/* $NetBSD: kern_exec.c,v 1.525 2024/12/06 16:48:13 riastradh Exp $ */ /*- * Copyright (c) 2008, 2019, 2020 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Andrew Doran. * * 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) 1993, 1994, 1996 Christopher G. Demetriou * Copyright (C) 1992 Wolfgang Solfrank. * Copyright (C) 1992 TooLs GmbH. * 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 TooLs GmbH. * 4. The name of TooLs GmbH may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``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 TOOLS GMBH 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: kern_exec.c,v 1.525 2024/12/06 16:48:13 riastradh Exp $"); #include "opt_exec.h" #include "opt_execfmt.h" #include "opt_ktrace.h" #include "opt_modular.h" #include "opt_pax.h" #include "opt_syscall_debug.h" #include "veriexec.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #if NVERIEXEC > 0 #include #endif /* NVERIEXEC > 0 */ #include #include #include #include #include #include #ifndef MD_TOPDOWN_INIT #ifdef __USE_TOPDOWN_VM #define MD_TOPDOWN_INIT(epp) (epp)->ep_flags |= EXEC_TOPDOWN_VM #else #define MD_TOPDOWN_INIT(epp) #endif #endif struct execve_data; extern int user_va0_disable; static size_t calcargs(struct execve_data * restrict, const size_t); static size_t calcstack(struct execve_data * restrict, const size_t); static int copyoutargs(struct execve_data * restrict, struct lwp *, char * const); static int copyoutpsstrs(struct execve_data * restrict, struct proc *); static int copyinargs(struct execve_data * restrict, char * const *, char * const *, execve_fetch_element_t, char **); static int copyinargstrs(struct execve_data * restrict, char * const *, execve_fetch_element_t, char **, size_t *, void (*)(const void *, size_t)); static int exec_sigcode_map(struct proc *, const struct emul *); #if defined(DEBUG) && !defined(DEBUG_EXEC) #define DEBUG_EXEC #endif #ifdef DEBUG_EXEC #define DPRINTF(a) printf a #define COPYPRINTF(s, a, b) printf("%s, %d: copyout%s @%p %zu\n", __func__, \ __LINE__, (s), (a), (b)) static void dump_vmcmds(const struct exec_package * const, size_t, int); #define DUMPVMCMDS(p, x, e) do { dump_vmcmds((p), (x), (e)); } while (0) #else #define DPRINTF(a) #define COPYPRINTF(s, a, b) #define DUMPVMCMDS(p, x, e) do {} while (0) #endif /* DEBUG_EXEC */ /* * DTrace SDT provider definitions */ SDT_PROVIDER_DECLARE(proc); SDT_PROBE_DEFINE1(proc, kernel, , exec, "char *"); SDT_PROBE_DEFINE1(proc, kernel, , exec__success, "char *"); SDT_PROBE_DEFINE1(proc, kernel, , exec__failure, "int"); /* * Exec function switch: * * Note that each makecmds function is responsible for loading the * exec package with the necessary functions for any exec-type-specific * handling. * * Functions for specific exec types should be defined in their own * header file. */ static const struct execsw **execsw = NULL; static int nexecs; u_int exec_maxhdrsz; /* must not be static - used by netbsd32 */ /* list of dynamically loaded execsw entries */ static LIST_HEAD(execlist_head, exec_entry) ex_head = LIST_HEAD_INITIALIZER(ex_head); struct exec_entry { LIST_ENTRY(exec_entry) ex_list; SLIST_ENTRY(exec_entry) ex_slist; const struct execsw *ex_sw; }; #ifndef __HAVE_SYSCALL_INTERN void syscall(void); #endif /* NetBSD autoloadable syscalls */ #ifdef MODULAR #include #endif /* NetBSD emul struct */ struct emul emul_netbsd = { .e_name = "netbsd", #ifdef EMUL_NATIVEROOT .e_path = EMUL_NATIVEROOT, #else .e_path = NULL, #endif #ifndef __HAVE_MINIMAL_EMUL .e_flags = EMUL_HAS_SYS___syscall, .e_errno = NULL, .e_nosys = SYS_syscall, .e_nsysent = SYS_NSYSENT, #endif #ifdef MODULAR .e_sc_autoload = netbsd_syscalls_autoload, #endif .e_sysent = sysent, .e_nomodbits = sysent_nomodbits, #ifdef SYSCALL_DEBUG .e_syscallnames = syscallnames, #else .e_syscallnames = NULL, #endif .e_sendsig = sendsig, .e_trapsignal = trapsignal, .e_sigcode = NULL, .e_esigcode = NULL, .e_sigobject = NULL, .e_setregs = setregs, .e_proc_exec = NULL, .e_proc_fork = NULL, .e_proc_exit = NULL, .e_lwp_fork = NULL, .e_lwp_exit = NULL, #ifdef __HAVE_SYSCALL_INTERN .e_syscall_intern = syscall_intern, #else .e_syscall = syscall, #endif .e_sysctlovly = NULL, .e_vm_default_addr = uvm_default_mapaddr, .e_usertrap = NULL, .e_ucsize = sizeof(ucontext_t), .e_startlwp = startlwp }; /* * Exec lock. Used to control access to execsw[] structures. * This must not be static so that netbsd32 can access it, too. */ krwlock_t exec_lock __cacheline_aligned; /* * Data used between a loadvm and execve part of an "exec" operation */ struct execve_data { struct exec_package ed_pack; struct pathbuf *ed_pathbuf; struct vattr ed_attr; struct ps_strings ed_arginfo; char *ed_argp; const char *ed_pathstring; char *ed_resolvedname; size_t ed_ps_strings_sz; int ed_szsigcode; size_t ed_argslen; long ed_argc; long ed_envc; }; /* * data passed from parent lwp to child during a posix_spawn() */ struct spawn_exec_data { struct execve_data sed_exec; struct posix_spawn_file_actions *sed_actions; struct posix_spawnattr *sed_attrs; struct proc *sed_parent; kcondvar_t sed_cv_child_ready; kmutex_t sed_mtx_child; int sed_error; volatile uint32_t sed_refcnt; }; static struct vm_map *exec_map; static struct pool exec_pool; static void * exec_pool_alloc(struct pool *pp, int flags) { return (void *)uvm_km_alloc(exec_map, NCARGS, 0, UVM_KMF_PAGEABLE | UVM_KMF_WAITVA); } static void exec_pool_free(struct pool *pp, void *addr) { uvm_km_free(exec_map, (vaddr_t)addr, NCARGS, UVM_KMF_PAGEABLE); } static struct pool_allocator exec_palloc = { .pa_alloc = exec_pool_alloc, .pa_free = exec_pool_free, .pa_pagesz = NCARGS }; static void exec_path_free(struct execve_data *data) { pathbuf_stringcopy_put(data->ed_pathbuf, data->ed_pathstring); pathbuf_destroy(data->ed_pathbuf); if (data->ed_resolvedname) PNBUF_PUT(data->ed_resolvedname); } static int exec_resolvename(struct lwp *l, struct exec_package *epp, struct vnode *vp, char **rpath) { int error; char *p; KASSERT(rpath != NULL); *rpath = PNBUF_GET(); error = vnode_to_path(*rpath, MAXPATHLEN, vp, l, l->l_proc); if (error) { DPRINTF(("%s: can't resolve name for %s, error %d\n", __func__, epp->ep_kname, error)); PNBUF_PUT(*rpath); *rpath = NULL; return error; } epp->ep_resolvedname = *rpath; if ((p = strrchr(*rpath, '/')) != NULL) epp->ep_kname = p + 1; return 0; } /* * check exec: * given an "executable" described in the exec package's namei info, * see what we can do with it. * * ON ENTRY: * exec package with appropriate namei info * lwp pointer of exec'ing lwp * NO SELF-LOCKED VNODES * * ON EXIT: * error: nothing held, etc. exec header still allocated. * ok: filled exec package, executable's vnode (unlocked). * * EXEC SWITCH ENTRY: * Locked vnode to check, exec package, proc. * * EXEC SWITCH EXIT: * ok: return 0, filled exec package, executable's vnode (unlocked). * error: destructive: * everything deallocated execept exec header. * non-destructive: * error code, executable's vnode (unlocked), * exec header unmodified. */ int /*ARGSUSED*/ check_exec(struct lwp *l, struct exec_package *epp, struct pathbuf *pb, char **rpath) { int error, i; struct vnode *vp; size_t resid; if (epp->ep_resolvedname) { struct nameidata nd; // grab the absolute pathbuf here before namei() trashes it. pathbuf_copystring(pb, epp->ep_resolvedname, PATH_MAX); NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | TRYEMULROOT, pb); /* first get the vnode */ if ((error = namei(&nd)) != 0) return error; epp->ep_vp = vp = nd.ni_vp; #ifdef DIAGNOSTIC /* paranoia (take this out once namei stuff stabilizes) */ memset(nd.ni_pnbuf, '~', PATH_MAX); #endif } else { struct file *fp; if ((error = fd_getvnode(epp->ep_xfd, &fp)) != 0) return error; epp->ep_vp = vp = fp->f_vnode; vref(vp); fd_putfile(epp->ep_xfd); if ((error = exec_resolvename(l, epp, vp, rpath)) != 0) return error; vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); } /* check access and type */ if (vp->v_type != VREG) { error = SET_ERROR(EACCES); goto bad1; } if ((error = VOP_ACCESS(vp, VEXEC, l->l_cred)) != 0) goto bad1; /* get attributes */ /* XXX VOP_GETATTR is the only thing that needs LK_EXCLUSIVE here */ if ((error = VOP_GETATTR(vp, epp->ep_vap, l->l_cred)) != 0) goto bad1; /* Check mount point */ if (vp->v_mount->mnt_flag & MNT_NOEXEC) { error = SET_ERROR(EACCES); goto bad1; } if (vp->v_mount->mnt_flag & MNT_NOSUID) epp->ep_vap->va_mode &= ~(S_ISUID | S_ISGID); /* try to open it */ if ((error = VOP_OPEN(vp, FREAD, l->l_cred)) != 0) goto