474 lines
13 KiB
C
474 lines
13 KiB
C
/* $NetBSD: exec_subr.c,v 1.88 2023/11/21 14:35:36 riastradh Exp $ */
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/*
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* Copyright (c) 1993, 1994, 1996 Christopher G. Demetriou
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by Christopher G. Demetriou.
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* 4. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: exec_subr.c,v 1.88 2023/11/21 14:35:36 riastradh Exp $");
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#include "opt_pax.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/proc.h>
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#include <sys/kmem.h>
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#include <sys/vnode.h>
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#include <sys/filedesc.h>
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#include <sys/exec.h>
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#include <sys/mman.h>
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#include <sys/resourcevar.h>
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#include <sys/device.h>
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#include <sys/pax.h>
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#include <uvm/uvm_extern.h>
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#define VMCMD_EVCNT_DECL(name) \
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static struct evcnt vmcmd_ev_##name = \
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EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, "vmcmd", #name); \
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EVCNT_ATTACH_STATIC(vmcmd_ev_##name)
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#define VMCMD_EVCNT_INCR(name) \
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vmcmd_ev_##name.ev_count++
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VMCMD_EVCNT_DECL(calls);
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VMCMD_EVCNT_DECL(extends);
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VMCMD_EVCNT_DECL(kills);
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#ifdef DEBUG_STACK
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#define DPRINTF(a) uprintf a
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#else
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#define DPRINTF(a)
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#endif
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unsigned int user_stack_guard_size = 1024 * 1024;
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unsigned int user_thread_stack_guard_size = 64 * 1024;
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/*
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* new_vmcmd():
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* create a new vmcmd structure and fill in its fields based
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* on function call arguments. make sure objects ref'd by
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* the vmcmd are 'held'.
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*/
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void
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new_vmcmd(struct exec_vmcmd_set *evsp,
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int (*proc)(struct lwp * l, struct exec_vmcmd *),
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vsize_t len, vaddr_t addr, struct vnode *vp, u_long offset,
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u_int prot, int flags)
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{
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struct exec_vmcmd *vcp;
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VMCMD_EVCNT_INCR(calls);
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KASSERT(proc != vmcmd_map_pagedvn || (vp->v_iflag & VI_TEXT));
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KASSERT(vp == NULL || vrefcnt(vp) > 0);
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if (evsp->evs_used >= evsp->evs_cnt)
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vmcmdset_extend(evsp);
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vcp = &evsp->evs_cmds[evsp->evs_used++];
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vcp->ev_proc = proc;
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vcp->ev_len = len;
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vcp->ev_addr = addr;
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if ((vcp->ev_vp = vp) != NULL)
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vref(vp);
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vcp->ev_offset = offset;
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vcp->ev_prot = prot;
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vcp->ev_flags = flags;
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}
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void
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vmcmdset_extend(struct exec_vmcmd_set *evsp)
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{
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struct exec_vmcmd *nvcp;
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u_int ocnt;
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#ifdef DIAGNOSTIC
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if (evsp->evs_used < evsp->evs_cnt)
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panic("vmcmdset_extend: not necessary");
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#endif
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/* figure out number of entries in new set */
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if ((ocnt = evsp->evs_cnt) != 0) {
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evsp->evs_cnt += ocnt;
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VMCMD_EVCNT_INCR(extends);
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} else
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evsp->evs_cnt = EXEC_DEFAULT_VMCMD_SETSIZE;
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/* allocate it */
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nvcp = kmem_alloc(evsp->evs_cnt * sizeof(struct exec_vmcmd), KM_SLEEP);
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/* free the old struct, if there was one, and record the new one */
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if (ocnt) {
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memcpy(nvcp, evsp->evs_cmds,
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(ocnt * sizeof(struct exec_vmcmd)));
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kmem_free(evsp->evs_cmds, ocnt * sizeof(struct exec_vmcmd));
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}
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evsp->evs_cmds = nvcp;
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}
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void
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kill_vmcmds(struct exec_vmcmd_set *evsp)
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{
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struct exec_vmcmd *vcp;
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u_int i;
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VMCMD_EVCNT_INCR(kills);
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if (evsp->evs_cnt == 0)
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return;
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for (i = 0; i < evsp->evs_used; i++) {
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vcp = &evsp->evs_cmds[i];
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if (vcp->ev_vp != NULL)
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vrele(vcp->ev_vp);
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}
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kmem_free(evsp->evs_cmds, evsp->evs_cnt * sizeof(struct exec_vmcmd));
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evsp->evs_used = evsp->evs_cnt = 0;
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}
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/*
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* vmcmd_map_pagedvn():
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* handle vmcmd which specifies that a vnode should be mmap'd.
