/* $NetBSD: exec_subr.c,v 1.52 2007/03/04 06:03:03 christos 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 1.52 2007/03/04 06:03:03 christos Exp $"); #include "opt_pax.h" #include #include #include #include #include #include #include #include #include #include #ifdef PAX_MPROTECT #include #endif /* PAX_MPROTECT */ #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); /* * 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 *), u_long len, u_long addr, struct vnode *vp, u_long offset, u_int prot, int flags) { struct exec_vmcmd *vcp; VMCMD_EVCNT_INCR(calls); 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 = malloc(evsp->evs_cnt * sizeof(struct exec_vmcmd), M_EXEC, M_WAITOK); /* 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))); free(evsp->evs_cmds, M_EXEC); } 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); } evsp->evs_used = evsp->evs_cnt = 0; free(evsp->evs_cmds, M_EXEC); } /* * 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 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_flag & VTEXT); /* * 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(vp, VM_PROT_READ|VM_PROT_EXECUTE); if (uobj == NULL) return(ENOMEM); VREF(vp); if ((vp->v_flag & VMAPPED) == 0) { vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); simple_lock(&vp->v_interlock); vp->v_flag |= VMAPPED; simple_unlock(&vp->v_interlock); VOP_UNLOCK(vp, 0); } prot = cmd->ev_prot; maxprot = UVM_PROT_ALL; #ifdef PAX_MPROTECT pax_mprotect(l, &prot, &maxprot); #endif /* PAX_MPROTECT */ /* * do the map */ 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; prot = cmd->ev_prot; maxprot = VM_PROT_ALL; #ifdef PAX_MPROTECT pax_mprotect(l, &prot, &maxprot); #endif /* PAX_MPROTECT */ #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; prot = cmd->ev_prot; maxprot = UVM_PROT_ALL; #ifdef PAX_MPROTECT pax_mprotect(l, &prot, &maxprot); #endif /* PAX_MPROTECT */ 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)); 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) { u_long max_stack_size; u_long access_linear_min, access_size; u_long noaccess_linear_min, noaccess_size; #ifndef USRSTACK32 #define USRSTACK32 (0x00000000ffffffffL&~PGOFSET) #endif if (epp->ep_flags & EXEC_32) { epp->ep_minsaddr = USRSTACK32; max_stack_size = MAXSSIZ; } else { epp->ep_minsaddr = USRSTACK; max_stack_size = MAXSSIZ; } epp->ep_maxsaddr = (u_long)STACK_GROW(epp->ep_minsaddr, max_stack_size); epp->ep_ssize = l->l_proc->p_rlimit[RLIMIT_STACK].rlim_cur; /* * 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 = (u_long)STACK_ALLOC(epp->ep_minsaddr, access_size); noaccess_size = max_stack_size - access_size; noaccess_linear_min = (u_long)STACK_ALLOC(STACK_GROW(epp->ep_minsaddr, access_size), noaccess_size); if (noaccess_size > 0) { NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, noaccess_size, noaccess_linear_min, NULL, 0, VM_PROT_NONE); } KASSERT(access_size > 0); NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, access_size, access_linear_min, NULL, 0, VM_PROT_READ | VM_PROT_WRITE); return 0; }