bad1; /* now we have the file, get the exec header */ error = vn_rdwr(UIO_READ, vp, epp->ep_hdr, epp->ep_hdrlen, 0, UIO_SYSSPACE, IO_NODELOCKED, l->l_cred, &resid, NULL); if (error) goto bad1; /* unlock vp, since we need it unlocked from here on out. */ VOP_UNLOCK(vp); #if NVERIEXEC > 0 error = veriexec_verify(l, vp, epp->ep_resolvedname ? epp->ep_resolvedname : epp->ep_kname, epp->ep_flags & EXEC_INDIR ? VERIEXEC_INDIRECT : VERIEXEC_DIRECT, NULL); if (error) goto bad2; #endif /* NVERIEXEC > 0 */ #ifdef PAX_SEGVGUARD error = pax_segvguard(l, vp, epp->ep_resolvedname, false); if (error) goto bad2; #endif /* PAX_SEGVGUARD */ epp->ep_hdrvalid = epp->ep_hdrlen - resid; /* * Set up default address space limits. Can be overridden * by individual exec packages. */ epp->ep_vm_minaddr = exec_vm_minaddr(VM_MIN_ADDRESS); epp->ep_vm_maxaddr = VM_MAXUSER_ADDRESS; /* * set up the vmcmds for creation of the process * address space */ error = nexecs == 0 ? SET_ERROR(ENOEXEC) : ENOEXEC; for (i = 0; i < nexecs; i++) { int newerror; epp->ep_esch = execsw[i]; newerror = (*execsw[i]->es_makecmds)(l, epp); if (!newerror) { /* Seems ok: check that entry point is not too high */ if (epp->ep_entry >= epp->ep_vm_maxaddr) { #ifdef DIAGNOSTIC printf("%s: rejecting %p due to " "too high entry address (>= %p)\n", __func__, (void *)epp->ep_entry, (void *)epp->ep_vm_maxaddr); #endif error = SET_ERROR(ENOEXEC); break; } /* Seems ok: check that entry point is not too low */ if (epp->ep_entry < epp->ep_vm_minaddr) { #ifdef DIAGNOSTIC printf("%s: rejecting %p due to " "too low entry address (< %p)\n", __func__, (void *)epp->ep_entry, (void *)epp->ep_vm_minaddr); #endif error = SET_ERROR(ENOEXEC); break; } /* check limits */ #ifdef DIAGNOSTIC #define LMSG "%s: rejecting due to %s limit (%ju > %ju)\n" #endif #ifdef MAXTSIZ if (epp->ep_tsize > MAXTSIZ) { #ifdef DIAGNOSTIC printf(LMSG, __func__, "text", (uintmax_t)epp->ep_tsize, (uintmax_t)MAXTSIZ); #endif error = SET_ERROR(ENOMEM); break; } #endif vsize_t dlimit = (vsize_t)l->l_proc->p_rlimit[RLIMIT_DATA].rlim_cur; if (epp->ep_dsize > dlimit) { #ifdef DIAGNOSTIC printf(LMSG, __func__, "data", (uintmax_t)epp->ep_dsize, (uintmax_t)dlimit); #endif error = SET_ERROR(ENOMEM); break; } return 0; } /* * Reset all the fields that may have been modified by the * loader. */ KASSERT(epp->ep_emul_arg == NULL); if (epp->ep_emul_root != NULL) { vrele(epp->ep_emul_root); epp->ep_emul_root = NULL; } if (epp->ep_interp != NULL) { vrele(epp->ep_interp); epp->ep_interp = NULL; } epp->ep_pax_flags = 0; /* make sure the first "interesting" error code is saved. */ if (error == ENOEXEC) error = newerror; if (epp->ep_flags & EXEC_DESTR) /* Error from "#!" code, tidied up by recursive call */ return error; } /* not found, error */ /* * free any vmspace-creation commands, * and release their references */ kill_vmcmds(&epp->ep_vmcmds); #if NVERIEXEC > 0 || defined(PAX_SEGVGUARD) bad2: #endif /* * close and release the vnode, restore the old one, free the * pathname buf, and punt. */ vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); VOP_CLOSE(vp, FREAD, l->l_cred); vput(vp); return error; bad1: /* * free the namei pathname buffer, and put the vnode * (which we don't yet have open). */ vput(vp); /* was still locked */ return error; } #ifdef __MACHINE_STACK_GROWS_UP #define STACK_PTHREADSPACE NBPG #else #define STACK_PTHREADSPACE 0 #endif static int execve_fetch_element(char * const *array, size_t index, char **value) { return copyin(array + index, value, sizeof(*value)); } /* * exec system call */ int sys_execve(struct lwp *l, const struct sys_execve_args *uap, register_t *retval) { /* { syscallarg(const char *) path; syscallarg(char * const *) argp; syscallarg(char * const *) envp; } */ return execve1(l, true, SCARG(uap, path), -1, SCARG(uap, argp), SCARG(uap, envp), execve_fetch_element); } int sys_fexecve(struct lwp *l, const struct sys_fexecve_args *uap, register_t *retval) { /* { syscallarg(int) fd; syscallarg(char * const *) argp; syscallarg(char * const *) envp; } */ return execve1(l, false, NULL, SCARG(uap, fd), SCARG(uap, argp), SCARG(uap, envp), execve_fetch_element); } /* * Load modules to try and execute an image that we do not understand. * If no execsw entries are present, we load those likely to be needed * in order to run native images only. Otherwise, we autoload all * possible modules that could let us run the binary. XXX lame */ static void exec_autoload(void) { #ifdef MODULAR static const char * const native[] = { "exec_elf32", "exec_elf64", "exec_script", NULL }; static const char * const compat[] = { "exec_elf32", "exec_elf64", "exec_script", "exec_aout", "exec_coff", "exec_ecoff", "compat_aoutm68k", "compat_netbsd32", #if 0 "compat_linux", "compat_linux32", #endif "compat_sunos", "compat_sunos32", "compat_ultrix", NULL }; char const * const *list; int i; list = nexecs == 0 ? native : compat; for (i = 0; list[i] != NULL; i++) { if (module_autoload(list[i], MODULE_CLASS_EXEC) != 0) { continue; } yield(); } #endif } /* * Copy the user or kernel supplied upath to the allocated pathbuffer pbp * making it absolute in the process, by prepending the current working * directory if it is not. If offs is supplied it will contain the offset * where the original supplied copy of upath starts. */ int exec_makepathbuf(struct lwp *l, const char *upath, enum uio_seg seg, struct pathbuf **pbp, size_t *offs) { char *path, *bp; size_t len, tlen; int error; struct cwdinfo *cwdi; path = PNBUF_GET(); if (seg == UIO_SYSSPACE) { error = copystr(upath, path, MAXPATHLEN, &len); } else { error = copyinstr(upath, path, MAXPATHLEN, &len); } if (error) goto err; if (path[0] == '/') { if (offs) *offs = 0; goto out; } len++; if (len + 1 >= MAXPATHLEN) { error = SET_ERROR(ENAMETOOLONG); goto err; } bp = path + MAXPATHLEN - len; memmove(bp, path, len); *(--bp) = '/'; cwdi = l->l_proc->p_cwdi; rw_enter(&cwdi->cwdi_lock, RW_READER); error = getcwd_common(cwdi->cwdi_cdir, NULL, &bp, path, MAXPATHLEN / 2, GETCWD_CHECK_ACCESS, l); rw_exit(&cwdi->cwdi_lock); if (error) goto err; tlen = path + MAXPATHLEN - bp; memmove(path, bp, tlen); path[tlen - 1] = '\0'; if (offs) *offs = tlen - len; out: *pbp = pathbuf_assimilate(path); return 0; err: PNBUF_PUT(path); return error; } vaddr_t exec_vm_minaddr(vaddr_t va_min) { /* * Increase va_min if we don't want NULL to be mappable by the * process. */ #define VM_MIN_GUARD PAGE_SIZE if (user_va0_disable && (va_min < VM_MIN_GUARD)) return VM_MIN_GUARD; return va_min; } static int execve_loadvm(struct lwp *l, bool has_path, const char *path, int fd, char * const *args, char * const *envs, execve_fetch_element_t fetch_element, struct execve_data * restrict data) { struct exec_package * const epp = &data->ed_pack; int error; struct proc *p; char *dp; u_int modgen; KASSERT(data != NULL); p = l->l_proc; modgen = 0; SDT_PROBE(proc, kernel, , exec, path, 0, 0, 0, 0); /* * Check if we have exceeded our number of processes limit. * This is so that we handle the case where a root daemon * forked, ran setuid to become the desired user and is trying * to exec. The obvious place to do the reference counting check * is setuid(), but we don't do the reference counting check there * like other OS's do because then all the programs that use setuid() * must be modified to check the return code of setuid() and exit(). * It is dangerous to make setuid() fail, because it fails open and * the program will continue to run as root. If we make it succeed * and return an error code, again we are not enforcing the limit. * The best place to enforce the limit is here, when the process tries * to execute a new image, because eventually the process will need * to call exec in order to do something useful. */ retry: if (p->p_flag & PK_SUGID) { if (kauth_authorize_process(l->l_cred, KAUTH_PROCESS_RLIMIT, p, KAUTH_ARG(KAUTH_REQ_PROCESS_RLIMIT_BYPASS), &p->p_rlimit[RLIMIT_NPROC], KAUTH_ARG(RLIMIT_NPROC)) != 0 && chgproccnt(kauth_cred_getuid(l->l_cred), 0) > p->p_rlimit[RLIMIT_NPROC].rlim_cur) return SET_ERROR(EAGAIN); } /* * Drain existing references and forbid new ones. The process * should be left alone until we're done here. This is necessary * to avoid race conditions - e.g. in ptrace() - that might allow * a local user to illicitly obtain elevated privileges. */ rw_enter(&p->p_reflock, RW_WRITER); if (has_path) { size_t offs; /* * Init the namei data to point the file user's program name. * This is done here rather than in check_exec(), so