/* * Copyright (c) 2000-2007 Apple Inc. All rights reserved. * * @APPLE_OSREFERENCE_LICENSE_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_OSREFERENCE_LICENSE_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 <cputypes.h> /*- * 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 */ /* * NOTICE: This file was modified by SPARTA, Inc. in 2005 to introduce * support for mandatory and extensible security protections. This notice * is included in support of clause 2.2 (b) of the Apple Public License, * Version 2.0. */ #include <machine/reg.h> #include <sys/param.h> #include <sys/systm.h> #include <sys/filedesc.h> #include <sys/kernel.h> #include <sys/proc_internal.h> #include <sys/kauth.h> #include <sys/user.h> #include <sys/socketvar.h> #include <sys/malloc.h> #include <sys/namei.h> #include <sys/mount_internal.h> #include <sys/vnode_internal.h> #include <sys/file_internal.h> #include <sys/stat.h> #include <sys/uio_internal.h> #include <sys/acct.h> #include <sys/exec.h> #include <sys/kdebug.h> #include <sys/signal.h> #include <sys/aio_kern.h> #include <sys/sysproto.h> #if SYSV_SHM #include <sys/shm_internal.h> /* shmexec() */ #endif #include <sys/ubc_internal.h> /* ubc_map() */ #include <sys/spawn.h> #include <sys/spawn_internal.h> #include <sys/codesign.h> #include <bsm/audit_kernel.h> #include <ipc/ipc_types.h> #include <mach/mach_types.h> #include <mach/task.h> #include <mach/thread_act.h> #include <mach/vm_map.h> #include <mach/mach_vm.h> #include <mach/vm_param.h> #if CONFIG_MACF #include <security/mac.h> #include <security/mac_mach_internal.h> #endif #include <vm/vm_map.h> #include <vm/vm_kern.h> #include <vm/vm_protos.h> #include <vm/vm_kern.h> #if CONFIG_DTRACE /* Do not include dtrace.h, it redefines kmem_[alloc/free] */ extern void (*dtrace_fasttrap_exec_ptr)(proc_t); extern void (*dtrace_helpers_cleanup)(proc_t); extern void dtrace_lazy_dofs_destroy(proc_t); #include <sys/dtrace_ptss.h> #endif /* support for child creation in exec after vfork */ thread_t fork_create_child(task_t parent_task, proc_t child_proc, int inherit_memory, int is64bit); void vfork_exit(proc_t p, int rv); int setsigvec(proc_t, int, struct __user_sigaction *); /* * Mach things for which prototypes are unavailable from Mach headers */ void ipc_task_reset( task_t task); void ipc_thread_reset( thread_t thread); kern_return_t ipc_object_copyin( ipc_space_t space, mach_port_name_t name, mach_msg_type_name_t msgt_name, ipc_object_t *objectp); void ipc_port_release_send(ipc_port_t); extern struct savearea *get_user_regs(thread_t); #include <kern/thread.h> #include <kern/task.h> #include <kern/ast.h> #include <kern/mach_loader.h> #include <mach-o/fat.h> #include <mach-o/loader.h> #include <machine/vmparam.h> #include <sys/imgact.h> #include <sys/sdt.h> /* * 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) /* * EAI_ITERLIMIT The maximum number of times to iterate an image * activator in exec_activate_image() before treating * it as malformed/corrupt. */ #define EAI_ITERLIMIT 10 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_activate_image(struct image_params *imgp); 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, proc_t p); static int copyoutptr(user_addr_t ua, user_addr_t ptr, int ptr_size); static void exec_resettextvp(proc_t, struct image_params *); /* We don't want this one exported */ __private_extern__ int open1(vfs_context_t, struct nameidata *, int, struct vnode_attr *, register_t *); /* * 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 * * 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) { int error = 0; do { size_t len = 0; if (imgp->ip_strspace <= 0) { error = E2BIG; break; } if (IS_UIO_SYS_SPACE(imgp->ip_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 * int segment from which path comes * * Returns: int 0 Success * EFAULT Bad address * copy[in]str:EFAULT Bad address * copy[in]str:ENAMETOOLONG Filename too long * * 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, 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); } #ifdef IMGPF_POWERPC /* * exec_powerpc32_imgact * * Implicitly invoke the PowerPC handler for a byte-swapped image magic * number. This may happen either as a result of an attempt to invoke a * PowerPC image directly, or indirectly as the interpreter used in an * interpreter script. * * Parameters; struct image_params * image parameter block * * Returns: -1 not an PowerPC image (keep looking) * -3 Success: exec_archhandler_ppc: relookup * >0 Failure: exec_archhandler_ppc: error number * * Note: This image activator does not handle the case of a direct * invocation of the exec_archhandler_ppc, since in that case, the * exec_archhandler_ppc itself is not a PowerPC binary; instead, * binary image activators must recognize the exec_archhandler_ppc; * This is managed in exec_check_permissions(). * * Note: This image activator is limited to 32 bit powerpc images; * if support for 64 bit powerpc images is desired, it would * be more in line with this design to write a separate 64 bit * image activator. */ static int exec_powerpc32_imgact(struct image_params *imgp) { struct mach_header *mach_header = (struct mach_header *)imgp->ip_vdata; int error; size_t len = 0; /* * Make sure it's a PowerPC binary. If we've already redirected * from an interpreted file once, don't do it again. */ if (mach_header->magic != MH_CIGAM) { /* * If it's a cross-architecture 64 bit binary, then claim * it, but refuse to run it. */ if (mach_header->magic == MH_CIGAM_64) return (EBADARCH); return (-1); } /* If there is no exec_archhandler_ppc, we can't run it */ if (exec_archhandler_ppc.path[0] == 0) return (EBADARCH); /* Remember the type of the original file for later grading */ if (!imgp->ip_origcputype) { imgp->ip_origcputype = OSSwapBigToHostInt32(mach_header->cputype); imgp->ip_origcpusubtype = OSSwapBigToHostInt32(mach_header->cpusubtype); } /* * The PowerPC flag will be set by the exec_check_permissions() * call anyway; however, we set this flag here so that the relookup * in execve() does not follow symbolic links, as a side effect. */ imgp->ip_flags |= IMGPF_POWERPC; /* impute an interpreter */ error = copystr(exec_archhandler_ppc.path, imgp->ip_interp_name, IMG_SHSIZE, &len); if (error) return (error); /* * provide a replacement string for p->p_comm; we have to use an * an alternate buffer for this, rather than replacing it directly, * since the exec may fail and return to the parent. In that case, * we would have erroneously changed the parent p->p_comm instead. */ strlcpy(imgp->ip_p_comm, imgp->ip_ndp->ni_cnd.cn_nameptr, MAXCOMLEN); return (-3); } #endif /* IMGPF_POWERPC */ /* * 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 PowerPC 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; char temp[16]; proc_t p; struct fileproc *fp; int fd; int error; size_t len; /* * 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 PowerPC, since the expectation is that we * may run a PowerPC interpreter, but not an interpret a PowerPC * image. This is consistent with historical behaviour. */ if (vdata[0] != '#' || vdata[1] != '!' || (imgp->ip_flags & IMGPF_INTERPRET) != 0) { return (-1); } #ifdef IMGPF_POWERPC if ((imgp->ip_flags & IMGPF_POWERPC) != 0) return (EBADARCH); #endif /* IMGPF_POWERPC */ 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++; } /* * If we have a SUID oder SGID script, create a file descriptor * from the vnode and pass /dev/fd/%d instead of the actual * path name so that the script does