.h>
|
|
#include <sys/vnode.h>
|
|
#include <sys/exec.h>
|
|
#include <sys/mman.h>
|
|
#include <sys/resourcevar.h>
|
|
|
|
#include <uvm/uvm_extern.h>
|
|
|
|
#ifdef DEBUG
|
|
/*
|
|
* new_vmcmd():
|
|
* create a new vmcmd structure and fill in its fields based
|
|
* on function call arguments. make sure objects ref'd by
|
|
* the vmcmd are 'held'.
|
|
*
|
|
* If not debugging, this is a macro, so it's expanded inline.
|
|
*/
|
|
|
|
void
|
|
new_vmcmd(struct exec_vmcmd_set *evsp,
|
|
int (*proc)(struct proc *, struct exec_vmcmd *), u_long len, u_long addr,
|
|
struct vnode *vp, u_long offset, u_int prot, int flags)
|
|
{
|
|
struct exec_vmcmd *vcp;
|
|
|
|
if (evsp->evs_used >= evsp->evs_cnt)
|
|
vmcmdset_extend(evsp);
|
|
vcp = &evsp->evs_cmds[evsp->evs_used++];
|
|
vcp->ev_proc = proc;
|
|
vcp->ev_len = len;
|
|
vcp->ev_addr = addr;
|
|
if ((vcp->ev_vp = vp) != NULL)
|
|
vref(vp);
|
|
vcp->ev_offset = offset;
|
|
vcp->ev_prot = prot;
|
|
vcp->ev_flags = flags;
|
|
}
|
|
#endif /* DEBUG */
|
|
|
|
void
|
|
vmcmdset_extend(struct exec_vmcmd_set *evsp)
|
|
{
|
|
struct exec_vmcmd *nvcp;
|
|
u_int ocnt;
|
|
|
|
#ifdef DIAGNOSTIC
|
|
if (evsp->evs_used < evsp->evs_cnt)
|
|
panic("vmcmdset_extend: not necessary");
|
|
#endif
|
|
|
|
ocnt = evsp->evs_cnt;
|
|
KASSERT(ocnt > 0);
|
|
/* figure out number of entries in new set */
|
|
evsp->evs_cnt += ocnt;
|
|
|
|
/* reallocate the command set */
|
|
nvcp = mallocarray(evsp->evs_cnt, sizeof(*nvcp), M_EXEC,
|
|
M_WAITOK);
|
|
memcpy(nvcp, evsp->evs_cmds, ocnt * sizeof(*nvcp));
|
|
if (evsp->evs_cmds != evsp->evs_start)
|
|
free(evsp->evs_cmds, M_EXEC, ocnt * sizeof(*nvcp));
|
|
evsp->evs_cmds = nvcp;
|
|
}
|
|
|
|
void
|
|
kill_vmcmds(struct exec_vmcmd_set *evsp)
|
|
{
|
|
struct exec_vmcmd *vcp;
|
|
int i;
|
|
|
|
for (i = 0; i < evsp->evs_used; i++) {
|
|
vcp = &evsp->evs_cmds[i];
|
|
if (vcp->ev_vp != NULLVP)
|
|
vrele(vcp->ev_vp);
|
|
}
|
|
|
|
/*
|
|
* Free old vmcmds and reset the array.
|
|
*/
|
|
evsp->evs_used = 0;
|
|
if (evsp->evs_cmds != evsp->evs_start)
|
|
free(evsp->evs_cmds, M_EXEC,
|
|
evsp->evs_cnt * sizeof(struct exec_vmcmd));
|
|
evsp->evs_cmds = evsp->evs_start;
|
|
evsp->evs_cnt = EXEC_DEFAULT_VMCMD_SETSIZE;
|
|
}
|
|
|
|
int
|
|
exec_process_vmcmds(struct proc *p, struct exec_package *epp)
|
|
{
|
|
struct exec_vmcmd *base_vc = NULL;
|
|
int error = 0;
|
|
int i;
|
|
|
|
for (i = 0; i < epp->ep_vmcmds.evs_used && !error; i++) {
|
|
struct exec_vmcmd *vcp;
|
|
|
|
vcp = &epp->ep_vmcmds.evs_cmds[i];
|
|
|
|
if (vcp->ev_flags & VMCMD_RELATIVE) {
|
|
#ifdef DIAGNOSTIC
|
|
if (base_vc == NULL)
|
|
panic("exec_process_vmcmds: RELATIVE no base");
|
|
#endif
|
|
vcp->ev_addr += base_vc->ev_addr;
|
|
}
|
|
error = (*vcp->ev_proc)(p, vcp);
|
|
if (vcp->ev_flags & VMCMD_BASE) {
|
|
base_vc = vcp;
|
|
}
|
|
}
|
|
|
|
kill_vmcmds(&epp->ep_vmcmds);
|
|
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* vmcmd_map_pagedvn():
|
|
* handle vmcmd which specifies that a vnode should be mmap'd.