that it's * possible to override this settings if any of makecmd/probe * functions call check_exec() recursively - for example, * see exec_script_makecmds(). */ if ((error = exec_makepathbuf(l, path, UIO_USERSPACE, &data->ed_pathbuf, &offs)) != 0) goto clrflg; data->ed_pathstring = pathbuf_stringcopy_get(data->ed_pathbuf); epp->ep_kname = data->ed_pathstring + offs; data->ed_resolvedname = PNBUF_GET(); epp->ep_resolvedname = data->ed_resolvedname; epp->ep_xfd = -1; } else { data->ed_pathbuf = pathbuf_assimilate(strcpy(PNBUF_GET(), "/")); data->ed_pathstring = pathbuf_stringcopy_get(data->ed_pathbuf); epp->ep_kname = "*fexecve*"; data->ed_resolvedname = NULL; epp->ep_resolvedname = NULL; epp->ep_xfd = fd; } /* * initialize the fields of the exec package. */ epp->ep_hdr = kmem_alloc(exec_maxhdrsz, KM_SLEEP); epp->ep_hdrlen = exec_maxhdrsz; epp->ep_hdrvalid = 0; epp->ep_emul_arg = NULL; epp->ep_emul_arg_free = NULL; memset(&epp->ep_vmcmds, 0, sizeof(epp->ep_vmcmds)); epp->ep_vap = &data->ed_attr; epp->ep_flags = (p->p_flag & PK_32) ? EXEC_FROM32 : 0; MD_TOPDOWN_INIT(epp); epp->ep_emul_root = NULL; epp->ep_interp = NULL; epp->ep_esch = NULL; epp->ep_pax_flags = 0; memset(epp->ep_machine_arch, 0, sizeof(epp->ep_machine_arch)); rw_enter(&exec_lock, RW_READER); /* see if we can run it. */ if ((error = check_exec(l, epp, data->ed_pathbuf, &data->ed_resolvedname)) != 0) { if (error != ENOENT && error != EACCES && error != ENOEXEC) { DPRINTF(("%s: check exec failed for %s, error %d\n", __func__, epp->ep_kname, error)); } goto freehdr; } /* allocate an argument buffer */ data->ed_argp = pool_get(&exec_pool, PR_WAITOK); KASSERT(data->ed_argp != NULL); dp = data->ed_argp; if ((error = copyinargs(data, args, envs, fetch_element, &dp)) != 0) { goto bad; } /* * Calculate the new stack size. */ #ifdef __MACHINE_STACK_GROWS_UP /* * copyargs() fills argc/argv/envp from the lower address even on * __MACHINE_STACK_GROWS_UP machines. Reserve a few words just below the SP * so that _rtld() use it. */ #define RTLD_GAP 32 #else #define RTLD_GAP 0 #endif const size_t argenvstrlen = (char *)ALIGN(dp) - data->ed_argp; data->ed_argslen = calcargs(data, argenvstrlen); const size_t len = calcstack(data, pax_aslr_stack_gap(epp) + RTLD_GAP); if (len > epp->ep_ssize) { /* in effect, compare to initial limit */ DPRINTF(("%s: stack limit exceeded %zu\n", __func__, len)); error = SET_ERROR(ENOMEM); goto bad; } /* adjust "active stack depth" for process VSZ */ epp->ep_ssize = len; return 0; bad: /* free the vmspace-creation commands, and release their references */ kill_vmcmds(&epp->ep_vmcmds); /* kill any opened file descriptor, if necessary */ if (epp->ep_flags & EXEC_HASFD) { epp->ep_flags &= ~EXEC_HASFD; fd_close(epp->ep_fd); } /* close and put the exec'd file */ vn_lock(epp->ep_vp, LK_EXCLUSIVE | LK_RETRY); VOP_CLOSE(epp->ep_vp, FREAD, l->l_cred); vput(epp->ep_vp); pool_put(&exec_pool, data->ed_argp); freehdr: kmem_free(epp->ep_hdr, epp->ep_hdrlen); if (epp->ep_emul_root != NULL) vrele(epp->ep_emul_root); if (epp->ep_interp != NULL) vrele(epp->ep_interp); rw_exit(&exec_lock); exec_path_free(data); clrflg: rw_exit(&p->p_reflock); if (modgen != module_gen && error == ENOEXEC) { modgen = module_gen; exec_autoload(); goto retry; } SDT_PROBE(proc, kernel, , exec__failure, error, 0, 0, 0, 0); return error; } static int execve_dovmcmds(struct lwp *l, struct execve_data * restrict data) { struct exec_package * const epp = &data->ed_pack; struct proc *p = l->l_proc; struct exec_vmcmd *base_vcp; int error = 0; size_t i; /* record proc's vnode, for use by procfs and others */ if (p->p_textvp) vrele(p->p_textvp); vref(epp->ep_vp); p->p_textvp = epp->ep_vp; /* create the new process's VM space by running the vmcmds */ KASSERTMSG(epp->ep_vmcmds.evs_used != 0, "%s: no vmcmds", __func__); #ifdef TRACE_EXEC DUMPVMCMDS(epp, 0, 0); #endif base_vcp = NULL; 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) { KASSERTMSG(base_vcp != NULL, "%s: relative vmcmd with no base", __func__); KASSERTMSG((vcp->ev_flags & VMCMD_BASE) == 0, "%s: illegal base & relative vmcmd", __func__); vcp->ev_addr += base_vcp->ev_addr; } error = (*vcp->ev_proc)(l, vcp); if (error) DUMPVMCMDS(epp, i, error); if (vcp->ev_flags & VMCMD_BASE) base_vcp = vcp; } /* free the vmspace-creation commands, and release their references */ kill_vmcmds(&epp->ep_vmcmds); vn_lock(epp->ep_vp, LK_EXCLUSIVE | LK_RETRY); VOP_CLOSE(epp->ep_vp, FREAD, l->l_cred); vput(epp->ep_vp); /* if an error happened, deallocate and punt */ if (error != 0) { DPRINTF(("%s: vmcmd %zu failed: %d\n", __func__, i - 1, error)); } return error; } static void execve_free_data(struct execve_data *data) { struct exec_package * const epp = &data->ed_pack; /* free the vmspace-creation commands, and release their references */ kill_vmcmds(&epp->ep_vmcmds); /* kill any opened file descriptor, if necessary */ if (epp->ep_flags & EXEC_HASFD) { epp->ep_flags &= ~EXEC_HASFD; fd_close(epp->ep_fd); } /* close and put the exec'd file */ vn_lock(epp->ep_vp, LK_EXCLUSIVE | LK_RETRY); VOP_CLOSE(epp->ep_vp, FREAD, curlwp->l_cred); vput(epp->ep_vp); pool_put(&exec_pool, data->ed_argp); kmem_free(epp->ep_hdr, epp->ep_hdrlen); if (epp->ep_emul_root != NULL) vrele(epp->ep_emul_root); if (epp->ep_interp != NULL) vrele(epp->ep_interp); exec_path_free(data); } static void pathexec(struct proc *p, const char *resolvedname) { /* set command name & other accounting info */ const char *cmdname; if (resolvedname == NULL) { cmdname = "*fexecve*"; resolvedname = "/"; } else { cmdname = strrchr(resolvedname, '/') + 1; } KASSERTMSG(resolvedname[0] == '/', "bad resolvedname `%s'", resolvedname); strlcpy(p->p_comm, cmdname, sizeof(p->p_comm)); kmem_strfree(p->p_path); p->p_path = kmem_strdupsize(resolvedname, NULL, KM_SLEEP); } /* XXX elsewhere */ static int credexec(struct lwp *l, struct execve_data *data) { struct proc *p = l->l_proc; struct vattr *attr = &data->ed_attr; int error; /* * Deal with set[ug]id. MNT_NOSUID has already been used to disable * s[ug]id. It's OK to check for PSL_TRACED here as we have blocked * out additional references on the process for the moment. */ if ((p->p_slflag & PSL_TRACED) == 0 && (((attr->va_mode & S_ISUID) != 0 && kauth_cred_geteuid(l->l_cred) != attr->va_uid) || ((attr->va_mode & S_ISGID) != 0 && kauth_cred_getegid(l->l_cred) != attr->va_gid))) { /* * Mark the process as SUGID before we do * anything that might block. */ proc_crmod_enter(); proc_crmod_leave(NULL, NULL, true); if (data->ed_argc == 0) { DPRINTF(( "%s: not executing set[ug]id binary with no args\n", __func__)); return SET_ERROR(EINVAL); } /* Make sure file descriptors 0..2 are in use. */ if ((error = fd_checkstd()) != 0) { DPRINTF(("%s: fdcheckstd failed %d\n", __func__, error)); return error; } /* * Copy the credential so other references don't see our * changes. */ l->l_cred = kauth_cred_copy(l->l_cred); #ifdef KTRACE /* * If the persistent trace flag isn't set, turn off. */ if (p->p_tracep) { mutex_enter(&ktrace_lock); if (!(p->p_traceflag & KTRFAC_PERSISTENT)) ktrderef(p); mutex_exit(&ktrace_lock); } #endif if (attr->va_mode & S_ISUID) kauth_cred_seteuid(l->l_cred, attr->va_uid); if (attr->va_mode & S_ISGID) kauth_cred_setegid(l->l_cred, attr->va_gid); } else { if (kauth_cred_geteuid(l->l_cred) == kauth_cred_getuid(l->l_cred) && kauth_cred_getegid(l->l_cred) == kauth_cred_getgid(l->l_cred)) p->p_flag &= ~PK_SUGID; } /* * Copy the credential so other references don't see our changes. * Test to see if this is necessary first, since in the common case * we won't need a private reference. */ if (kauth_cred_geteuid(l->l_cred) != kauth_cred_getsvuid(l->l_cred) || kauth_cred_getegid(l->l_cred) != kauth_cred_getsvgid(l->l_cred)) { l->l_cred = kauth_cred_copy(l->l_cred); kauth_cred_setsvuid(l->l_cred, kauth_cred_geteuid(l->l_cred)); kauth_cred_setsvgid(l->l_cred, kauth_cred_getegid(l->l_cred)); } /* Update the master credentials. */ if (l->l_cred != p->p_cred) { kauth_cred_t ocred; mutex_enter(p->p_lock); ocred = p->p_cred; p->p_cred = kauth_cred_hold(l->l_cred); mutex_exit(p->p_lock); kauth_cred_free(ocred); } return 0; } static void emulexec(struct lwp *l, struct exec_package *epp) { struct proc *p = l->l_proc; /* The emulation root will usually have been found when we looked * for the elf interpreter (or similar), if not look now. */ if (epp->ep_esch->es_emul->e_path != NULL && epp->ep_emul_root == NULL) emul_find_root(l, epp); /* Any old emulation root got removed by fdcloseexec */ rw_enter(&p->p_cwdi->cwdi_lock, RW_WRITER); p->p_cwdi->cwdi_edir = epp->ep_emul_root; rw_exit(&p->p_cwdi->cwdi_lock); epp->ep_emul_root = NULL; if (epp->ep_interp != NULL) vrele(epp->ep_interp); /* * Call emulation specific exec hook. This can setup per-process * p->p_emuldata or do any other per-process stuff an emulation needs. * * If we are executing process of different emulation than the * original forked process, call e_proc_exit() of the old emulation * first, then e_proc_exec() of new emulation. If the emulation is * same, the exec hook code should deallocate any old emulation * resources held previously by this process. */ if (p->p_emul && p->p_emul->e_proc_exit && p->p_emul != epp->ep_esch->es_emul) (*p->p_emul->e_proc_exit)(p); /* * Call exec hook. Emulation code may NOT store reference to anything * from &pack. */ if (epp->ep_esch->es_emul->e_proc_exec) (*epp->ep_esch->es_emul->e_proc_exec)(p, epp); /* update p_emul, the old value is no longer needed */ p->p_emul = epp->ep_esch->es_emul; /* ...and the same for p_execsw */ p->p_execsw = epp->ep_esch; #ifdef __HAVE_SYSCALL_INTERN (*p->p_emul->e_syscall_intern)(p); #endif ktremul(); } static int execve_runproc(struct lwp *l, struct execve_data * restrict data, bool no_local_exec_lock, bool is_spawn) { struct exec_package * const epp = &data->ed_pack; int error = 0; struct proc *p; struct vmspace *vm; /* * In case of a posix_spawn operation, the child doing the exec * might not hold the reader lock on exec_lock, but the parent * will do this instead. */ KASSERT(no_local_exec_lock || rw_lock_held(&exec_lock)); KASSERT(!no_local_exec_lock || is_spawn); KASSERT(data != NULL); p = l->l_proc; /* Get rid of other LWPs. */ if (p->p_nlwps > 1) { mutex_enter(p->p_lock); exit_lwps(l); mutex_exit(p->p_lock); } KDASSERT(p->p_nlwps == 1); /* * All of the other LWPs got rid of their robust futexes * when they exited above, but we might still have some * to dispose of. Do that now. */ if (__predict_false(l->l_robust_head != 0)) { futex_release_all_lwp(l); /* * Since this LWP will live on with a different * program image, we need to clear the robust * futex list pointer here. */ l->l_robust_head = 0; } /* Destroy any lwpctl info. */ if (p->p_lwpctl != NULL) lwp_ctl_exit(); /* Remove POSIX timers */ ptimers_free(p, TIMERS_POSIX); /* Set the PaX flags. */ pax_set_flags(epp, p); /* * Do whatever is necessary to prepare the address space * for remapping. Note that this might replace the current * vmspace with another! * * vfork(): do not touch any user space data in the new child * until we have awoken the parent below, or it will defeat * lazy pmap switching (on x86). */ if (is_spawn) uvmspace_spawn(l, epp->ep_vm_minaddr, epp->ep_vm_maxaddr, epp->ep_flags & EXEC_TOPDOWN_VM); else uvmspace_exec(l, epp->ep_vm_minaddr, epp->ep_vm_maxaddr, epp->ep_flags & EXEC_TOPDOWN_VM); vm = p->p_vmspace; vm->vm_taddr = (void *)epp->ep_taddr; vm->vm_tsize = btoc(epp->ep_tsize); vm->vm_daddr = (void*)epp->ep_daddr; vm->vm_dsize = btoc(epp->ep_dsize); vm->vm_ssize = btoc(epp->ep_ssize); vm->vm_issize = 0; vm->vm_maxsaddr = (void *)epp->ep_maxsaddr; vm->vm_minsaddr = (void *)epp->ep_minsaddr; pax_aslr_init_vm(l, vm, epp); cwdexec(p); fd_closeexec(); /* handle close on exec */ if (__predict_false(ktrace_on)) fd_ktrexecfd(); execsigs(p); /* reset caught signals */ mutex_enter(p->p_lock); l->l_ctxlink = NULL; /* reset ucontext link */ p->p_acflag &= ~AFORK; p->p_flag |= PK_EXEC; mutex_exit(p->p_lock); error = credexec(l, data); if (error) goto exec_abort; #if defined(__HAVE_RAS) /* * Remove all RASs from the address space. */ ras_purgeall(); #endif /* * Stop profiling. */ if ((p->p_stflag & PST_PROFIL) != 0) { mutex_spin_enter(&p->p_stmutex); stopprofclock(p); mutex_spin_exit(&p->p_stmutex); } /* * It's OK to test PL_PPWAIT unlocked here, as other LWPs have * exited and exec()/exit() are the only places it will be cleared. * * Once the parent has been awoken, curlwp may teleport to a new CPU * in sched_vforkexec(), and it's then OK to start messing with user * data. See comment above. */ if ((p->p_lflag & PL_PPWAIT) != 0) { bool samecpu; lwp_t *lp; mutex_enter(&proc_lock); lp = p->p_vforklwp; p->p_vforklwp = NULL; l->l_lwpctl = NULL; /* was on loan from blocked parent */ /* Clear flags after cv_broadcast() (scheduler needs them). */ p->p_lflag &= ~PL_PPWAIT; lp->l_vforkwaiting = false; /* If parent is still on same CPU, teleport curlwp elsewhere. */ samecpu = (lp->l_cpu == curlwp->l_cpu); cv_broadcast(&lp->l_waitcv); mutex_exit(&proc_lock); /* Give the parent its CPU back - find a new home. */ KASSERT(!is_spawn); sched_vforkexec(l, samecpu); } /* Now map address space. */ error = execve_dovmcmds(l, data); if (error != 0) goto exec_abort; pathexec(p, epp->ep_resolvedname); char * const newstack = STACK_GROW(vm->vm_minsaddr, epp->ep_ssize); error = copyoutargs(data, l, newstack); if (error != 0) goto exec_abort; doexechooks(p); /* * Set initial SP at the top of the stack. * * Note that on machines where stack grows up (e.g. hppa), SP points to * the end of arg/env strings. Userland guesses the address of argc * via ps_strings::ps_argvstr. */ /* Setup new registers and do misc. setup. */ (*epp->ep_esch->es_emul->e_setregs)(l, epp, (vaddr_t)newstack); if (epp->ep_esch->es_setregs) (*epp->ep_esch->es_setregs)(l, epp, (vaddr_t)newstack); /* Provide a consistent LWP private setting */ (void)lwp_setprivate(l, NULL); /* Discard all PCU state; need to start fresh */ pcu_discard_all(l); /* map the process's signal trampoline code */ if ((error = exec_sigcode_map(p, epp->ep_esch->es_emul)) != 0) { DPRINTF(("%s: map sigcode failed %d\n", __func__, error)); goto exec_abort; } pool_put(&exec_pool, data->ed_argp); /* * Notify anyone who might care that we've exec'd. * * This is slightly racy; someone could sneak in and * attach a knote after we've decided not to notify, * or vice-versa, but that's not particularly bothersome. * knote_proc_exec() will acquire p->p_lock as needed. */ if (!SLIST_EMPTY(&p->p_klist)) { knote_proc_exec(p); } kmem_free(epp->ep_hdr, epp->ep_hdrlen); SDT_PROBE(proc, kernel, , exec__success, epp->ep_kname, 0, 0, 0, 0); emulexec(l, epp); /* Allow new references from the debugger/procfs. */ rw_exit(&p->p_reflock); if (!no_local_exec_lock) rw_exit(&exec_lock); mutex_enter(&proc_lock); /* posix_spawn(3) reports a single event with implied exec(3) */ if ((p->p_slflag & PSL_TRACED) && !is_spawn) { mutex_enter(p->p_lock); eventswitch(TRAP_EXEC, 0, 0); mutex_enter(&proc_lock); } if (p->p_sflag & PS_STOPEXEC) { ksiginfoq_t kq; KASSERT(l->l_blcnt == 0); p->p_pptr->p_nstopchild++; p->p_waited = 0; mutex_enter(p->p_lock); ksiginfo_queue_init(&kq); sigclearall(p, &contsigmask, &kq); lwp_lock(l); l->l_stat = LSSTOP; p->p_stat = SSTOP; p->p_nrlwps--; lwp_unlock(l); mutex_exit(p->p_lock); mutex_exit(&proc_lock); lwp_lock(l); spc_lock(l->l_cpu); mi_switch(l); ksiginfo_queue_drain(&kq); } else { mutex_exit(&proc_lock); } exec_path_free(data); #ifdef TRACE_EXEC DPRINTF(("%s finished\n", __func__)); #endif return EJUSTRETURN; exec_abort: SDT_PROBE(proc, kernel, , exec__failure, error, 0, 0, 0, 0); rw_exit(&p->p_reflock); if (!no_local_exec_lock) rw_exit(&exec_lock); exec_path_free(data); /* * the old process doesn't exist anymore. exit gracefully. * get rid of the (new) address space we have created, if any, get rid * of our namei data and vnode, and exit noting failure */ if (vm != NULL) { uvm_deallocate(&vm->vm_map, VM_MIN_ADDRESS, VM_MAXUSER_ADDRESS - VM_MIN_ADDRESS); } exec_free_emul_arg(epp); pool_put(&exec_pool, data->ed_argp); kmem_free(epp->ep_hdr, epp->ep_hdrlen); if (epp->ep_emul_root != NULL) vrele(epp->ep_emul_root); if (epp->ep_interp != NULL) vrele(epp->ep_interp); /* Acquire the sched-state mutex (exit1() will release it). */ if (!is_spawn) { mutex_enter(p->p_lock); exit1(l, error, SIGABRT); } return error; } int execve1(struct lwp *l, bool has_path, const char *path, int fd, char * const *args, char * const *envs, execve_fetch_element_t fetch_element) { struct execve_data data; int error; error = execve_loadvm(l, has_path, path, fd, args, envs, fetch_element, &data); if (error) return error; error = execve_runproc(l, &data, false, false); return error; } static size_t fromptrsz(const struct exec_package *epp) { return (epp->ep_flags & EXEC_FROM32) ? sizeof(int) : sizeof(char *); } static size_t ptrsz(const struct exec_package *epp) { return (epp->ep_flags & EXEC_32) ? sizeof(int) : sizeof(char *); } static size_t calcargs(struct execve_data * restrict data, const size_t argenvstrlen) { struct exec_package * const epp = &data->ed_pack; const size_t nargenvptrs = 1 + /* long argc */ data->ed_argc + /* char *argv[] */ 1 + /* \0 */ data->ed_envc + /* char *env[] */ 1; /* \0 */ return (nargenvptrs * ptrsz(epp)) /* pointers */ + argenvstrlen /* strings */ + epp->ep_esch->es_arglen; /* auxinfo */ } static size_t calcstack(struct execve_data * restrict data, const size_t gaplen) { struct exec_package * const epp = &data->ed_pack; data->ed_szsigcode = epp->ep_esch->es_emul->e_esigcode - epp->ep_esch->es_emul->e_sigcode; data->ed_ps_strings_sz = (epp->ep_flags & EXEC_32) ? sizeof(struct ps_strings32) : sizeof(struct ps_strings); const size_t sigcode_psstr_sz = data->ed_szsigcode + /* sigcode */ data->ed_ps_strings_sz + /* ps_strings */ STACK_PTHREADSPACE; /* pthread space */ const size_t stacklen = data->ed_argslen + gaplen + sigcode_psstr_sz; /* make the stack "safely" aligned */ return STACK_LEN_ALIGN(stacklen, STACK_ALIGNBYTES); } static int copyoutargs(struct execve_data * restrict data, struct lwp *l, char * const newstack) { struct exec_package * const epp = &data->ed_pack; struct proc *p = l->l_proc; int error; memset(&data->ed_arginfo, 0, sizeof(data->ed_arginfo)); /* remember information about the process */ data->ed_arginfo.ps_nargvstr = data->ed_argc; data->ed_arginfo.ps_nenvstr = data->ed_envc; /* * Allocate the stack address passed to the newly execve()'ed process. * * The new stack address will be set to the SP (stack pointer) register * in setregs(). */ char *newargs = STACK_ALLOC( STACK_SHRINK(newstack, data->ed_argslen), data->ed_argslen); error = (*epp->ep_esch->es_copyargs)(l, epp, &data->ed_arginfo, &newargs, data->ed_argp); if (error) { DPRINTF(("%s: copyargs failed %d\n", __func__, error)); return error; } error = copyoutpsstrs(data, p); if (error != 0) return error; return 0; } static int copyoutpsstrs(struct execve_data * restrict data, struct proc *p) { struct exec_package * const epp = &data->ed_pack; struct ps_strings32 arginfo32; void *aip; int error; /* fill process ps_strings info */ p->p_psstrp = (vaddr_t)STACK_ALLOC(STACK_GROW(epp->ep_minsaddr, STACK_PTHREADSPACE), data->ed_ps_strings_sz); if (epp->ep_flags & EXEC_32) { aip = &arginfo32; arginfo32.ps_argvstr = (vaddr_t)data->ed_arginfo.ps_argvstr; arginfo32.ps_nargvstr = data->ed_arginfo.ps_nargvstr; arginfo32.ps_envstr = (vaddr_t)data->ed_arginfo.ps_envstr; arginfo32.ps_nenvstr = data->ed_arginfo.ps_nenvstr; } else aip = &data->ed_arginfo; /* copy out the process's ps_strings structure */ if ((error = copyout(aip, (void *)p->p_psstrp, data->ed_ps_strings_sz)) != 0) { DPRINTF(("%s: ps_strings copyout %p->%p size %zu failed\n", __func__, aip, (void *)p->p_psstrp, data->ed_ps_strings_sz)); return error; } return 0; } static int copyinargs(struct execve_data * restrict data, char * const *args, char * const *envs, execve_fetch_element_t fetch_element, char **dpp) { struct exec_package * const epp = &data->ed_pack; char *dp; size_t i; int error; dp = *dpp; data->ed_argc = 0; /* copy the fake args list, if there's one, freeing it as we go */ if (epp->ep_flags & EXEC_HASARGL) { struct exec_fakearg *fa = epp->ep_fa; while (fa->fa_arg != NULL) { const size_t maxlen = ARG_MAX - (dp - data->ed_argp); size_t len; len = strlcpy(dp, fa->fa_arg, maxlen); /* Count NUL into len. */ if (len < maxlen) len++; else { while (fa->fa_arg != NULL) { kmem_free(fa->fa_arg, fa->fa_len); fa++; } kmem_free(epp->ep_fa, epp->ep_fa_len); epp->ep_flags &= ~EXEC_HASARGL; return SET_ERROR(E2BIG); } ktrexecarg(fa->fa_arg, len - 1); dp += len; kmem_free(fa->fa_arg, fa->fa_len); fa++; data->ed_argc++; } kmem_free(epp->ep_fa, epp->ep_fa_len); epp->ep_flags &= ~EXEC_HASARGL; } /* * Read and count argument strings from user. */ if (args == NULL) { DPRINTF(("%s: null args\n", __func__)); return SET_ERROR(EINVAL); } if (epp->ep_flags & EXEC_SKIPARG) args = (const void *)((const char *)args + fromptrsz(epp)); i = 0; error = copyinargstrs(data, args, fetch_element, &dp, &i, ktr_execarg); if (error != 0) { DPRINTF(("%s: copyin arg %d\n", __func__, error)); return error; } data->ed_argc += i; /* * Read and count environment strings from user. */ data->ed_envc = 0; /* environment need not be there */ if (envs == NULL) goto done; i = 0; error = copyinargstrs(data, envs, fetch_element, &dp, &i, ktr_execenv); if (error != 0) { DPRINTF(("%s: copyin env %d\n", __func__, error)); return error; } data->ed_envc += i; done: *dpp = dp; return 0; } static int copyinargstrs(struct execve_data * restrict data, char * const *strs, execve_fetch_element_t fetch_element, char **dpp, size_t *ip, void (*ktr)(const void *, size_t)) { char *dp, *sp; size_t i; int error; dp = *dpp; i = 0; while (1) { const size_t maxlen = ARG_MAX - (dp - data->ed_argp); size_t len; if ((error = (*fetch_element)(strs, i, &sp)) != 0) { return error; } if (!sp) break; if ((error = copyinstr(sp, dp, maxlen, &len)) != 0) { if (error == ENAMETOOLONG) error = SET_ERROR(E2BIG); return error; } if (__predict_false(ktrace_on)) (*ktr)(dp, len - 1); dp += len; i++; } *dpp = dp; *ip = i; return 0; } /* * Copy argv and env strings from kernel buffer (argp) to the new stack. * Those strings are located just after auxinfo. */ int copyargs(struct lwp *l, struct exec_package *pack, struct ps_strings *arginfo, char **stackp, void *argp) { char **cpp, *dp, *sp; size_t len; void *nullp; long argc, envc; int error; cpp = (char **)*stackp; nullp = NULL; argc = arginfo->ps_nargvstr; envc = arginfo->ps_nenvstr; /* argc on stack is long */ CTASSERT(sizeof(*cpp) == sizeof(argc)); dp = (char *)(cpp + 1 + /* long argc */ argc + /* char *argv[] */ 1 + /* \0 */ envc + /* char *env[] */ 1) + /* \0 */ pack->ep_esch->es_arglen; /* auxinfo */ sp = argp; if ((error = copyout(&argc, cpp++, sizeof(argc))) != 0) { COPYPRINTF("", cpp - 1, sizeof(argc)); return error; } /* XXX don't copy them out, remap them! */ arginfo->ps_argvstr = cpp; /* remember location of argv for later */ for (; --argc >= 0; sp += len, dp += len) { if ((error = copyout(&dp, cpp++, sizeof(dp))) != 0) { COPYPRINTF("", cpp - 1, sizeof(dp)); return error; } if ((error = copyoutstr(sp, dp, ARG_MAX, &len)) != 0) { COPYPRINTF("str", dp, (size_t)ARG_MAX); return error; } } if ((error = copyout(&nullp, cpp++, sizeof(nullp))) != 0) { COPYPRINTF("", cpp - 1, sizeof(nullp)); return error; } arginfo->ps_envstr = cpp; /* remember location of envp for later */ for (; --envc >= 0; sp += len, dp += len) { if ((error = copyout(&dp, cpp++, sizeof(dp))) != 0) { COPYPRINTF("", cpp - 1, sizeof(dp)); return error; } if ((error = copyoutstr(sp, dp, ARG_MAX, &len)) != 0) { COPYPRINTF("str", dp, (size_t)ARG_MAX); return error; } } if ((error = copyout(&nullp, cpp++, sizeof(nullp))) != 0) { COPYPRINTF("", cpp - 1, sizeof(nullp)); return error; } *stackp = (char *)cpp; return 0; } /* * Add execsw[] entries. */ int exec_add(struct execsw *esp, int count) { struct exec_entry *it; int i, error = 0; if (count == 0) { return 0; } /* Check for duplicates. */ rw_enter(&exec_lock, RW_WRITER); for (i = 0; i < count; i++) { LIST_FOREACH(it, &ex_head, ex_list) { /* assume unique (makecmds, probe_func, emulation) */ if (it->ex_sw->es_makecmds == esp[i].es_makecmds && it->ex_sw->u.elf_probe_func == esp[i].u.elf_probe_func && it->ex_sw->es_emul == esp[i].es_emul) { rw_exit(&exec_lock); return SET_ERROR(EEXIST); } } } /* Allocate new entries. */ for (i = 0; i < count; i++) { it = kmem_alloc(sizeof(*it), KM_SLEEP); it->ex_sw = &esp[i]; error = exec_sigcode_alloc(it->ex_sw->es_emul); if (error != 0) { kmem_free(it, sizeof(*it)); break; } LIST_INSERT_HEAD(&ex_head, it, ex_list); } /* If even one fails, remove them all back. */ if (error != 0) { for (i--; i >= 0; i--) { it = LIST_FIRST(&ex_head); LIST_REMOVE(it, ex_list); exec_sigcode_free(it->ex_sw->es_emul); kmem_free(it, sizeof(*it)); } rw_exit(&exec_lock); return error; } /* update execsw[] */ exec_init(0); rw_exit(&exec_lock); return 0; } /* * Remove execsw[] entry. */ int exec_remove(struct execsw *esp, int count) { struct exec_entry *it, *next; int i; const struct proclist_desc *pd; proc_t *p; if (count == 0) { return 0; } /* Abort if any are busy. */ rw_enter(&exec_lock, RW_WRITER); for (i = 0; i < count; i++) { mutex_enter(&proc_lock); for (pd = proclists; pd->pd_list != NULL; pd++) { PROCLIST_FOREACH(p, pd->pd_list) { if (p->p_execsw == &esp[i]) { mutex_exit(&proc_lock); rw_exit(&exec_lock); return