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* appropriate for handling demand-paged text and data segments.
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*/
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static int
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vmcmd_get_prot(struct lwp *l, const struct exec_vmcmd *cmd, vm_prot_t *prot,
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vm_prot_t *maxprot)
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{
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vm_prot_t extraprot = PROT_MPROTECT_EXTRACT(cmd->ev_prot);
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*prot = cmd->ev_prot & UVM_PROT_ALL;
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*maxprot = PAX_MPROTECT_MAXPROTECT(l, *prot, extraprot, UVM_PROT_ALL);
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if ((*prot & *maxprot) != *prot)
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return EACCES;
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return PAX_MPROTECT_VALIDATE(l, *prot);
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}
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int
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vmcmd_map_pagedvn(struct lwp *l, struct exec_vmcmd *cmd)
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{
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struct uvm_object *uobj;
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struct vnode *vp = cmd->ev_vp;
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struct proc *p = l->l_proc;
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int error;
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vm_prot_t prot, maxprot;
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KASSERT(vp->v_iflag & VI_TEXT);
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/*
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* map the vnode in using uvm_map.
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*/
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if (cmd->ev_len == 0)
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return 0;
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if (cmd->ev_offset & PAGE_MASK)
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return EINVAL;
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if (cmd->ev_addr & PAGE_MASK)
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return EINVAL;
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if (cmd->ev_len & PAGE_MASK)
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return EINVAL;
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if ((error = vmcmd_get_prot(l, cmd, &prot, &maxprot)) != 0)
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return error;
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/*
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* check the file system's opinion about mmapping the file
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*/
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error = VOP_MMAP(vp, prot, l->l_cred);
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if (error)
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return error;
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if ((vp->v_vflag & VV_MAPPED) == 0) {
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vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
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vp->v_vflag |= VV_MAPPED;
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VOP_UNLOCK(vp);
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}
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/*
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* do the map, reference the object for this map entry
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*/
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uobj = &vp->v_uobj;
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vref(vp);
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error = uvm_map(&p->p_vmspace->vm_map, &cmd->ev_addr, cmd->ev_len,
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uobj, cmd->ev_offset, 0,
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UVM_MAPFLAG(prot, maxprot, UVM_INH_COPY,
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UVM_ADV_NORMAL, UVM_FLAG_COPYONW|UVM_FLAG_FIXED));
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if (error) {
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uobj->pgops->pgo_detach(uobj);
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}
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return error;
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}
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/*
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* vmcmd_map_readvn():
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* handle vmcmd which specifies that a vnode should be read from.
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* appropriate for non-demand-paged text/data segments, i.e. impure
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* objects (a la OMAGIC and NMAGIC).
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*/
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int
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vmcmd_map_readvn(struct lwp *l, struct exec_vmcmd *cmd)
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{
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struct proc *p = l->l_proc;
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int error;
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long diff;
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if (cmd->ev_len == 0)
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return 0;
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diff = cmd->ev_addr - trunc_page(cmd->ev_addr);
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cmd->ev_addr -= diff; /* required by uvm_map */
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cmd->ev_offset -= diff;
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cmd->ev_len += diff;
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error = uvm_map(&p->p_vmspace->vm_map, &cmd->ev_addr,
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round_page(cmd->ev_len), NULL, UVM_UNKNOWN_OFFSET, 0,
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UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL, UVM_INH_COPY,
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UVM_ADV_NORMAL,
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UVM_FLAG_FIXED|UVM_FLAG_OVERLAY|UVM_FLAG_COPYONW));
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if (error)
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return error;
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return vmcmd_readvn(l, cmd);
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}
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int
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vmcmd_readvn(struct lwp *l, struct exec_vmcmd *cmd)
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{
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struct proc *p = l->l_proc;
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int error;
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vm_prot_t prot, maxprot;
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error = vn_rdwr(UIO_READ, cmd->ev_vp, (void *)cmd->ev_addr,
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cmd->ev_len, cmd->ev_offset, UIO_USERSPACE, IO_UNIT,
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l->l_cred, NULL, l);
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if (error)
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return error;
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if ((error = vmcmd_get_prot(l, cmd, &prot, &maxprot)) != 0)
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return error;
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#ifdef PMAP_NEED_PROCWR
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/*
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* we had to write the process, make sure the pages are synched
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* with the instruction cache.
