/* * Copyright (c) 2006 Apple Computer, Inc. All Rights Reserved. * * @APPLE_LICENSE_OSREFERENCE_HEADER_START@ * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. The rights granted to you under the * License may not be used to create, or enable the creation or * redistribution of, unlawful or unlicensed copies of an Apple operating * system, or to circumvent, violate, or enable the circumvention or * violation of, any terms of an Apple operating system software license * agreement. * * Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this * file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_LICENSE_OSREFERENCE_HEADER_END@ */ /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */ /* * Mach Operating System * Copyright (c) 1987 Carnegie-Mellon University * All rights reserved. The CMU software License Agreement specifies * the terms and conditions for use and redistribution. */ #include /*- * Copyright (c) 1982, 1986, 1991, 1993 * The Regents of the University of California. All rights reserved. * (c) UNIX System Laboratories, Inc. * All or some portions of this file are derived from material licensed * to the University of California by American Telephone and Telegraph * Co. or Unix System Laboratories, Inc. and are reproduced herein with * the permission of UNIX System Laboratories, Inc. * * 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 the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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. * * from: @(#)kern_exec.c 8.1 (Berkeley) 6/10/93 */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* shmexec() */ #include /* ubc_map() */ #include #include #include #include #include #include #include #include #include #include #include #include #include /* * Mach things for which prototypes are unavailable from Mach headers */ void ipc_task_reset( task_t task); extern struct savearea *get_user_regs(thread_t); #include #include #include #include #include #include #include #if KTRACE #include #endif #include /* * SIZE_MAXPTR The maximum size of a user space pointer, in bytes * SIZE_IMG_STRSPACE The available string space, minus two pointers; we * define it interms of the maximum, since we don't * know the pointer size going in, until after we've * parsed the executable image. */ #define SIZE_MAXPTR 8 /* 64 bits */ #define SIZE_IMG_STRSPACE (NCARGS - 2 * SIZE_MAXPTR) int app_profile = 0; extern vm_map_t bsd_pageable_map; extern struct fileops vnops; #define ROUND_PTR(type, addr) \ (type *)( ( (unsigned)(addr) + 16 - 1) \ & ~(16 - 1) ) struct image_params; /* Forward */ static int exec_copyout_strings(struct image_params *imgp, user_addr_t *stackp); static int load_return_to_errno(load_return_t lrtn); static int execargs_alloc(struct image_params *imgp); static int execargs_free(struct image_params *imgp); static int exec_check_permissions(struct image_params *imgp); static int exec_extract_strings(struct image_params *imgp); static int exec_handle_sugid(struct image_params *imgp); static int sugid_scripts = 0; SYSCTL_INT (_kern, OID_AUTO, sugid_scripts, CTLFLAG_RW, &sugid_scripts, 0, ""); static kern_return_t create_unix_stack(vm_map_t map, user_addr_t user_stack, int customstack, struct proc *p); static int copyoutptr(user_addr_t ua, user_addr_t ptr, int ptr_size); /* XXX forward; should be in headers, but can't be for one reason or another */ extern int grade_binary(cpu_type_t exectype, cpu_subtype_t execsubtype); extern void vfork_return(thread_t th_act, struct proc * p, struct proc *p2, register_t *retval); extern char classichandler[32]; extern uint32_t classichandler_fsid; extern long classichandler_fileid; /* * exec_add_string * * Add the requested string to the string space area. * * Parameters; struct image_params * image parameter block * user_addr_t string to add to strings area * uio_seg segment where string is located * * Returns: 0 Success * !0 Failure errno from copyinstr() * * Implicit returns: * (imgp->ip_strendp) updated location of next add, if any * (imgp->ip_strspace) updated byte count of space remaining */ static int exec_add_string(struct image_params *imgp, user_addr_t str, /*uio_seg*/int seg) { int error = 0; do { size_t len = 0; if (imgp->ip_strspace <= 0) { error = E2BIG; break; } if (IS_UIO_SYS_SPACE(seg)) { char *kstr = CAST_DOWN(char *,str); /* SAFE */ error = copystr(kstr, imgp->ip_strendp, imgp->ip_strspace, &len); } else { error = copyinstr(str, imgp->ip_strendp, imgp->ip_strspace, &len); } imgp->ip_strendp += len; imgp->ip_strspace -= len; } while (error == ENAMETOOLONG); return error; } /* * exec_save_path * * To support new app package launching for Mac OS X, the dyld needs the * first argument to execve() stored on the user stack. * * Save the executable path name at the top of the strings area and set * the argument vector pointer to the location following that to indicate * the start of the argument and environment tuples, setting the remaining * string space count to the size of the string area minus the path length * and a reserve for two pointers. * * Parameters; struct image_params * image parameter block * char * path used to invoke program * uio_seg segment where path is located * * Returns: int 0 Success * !0 Failure: error number * Implicit returns: * (imgp->ip_strings) saved path * (imgp->ip_strspace) space remaining in ip_strings * (imgp->ip_argv) beginning of argument list * (imgp->ip_strendp) start of remaining copy area * * Note: We have to do this before the initial namei() since in the * path contains symbolic links, namei() will overwrite the * original path buffer contents. If the last symbolic link * resolved was a relative pathname, we would lose the original * "path", which could be an absolute pathname. This might be * unacceptable for dyld. */ static int exec_save_path(struct image_params *imgp, user_addr_t path, /*uio_seg*/int seg) { int error; size_t len; char *kpath = CAST_DOWN(char *,path); /* SAFE */ imgp->ip_strendp = imgp->ip_strings; imgp->ip_strspace = SIZE_IMG_STRSPACE; len = MIN(MAXPATHLEN, imgp->ip_strspace); switch( seg) { case UIO_USERSPACE32: case UIO_USERSPACE64: /* Same for copyin()... */ error = copyinstr(path, imgp->ip_strings, len, &len); break; case UIO_SYSSPACE32: error = copystr(kpath, imgp->ip_strings, len, &len); break; default: error = EFAULT; break; } if (!error) { imgp->ip_strendp += len; imgp->ip_strspace -= len; imgp->ip_argv = imgp->ip_strendp; } return(error); } /* * exec_shell_imgact * * Image activator for interpreter scripts. If the image begins with the * characters "#!", then it is an interpreter script. Verify that we are * not already executing in Classic mode, and that the length of the script * line indicating the interpreter is not in excess of the maximum allowed * size. If this is the case, then break out the arguments, if any, which * are separated by white space, and copy them into the argument save area * as if they were provided on the command line before all other arguments. * The line ends when we encounter a comment character ('#') or newline. * * Parameters; struct image_params * image parameter block * * Returns: -1 not an interpreter (keep looking) * -3 Success: interpreter: relookup * >0 Failure: interpreter: error number * * A return value other than -1 indicates subsequent image activators should * not be given the opportunity to attempt to activate the image. */ static int exec_shell_imgact(struct image_params *imgp) { char *vdata = imgp->ip_vdata; char *ihp; char *line_endp; char *interp; /* * Make sure it's a shell script. If we've already redirected * from an interpreted file once, don't do it again. * * Note: We disallow Classic, since the expectation is that we * may run a Classic interpreter, but not an interpret a Classic * image. This is consistent with historical behaviour. */ if (vdata[0] != '#' || vdata[1] != '!' || (imgp->ip_flags & IMGPF_INTERPRET) != 0) { return (-1); } imgp->ip_flags |= IMGPF_INTERPRET; /* Check to see if SUGID scripts are permitted. If they aren't then * clear the SUGID bits. * imgp->ip_vattr is known to be valid. */ if (sugid_scripts == 0) { imgp->ip_origvattr->va_mode &= ~(VSUID | VSGID); } /* Find the nominal end of the interpreter line */ for( ihp = &vdata[2]; *ihp != '\n' && *ihp != '#'; ihp++) { if (ihp >= &vdata[IMG_SHSIZE]) return (ENOEXEC); } line_endp = ihp; ihp = &vdata[2]; /* Skip over leading spaces - until the interpreter name */ while ( ihp < line_endp && ((*ihp == ' ') || (*ihp == '\t'))) ihp++; /* * Find the last non-whitespace character before the end of line or * the beginning of a comment; this is our new end of line. */ for (;line_endp > ihp && ((*line_endp == ' ') || (*line_endp == '\t')); line_endp--) continue; /* Empty? */ if (line_endp == ihp) return (ENOEXEC); /* copy the interpreter name */ interp = imgp->ip_interp_name; while ((ihp < line_endp) && (*ihp != ' ') && (*ihp != '\t')) *interp++ = *ihp++; *interp = '\0'; exec_save_path(imgp, CAST_USER_ADDR_T(imgp->ip_interp_name), UIO_SYSSPACE32); ihp = &vdata[2]; while (ihp < line_endp) { /* Skip leading whitespace before each argument */ while ((*ihp == ' ') || (*ihp == '\t')) ihp++; if (ihp >= line_endp) break; /* We have an argument; copy it */ while ((ihp < line_endp) && (*ihp != ' ') && (*ihp != '\t')) { *imgp->ip_strendp++ = *ihp++; imgp->ip_strspace--; } *imgp->ip_strendp++ = 0; imgp->ip_strspace--; imgp->ip_argc++; } return (-3); } /* * exec_fat_imgact * * Image activator for fat 1.0 binaries. If the binary is fat, then we * need to select an image from it internally, and make that the image * we are going to attempt to execute. At present, this consists of * reloading the first page for the image with a first page from the * offset location indicated by the fat header. * * Important: This image activator is byte order neutral. * * Note: If we find an encapsulated binary, we make no assertions * about its validity; instead, we leave that up to a rescan * for an activator to claim it, and, if it is claimed by one, * that activator is responsible for determining validity. */ static int exec_fat_imgact(struct image_params *imgp) { struct proc *p = vfs_context_proc(imgp->ip_vfs_context); kauth_cred_t cred = p->p_ucred; struct fat_header *fat_header = (struct fat_header *)imgp->ip_vdata; struct fat_arch fat_arch; int resid, error; load_return_t lret; /* Make sure it's a fat binary */ if ((fat_header->magic != FAT_MAGIC) && (fat_header->magic != FAT_CIGAM)) { error = -1; goto bad; } /* Look up our preferred architecture in the fat file. */ lret = fatfile_getarch_affinity(imgp->ip_vp, (vm_offset_t)fat_header, &fat_arch, (p->p_flag & P_AFFINITY)); if (lret != LOAD_SUCCESS) { error = load_return_to_errno(lret); goto bad; } /* Read the Mach-O header out of it */ error = vn_rdwr(UIO_READ, imgp->ip_vp, imgp->ip_vdata, PAGE_SIZE, fat_arch.offset, UIO_SYSSPACE32, (IO_UNIT|IO_NODELOCKED), cred, &resid, p); if (error) { goto bad; } /* Did we read a complete header? */ if (resid) { error = EBADEXEC; goto bad; } /* Success. Indicate we have identified an encapsulated binary */ error = -2; imgp->ip_arch_offset = (user_size_t)fat_arch.offset; imgp->ip_arch_size = (user_size_t)fat_arch.size; bad: return (error); } /* * exec_mach_imgact * * Image activator for mach-o 1.0 binaries. * * Important: This image activator is NOT byte order neutral. */ static int exec_mach_imgact(struct image_params *imgp) { struct mach_header *mach_header = (struct mach_header *)imgp->ip_vdata; kauth_cred_t cred = vfs_context_ucred(imgp->ip_vfs_context); struct proc *p = vfs_context_proc(imgp->ip_vfs_context); int error = 0; int vfexec = 0; task_t task; task_t new_task; thread_t thread; struct uthread *uthread; vm_map_t old_map = VM_MAP_NULL; vm_map_t map; boolean_t clean_regions = FALSE; shared_region_mapping_t initial_region = NULL; load_return_t lret; load_result_t load_result; /* * make sure it's a Mach-O 1.0 or Mach-O 2.0 binary; the difference * is a reserved field on the end, so for the most part, we can * treat them as if they were identical. */ if ((mach_header->magic != MH_MAGIC) && (mach_header->magic != MH_MAGIC_64)) { error = -1; goto bad; } task = current_task(); thread = current_thread(); uthread = get_bsdthread_info(thread); if (uthread->uu_flag & UT_VFORK) vfexec = 1; /* Mark in exec */ if ((mach_header->cputype & CPU_ARCH_ABI64) == CPU_ARCH_ABI64) imgp->ip_flags |= IMGPF_IS_64BIT; if (!grade_binary(mach_header->cputype, mach_header->cpusubtype)) { error = EBADARCH; goto bad; } /* * Copy in arguments/environment from the old process, if the * vector is non-NULL (i.e. exec is not being called from * load_init_program(), as a special case, at system startup). */ if (imgp->ip_user_argv != 0LL) { error = exec_extract_strings(imgp); if (error) goto bad; } /* * Hack for binary compatability; put three NULs on the end of the * string area, and round it up to the next word boundary. This * ensures padding with NULs to the boundary. */ imgp->ip_strendp[0] = 0; imgp->ip_strendp[1] = 0; imgp->ip_strendp[2] = 0; imgp->ip_strendp += (((imgp->ip_strendp - imgp->ip_strings) + NBPW-1) & ~(NBPW-1)); if (vfexec) { kern_return_t result; result = task_create_internal(task, FALSE, &new_task); if (result != KERN_SUCCESS) printf("execve: task_create failed. Code: 0x%x\n", result); p->task = new_task; set_bsdtask_info(new_task, p); if (p->p_nice != 0) resetpriority(p); map = get_task_map(new_task); result = thread_create(new_task, &imgp->ip_vfork_thread); if (result != KERN_SUCCESS) printf("execve: thread_create failed. Code: 0x%x\n", result); /* reset local idea of task, thread, uthread */ task = new_task; thread = imgp->ip_vfork_thread; uthread = get_bsdthread_info(thread); } else { map = VM_MAP_NULL; } /* * We set these flags here; this is OK, since if we fail after * this point, we have already destroyed the parent process anyway. */ if (imgp->ip_flags & IMGPF_IS_64BIT) { task_set_64bit(task, TRUE); p->p_flag |= P_LP64; } else { task_set_64bit(task, FALSE); p->p_flag &= ~P_LP64; } /* * Load the Mach-O file. */ /* LP64 - remove following "if" statement after osfmk/vm/task_working_set.c */ if((imgp->ip_flags & IMGPF_IS_64BIT) == 0) if(imgp->ip_tws_cache_name) { tws_handle_startup_file(task, kauth_cred_getuid(cred), imgp->ip_tws_cache_name, imgp->ip_vp, &clean_regions); } vm_get_shared_region(task, &initial_region); /* * NOTE: An error after this point indicates we have potentially * destroyed or overwrote some process state while attempting an * execve() following a vfork(), which is an unrecoverable condition. */ /* * We reset the task to 64-bit (or not) here. It may have picked up * a new map, and we need that to reflect its true 64-bit nature. */ task_set_64bit(task, ((imgp->ip_flags & IMGPF_IS_64BIT) == IMGPF_IS_64BIT)); /* * Actually load the image file we previously decided to load. */ lret = load_machfile(imgp, mach_header, thread, map, clean_regions, &load_result); if (lret != LOAD_SUCCESS) { error = load_return_to_errno(lret); goto badtoolate; } /* load_machfile() maps the vnode */ (void)ubc_map(imgp->ip_vp, PROT_EXEC); /* * deal with set[ug]id. */ error = exec_handle_sugid(imgp); KNOTE(&p->p_klist, NOTE_EXEC); if (!vfexec && (p->p_flag & P_TRACED)) psignal(p, SIGTRAP); if (error) { goto badtoolate; } vnode_put(imgp->ip_vp); imgp->ip_vp = NULL; if (load_result.unixproc && create_unix_stack(get_task_map(task), load_result.user_stack, load_result.customstack, p)) { error = load_return_to_errno(LOAD_NOSPACE); goto badtoolate; } if (vfexec) { uthread->uu_ar0 = (void *)get_user_regs(thread); old_map = vm_map_switch(get_task_map(task)); } if (load_result.unixproc) { user_addr_t ap; /* * Copy the strings area out into the new process address * space. */ ap = p->user_stack; error = exec_copyout_strings(imgp, &ap); if (error) { if (vfexec) vm_map_switch(old_map); goto badtoolate; } /* Set the stack */ thread_setuserstack(thread, ap); } if (load_result.dynlinker) { uint64_t ap; /* Adjust the stack */ if (imgp->ip_flags & IMGPF_IS_64BIT) { ap = thread_adjuserstack(thread, -8); (void)copyoutptr(load_result.mach_header, ap, 8); } else { ap = thread_adjuserstack(thread, -4); (void)suword(ap, load_result.mach_header); } } if (vfexec) { vm_map_switch(old_map); } /* Set the entry point */ thread_setentrypoint(thread, load_result.entry_point); /* Stop profiling */ stopprofclock(p); /* * Reset signal state. */ execsigs(p, thread); /* * Close file descriptors * which specify close-on-exec. */ fdexec(p); /* * need to cancel async IO requests that can be cancelled and wait for those * already active. MAY BLOCK! */ _aio_exec( p ); /* FIXME: Till vmspace inherit is fixed: */ if (!vfexec && p->vm_shm) shmexec(p); /* Clean up the semaphores */ semexit(p); /* * Remember file name for accounting. */ p->p_acflag &= ~AFORK; /* If the translated name isn't NULL, then we want to use * that translated name as the name we show as the "real" name. * Otherwise, use the name passed into exec. */ if (0 != imgp->ip_p_comm[0]) { bcopy((caddr_t)imgp->ip_p_comm, (caddr_t)p->p_comm, sizeof(p->p_comm)); } else { if (imgp->ip_ndp->ni_cnd.cn_namelen > MAXCOMLEN) imgp->ip_ndp->ni_cnd.cn_namelen = MAXCOMLEN; bcopy((caddr_t)imgp->ip_ndp->ni_cnd.cn_nameptr, (caddr_t)p->p_comm, (unsigned)imgp->ip_ndp->ni_cnd.cn_namelen); p->p_comm[imgp->ip_ndp->ni_cnd.cn_namelen] = '\0'; } { /* This is for kdebug */ long dbg_arg1, dbg_arg2, dbg_arg3, dbg_arg4; /* Collect the pathname for tracing */ kdbg_trace_string(p, &dbg_arg1, &dbg_arg2, &dbg_arg3, &dbg_arg4); if (vfexec) { KERNEL_DEBUG_CONSTANT1((TRACEDBG_CODE(DBG_TRACE_DATA, 2)) | DBG_FUNC_NONE, p->p_pid ,0,0,0, (unsigned int)thread); KERNEL_DEBUG_CONSTANT1((TRACEDBG_CODE(DBG_TRACE_STRING, 2)) | DBG_FUNC_NONE, dbg_arg1, dbg_arg2, dbg_arg3, dbg_arg4, (unsigned int)thread); } else { KERNEL_DEBUG_CONSTANT((TRACEDBG_CODE(DBG_TRACE_DATA, 2)) | DBG_FUNC_NONE, p->p_pid ,0,0,0,0); KERNEL_DEBUG_CONSTANT((TRACEDBG_CODE(DBG_TRACE_STRING, 2)) | DBG_FUNC_NONE, dbg_arg1, dbg_arg2, dbg_arg3, dbg_arg4, 0); } } p->p_flag &= ~P_CLASSIC; /* * mark as execed, wakeup the process that vforked (if any) and tell * it that it now has it's own resources back */ p->p_flag |= P_EXEC; if (p->p_pptr && (p->p_flag & P_PPWAIT)) { p->p_flag &= ~P_PPWAIT; wakeup((caddr_t)p->p_pptr); } if (vfexec && (p->p_flag & P_TRACED)) { psignal_vfork(p, new_task, thread, SIGTRAP); } badtoolate: if (vfexec) { task_deallocate(new_task); thread_deallocate(thread); if (error) error = 0; } bad: return(error); } /* * Our image activator table; this is the table of the image types we are * capable of loading. We list them in order of preference to ensure the * fastest image load speed. * * XXX hardcoded, for now; should use linker sets */ struct execsw { int (*ex_imgact)(struct image_params *); const char *ex_name; } execsw[] = { { exec_mach_imgact, "Mach-o Binary" }, { exec_fat_imgact, "Fat Binary" }, { exec_shell_imgact, "Interpreter Script" }, { NULL, NULL} }; /* * TODO: Dynamic linker header address on stack is copied via suword() */ /* ARGSUSED */ int execve(struct proc *p, struct execve_args *uap, register_t *retval) { kauth_cred_t cred = p->p_ucred; struct image_params image_params, *imgp; struct vnode_attr va; struct vnode_attr origva; struct nameidata nd; struct uthread *uthread; int i; int resid, error; task_t task; int numthreads; int vfexec=0; int once = 1; /* save SGUID-ness for interpreted files */ char alt_p_comm[sizeof(p->p_comm)] = {0}; /* for Classic */ int is_64 = IS_64BIT_PROCESS(p); int seg = (is_64 ? UIO_USERSPACE64 : UIO_USERSPACE32); struct vfs_context context; context.vc_proc = p; context.vc_ucred = p->p_ucred; /* XXX must NOT be kauth_cred_get() */ imgp = &image_params; /* Initialize the common data in the image_params structure */ bzero(imgp, sizeof(*imgp)); imgp->ip_user_fname = uap->fname; imgp->ip_user_argv = uap->argp; imgp->ip_user_envv = uap->envp; imgp->ip_vattr = &va; imgp->ip_origvattr = &origva; imgp->ip_vfs_context = &context; imgp->ip_flags = (is_64 ? IMGPF_WAS_64BIT : IMGPF_NONE); imgp->ip_tws_cache_name = NULL; imgp->ip_p_comm = alt_p_comm; /* for Classic */ /* * XXXAUDIT: Currently, we only audit the pathname of the binary. * There may also be poor interaction with dyld. */ task = current_task(); uthread = get_bsdthread_info(current_thread()); if (uthread->uu_flag & UT_VFORK) { vfexec = 1; /* Mark in exec */ } else { if (task != kernel_task) { numthreads = get_task_numacts(task); if (numthreads <= 0 ) return(EINVAL); if (numthreads > 1) { return(ENOTSUP); } } } error = execargs_alloc(imgp); if (error) return(error); /* * XXXAUDIT: Note: the double copyin introduces an audit * race. To correct this race, we must use a single * copyin(), e.g. by passing a flag to namei to indicate an * external path buffer is being used. */ error = exec_save_path(imgp, uap->fname, seg); if (error) { execargs_free(imgp); return(error); } /* * No app profiles under chroot */ if((p->p_fd->fd_rdir == NULLVP) && (app_profile != 0)) { /* grab the name of the file out of its path */ /* we will need this for lookup within the */ /* name file */ /* Scan backwards for the first '/' or start of string */ imgp->ip_tws_cache_name = imgp->ip_strendp; while (imgp->ip_tws_cache_name[0] != '/') { if(imgp->ip_tws_cache_name == imgp->ip_strings) { imgp->ip_tws_cache_name--; break; } imgp->ip_tws_cache_name--; } imgp->ip_tws_cache_name++; } NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | AUDITVNPATH1, seg, uap->fname, imgp->ip_vfs_context); again: error = namei(&nd); if (error) goto bad; imgp->ip_ndp = &nd; /* successful namei(); call nameidone() later */ imgp->ip_vp = nd.ni_vp; /* if set, need to vnode_put() at some point */ error = exec_check_permissions(imgp); if (error) goto bad; /* Copy; avoid invocation of an interpreter overwriting the original */ if (once) { once = 0; origva = va; } error = vn_rdwr(UIO_READ, imgp->ip_vp, imgp->ip_vdata, PAGE_SIZE, 0, UIO_SYSSPACE32, IO_NODELOCKED, cred, &resid, p); if (error) goto bad; encapsulated_binary: error = -1; for(i = 0; error == -1 && execsw[i].ex_imgact != NULL; i++) { error = (*execsw[i].ex_imgact)(imgp); switch (error) { /* case -1: not claimed: continue */ case -2: /* Encapsulated binary */ goto encapsulated_binary; case -3: /* Interpreter */ vnode_put(imgp->ip_vp); imgp->ip_vp = NULL; /* already put */ nd.ni_cnd.cn_nameiop = LOOKUP; nd.ni_cnd.cn_flags = (nd.ni_cnd.cn_flags & HASBUF) | (FOLLOW | LOCKLEAF); nd.ni_segflg = UIO_SYSSPACE32; nd.ni_dirp = CAST_USER_ADDR_T(imgp->ip_interp_name); goto again; default: break; } } /* call out to allow 3rd party notification of exec. * Ignore result of kauth_authorize_fileop call. */ if (error == 0 && kauth_authorize_fileop_has_listeners()) { kauth_authorize_fileop(vfs_context_ucred(&context), KAUTH_FILEOP_EXEC, (uintptr_t)nd.ni_vp, 0); } /* Image not claimed by any activator? */ if (error == -1) error = ENOEXEC; bad: if (imgp->ip_ndp) nameidone(imgp->ip_ndp); if (imgp->ip_vp) vnode_put(imgp->ip_vp); if (imgp->ip_strings) execargs_free(imgp); if (!error && vfexec) { vfork_return(current_thread(), p->p_pptr, p, retval); (void)thread_resume(imgp->ip_vfork_thread); return(0); } return(error); } static int copyinptr(user_addr_t froma, user_addr_t *toptr, int ptr_size) { int error; if (ptr_size == 4) { /* 64 bit value containing 32 bit address */ unsigned int i; error = copyin(froma, &i, 4); *toptr = CAST_USER_ADDR_T(i); /* SAFE */ } else { error = copyin(froma, toptr, 8); } return (error); } static int copyoutptr(user_addr_t ua, user_addr_t ptr, int ptr_size) { int error; if (ptr_size == 4) { /* 64 bit value containing 32 bit address */ unsigned int i = CAST_DOWN(unsigned int,ua); /* SAFE */ error = copyout(&i, ptr, 4); } else { error = copyout(&ua, ptr, 8); } return (error); } /* * exec_copyout_strings * * Copy out the strings segment to user space. The strings segment is put * on a preinitialized stack frame. * * Parameters: struct image_params * the image parameter block * int * a pointer to the stack offset variable * * Returns: 0 Success * !0 Faiure: errno * * Implicit returns: * (*stackp) The stack offset, modified * * Note: The strings segment layout is backward, from the beginning * of the top of the stack to consume the minimal amount of * space possible; the returned stack pointer points to the * end of the area consumed (stacks grow upward). * * argc is an int; arg[i] are pointers; env[i] are pointers; * exec_path is a pointer; the 0's are (void *)NULL's * * The stack frame layout is: * * +-------------+ * sp-> | argc | * +-------------+ * | arg[0] | * +-------------+ * : * : * +-------------+ * | arg[argc-1] | * +-------------+ * | 0 | * +-------------+ * | env[0] | * +-------------+ * : * : * +-------------+ * | env[n] | * +-------------+ * | 0 | * +-------------+ * | exec_path | In MacOS X PR2 Beaker2E the path passed to exec() is * +-------------+ passed on the stack just after the trailing 0 of the * | 0 | the envp[] array as a pointer to a string. * +-------------+ * | PATH AREA | * +-------------+ * | STRING AREA | * : * : * | | <- p->user_stack * +-------------+ * * Although technically a part of the STRING AREA, we treat the PATH AREA as * a separate entity. This allows us to align the beginning of the PATH AREA * to a pointer boundary so that the exec_path, env[i], and argv[i] pointers * which preceed it on the stack are properly aligned. * * TODO: argc copied with suword(), which takes a 64 bit address */ static int exec_copyout_strings(struct image_params *imgp, user_addr_t *stackp) { struct proc *p = vfs_context_proc(imgp->ip_vfs_context); int ptr_size = (imgp->ip_flags & IMGPF_IS_64BIT) ? 