/* $NetBSD: exec_subr.c,v 1.82.10.2 2023/11/29 12:27:05 martin Exp $ */ /* * Copyright (c) 1993, 1994, 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. 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 __KERNEL_RCSID(0, "$NetBSD: exec_subr.c,v 1.82.10.2 2023/11/29 12:27:05 martin Exp $"); #include "opt_pax.h" #include #include #include #include #include #include #include #include #include #include #include #include #define VMCMD_EVCNT_DECL(name) \ static struct evcnt vmcmd_ev_##name = \ EVCNT_INITIALIZER(EVCNT_TYPE_MISC, NULL, "vmcmd", #name); \ EVCNT_ATTACH_STATIC(vmcmd_ev_##name) #define VMCMD_EVCNT_INCR(name) \ vmcmd_ev_##name.ev_count++ VMCMD_EVCNT_DECL(calls); VMCMD_EVCNT_DECL(extends); VMCMD_EVCNT_DECL(kills); #ifdef DEBUG_STACK #define DPRINTF(a) uprintf a #else #define DPRINTF(a) #endif unsigned int user_stack_guard_size = 1024 * 1024; unsigned int user_thread_stack_guard_size = 64 * 1024; /* * 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'. */ void new_vmcmd(struct exec_vmcmd_set *evsp, int (*proc)(struct lwp * l, struct exec_vmcmd *), vsize_t len, vaddr_t addr, struct vnode *vp, u_long offset, u_int prot, int flags) { struct exec_vmcmd *vcp; VMCMD_EVCNT_INCR(calls); KASSERT(proc != vmcmd_map_pagedvn || (vp->v_iflag & VI_TEXT)); KASSERT(vp == NULL || vp->v_usecount > 0); 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; } 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 /* figure out number of entries in new set */ if ((ocnt = evsp->evs_cnt) != 0) { evsp->evs_cnt += ocnt; VMCMD_EVCNT_INCR(extends); } else evsp->evs_cnt = EXEC_DEFAULT_VMCMD_SETSIZE; /* allocate it */ nvcp = kmem_alloc(evsp->evs_cnt * sizeof(struct exec_vmcmd), KM_SLEEP); /* free the old struct, if there was one, and record the new one */ if (ocnt) { memcpy(nvcp, evsp->evs_cmds, (ocnt * sizeof(struct exec_vmcmd))); kmem_free(evsp->evs_cmds, ocnt * sizeof(struct exec_vmcmd)); } evsp->evs_cmds = nvcp; } void kill_vmcmds(struct exec_vmcmd_set *evsp) { struct exec_vmcmd *vcp; u_int i; VMCMD_EVCNT_INCR(kills); if (evsp->evs_cnt == 0) return; for (i = 0; i < evsp->evs_used; i++) { vcp = &evsp->evs_cmds[i]; if (vcp->ev_vp != NULL) vrele(vcp->ev_vp); } kmem_free(evsp->evs_cmds, evsp->evs_cnt * sizeof(struct exec_vmcmd)); evsp->evs_used = evsp->evs_cnt = 0; } /* * vmcmd_map_pagedvn(): * handle vmcmd which specifies that a vnode should be mmap'd. * appropriate for handling demand-paged text and data segments. */ static int vmcmd_get_prot(struct lwp *l, const struct exec_vmcmd *cmd, vm_prot_t *prot, vm_prot_t *maxprot) { vm_prot_t extraprot __unused = PROT_MPROTECT_EXTRACT(cmd->ev_prot); *prot = cmd->ev_prot & UVM_PROT_ALL; *maxprot = PAX_MPROTECT_MAXPROTECT(l, *prot, extraprot, UVM_PROT_ALL); if ((*prot & *maxprot) != *prot) return EACCES; return PAX_MPROTECT_VALIDATE(l, *prot); } int vmcmd_map_pagedvn(struct lwp *l, struct exec_vmcmd *cmd) { struct uvm_object *uobj; struct vnode *vp = cmd->ev_vp; struct proc *p = l->l_proc; int error; vm_prot_t prot, maxprot; KASSERT(vp->v_iflag & VI_TEXT); /* * 