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*/
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if (prot & VM_PROT_EXECUTE)
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pmap_procwr(p, cmd->ev_addr, cmd->ev_len);
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#endif
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/*
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* we had to map in the area at PROT_ALL so that vn_rdwr()
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* could write to it. however, the caller seems to want
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* it mapped read-only, so now we are going to have to call
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* uvm_map_protect() to fix up the protection. ICK.
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*/
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if (maxprot != VM_PROT_ALL) {
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error = uvm_map_protect(&p->p_vmspace->vm_map,
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trunc_page(cmd->ev_addr),
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round_page(cmd->ev_addr + cmd->ev_len),
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maxprot, true);
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if (error)
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return error;
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}
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if (prot != maxprot) {
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error = uvm_map_protect(&p->p_vmspace->vm_map,
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trunc_page(cmd->ev_addr),
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round_page(cmd->ev_addr + cmd->ev_len),
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prot, false);
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if (error)
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return error;
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}
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return 0;
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}
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/*
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* vmcmd_map_zero():
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* handle vmcmd which specifies a zero-filled address space region. The
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* address range must be first allocated, then protected appropriately.
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*/
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int
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vmcmd_map_zero(struct lwp *l, struct exec_vmcmd *cmd)
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{
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struct proc *p = l->l_proc;
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int error;
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long diff;
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vm_prot_t prot, maxprot;
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diff = cmd->ev_addr - trunc_page(cmd->ev_addr);
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cmd->ev_addr -= diff; /* required by uvm_map */
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cmd->ev_len += diff;
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if ((error = vmcmd_get_prot(l, cmd, &prot, &maxprot)) != 0)
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return error;
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error = uvm_map(&p->p_vmspace->vm_map, &cmd->ev_addr,
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round_page(cmd->ev_len), NULL, UVM_UNKNOWN_OFFSET, 0,
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UVM_MAPFLAG(prot, maxprot, UVM_INH_COPY,
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UVM_ADV_NORMAL,
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UVM_FLAG_FIXED|UVM_FLAG_COPYONW));
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if (cmd->ev_flags & VMCMD_STACK)
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curproc->p_vmspace->vm_issize += atop(round_page(cmd->ev_len));
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return error;
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}
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/*
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* exec_read():
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*
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* Read from vnode into buffer at offset.
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*/
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int
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exec_read(struct lwp *l, struct vnode *vp, u_long off, void *bf, size_t size,
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int ioflg)
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{
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int error;
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size_t resid;
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KASSERT((ioflg & IO_NODELOCKED) == 0 || VOP_ISLOCKED(vp) != LK_NONE);
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if ((error = vn_rdwr(UIO_READ, vp, bf, size, off, UIO_SYSSPACE,
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ioflg, l->l_cred, &resid, NULL)) != 0)
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return error;
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/*
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* See if we got all of it
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*/
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if (resid != 0)
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return ENOEXEC;
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return 0;
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}
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/*
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* exec_setup_stack(): Set up the stack segment for an elf
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* executable.
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*
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* Note that the ep_ssize parameter must be set to be the current stack
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* limit; this is adjusted in the body of execve() to yield the
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* appropriate stack segment usage once the argument length is
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* calculated.
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*
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* This function returns an int for uniformity with other (future) formats'
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* stack setup functions. They might have errors to return.