|
|
* appropriate for handling demand-paged text and data segments.
|
|
*/
|
|
|
|
int
|
|
vmcmd_map_pagedvn(struct proc *p, struct exec_vmcmd *cmd)
|
|
{
|
|
/*
|
|
* note that if you're going to map part of a process as being
|
|
* paged from a vnode, that vnode had damn well better be marked as
|
|
* VTEXT. that's handled in the routine which sets up the vmcmd to
|
|
* call this routine.
|
|
*/
|
|
struct uvm_object *uobj;
|
|
unsigned int flags = UVM_FLAG_COPYONW | UVM_FLAG_FIXED;
|
|
int error;
|
|
|
|
/*
|
|
* map the vnode in using uvm_map.
|
|
*/
|
|
|
|
if (cmd->ev_len == 0)
|
|
return (0);
|
|
if (cmd->ev_offset & PAGE_MASK)
|
|
return (EINVAL);
|
|
if (cmd->ev_addr & PAGE_MASK)
|
|
return (EINVAL);
|
|
if (cmd->ev_len & PAGE_MASK)
|
|
return (EINVAL);
|
|
|
|
/*
|
|
* first, attach to the object
|
|
*/
|
|
|
|
uobj = uvn_attach(cmd->ev_vp, PROT_READ | PROT_EXEC);
|
|
if (uobj == NULL)
|
|
return (ENOMEM);
|
|
|
|
/*
|
|
* do the map
|
|
*/
|
|
error = uvm_map(&p->p_vmspace->vm_map, &cmd->ev_addr, cmd->ev_len,
|
|
uobj, cmd->ev_offset, 0,
|
|
UVM_MAPFLAG(cmd->ev_prot, PROT_MASK, MAP_INHERIT_COPY,
|
|
MADV_NORMAL, flags));
|
|
|
|
/*
|
|
* check for error
|
|
*/
|
|
|
|
if (error) {
|
|
/*
|
|
* error: detach from object
|
|
*/
|
|
uobj->pgops->pgo_detach(uobj);
|
|
} else {
|
|
if (cmd->ev_flags & VMCMD_IMMUTABLE)
|
|
uvm_map_immutable(&p->p_vmspace->vm_map, cmd->ev_addr,
|
|
round_page(cmd->ev_addr + cmd->ev_len), 1);
|
|
#ifdef PMAP_CHECK_COPYIN
|
|
if (PMAP_CHECK_COPYIN &&
|
|
((cmd->ev_flags & VMCMD_IMMUTABLE) && (cmd->ev_prot & PROT_EXEC)))
|
|
uvm_map_check_copyin_add(&p->p_vmspace->vm_map,
|
|
cmd->ev_addr, round_page(cmd->ev_addr + cmd->ev_len));
|
|
#endif
|
|
}
|
|
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* vmcmd_map_readvn():
|
|
* handle vmcmd which specifies that a vnode should be read from.
|
|
* appropriate for non-demand-paged text/data segments, i.e. impure
|
|
* objects (a la OMAGIC and NMAGIC).
|
|
*/
|
|
|
|
int
|
|
vmcmd_map_readvn(struct proc *p, struct exec_vmcmd *cmd)
|
|
{
|
|
int error;
|
|
vm_prot_t prot;
|
|
|
|
if (cmd->ev_len == 0)
|
|
return (0);
|
|
|
|
prot = cmd->ev_prot;
|
|
|
|
KASSERT((cmd->ev_addr & PAGE_MASK) == 0);
|
|
error = uvm_map(&p->p_vmspace->vm_map, &cmd->ev_addr,
|
|
round_page(cmd->ev_len), NULL, UVM_UNKNOWN_OFFSET, 0,
|
|
UVM_MAPFLAG(prot | PROT_WRITE, PROT_MASK, MAP_INHERIT_COPY,
|
|
MADV_NORMAL, UVM_FLAG_FIXED|UVM_FLAG_OVERLAY|UVM_FLAG_COPYONW));
|
|
|
|
if (error)
|
|
return (error);
|
|
|
|
error = vn_rdwr(UIO_READ, cmd->ev_vp, (caddr_t)cmd->ev_addr,
|
|
cmd->ev_len, cmd->ev_offset, UIO_USERSPACE, IO_UNIT,
|
|
p->p_ucred, NULL, p);
|
|
if (error)
|
|
return (error);
|
|
|
|
if ((prot & PROT_WRITE) == 0) {
|
|
/*
|
|
* we had to map in the area at PROT_WRITE so that vn_rdwr()
|
|
* could write to it. however, the caller seems to want
|
|
* it mapped read-only, so now we are going to have to call
|
|
* uvm_map_protect() to fix up the protection. ICK.