SET_ERROR(EBUSY); } } } mutex_exit(&proc_lock); } /* None are busy, so remove them all. */ for (i = 0; i < count; i++) { for (it = LIST_FIRST(&ex_head); it != NULL; it = next) { next = LIST_NEXT(it, ex_list); if (it->ex_sw == &esp[i]) { LIST_REMOVE(it, ex_list); exec_sigcode_free(it->ex_sw->es_emul); kmem_free(it, sizeof(*it)); break; } } } /* update execsw[] */ exec_init(0); rw_exit(&exec_lock); return 0; } /* * Initialize exec structures. If init_boot is true, also does necessary * one-time initialization (it's called from main() that way). * Once system is multiuser, this should be called with exec_lock held, * i.e. via exec_{add|remove}(). */ int exec_init(int init_boot) { const struct execsw **sw; struct exec_entry *ex; SLIST_HEAD(,exec_entry) first; SLIST_HEAD(,exec_entry) any; SLIST_HEAD(,exec_entry) last; int i, sz; if (init_boot) { /* do one-time initializations */ vaddr_t vmin = 0, vmax; rw_init(&exec_lock); exec_map = uvm_km_suballoc(kernel_map, &vmin, &vmax, maxexec*NCARGS, VM_MAP_PAGEABLE, false, NULL); pool_init(&exec_pool, NCARGS, 0, 0, PR_NOALIGN|PR_NOTOUCH, "execargs", &exec_palloc, IPL_NONE); pool_sethardlimit(&exec_pool, maxexec, "should not happen", 0); } else { KASSERT(rw_write_held(&exec_lock)); } /* Sort each entry onto the appropriate queue. */ SLIST_INIT(&first); SLIST_INIT(&any); SLIST_INIT(&last); sz = 0; LIST_FOREACH(ex, &ex_head, ex_list) { switch(ex->ex_sw->es_prio) { case EXECSW_PRIO_FIRST: SLIST_INSERT_HEAD(&first, ex, ex_slist); break; case EXECSW_PRIO_ANY: SLIST_INSERT_HEAD(&any, ex, ex_slist); break; case EXECSW_PRIO_LAST: SLIST_INSERT_HEAD(&last, ex, ex_slist); break; default: panic("%s", __func__); break; } sz++; } /* * Create new execsw[]. Ensure we do not try a zero-sized * allocation. */ sw = kmem_alloc(sz * sizeof(struct execsw *) + 1, KM_SLEEP); i = 0; SLIST_FOREACH(ex, &first, ex_slist) { sw[i++] = ex->ex_sw; } SLIST_FOREACH(ex, &any, ex_slist) { sw[i++] = ex->ex_sw; } SLIST_FOREACH(ex, &last, ex_slist) { sw[i++] = ex->ex_sw; } /* Replace old execsw[] and free used memory. */ if (execsw != NULL) { kmem_free(__UNCONST(execsw), nexecs * sizeof(struct execsw *) + 1); } execsw = sw; nexecs = sz; /* Figure out the maximum size of an exec header. */ exec_maxhdrsz = sizeof(int); for (i = 0; i < nexecs; i++) { if (execsw[i]->es_hdrsz > exec_maxhdrsz) exec_maxhdrsz = execsw[i]->es_hdrsz; } return 0; } int exec_sigcode_alloc(const struct emul *e) { vaddr_t va; vsize_t sz; int error; struct uvm_object *uobj; KASSERT(rw_lock_held(&exec_lock)); if (e == NULL || e->e_sigobject == NULL) return 0; sz = (vaddr_t)e->e_esigcode - (vaddr_t)e->e_sigcode; if (sz == 0) return 0; /* * Create a sigobject for this emulation. * * sigobject is an anonymous memory object (just like SYSV shared * memory) that we keep a permanent reference to and that we map * in all processes that need this sigcode. The creation is simple, * we create an object, add a permanent reference to it, map it in * kernel space, copy out the sigcode to it and unmap it. * We map it with PROT_READ|PROT_EXEC into the process just * the way sys_mmap() would map it. */ if (*e->e_sigobject == NULL) { uobj = uao_create(sz, 0); (*uobj->pgops->pgo_reference)(uobj); va = vm_map_min(kernel_map); if ((error = uvm_map(kernel_map, &va, round_page(sz), uobj, 0, 0, UVM_MAPFLAG(UVM_PROT_RW, UVM_PROT_RW, UVM_INH_SHARE, UVM_ADV_RANDOM, 0)))) { printf("sigcode kernel mapping failed %d\n", error); (*uobj->pgops->pgo_detach)(uobj); return error; } memcpy((void *)va, e->e_sigcode, sz); #ifdef PMAP_NEED_PROCWR pmap_procwr(&proc0, va, sz); #endif uvm_unmap(kernel_map, va, va + round_page(sz)); *e->e_sigobject = uobj; KASSERT(uobj->uo_refs == 1); } else { /* if already created, reference++ */ uobj = *e->e_sigobject; (*uobj->pgops->pgo_reference)(uobj); } return 0; } void exec_sigcode_free(const struct emul *e) { struct uvm_object *uobj; KASSERT(rw_lock_held(&exec_lock)); if (e == NULL || e->e_sigobject == NULL) return; uobj = *e->e_sigobject; if (uobj == NULL) return; if (uobj->uo_refs == 1) *e->e_sigobject = NULL; /* I'm the last person to reference. */ (*uobj->pgops->pgo_detach)(uobj); } static int exec_sigcode_map(struct proc *p, const struct emul *e) { vaddr_t va; vsize_t sz; int error; struct uvm_object *uobj; sz = (vaddr_t)e->e_esigcode - (vaddr_t)e->e_sigcode; if (e->e_sigobject == NULL || sz == 0) return 0; uobj = *e->e_sigobject; if (uobj == NULL) return 0; /* Just a hint to uvm_map where to put it. */ va = e->e_vm_default_addr(p, (vaddr_t)p->p_vmspace->vm_daddr, round_page(sz), p->p_vmspace->vm_map.flags & VM_MAP_TOPDOWN); #ifdef __alpha__ /* * Tru64 puts /sbin/loader at the end of user virtual memory, * which causes the above calculation to put the sigcode at * an invalid address. Put it just below the text instead. */ if (va == (vaddr_t)vm_map_max(&p->p_vmspace->vm_map)) { va = (vaddr_t)p->p_vmspace->vm_taddr - round_page(sz); } #endif (*uobj->pgops->pgo_reference)(uobj); error = uvm_map(&p->p_vmspace->vm_map, &va, round_page(sz), uobj, 0, 0, UVM_MAPFLAG(UVM_PROT_RX, UVM_PROT_RX, UVM_INH_SHARE, UVM_ADV_RANDOM, 0)); if (error) { DPRINTF(("%s, %d: map %p " "uvm_map %#"PRIxVSIZE"@%#"PRIxVADDR" failed %d\n", __func__, __LINE__, &p->p_vmspace->vm_map, round_page(sz), va, error)); (*uobj->pgops->pgo_detach)(uobj); return error; } p->p_sigctx.ps_sigcode = (void *)va; return 0; } /* * Release a refcount on spawn_exec_data and destroy memory, if this * was the last one. */ static void spawn_exec_data_release(struct spawn_exec_data *data) { membar_release(); if (atomic_dec_32_nv(&data->sed_refcnt) != 0) return; membar_acquire(); cv_destroy(&data->sed_cv_child_ready); mutex_destroy(&data->sed_mtx_child); if (data->sed_actions) posix_spawn_fa_free(data->sed_actions, data->sed_actions->len); if (data->sed_attrs) kmem_free(data->sed_attrs, sizeof(*data->sed_attrs)); kmem_free(data, sizeof(*data)); } static int handle_posix_spawn_file_actions(struct posix_spawn_file_actions *actions) { struct lwp *l = curlwp; register_t retval; int error, newfd; if (actions == NULL) return 0; for (size_t i = 0; i < actions->len; i++) { const struct posix_spawn_file_actions_entry *fae = &actions->fae[i]; switch (fae->fae_action) { case FAE_OPEN: if (fd_getfile(fae->fae_fildes) != NULL) { error = fd_close(fae->fae_fildes); if (error) return error; } error = fd_open(fae->fae_path, fae->fae_oflag, fae->fae_mode, &newfd); if (error) return error; if (newfd != fae->fae_fildes) { error = dodup(l, newfd, fae->fae_fildes, 0, &retval); if (fd_getfile(newfd) != NULL) fd_close(newfd); } break; case FAE_DUP2: error = dodup(l, fae->fae_fildes, fae->fae_newfildes, 0, &retval); break; case FAE_CLOSE: if (fd_getfile(fae->fae_fildes) == NULL) { return SET_ERROR(EBADF); } error = fd_close(fae->fae_fildes); break; case FAE_CHDIR: error = do_sys_chdir(l, fae->fae_chdir_path, UIO_SYSSPACE, &retval); break; case FAE_FCHDIR: error = do_sys_fchdir(l, fae->fae_fildes, &retval); break; } if (error) return error; } return 0; } static int handle_posix_spawn_attrs(struct posix_spawnattr *attrs, struct proc *parent) { struct sigaction sigact; int error; struct proc *p = curproc; struct lwp *l = curlwp; if (attrs == NULL) return 0; memset(&sigact, 0, sizeof(sigact)); sigact._sa_u._sa_handler = SIG_DFL; sigact.sa_flags = 0; /* * set state to SSTOP so that this proc can be found by pid. * see proc_enterprp, do_sched_setparam below */ mutex_enter(&proc_lock); /* * p_stat should be SACTIVE, so we need to adjust the * parent's p_nstopchild here. For safety, just make * we're on the good side of SDEAD before we adjust. */ int ostat = p->p_stat; KASSERT(ostat < SSTOP); p->p_stat = SSTOP; p->p_waited = 0; p->p_pptr->p_nstopchild++; mutex_exit(&proc_lock); /* Set process group */ if (attrs->sa_flags & POSIX_SPAWN_SETPGROUP) { pid_t mypid = p->p_pid; pid_t pgrp = attrs->sa_pgroup; if (pgrp == 0) pgrp = mypid; error = proc_enterpgrp(parent, mypid, pgrp, false); if (error) goto out; } /* Set scheduler policy */ if (attrs->sa_flags & POSIX_SPAWN_SETSCHEDULER) error = do_sched_setparam(p->p_pid, 0, attrs->sa_schedpolicy, &attrs->sa_schedparam); else if (attrs->sa_flags & POSIX_SPAWN_SETSCHEDPARAM) { error = do_sched_setparam(parent->p_pid, 0, SCHED_NONE, &attrs->sa_schedparam); } if (error) goto out; /* Reset user ID's */ if (attrs->sa_flags & POSIX_SPAWN_RESETIDS) { error = do_setresgid(l, -1, kauth_cred_getgid(l->l_cred), -1, ID_E_EQ_R | ID_E_EQ_S); if (error) return error; error = do_setresuid(l, -1, kauth_cred_getuid(l->l_cred), -1, ID_E_EQ_R | ID_E_EQ_S); if (error) goto out; } /* Set signal masks/defaults */ if (attrs->sa_flags & POSIX_SPAWN_SETSIGMASK) { mutex_enter(p->p_lock); error = sigprocmask1(l, SIG_SETMASK, &attrs->sa_sigmask, NULL); mutex_exit(p->p_lock); if (error) goto out; } if (attrs->sa_flags & POSIX_SPAWN_SETSIGDEF) { /* * The following sigaction call is using a sigaction * version 0 trampoline which is in the compatibility * code only. This is not a problem because for SIG_DFL * and SIG_IGN, the trampolines are now ignored. If they * were not, this would be a problem because we are * holding the exec_lock, and the compat code needs * to do the same in order to replace the trampoline * code of the process. */ for (int i = 1; i <= NSIG; i++) { if (sigismember(&attrs->sa_sigdefault, i)) sigaction1(l, i, &sigact, NULL, NULL, 0); } } error = 0; out: mutex_enter(&proc_lock); p->p_stat = ostat; p->p_pptr->p_nstopchild--; mutex_exit(&proc_lock); return error; } /* * A child lwp of a posix_spawn operation starts here and ends up in * cpu_spawn_return, dealing with all filedescriptor and scheduler * manipulations in between. * The parent waits for the child, as it is not clear whether the child * will be able to acquire its own exec_lock. If it can, the parent can * be released early and continue running in parallel. If not (or if the * magic debug flag is passed in the scheduler attribute struct), the * child rides on the parent's exec lock until it is ready to return to * to userland - and only then releases the parent. This method loses * concurrency, but improves error reporting. */ static void spawn_return(void *arg) { struct spawn_exec_data *spawn_data = arg; struct lwp *l = curlwp; struct proc *p = l->l_proc; int error; bool have_reflock; bool parent_is_waiting = true; /* * Check if we can release parent early. * We either need to have no sed_attrs, or sed_attrs does not * have POSIX_SPAWN_RETURNERROR or one of the flags, that require * safe access to the parent proc (passed in sed_parent). * We then try to get the exec_lock, and only if that works, we can * release the parent here already. */ struct posix_spawnattr *attrs = spawn_data->sed_attrs; if ((!attrs || (attrs->sa_flags & (POSIX_SPAWN_RETURNERROR|POSIX_SPAWN_SETPGROUP)) == 0) && rw_tryenter(&exec_lock, RW_READER)) { parent_is_waiting = false; mutex_enter(&spawn_data->sed_mtx_child); cv_signal(&spawn_data->sed_cv_child_ready); mutex_exit(&spawn_data->sed_mtx_child); } /* don't allow debugger access yet */ rw_enter(&p->p_reflock, RW_WRITER); have_reflock = true; /* handle posix_spawnattr */ error = handle_posix_spawn_attrs(attrs, spawn_data->sed_parent); if (error) goto report_error; /* handle posix_spawn_file_actions */ error = handle_posix_spawn_file_actions(spawn_data->sed_actions); if (error) goto report_error; /* now do the real exec */ error = execve_runproc(l, &spawn_data->sed_exec, parent_is_waiting, true); have_reflock = false; if (error == EJUSTRETURN) error = 0; else if (error) goto report_error; if (parent_is_waiting) { mutex_enter(&spawn_data->sed_mtx_child); cv_signal(&spawn_data->sed_cv_child_ready); mutex_exit(&spawn_data->sed_mtx_child); } /* release our refcount on the data */ spawn_exec_data_release(spawn_data); if ((p->p_slflag & (PSL_TRACED|PSL_TRACEDCHILD)) == (PSL_TRACED|PSL_TRACEDCHILD)) { eventswitchchild(p, TRAP_CHLD, PTRACE_POSIX_SPAWN); } /* and finally: leave to userland for the first time */ cpu_spawn_return(l); /* NOTREACHED */ return; report_error: if (have_reflock) { /* * We have not passed through execve_runproc(), * which would have released the p_reflock and also * taken ownership of the sed_exec part of spawn_data, * so release/free both here. */ rw_exit(&p->p_reflock); execve_free_data(&spawn_data->sed_exec); } if (parent_is_waiting) { /* pass error to parent */ mutex_enter(&spawn_data->sed_mtx_child); spawn_data->sed_error = error; cv_signal(&spawn_data->sed_cv_child_ready); mutex_exit(&spawn_data->sed_mtx_child); } else { rw_exit(&exec_lock); } /* release our refcount on the data */ spawn_exec_data_release(spawn_data); /* done, exit */ mutex_enter(p->p_lock); /* * Posix explicitly asks for an exit code of 127 if we report * errors from the child process - so, unfortunately, there * is no way to report a more exact error code. * A NetBSD specific workaround is POSIX_SPAWN_RETURNERROR as * flag bit in the attrp argument to posix_spawn(2), see above. */ exit1(l, 127, 0); } static __inline char ** posix_spawn_fae_path(struct posix_spawn_file_actions_entry *fae) { switch (fae->fae_action) { case FAE_OPEN: return &fae->fae_path; case FAE_CHDIR: return &fae->fae_chdir_path; default: return NULL; } } void posix_spawn_fa_free(struct posix_spawn_file_actions *fa, size_t len) { for (size_t i = 0; i < len; i++) { char **pathp = posix_spawn_fae_path(&fa->fae[i]); if (pathp) kmem_strfree(*pathp); } if (fa->len > 0) kmem_free(fa->fae, sizeof(*fa->fae) * fa->len); kmem_free(fa, sizeof(*fa)); } static int posix_spawn_fa_alloc(struct posix_spawn_file_actions **fap, const struct posix_spawn_file_actions *ufa, rlim_t lim) { struct posix_spawn_file_actions *fa; struct posix_spawn_file_actions_entry *fae; char *pbuf = NULL; int error; size_t i = 0; fa = kmem_alloc(sizeof(*fa), KM_SLEEP); error = copyin(ufa, fa, sizeof(*fa)); if (error || fa->len == 0) { kmem_free(fa, sizeof(*fa)); return error; /* 0 if not an error, and len == 0 */ } if (fa->len > lim) { kmem_free(fa, sizeof(*fa)); return SET_ERROR(EINVAL); } fa->size = fa->len; size_t fal = fa->len * sizeof(*fae); fae = fa->fae; fa->fae = kmem_alloc(fal, KM_SLEEP); error = copyin(fae, fa->fae, fal); if (error) goto out; pbuf = PNBUF_GET(); for (; i < fa->len; i++) { char **pathp = posix_spawn_fae_path(&fa->fae[i]); if (pathp == NULL) continue; error = copyinstr(*pathp, pbuf, MAXPATHLEN, &fal); if (error) goto out; *pathp = kmem_alloc(fal, KM_SLEEP); memcpy(*pathp, pbuf, fal); } PNBUF_PUT(pbuf); *fap = fa; return 0; out: if (pbuf) PNBUF_PUT(pbuf); posix_spawn_fa_free(fa, i); return error; } /* * N.B. increments nprocs upon success. Callers need to drop nprocs if * they fail for some other reason. */ int check_posix_spawn(struct lwp *l1) { int error, tnprocs, count; uid_t uid; struct proc *p1; p1 = l1->l_proc; uid = kauth_cred_getuid(l1->l_cred); tnprocs = atomic_inc_uint_nv(&nprocs); /* * Although process entries are dynamically created, we still keep * a global limit on the maximum number we will create. */ if (__predict_false(tnprocs >= maxproc)) error = -1; else error = kauth_authorize_process(l1->l_cred, KAUTH_PROCESS_FORK, p1, KAUTH_ARG(tnprocs), NULL, NULL); if (error) { atomic_dec_uint(&nprocs); return SET_ERROR(EAGAIN); } /* * Enforce limits. */ count = chgproccnt(uid, 1); if (kauth_authorize_process(l1->l_cred, KAUTH_PROCESS_RLIMIT, p1, KAUTH_ARG(KAUTH_REQ_PROCESS_RLIMIT_BYPASS), &p1->p_rlimit[RLIMIT_NPROC], KAUTH_ARG(RLIMIT_NPROC)) != 0 && __predict_false(count > p1->p_rlimit[RLIMIT_NPROC].rlim_cur)) { (void)chgproccnt(uid, -1); atomic_dec_uint(&nprocs); return SET_ERROR(EAGAIN); } return 0; } int do_posix_spawn(struct lwp *l1, pid_t *pid_res, bool *child_ok, const char *path, struct posix_spawn_file_actions *fa, struct posix_spawnattr *sa, char *const *argv, char *const *envp, execve_fetch_element_t fetch) { struct proc *p1, *p2; struct lwp *l2; int error; struct spawn_exec_data *spawn_data; vaddr_t uaddr = 0; pid_t pid; bool have_exec_lock = false; p1 = l1->l_proc; /* Allocate and init spawn_data */ spawn_data = kmem_zalloc(sizeof(*spawn_data), KM_SLEEP); spawn_data->sed_refcnt = 1; /* only parent so far */ cv_init(&spawn_data->sed_cv_child_ready, "pspawn"); mutex_init(&spawn_data->sed_mtx_child, MUTEX_DEFAULT, IPL_NONE); mutex_enter(&spawn_data->sed_mtx_child); /* * Do the first part of the exec now, collect state * in spawn_data. */ error = execve_loadvm(l1, true, path, -1, argv, envp, fetch, &spawn_data->sed_exec); if (error == EJUSTRETURN) error = 0; else if (error) goto error_exit; have_exec_lock = true; /* * Allocate virtual address space for the U-area now, while it * is still easy to abort the fork operation if we're out of * kernel virtual address space. */ uaddr = uvm_uarea_alloc(); if (__predict_false(uaddr == 0)) { error = SET_ERROR(ENOMEM); goto error_exit; } /* * Allocate new proc. Borrow proc0 vmspace for it, we will * replace it with its own before returning to userland * in the child. */ p2 = proc_alloc(); if (p2 == NULL) { /* We were unable to allocate