8 : 4; char *argv = imgp->ip_argv; /* modifiable copy of argv */ user_addr_t string_area; /* *argv[], *env[] */ user_addr_t path_area; /* package launch path */ user_addr_t ptr_area; /* argv[], env[], exec_path */ user_addr_t stack; int stringc = imgp->ip_argc + imgp->ip_envc; int len; int error; int strspace; stack = *stackp; /* * Set up pointers to the beginning of the string area, the beginning * of the path area, and the beginning of the pointer area (actually, * the location of argc, an int, which may be smaller than a pointer, * but we use ptr_size worth of space for it, for alignment). */ string_area = stack - (((imgp->ip_strendp - imgp->ip_strings) + ptr_size-1) & ~(ptr_size-1)) - ptr_size; path_area = string_area - (((imgp->ip_argv - imgp->ip_strings) + ptr_size-1) & ~(ptr_size-1)); ptr_area = path_area - ((imgp->ip_argc + imgp->ip_envc + 4) * ptr_size) - ptr_size /*argc*/; /* Return the initial stack address: the location of argc */ *stackp = ptr_area; /* * Record the size of the arguments area so that sysctl_procargs() * can return the argument area without having to parse the arguments. */ p->p_argc = imgp->ip_argc; p->p_argslen = (int)(stack - path_area); /* * Support for new app package launching for Mac OS X allocates * the "path" at the begining of the imgp->ip_strings buffer. * copy it just before the string area. */ len = 0; error = copyoutstr(imgp->ip_strings, path_area, (unsigned)(imgp->ip_argv - imgp->ip_strings), (size_t *)&len); if (error) goto bad; /* Save a NULL pointer below it */ (void)copyoutptr(0LL, path_area - ptr_size, ptr_size); /* Save the pointer to "path" just below it */ (void)copyoutptr(path_area, path_area - 2*ptr_size, ptr_size); /* * ptr_size for 2 NULL one each ofter arg[argc -1] and env[n] * ptr_size for argc * skip over saved path, ptr_size for pointer to path, * and ptr_size for the NULL after pointer to path. */ /* argc (int32, stored in a ptr_size area) */ (void)suword(ptr_area, imgp->ip_argc); ptr_area += sizeof(int); /* pad to ptr_size, if 64 bit image, to ensure user stack alignment */ if (imgp->ip_flags & IMGPF_IS_64BIT) { (void)suword(ptr_area, 0); /* int, not long: ignored */ ptr_area += sizeof(int); } /* * We use (string_area - path_area) here rather than the more * intuitive (imgp->ip_argv - imgp->ip_strings) because we are * interested in the length of the PATH_AREA in user space, * rather than the actual length of the execution path, since * it includes alignment padding of the PATH_AREA + STRING_AREA * to a ptr_size boundary. */ strspace = SIZE_IMG_STRSPACE - (string_area - path_area); for (;;) { if (stringc == imgp->ip_envc) { /* argv[n] = NULL */ (void)copyoutptr(0LL, ptr_area, ptr_size); ptr_area += ptr_size; } if (--stringc < 0) break; /* pointer: argv[n]/env[n] */ (void)copyoutptr(string_area, ptr_area, ptr_size); /* string : argv[n][]/env[n][] */ do { if (strspace <= 0) { error = E2BIG; break; } error = copyoutstr(argv, string_area, (unsigned)strspace, (size_t *)&len); string_area += len; argv += len; strspace -= len; } while (error == ENAMETOOLONG); if (error == EFAULT || error == E2BIG) break; /* bad stack - user's problem */ ptr_area += ptr_size; } /* env[n] = NULL */ (void)copyoutptr(0LL, ptr_area, ptr_size); bad: return(error); } /* * exec_extract_strings * * Copy arguments and environment from user space into work area; we may * have already copied some early arguments into the work area, and if * so, any arguments opied in are appended to those already there. * * Parameters: struct image_params * the image parameter block * * Returns: 0 Success * !0 Failure: errno * * Implicit returns; * (imgp->ip_argc) Count of arguments, updated * (imgp->ip_envc) Count of environment strings, updated * * * Notes: The argument and environment vectors are user space pointers * to arrays of user space pointers. */ static int exec_extract_strings(struct image_params *imgp) { int error = 0; struct proc *p = vfs_context_proc(imgp->ip_vfs_context); int seg = (IS_64BIT_PROCESS(p) ? UIO_USERSPACE64 : UIO_USERSPACE32); int ptr_size = (imgp->ip_flags & IMGPF_WAS_64BIT) ? 8 : 4; user_addr_t argv = imgp->ip_user_argv; user_addr_t envv = imgp->ip_user_envv; /* Now, get rest of arguments */ /* * If we are running an interpreter, replace the av[0] that was * passed to execve() with the fully qualified path name that was * passed to execve() for interpreters which do not use the PATH * to locate their script arguments. */ if((imgp->ip_flags & IMGPF_INTERPRET) != 0 && argv != 0LL) { user_addr_t arg; error = copyinptr(argv, &arg, ptr_size); if (error) goto bad; if (arg != 0LL && arg != (user_addr_t)-1) { argv += ptr_size; error = exec_add_string(imgp, imgp->ip_user_fname, seg); if (error) goto bad; imgp->ip_argc++; } } while (argv != 0LL) { user_addr_t arg; error = copyinptr(argv, &arg, ptr_size); if (error) goto bad; argv += ptr_size; if (arg == 0LL) { break; } else if (arg == (user_addr_t)-1) { /* Um... why would it be -1? */ error = EFAULT; goto bad; } /* * av[n...] = arg[n] */ error = exec_add_string(imgp, arg, seg); if (error) goto bad; imgp->ip_argc++; } /* Now, get the environment */ while (envv != 0LL) { user_addr_t env; error = copyinptr(envv, &env, ptr_size); if (error) goto bad; envv += ptr_size; if (env == 0LL) { break; } else if (env == (user_addr_t)-1) { error = EFAULT; goto bad; } /* * av[n...] = env[n] */ error = exec_add_string(imgp, env, seg); if (error) goto bad; imgp->ip_envc++; } bad: return error; } #define unix_stack_size(p) (p->p_rlimit[RLIMIT_STACK].rlim_cur) static int exec_check_permissions(struct image_params *imgp) { struct vnode *vp = imgp->ip_vp; struct vnode_attr *vap = imgp->ip_vattr; struct proc *p = vfs_context_proc(imgp->ip_vfs_context); int error; kauth_action_t action; /* Only allow execution of regular files */ if (!vnode_isreg(vp)) return (EACCES); /* Get the file attributes that we will be using here and elsewhere */ VATTR_INIT(vap); VATTR_WANTED(vap, va_uid); VATTR_WANTED(vap, va_gid); VATTR_WANTED(vap, va_mode); VATTR_WANTED(vap, va_fsid); VATTR_WANTED(vap, va_fileid); VATTR_WANTED(vap, va_data_size); if ((error = vnode_getattr(vp, vap, imgp->ip_vfs_context)) != 0) return (error); /* * Ensure that at least one execute bit is on - otherwise root * will always succeed, and we don't want to happen unless the * file really is executable. */ if ((vap->va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0) return (EACCES); /* Disallow zero length files */ if (vap->va_data_size == 0) return (ENOEXEC); imgp->ip_arch_offset = (user_size_t)0; imgp->ip_arch_size = vap->va_data_size; /* Disable setuid-ness for traced programs or if MNT_NOSUID */ if ((vp->v_mount->mnt_flag & MNT_NOSUID) || (p->p_flag & P_TRACED)) vap->va_mode &= ~(VSUID | VSGID); /* Check for execute permission */ action = KAUTH_VNODE_EXECUTE; /* Traced images must also be readable */ if (p->p_flag & P_TRACED) action |= KAUTH_VNODE_READ_DATA; if ((error = vnode_authorize(vp, NULL, action, imgp->ip_vfs_context)) != 0) return (error); /* Don't let it run if anyone had it open for writing */ if (vp->v_writecount) return (ETXTBSY); /* XXX May want to indicate to underlying FS that vnode is open */ return (error); } /* * exec_handle_sugid * * Initially clear the P_SUGID in the process flags; if an SUGID process is * exec'ing a non-SUGID image, then this is the point of no return. * * If the image being activated is SUGI, then replace the credential with a * copy, disable tracing (unless the tracing process is root), reset the * mach task port to revoke it, set the P_SUGID bit, * * If the saved user and group ID will be changing, then make sure it happens * to a new credential, rather than a shared one. * * Set the security token (this is probably obsolete, given that the token * should not technically be separate from the credential itself). * * Parameters: struct image_params * the image parameter block * * Returns: void No failure indication * * Implicit returns: * Potentially modified/replaced * Potentially revoked * P_SUGID bit potentially modified * Potentially modified */ static int exec_handle_sugid(struct image_params *imgp) { kauth_cred_t cred = vfs_context_ucred(imgp->ip_vfs_context); struct proc *p = vfs_context_proc(imgp->ip_vfs_context); int i; int error = 0; static struct vnode *dev_null = NULLVP; p->p_flag &= ~P_SUGID; if (((imgp->ip_origvattr->va_mode & VSUID) != 0 && kauth_cred_getuid(cred) != imgp->ip_origvattr->va_uid) || ((imgp->ip_origvattr->va_mode & VSGID) != 0 && cred->cr_gid != imgp->ip_origvattr->va_gid)) { #if KTRACE /* * If process is being ktraced, turn off - unless * root set it. */ if (p->p_tracep && !(p->p_traceflag & KTRFAC_ROOT)) { struct vnode *tvp = p->p_tracep; p->p_tracep = NULL; p->p_traceflag = 0; vnode_rele(tvp); } #endif /* * Replace the credential with a copy of itself if euid or egid change. */ if (imgp->ip_origvattr->va_mode & VSUID) { p->p_ucred = kauth_cred_seteuid(p->p_ucred, imgp->ip_origvattr->va_uid); } if (imgp->ip_origvattr->va_mode & VSGID) { p->p_ucred = kauth_cred_setegid(p->p_ucred, imgp->ip_origvattr->va_gid); } /* * Have mach reset the task port. We don't want * anyone who had the task port before a setuid * exec to be able to access/control the task * after. */ if (current_task() == p->task) ipc_task_reset(p->task); p->p_flag |= P_SUGID; /* Cache the vnode for /dev/null the first time around */ if (dev_null == NULLVP) { struct nameidata nd1; NDINIT(&nd1, LOOKUP, FOLLOW, UIO_SYSSPACE32, CAST_USER_ADDR_T("/dev/null"), imgp->ip_vfs_context); if ((error = vn_open(&nd1, FREAD, 0)) == 0) { dev_null = nd1.ni_vp; /* * vn_open returns with both a use_count * and an io_count on the found vnode * drop the io_count, but keep the use_count */ vnode_put(nd1.ni_vp); } } /* Radar 2261856; setuid security hole fix */ /* Patch from OpenBSD: A. Ramesh */ /* * XXX For setuid processes, attempt to ensure that * stdin, stdout, and stderr are already allocated. * We do not want userland to accidentally allocate * descriptors in this range which has implied meaning * to libc. */ if (dev_null != NULLVP) { for (i = 0; i < 3; i++) { struct fileproc *fp; int indx; if (p->p_fd->fd_ofiles[i] != NULL) continue; if ((error = falloc(p, &fp, &indx)) != 0) continue; if ((error = vnode_ref_ext(dev_null, FREAD)) != 