|
|
*/
|
|
error = (uvm_map_protect(&p->p_vmspace->vm_map,
|
|
cmd->ev_addr, round_page(cmd->ev_len),
|
|
prot, 0, FALSE, TRUE));
|
|
}
|
|
if (error == 0) {
|
|
if (cmd->ev_flags & VMCMD_IMMUTABLE)
|
|
uvm_map_immutable(&p->p_vmspace->vm_map, cmd->ev_addr,
|
|
round_page(cmd->ev_addr + cmd->ev_len), 1);
|
|
}
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* vmcmd_map_zero():
|
|
* handle vmcmd which specifies a zero-filled address space region.
|
|
*/
|
|
|
|
int
|
|
vmcmd_map_zero(struct proc *p, struct exec_vmcmd *cmd)
|
|
{
|
|
int error;
|
|
|
|
if (cmd->ev_len == 0)
|
|
return (0);
|
|
|
|
KASSERT((cmd->ev_addr & PAGE_MASK) == 0);
|
|
error = uvm_map(&p->p_vmspace->vm_map, &cmd->ev_addr,
|
|
round_page(cmd->ev_len), NULL, UVM_UNKNOWN_OFFSET, 0,
|
|
UVM_MAPFLAG(cmd->ev_prot, PROT_MASK, MAP_INHERIT_COPY,
|
|
MADV_NORMAL, UVM_FLAG_FIXED|UVM_FLAG_COPYONW |
|
|
(cmd->ev_flags & VMCMD_STACK ? UVM_FLAG_STACK : 0)));
|
|
if (cmd->ev_flags & VMCMD_IMMUTABLE)
|
|
uvm_map_immutable(&p->p_vmspace->vm_map, cmd->ev_addr,
|
|
round_page(cmd->ev_addr + cmd->ev_len), 1);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* vmcmd_mutable():
|
|
* handle vmcmd which changes an address space region.back to mutable
|
|
*/
|
|
|
|
int
|
|
vmcmd_mutable(struct proc *p, struct exec_vmcmd *cmd)
|
|
{
|
|
if (cmd->ev_len == 0)
|
|
return (0);
|
|
|
|
/* ev_addr, ev_len may be misaligned, so maximize the region */
|
|
uvm_map_immutable(&p->p_vmspace->vm_map, trunc_page(cmd->ev_addr),
|
|
round_page(cmd->ev_addr + cmd->ev_len), 0);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* vmcmd_randomize():
|
|
* handle vmcmd which specifies a randomized address space region.
|
|
*/
|
|
#define RANDOMIZE_CTX_THRESHOLD 512
|
|
int
|
|
vmcmd_randomize(struct proc *p, struct exec_vmcmd *cmd)
|
|
{
|
|
int error;
|
|
struct arc4random_ctx *ctx;
|
|
char *buf;
|
|
size_t sublen, off = 0;
|
|
size_t len = cmd->ev_len;
|
|
|
|
if (len == 0)
|
|
return (0);
|
|
if (len > ELF_RANDOMIZE_LIMIT)
|
|
return (EINVAL);
|
|
|
|
buf = malloc(PAGE_SIZE, M_TEMP, M_WAITOK);
|
|
if (len < RANDOMIZE_CTX_THRESHOLD) {
|
|
arc4random_buf(buf, len);
|
|
error = copyout(buf, (void *)cmd->ev_addr, len);
|
|
explicit_bzero(buf, len);
|
|
} else {
|
|
ctx = arc4random_ctx_new();
|
|
do {
|
|
sublen = MIN(len, PAGE_SIZE);
|
|
arc4random_ctx_buf(ctx, buf, sublen);
|
|
error = copyout(buf, (void *)cmd->ev_addr + off, sublen);
|
|
if (error)
|
|
break;
|
|
off += sublen;
|
|
len -= sublen;
|
|
sched_pause(yield);
|
|
} while (len);
|
|
arc4random_ctx_free(ctx);
|
|
explicit_bzero(buf, PAGE_SIZE);
|
|
}
|
|
free(buf, M_TEMP, PAGE_SIZE);
|
|
return (error);
|
|
}
|
|
|
|
#ifndef MAXSSIZ_GUARD
|
|
#define MAXSSIZ_GUARD (1024 * 1024)
|
|
#endif
|
|
|
|
/*
|
|
* exec_setup_stack(): Set up the stack segment for an executable.