a process ID. */ error = SET_ERROR(EAGAIN); goto error_exit; } /* * This is a point of no return, we will have to go through * the child proc to properly clean it up past this point. */ pid = p2->p_pid; /* * Make a proc table entry for the new process. * Start by zeroing the section of proc that is zero-initialized, * then copy the section that is copied directly from the parent. */ memset(&p2->p_startzero, 0, (unsigned) ((char *)&p2->p_endzero - (char *)&p2->p_startzero)); memcpy(&p2->p_startcopy, &p1->p_startcopy, (unsigned) ((char *)&p2->p_endcopy - (char *)&p2->p_startcopy)); p2->p_vmspace = proc0.p_vmspace; TAILQ_INIT(&p2->p_sigpend.sp_info); LIST_INIT(&p2->p_lwps); LIST_INIT(&p2->p_sigwaiters); /* * Duplicate sub-structures as needed. * Increase reference counts on shared objects. * Inherit flags we want to keep. The flags related to SIGCHLD * handling are important in order to keep a consistent behaviour * for the child after the fork. If we are a 32-bit process, the * child will be too. */ p2->p_flag = p1->p_flag & (PK_SUGID | PK_NOCLDWAIT | PK_CLDSIGIGN | PK_32); p2->p_emul = p1->p_emul; p2->p_execsw = p1->p_execsw; mutex_init(&p2->p_stmutex, MUTEX_DEFAULT, IPL_HIGH); mutex_init(&p2->p_auxlock, MUTEX_DEFAULT, IPL_NONE); rw_init(&p2->p_reflock); cv_init(&p2->p_waitcv, "wait"); cv_init(&p2->p_lwpcv, "lwpwait"); p2->p_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NONE); kauth_proc_fork(p1, p2); p2->p_raslist = NULL; p2->p_fd = fd_copy(); /* XXX racy */ p2->p_mqueue_cnt = p1->p_mqueue_cnt; p2->p_cwdi = cwdinit(); /* * Note: p_limit (rlimit stuff) is copy-on-write, so normally * we just need increase pl_refcnt. */ if (!p1->p_limit->pl_writeable) { lim_addref(p1->p_limit); p2->p_limit = p1->p_limit; } else { p2->p_limit = lim_copy(p1->p_limit); } p2->p_lflag = 0; l1->l_vforkwaiting = false; p2->p_sflag = 0; p2->p_slflag = 0; p2->p_pptr = p1; p2->p_ppid = p1->p_pid; LIST_INIT(&p2->p_children); p2->p_aio = NULL; #ifdef KTRACE /* * Copy traceflag and tracefile if enabled. * If not inherited, these were zeroed above. */ if (p1->p_traceflag & KTRFAC_INHERIT) { mutex_enter(&ktrace_lock); p2->p_traceflag = p1->p_traceflag; if ((p2->p_tracep = p1->p_tracep) != NULL) ktradref(p2); mutex_exit(&ktrace_lock); } #endif /* * Create signal actions for the child process. */ p2->p_sigacts = sigactsinit(p1, 0); mutex_enter(p1->p_lock); p2->p_sflag |= (p1->p_sflag & (PS_STOPFORK | PS_STOPEXEC | PS_NOCLDSTOP)); sched_proc_fork(p1, p2); mutex_exit(p1->p_lock); p2->p_stflag = p1->p_stflag; /* * p_stats. * Copy parts of p_stats, and zero out the rest. */ p2->p_stats = pstatscopy(p1->p_stats); /* copy over machdep flags to the new proc */ cpu_proc_fork(p1, p2); /* * Prepare remaining parts of spawn data */ spawn_data->sed_actions = fa; spawn_data->sed_attrs = sa; spawn_data->sed_parent = p1; /* create LWP */ lwp_create(l1, p2, uaddr, 0, NULL, 0, spawn_return, spawn_data, &l2, l1->l_class, &l1->l_sigmask, &l1->l_sigstk); l2->l_ctxlink = NULL; /* reset ucontext link */ /* * Copy the credential so other references don't see our changes. * Test to see if this is necessary first, since in the common case * we won't need a private reference. */ if (kauth_cred_geteuid(l2->l_cred) != kauth_cred_getsvuid(l2->l_cred) || kauth_cred_getegid(l2->l_cred) != kauth_cred_getsvgid(l2->l_cred)) { l2->l_cred = kauth_cred_copy(l2->l_cred); kauth_cred_setsvuid(l2->l_cred, kauth_cred_geteuid(l2->l_cred)); kauth_cred_setsvgid(l2->l_cred, kauth_cred_getegid(l2->l_cred)); } /* Update the master credentials. */ if (l2->l_cred != p2->p_cred) { kauth_cred_t ocred; mutex_enter(p2->p_lock); ocred = p2->p_cred; p2->p_cred = kauth_cred_hold(l2->l_cred); mutex_exit(p2->p_lock); kauth_cred_free(ocred); } *child_ok = true; spawn_data->sed_refcnt = 2; /* child gets it as well */ #if 0 l2->l_nopreempt = 1; /* start it non-preemptable */ #endif /* * It's now safe for the scheduler and other processes to see the * child process. */ mutex_enter(&proc_lock); if (p1->p_session->s_ttyvp != NULL && p1->p_lflag & PL_CONTROLT) p2->p_lflag |= PL_CONTROLT; LIST_INSERT_HEAD(&p1->p_children, p2, p_sibling); p2->p_exitsig = SIGCHLD; /* signal for parent on exit */ if ((p1->p_slflag & (PSL_TRACEPOSIX_SPAWN|PSL_TRACED)) == (PSL_TRACEPOSIX_SPAWN|PSL_TRACED)) { proc_changeparent(p2, p1->p_pptr); SET(p2->p_slflag, PSL_TRACEDCHILD); } p2->p_oppid = p1->p_pid; /* Remember the original parent id. */ LIST_INSERT_AFTER(p1, p2, p_pglist); LIST_INSERT_HEAD(&allproc, p2, p_list); p2->p_trace_enabled = trace_is_enabled(p2); #ifdef __HAVE_SYSCALL_INTERN (*p2->p_emul->e_syscall_intern)(p2); #endif /* * Make child runnable, set start time, and add to run queue except * if the parent requested the child to start in SSTOP state. */ mutex_enter(p2->p_lock); getmicrotime(&p2->p_stats->p_start); lwp_lock(l2); KASSERT(p2->p_nrlwps == 1); KASSERT(l2->l_stat == LSIDL); p2->p_nrlwps = 1; p2->p_stat = SACTIVE; setrunnable(l2); /* LWP now unlocked */ mutex_exit(p2->p_lock); mutex_exit(&proc_lock); cv_wait(&spawn_data->sed_cv_child_ready, &spawn_data->sed_mtx_child); error = spawn_data->sed_error; mutex_exit(&spawn_data->sed_mtx_child); spawn_exec_data_release(spawn_data); rw_exit(&p1->p_reflock); rw_exit(&exec_lock); have_exec_lock = false; *pid_res = pid; if (error) return error; if (p1->p_slflag & PSL_TRACED) { /* Paranoid check */ mutex_enter(&proc_lock); if ((p1->p_slflag & (PSL_TRACEPOSIX_SPAWN|PSL_TRACED)) != (PSL_TRACEPOSIX_SPAWN|PSL_TRACED)) { mutex_exit(&proc_lock); return 0; } mutex_enter(p1->p_lock); eventswitch(TRAP_CHLD, PTRACE_POSIX_SPAWN, pid); } return 0; error_exit: if (have_exec_lock) { execve_free_data(&spawn_data->sed_exec); rw_exit(&p1->p_reflock); rw_exit(&exec_lock); } mutex_exit(&spawn_data->sed_mtx_child); spawn_exec_data_release(spawn_data); if (uaddr != 0) uvm_uarea_free(uaddr); return error; } int sys_posix_spawn(struct lwp *l1, const struct sys_posix_spawn_args *uap, register_t *retval) { /* { syscallarg(pid_t *) pid; syscallarg(const char *) path; syscallarg(const struct posix_spawn_file_actions *) file_actions; syscallarg(const struct posix_spawnattr *) attrp; syscallarg(char *const *) argv; syscallarg(char *const *) envp; } */ int error; struct posix_spawn_file_actions *fa = NULL; struct posix_spawnattr *sa = NULL; pid_t pid; bool child_ok = false; rlim_t max_fileactions; proc_t *p = l1->l_proc; /* check_posix_spawn() increments nprocs for us. */ error = check_posix_spawn(l1); if (error) { *retval = error; return 0; } /* copy in file_actions struct */ if (SCARG(uap, file_actions) != NULL) { max_fileactions = 2 * uimin(p->p_rlimit[RLIMIT_NOFILE].rlim_cur, maxfiles); error = posix_spawn_fa_alloc(&fa, SCARG(uap, file_actions), max_fileactions); if (error) goto error_exit; } /* copyin posix_spawnattr struct */ if (SCARG(uap, attrp) != NULL) { sa = kmem_alloc(sizeof(*sa), KM_SLEEP); error = copyin(SCARG(uap, attrp), sa, sizeof(*sa)); if (error) goto error_exit; } /* * Do the spawn */ error = do_posix_spawn(l1, &pid, &child_ok, SCARG(uap, path), fa, sa, SCARG(uap, argv), SCARG(uap, envp), execve_fetch_element); if (error) goto error_exit; if (error == 0 && SCARG(uap, pid) != NULL) error = copyout(&pid, SCARG(uap, pid), sizeof(pid)); *retval = error; return 0; error_exit: if (!child_ok) { (void)chgproccnt(kauth_cred_getuid(l1->l_cred), -1); atomic_dec_uint(&nprocs); if (sa) kmem_free(sa, sizeof(*sa)); if (fa) posix_spawn_fa_free(fa, fa->len); } *retval = error; return 0; } void exec_free_emul_arg(struct exec_package *epp) { if (epp->ep_emul_arg_free != NULL) { KASSERT(epp->ep_emul_arg != NULL); (*epp->ep_emul_arg_free)(epp->ep_emul_arg); epp->ep_emul_arg_free = NULL; epp->ep_emul_arg = NULL; } else { KASSERT(epp->ep_emul_arg == NULL); } } #ifdef DEBUG_EXEC static void dump_vmcmds(const struct exec_package * const epp, size_t x, int error) { struct exec_vmcmd *vp = &epp->ep_vmcmds.evs_cmds[0]; size_t j; if (error == 0) DPRINTF(("vmcmds %u\n", epp->ep_vmcmds.evs_used)); else DPRINTF(("vmcmds %zu/%u, error %d\n", x, epp->ep_vmcmds.evs_used, error)); for (j = 0; j < epp->ep_vmcmds.evs_used; j++) { DPRINTF(("vmcmd[%zu] = vmcmd_map_%s %#" PRIxVADDR"/%#"PRIxVSIZE" fd@%#" PRIxVSIZE" prot=0%o flags=%d\n", j, vp[j].ev_proc == vmcmd_map_pagedvn ? "pagedvn" : vp[j].ev_proc == vmcmd_map_readvn ? "readvn" : vp[j].ev_proc == vmcmd_map_zero ? "zero" : "*unknown*", vp[j].ev_addr, vp[j].ev_len, vp[j].ev_offset, vp[j].ev_prot, vp[j].ev_flags)); if (error != 0 && j == x) DPRINTF((" ^--- failed\n")); } } #endif