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*/
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int
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exec_setup_stack(struct lwp *l, struct exec_package *epp)
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{
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vsize_t max_stack_size;
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vaddr_t access_linear_min;
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vsize_t access_size;
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vaddr_t noaccess_linear_min;
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vsize_t noaccess_size;
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#ifndef USRSTACK32
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#define USRSTACK32 (0x00000000ffffffffL&~PGOFSET)
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#endif
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#ifndef MAXSSIZ32
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#define MAXSSIZ32 (MAXSSIZ >> 2)
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#endif
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if (epp->ep_flags & EXEC_32) {
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epp->ep_minsaddr = USRSTACK32;
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max_stack_size = MAXSSIZ32;
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} else {
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epp->ep_minsaddr = USRSTACK;
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max_stack_size = MAXSSIZ;
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}
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DPRINTF(("ep_minsaddr=%#jx max_stack_size=%#jx\n",
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(uintmax_t)epp->ep_minsaddr, (uintmax_t)max_stack_size));
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pax_aslr_stack(epp, &max_stack_size);
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DPRINTF(("[RLIMIT_STACK].lim_cur=%#jx max_stack_size=%#jx\n",
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(uintmax_t)l->l_proc->p_rlimit[RLIMIT_STACK].rlim_cur,
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(uintmax_t)max_stack_size));
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epp->ep_ssize = MIN(l->l_proc->p_rlimit[RLIMIT_STACK].rlim_cur,
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max_stack_size);
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l->l_proc->p_stackbase = epp->ep_minsaddr;
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epp->ep_maxsaddr = (vaddr_t)STACK_GROW(epp->ep_minsaddr,
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max_stack_size);
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DPRINTF(("ep_ssize=%#jx ep_minsaddr=%#jx ep_maxsaddr=%#jx\n",
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(uintmax_t)epp->ep_ssize, (uintmax_t)epp->ep_minsaddr,
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(uintmax_t)epp->ep_maxsaddr));
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/*
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* set up commands for stack. note that this takes *two*, one to
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* map the part of the stack which we can access, and one to map
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* the part which we can't.
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*
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* arguably, it could be made into one, but that would require the
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* addition of another mapping proc, which is unnecessary
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*/
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access_size = epp->ep_ssize;
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access_linear_min = (vaddr_t)STACK_ALLOC(epp->ep_minsaddr, access_size);
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noaccess_size = max_stack_size - access_size;
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noaccess_linear_min = (vaddr_t)STACK_ALLOC(STACK_GROW(epp->ep_minsaddr,
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access_size), noaccess_size);
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DPRINTF(("access_size=%#jx, access_linear_min=%#jx, "
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"noaccess_size=%#jx, noaccess_linear_min=%#jx\n",
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(uintmax_t)access_size, (uintmax_t)access_linear_min,
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(uintmax_t)noaccess_size, (uintmax_t)noaccess_linear_min));
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if (user_stack_guard_size > 0) {
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#ifdef __MACHINE_STACK_GROWS_UP
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vsize_t guard_size = MIN(VM_MAXUSER_ADDRESS - epp->ep_maxsaddr, user_stack_guard_size);
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if (guard_size > 0)
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NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, guard_size,
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epp->ep_maxsaddr, NULL, 0, VM_PROT_NONE);
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#else
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NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, user_stack_guard_size,
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epp->ep_maxsaddr - user_stack_guard_size, NULL, 0, VM_PROT_NONE);
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#endif
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}
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if (noaccess_size > 0 && noaccess_size <= MAXSSIZ) {
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NEW_VMCMD2(&epp->ep_vmcmds, vmcmd_map_zero, noaccess_size,
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noaccess_linear_min, NULL, 0,
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VM_PROT_NONE | PROT_MPROTECT(VM_PROT_READ | VM_PROT_WRITE),
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VMCMD_STACK);
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}
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KASSERT(access_size > 0);
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KASSERT(access_size <= MAXSSIZ);
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NEW_VMCMD2(&epp->ep_vmcmds, vmcmd_map_zero, access_size,
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access_linear_min, NULL, 0, VM_PROT_READ | VM_PROT_WRITE,
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VMCMD_STACK);
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return 0;
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}
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