|
|
*
|
|
* Note that the ep_ssize parameter must be set to be the current stack
|
|
* limit; this is adjusted in the body of execve() to yield the
|
|
* appropriate stack segment usage once the argument length is
|
|
* calculated.
|
|
*
|
|
* This function returns an int for uniformity with other (future) formats'
|
|
* stack setup functions. They might have errors to return.
|
|
*/
|
|
|
|
int
|
|
exec_setup_stack(struct proc *p, struct exec_package *epp)
|
|
{
|
|
vsize_t dist = 0;
|
|
|
|
#ifdef MACHINE_STACK_GROWS_UP
|
|
epp->ep_maxsaddr = USRSTACK;
|
|
epp->ep_minsaddr = USRSTACK + MAXSSIZ;
|
|
#else
|
|
epp->ep_maxsaddr = USRSTACK - MAXSSIZ - MAXSSIZ_GUARD;
|
|
epp->ep_minsaddr = USRSTACK;
|
|
#endif
|
|
epp->ep_ssize = round_page(lim_cur(RLIMIT_STACK));
|
|
|
|
#ifdef VM_MIN_STACK_ADDRESS
|
|
dist = USRSTACK - MAXSSIZ - MAXSSIZ_GUARD - VM_MIN_STACK_ADDRESS;
|
|
if (dist >> PAGE_SHIFT > 0xffffffff)
|
|
dist = (vsize_t)arc4random() << PAGE_SHIFT;
|
|
else
|
|
dist = (vsize_t)arc4random_uniform(dist >> PAGE_SHIFT) << PAGE_SHIFT;
|
|
#else
|
|
if (stackgap_random != 0) {
|
|
dist = arc4random() & (stackgap_random - 1);
|
|
dist = trunc_page(dist);
|
|
}
|
|
#endif
|
|
|
|
#ifdef MACHINE_STACK_GROWS_UP
|
|
epp->ep_maxsaddr += dist;
|
|
epp->ep_minsaddr += dist;
|
|
#else
|
|
epp->ep_maxsaddr -= dist;
|
|
epp->ep_minsaddr -= dist;
|
|
#endif
|
|
|
|
/*
|
|
* set up commands for stack. note that this takes *two*, one to
|
|
* map the part of the stack which we can access, and one to map
|
|
* the part which we can't.
|
|
*
|
|
* arguably, it could be made into one, but that would require the
|
|
* addition of another mapping proc, which is unnecessary
|
|
*
|
|
* note that in memory, things assumed to be: 0 ....... ep_maxsaddr
|
|
* <stack> ep_minsaddr
|
|
*/
|
|
#ifdef MACHINE_STACK_GROWS_UP
|
|
NEW_VMCMD2(&epp->ep_vmcmds, vmcmd_map_zero,
|
|
((epp->ep_minsaddr - epp->ep_ssize) - epp->ep_maxsaddr),
|
|
epp->ep_maxsaddr + epp->ep_ssize,
|
|
NULLVP, 0, PROT_NONE, VMCMD_IMMUTABLE);
|
|
NEW_VMCMD2(&epp->ep_vmcmds, vmcmd_map_zero, epp->ep_ssize,
|
|
epp->ep_maxsaddr,
|
|
NULLVP, 0, PROT_READ | PROT_WRITE, VMCMD_STACK | VMCMD_IMMUTABLE);
|
|
#else
|
|
NEW_VMCMD2(&epp->ep_vmcmds, vmcmd_map_zero,
|
|
((epp->ep_minsaddr - epp->ep_ssize) - epp->ep_maxsaddr),
|
|
epp->ep_maxsaddr,
|
|
NULLVP, 0, PROT_NONE, VMCMD_IMMUTABLE);
|
|
NEW_VMCMD2(&epp->ep_vmcmds, vmcmd_map_zero, epp->ep_ssize,
|
|
(epp->ep_minsaddr - epp->ep_ssize),
|
|
NULLVP, 0, PROT_READ | PROT_WRITE, VMCMD_STACK | VMCMD_IMMUTABLE);
|
|
#endif
|
|
|
|
return (0);
|
|
}
|