0) { fp_free(p, indx, fp); break; } fp->f_fglob->fg_flag = FREAD; fp->f_fglob->fg_type = DTYPE_VNODE; fp->f_fglob->fg_ops = &vnops; fp->f_fglob->fg_data = (caddr_t)dev_null; proc_fdlock(p); *fdflags(p, indx) &= ~UF_RESERVED; fp_drop(p, indx, fp, 1); proc_fdunlock(p); } /* * for now we need to drop the reference immediately * since we don't have any mechanism in place to * release it before starting to unmount "/dev" * during a reboot/shutdown */ vnode_rele(dev_null); dev_null = NULLVP; } } /* * Implement the semantic where the effective user and group become * the saved user and group in exec'ed programs. */ p->p_ucred = kauth_cred_setsvuidgid(p->p_ucred, kauth_cred_getuid(p->p_ucred), p->p_ucred->cr_gid); /* XXX Obsolete; security token should not be separate from cred */ set_security_token(p); return(error); } static kern_return_t create_unix_stack(vm_map_t map, user_addr_t user_stack, int customstack, struct proc *p) { mach_vm_size_t size; mach_vm_offset_t addr; p->user_stack = user_stack; if (!customstack) { size = mach_vm_round_page(unix_stack_size(p)); addr = mach_vm_trunc_page(user_stack - size); return (mach_vm_allocate(map, &addr, size, VM_MAKE_TAG(VM_MEMORY_STACK) | VM_FLAGS_FIXED)); } else return(KERN_SUCCESS); } #include static char init_program_name[128] = "/sbin/launchd"; static const char * other_init = "/sbin/mach_init"; char init_args[128] = ""; struct execve_args init_exec_args; int init_attempts = 0; void load_init_program(struct proc *p) { vm_offset_t init_addr; char *argv[3]; int error; register_t retval[2]; error = 0; /* init_args are copied in string form directly from bootstrap */ do { if (boothowto & RB_INITNAME) { printf("init program? "); #if FIXME /* [ */ gets(init_program_name, init_program_name); #endif /* FIXME ] */ } if (error && ((boothowto & RB_INITNAME) == 0) && (init_attempts == 1)) { printf("Load of %s, errno %d, trying %s\n", init_program_name, error, other_init); error = 0; bcopy(other_init, init_program_name, sizeof(other_init)); } init_attempts++; if (error) { printf("Load of %s failed, errno %d\n", init_program_name, error); error = 0; boothowto |= RB_INITNAME; continue; } /* * Copy out program name. */ init_addr = VM_MIN_ADDRESS; (void) vm_allocate(current_map(), &init_addr, PAGE_SIZE, VM_FLAGS_ANYWHERE); if (init_addr == 0) init_addr++; (void) copyout((caddr_t) init_program_name, CAST_USER_ADDR_T(init_addr), (unsigned) sizeof(init_program_name)+1); argv[0] = (char *) init_addr; init_addr += sizeof(init_program_name); init_addr = (vm_offset_t)ROUND_PTR(char, init_addr); /* * Put out first (and only) argument, similarly. * Assumes everything fits in a page as allocated * above. */ (void) copyout((caddr_t) init_args, CAST_USER_ADDR_T(init_addr), (unsigned) sizeof(init_args)); argv[1] = (char *) init_addr; init_addr += sizeof(init_args); init_addr = (vm_offset_t)ROUND_PTR(char, init_addr); /* * Null-end the argument list */ argv[2] = (char *) 0; /* * Copy out the argument list. */ (void) copyout((caddr_t) argv, CAST_USER_ADDR_T(init_addr), (unsigned) sizeof(argv)); /* * Set up argument block for fake call to execve. */ init_exec_args.fname = CAST_USER_ADDR_T(argv[0]); init_exec_args.argp = CAST_USER_ADDR_T((char **)init_addr); init_exec_args.envp = CAST_USER_ADDR_T(0); /* So that mach_init task * is set with uid,gid 0 token */ set_security_token(p); error = execve(p,&init_exec_args,retval); } while (error); } /* * Convert a load_return_t to an errno. */ static int load_return_to_errno(load_return_t lrtn) { switch (lrtn) { case LOAD_SUCCESS: return 0; case LOAD_BADARCH: return EBADARCH; case LOAD_BADMACHO: return EBADMACHO; case LOAD_SHLIB: return ESHLIBVERS; case LOAD_NOSPACE: case LOAD_RESOURCE: return ENOMEM; case LOAD_PROTECT: return EACCES; case LOAD_ENOENT: return ENOENT; case LOAD_IOERROR: return EIO; case LOAD_FAILURE: default: return EBADEXEC; } } #include #include #include #include #include #include extern semaphore_t execve_semaphore; /* * The block of memory used by the execve arguments. At the same time, * we allocate a page so that we can read in the first page of the image. */ static int execargs_alloc(struct image_params *imgp) { kern_return_t kret; kret = semaphore_wait(execve_semaphore); if (kret != KERN_SUCCESS) switch (kret) { default: return (EINVAL); case KERN_INVALID_ADDRESS: case KERN_PROTECTION_FAILURE: return (EACCES); case KERN_ABORTED: case KERN_OPERATION_TIMED_OUT: return (EINTR); } kret = kmem_alloc_pageable(bsd_pageable_map, (vm_offset_t *)&imgp->ip_strings, NCARGS + PAGE_SIZE); imgp->ip_vdata = imgp->ip_strings + NCARGS; if (kret != KERN_SUCCESS) { semaphore_signal(execve_semaphore); return (ENOMEM); } return (0); } static int execargs_free(struct image_params *imgp) { kern_return_t kret; kmem_free(bsd_pageable_map, (vm_offset_t)imgp->ip_strings, NCARGS + PAGE_SIZE); imgp->ip_strings = NULL; kret = semaphore_signal(execve_semaphore); switch (kret) { case KERN_INVALID_ADDRESS: case KERN_PROTECTION_FAILURE: return (EINVAL); case KERN_ABORTED: case KERN_OPERATION_TIMED_OUT: return (EINTR); case KERN_SUCCESS: return(0); default: return (EINVAL); } }