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; if ((error = vmcmd_get_prot(l, cmd, &prot, &maxprot)) != 0) return error; /* * check the file system's opinion about mmapping the file */ error = VOP_MMAP(vp, prot, l->l_cred); if (error) return error; if ((vp->v_vflag & VV_MAPPED) == 0) { vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); vp->v_vflag |= VV_MAPPED; VOP_UNLOCK(vp); } /* * do the map, reference the object for this map entry */ uobj = &vp->v_uobj; vref(vp); error = uvm_map(&p->p_vmspace->vm_map, &cmd->ev_addr, cmd->ev_len, uobj, cmd->ev_offset, 0, UVM_MAPFLAG(prot, maxprot, UVM_INH_COPY, UVM_ADV_NORMAL, UVM_FLAG_COPYONW|UVM_FLAG_FIXED)); if (error) { uobj->pgops->pgo_detach(uobj); } 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 lwp *l, struct exec_vmcmd *cmd) { struct proc *p = l->l_proc; int error; long diff; if (cmd->ev_len == 0) return 0; diff = cmd->ev_addr - trunc_page(cmd->ev_addr); cmd->ev_addr -= diff; /* required by uvm_map */ cmd->ev_offset -= diff; cmd->ev_len += diff; error = uvm_map(&p->p_vmspace->vm_map, &cmd->ev_addr, round_page(cmd->ev_len), NULL, UVM_UNKNOWN_OFFSET, 0, UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL, UVM_INH_COPY, UVM_ADV_NORMAL, UVM_FLAG_FIXED|UVM_FLAG_OVERLAY|UVM_FLAG_COPYONW)); if (error) return error; return vmcmd_readvn(l, cmd); } int vmcmd_readvn(struct lwp *l, struct exec_vmcmd *cmd) { struct proc *p = l->l_proc; int error; vm_prot_t prot, maxprot; error = vn_rdwr(UIO_READ, cmd->ev_vp, (void *)cmd->ev_addr, cmd->ev_len, cmd->ev_offset, UIO_USERSPACE, IO_UNIT, l->l_cred, NULL, l); if (error) return error; if ((error = vmcmd_get_prot(l, cmd, &prot, &maxprot)) != 0) return error; #ifdef PMAP_NEED_PROCWR /* * we had to write the process, make sure the pages are synched * with the instruction cache. */ if (prot & VM_PROT_EXECUTE) pmap_procwr(p, cmd->ev_addr, cmd->ev_len); #endif /* * we had to map in the area at PROT_ALL 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. */ if (maxprot != VM_PROT_ALL) { error = uvm_map_protect(&p->p_vmspace->vm_map, trunc_page(cmd->ev_addr), round_page(cmd->ev_addr + cmd->ev_len), maxprot, true); if (error) return error; } if (prot != maxprot) { error = uvm_map_protect(&p->p_vmspace->vm_map, trunc_page(cmd->ev_addr), round_page(cmd->ev_addr + cmd->ev_len), prot, false); if (error) return error; } return 0; } /* * vmcmd_map_zero(): * handle vmcmd which specifies a zero-filled address space region. The * address range must be first allocated, then protected appropriately. */ int vmcmd_map_zero(struct lwp *l, struct exec_vmcmd *cmd) { struct proc *p = l->l_proc; int error; long diff; vm_prot_t prot, maxprot; diff = cmd->ev_addr - trunc_page(cmd->ev_addr); cmd->ev_addr -= diff; /* required by uvm_map */ cmd->ev_len += diff; if ((error = vmcmd_get_prot(l, cmd, &prot, &maxprot)) != 0) return error; error = uvm_map(&p->p_vmspace->vm_map, &cmd->ev_addr, round_page(cmd->ev_len), NULL, UVM_UNKNOWN_OFFSET, 0, UVM_MAPFLAG(prot, maxprot, UVM_INH_COPY, UVM_ADV_NORMAL, UVM_FLAG_FIXED|UVM_FLAG_COPYONW)); if (cmd->ev_flags & VMCMD_STACK) curproc->p_vmspace->vm_issize += atop(round_page(cmd->ev_len)); return error; } /* * exec_read_from(): * * Read from vnode into buffer at offset. */ int exec_read_from(struct lwp *l, struct vnode *vp, u_long off, void *bf, size_t size) { int error; size_t resid; if ((error = vn_rdwr(UIO_READ, vp, bf, size, off, UIO_SYSSPACE, 0, l->l_cred, &resid, NULL)) != 0) return error; /* * See if we got all of it */ if (resid != 0) return ENOEXEC; return 0; } /* * exec_setup_stack(): Set up the stack segment for an elf * 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 lwp *l, struct exec_package *epp) { vsize_t max_stack_size; vaddr_t access_linear_min; vsize_t access_size; vaddr_t noaccess_linear_min; vsize_t noaccess_size; #ifndef USRSTACK32 #define USRSTACK32 (0x00000000ffffffffL&~PGOFSET) #endif #ifndef MAXSSIZ32 #define MAXSSIZ32 (MAXSSIZ >> 2) #endif if (epp->ep_flags & EXEC_32) { epp->ep_minsaddr = USRSTACK32; max_stack_size = MAXSSIZ32; } else { epp->ep_minsaddr = USRSTACK; max_stack_size = MAXSSIZ; } DPRINTF(("ep_minsaddr=%#jx max_stack_size=%#jx\n", (uintmax_t)epp->ep_minsaddr, (uintmax_t)max_stack_size)); pax_aslr_stack(epp, &max_stack_size); DPRINTF(("[RLIMIT_STACK].lim_cur=%#jx max_stack_size=%#jx\n", (uintmax_t)l->l_proc->p_rlimit[RLIMIT_STACK].rlim_cur, (uintmax_t)max_stack_size)); epp->ep_ssize = MIN(l->l_proc->p_rlimit[RLIMIT_STACK].rlim_cur, max_stack_size); l->l_proc->p_stackbase = epp->ep_minsaddr; epp->ep_maxsaddr = (vaddr_t)STACK_GROW(epp->ep_minsaddr, max_stack_size); DPRINTF(("ep_ssize=%#jx ep_minsaddr=%#jx ep_maxsaddr=%#jx\n", (uintmax_t)epp->ep_ssize, (uintmax_t)epp->ep_minsaddr, (uintmax_t)epp->ep_maxsaddr)); /* * 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 */ access_size = epp->ep_ssize; access_linear_min = (vaddr_t)STACK_ALLOC(epp->ep_minsaddr, access_size); noaccess_size = max_stack_size - access_size; noaccess_linear_min = (vaddr_t)STACK_ALLOC(STACK_GROW(epp->ep_minsaddr, access_size), noaccess_size); DPRINTF(("access_size=%#jx, access_linear_min=%#jx, " "noaccess_size=%#jx, noaccess_linear_min=%#jx\n", (uintmax_t)access_size, (uintmax_t)access_linear_min, (uintmax_t)noaccess_size, (uintmax_t)noaccess_linear_min)); if (user_stack_guard_size > 0) { #ifdef __MACHINE_STACK_GROWS_UP vsize_t guard_size = MIN(VM_MAXUSER_ADDRESS - epp->ep_maxsaddr, user_stack_guard_size); if (guard_size > 0) NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, guard_size, epp->ep_maxsaddr, NULL, 0, VM_PROT_NONE); #else NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, user_stack_guard_size, epp->ep_maxsaddr - user_stack_guard_size, NULL, 0, VM_PROT_NONE); #endif } if (noaccess_size > 0 && noaccess_size <= MAXSSIZ) { NEW_VMCMD2(&epp->ep_vmcmds, vmcmd_map_zero, noaccess_size, noaccess_linear_min, NULL, 0, VM_PROT_NONE | PROT_MPROTECT(VM_PROT_READ | VM_PROT_WRITE), VMCMD_STACK); } KASSERT(access_size > 0 && access_size <= MAXSSIZ); NEW_VMCMD2(&epp->ep_vmcmds, vmcmd_map_zero, access_size, access_linear_min, NULL, 0, VM_PROT_READ | VM_PROT_WRITE, VMCMD_STACK); return 0; }