not get opened twice */ if (imgp->ip_origvattr->va_mode & (VSUID | VSGID)) { p = vfs_context_proc(imgp->ip_vfs_context); error = falloc(p, &fp, &fd, imgp->ip_vfs_context); if (error) return(error); 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)imgp->ip_vp; proc_fdlock(p); procfdtbl_releasefd(p, fd, NULL); fp_drop(p, fd, fp, 1); proc_fdunlock(p); vnode_ref(imgp->ip_vp); snprintf(temp, sizeof(temp), "/dev/fd/%d", fd); error = copyoutstr(temp, imgp->ip_user_fname, sizeof(temp), &len); if (error) return(error); } 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. * * Parameters; struct image_params * image parameter block * * Returns: -1 not a fat binary (keep looking) * -2 Success: encapsulated binary: reread * >0 Failure: error number * * Important: This image activator is byte order neutral. * * Note: A return value other than -1 indicates subsequent image * activators should not be given the opportunity to attempt * to activate the image. * * 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) { proc_t p = vfs_context_proc(imgp->ip_vfs_context); kauth_cred_t cred = kauth_cred_proc_ref(p); struct fat_header *fat_header = (struct fat_header *)imgp->ip_vdata; struct _posix_spawnattr *psa = NULL; 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; } /* If posix_spawn binprefs exist, respect those prefs. */ psa = (struct _posix_spawnattr *) imgp->ip_px_sa; if (psa != NULL && psa->psa_binprefs[0] != 0) { struct fat_arch *arches = (struct fat_arch *) (fat_header + 1); int nfat_arch = 0, pr = 0, f = 0; nfat_arch = OSSwapBigToHostInt32(fat_header->nfat_arch); /* Check each preference listed against all arches in header */ for (pr = 0; pr < NBINPREFS; pr++) { cpu_type_t pref = psa->psa_binprefs[pr]; if (pref == 0) { /* No suitable arch in the pref list */ error = EBADARCH; goto bad; } if (pref == CPU_TYPE_ANY) { /* Fall through to regular grading */ break; } for (f = 0; f < nfat_arch; f++) { cpu_type_t archtype = OSSwapBigToHostInt32( arches[f].cputype); cpu_type_t archsubtype = OSSwapBigToHostInt32( arches[f].cpusubtype) & ~CPU_SUBTYPE_MASK; if (pref == archtype && grade_binary(archtype, archsubtype)) { /* We have a winner! */ fat_arch.cputype = archtype; fat_arch.cpusubtype = archsubtype; fat_arch.offset = OSSwapBigToHostInt32( arches[f].offset); fat_arch.size = OSSwapBigToHostInt32( arches[f].size); fat_arch.align = OSSwapBigToHostInt32( arches[f].align); goto use_arch; } } } } /* 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; } use_arch: /* Read the Mach-O header out of fat_arch */ 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: kauth_cred_unref(&cred); return (error); } /* * exec_mach_imgact * * Image activator for mach-o 1.0 binaries. * * Parameters; struct image_params * image parameter block * * Returns: -1 not a fat binary (keep looking) * -2 Success: encapsulated binary: reread * >0 Failure: error number * EBADARCH Mach-o binary, but with an unrecognized * architecture * ENOMEM No memory for child process after - * can only happen after vfork() * * Important: This image activator is NOT byte order neutral. * * Note: A return value other than -1 indicates subsequent image * activators should not be given the opportunity to attempt * to activate the image. * * TODO: More gracefully handle failures after vfork */ static int exec_mach_imgact(struct image_params *imgp) { struct mach_header *mach_header = (struct mach_header *)imgp->ip_vdata; proc_t p = vfs_context_proc(imgp->ip_vfs_context); int error = 0; int vfexec = 0; task_t task; task_t new_task = NULL; /* protected by vfexec */ thread_t thread; struct uthread *uthread; vm_map_t old_map = VM_MAP_NULL; vm_map_t map; load_return_t lret; load_result_t load_result; struct _posix_spawnattr *psa = NULL; /* * 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; } switch (mach_header->filetype) { case MH_DYLIB: case MH_BUNDLE: error = -1; goto bad; } if (!imgp->ip_origcputype) { imgp->ip_origcputype = mach_header->cputype; imgp->ip_origcpusubtype = mach_header->cpusubtype; } 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 posix_spawn binprefs exist, respect those prefs. */ psa = (struct _posix_spawnattr *) imgp->ip_px_sa; if (psa != NULL && psa->psa_binprefs[0] != 0) { int pr = 0; for (pr = 0; pr < NBINPREFS; pr++) { cpu_type_t pref = psa->psa_binprefs[pr]; if (pref == 0) { /* No suitable arch in the pref list */ error = EBADARCH; goto bad; } if (pref == CPU_TYPE_ANY) { /* Jump to regular grading */ goto grade; } if (pref == imgp->ip_origcputype) { /* We have a match! */ goto grade; } } error = EBADARCH; goto bad; } grade: if (!grade_binary(imgp->ip_origcputype & ~CPU_SUBTYPE_LIB64, imgp->ip_origcpusubtype & ~CPU_SUBTYPE_MASK)) { error = EBADARCH; goto bad; } /* Copy in arguments/environment from the old process */ 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)); #ifdef IMGPF_POWERPC /* * XXX * * Should be factored out; this is here because we might be getting * invoked this way as the result of a shell script, and the check * in exec_check_permissions() is not interior to the jump back up * to the "encapsulated_binary:" label in exec_activate_image(). */ if (imgp->ip_vattr->va_fsid == exec_archhandler_ppc.fsid && imgp->ip_vattr->va_fileid == (uint64_t)((u_long)exec_archhandler_ppc.fileid)) { imgp->ip_flags |= IMGPF_POWERPC; } #endif /* IMGPF_POWERPC */ if (vfexec) { imgp->ip_vfork_thread = fork_create_child(task, p, FALSE, (imgp->ip_flags & IMGPF_IS_64BIT)); if (imgp->ip_vfork_thread == NULL) { error = ENOMEM; goto bad; } /* reset local idea of thread, uthread, task */ thread = imgp->ip_vfork_thread; uthread = get_bsdthread_info(thread); task = new_task = get_threadtask(thread); map = get_task_map(task); } 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); OSBitOrAtomic(P_LP64, (UInt32 *)&p->p_flag); } else { task_set_64bit(task, FALSE); OSBitAndAtomic(~((uint32_t)P_LP64), (UInt32 *)&p->p_flag); } /* * Load the Mach-O file. */ /* * 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, &load_result); if (lret != LOAD_SUCCESS) { error = load_return_to_errno(lret); goto badtoolate; } vm_map_set_user_wire_limit(get_task_map(task), p->p_rlimit[RLIMIT_MEMLOCK].rlim_cur); /* * Set code-signing flags if this binary is signed, or if parent has * requested them on exec. */ if (load_result.csflags & CS_VALID) { imgp->ip_csflags |= load_result.csflags & (CS_VALID| CS_HARD|CS_KILL|CS_EXEC_SET_HARD|CS_EXEC_SET_KILL); } else { imgp->ip_csflags &= ~CS_VALID; } if (p->p_csflags & CS_EXEC_SET_HARD) imgp->ip_csflags |= CS_HARD; if (p->p_csflags & CS_EXEC_SET_KILL) imgp->ip_csflags |= CS_KILL; /* * Set up the system reserved areas in the new address space. */ vm_map_exec(get_task_map(task), task, (void *) p->p_fd->fd_rdir, #ifdef IMGPF_POWERPC imgp->ip_flags & IMGPF_POWERPC ? CPU_TYPE_POWERPC : #endif cpu_type()); /* * Close file descriptors * which specify close-on-exec. */ fdexec(p); /* * deal with set[ug]id. */ error = exec_handle_sugid(imgp); if (!vfexec && (p->p_lflag & P_LTRACED)) psignal(p, SIGTRAP); if (error) { goto badtoolate; } #if CONFIG_MACF /* Determine if the map will allow VM_PROT_COPY */ error = mac_proc_check_map_prot_copy_allow(p); vm_map_set_prot_copy_allow(get_task_map(task), error ? FALSE : TRUE); #endif if (load_result.unixproc && create_unix_stack(get_task_map(task), load_result.user_stack, load_result.customstack, p) != KERN_SUCCESS) { error = load_return_to_errno(LOAD_NOSPACE); goto badtoolate; } if (vfexec) { 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); error = copyoutptr(load_result.mach_header, ap, 8); } else { ap = thread_adjuserstack(thread, -4); error = suword(ap, load_result.mach_header); } if (error) { if (vfexec) vm_map_switch(old_map); goto badtoolate; } } 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); /* * need to cancel async IO requests that can be cancelled and wait for those * already active. MAY BLOCK! */ _aio_exec( p ); #if SYSV_SHM /* FIXME: Till vmspace inherit is fixed: */ if (!vfexec && p->vm_shm) shmexec(p); #endif #if SYSV_SEM /* Clean up the semaphores */ semexit(p); #endif /* * 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'; } #if CONFIG_DTRACE /* * Invalidate any predicate evaluation already cached for this thread by DTrace. * That's because we've just stored to p_comm and DTrace refers to that when it * evaluates the "execname" special variable. uid and gid may have changed as well. */ dtrace_set_thread_predcache(current_thread(), 0); /* * Free any outstanding lazy dof entries. It is imperative we * always call dtrace_lazy_dofs_destroy, rather than null check * and call if !NULL. If we NULL test, during lazy dof faulting * we can race with the faulting code and proceed from here to * beyond the helpers cleanup. The lazy dof faulting will then * install new helpers which no longer belong to this process! */ dtrace_lazy_dofs_destroy(p); /* * Clean up any DTrace helpers for the process. */ if (p->p_dtrace_helpers != NULL && dtrace_helpers_cleanup) { (*dtrace_helpers_cleanup)(p); } /* * Cleanup the DTrace provider associated with this process. */ proc_lock(p); if (p->p_dtrace_probes && dtrace_fasttrap_exec_ptr) { (*dtrace_fasttrap_exec_ptr)(p); } proc_unlock(p); #endif if (kdebug_enable) { 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); } } #ifdef IMGPF_POWERPC /* * Mark the process as powerpc or not. If powerpc, set the affinity * flag, which will be used for grading binaries in future exec's * from the process. */ if (((imgp->ip_flags & IMGPF_POWERPC) != 0)) OSBitOrAtomic(P_TRANSLATED, (UInt32 *)&p->p_flag); else #endif /* IMGPF_POWERPC */ OSBitAndAtomic(~((uint32_t)P_TRANSLATED), (UInt32 *)&p->p_flag); OSBitAndAtomic(~((uint32_t)P_AFFINITY), (UInt32 *)&p->p_flag); /* * If posix_spawned with the START_SUSPENDED flag, stop the * process before it runs. */ if (imgp->ip_px_sa != NULL) { psa = (struct _posix_spawnattr *) imgp->ip_px_sa; if (psa->psa_flags & POSIX_SPAWN_START_SUSPENDED) { proc_lock(p); p->p_stat = SSTOP; proc_unlock(p); (void) task_suspend(p->task); } } /* * mark as execed, wakeup the process that vforked (if any) and tell * it that it now has it's own resources back */ OSBitOrAtomic(P_EXEC, (UInt32 *)&p->p_flag); if (p->p_pptr && (p->p_lflag & P_LPPWAIT)) { proc_lock(p); p->p_lflag &= ~P_LPPWAIT; proc_unlock(p); wakeup((caddr_t)p->p_pptr); } if (vfexec && (p->p_lflag & P_LTRACED)) { psignal_vfork(p, new_task, thread, SIGTRAP); } badtoolate: proc_knote(p, NOTE_EXEC); 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" }, #ifdef IMGPF_POWERPC { exec_powerpc32_imgact, "PowerPC binary" }, #endif /* IMGPF_POWERPC */ { exec_shell_imgact, "Interpreter Script" }, { NULL, NULL} }; /* * exec_activate_image * * Description: Iterate through the available image activators, and activate * the image associated with the imgp structure. We start with * the * * Parameters: struct image_params * Image parameter block * * Returns: 0 Success * EBADEXEC The executable is corrupt/unknown * execargs_alloc:EINVAL Invalid argument * execargs_alloc:EACCES Permission denied * execargs_alloc:EINTR Interrupted function * execargs_alloc:ENOMEM Not enough space * exec_save_path:EFAULT Bad address * exec_save_path:ENAMETOOLONG Filename too long * exec_check_permissions:EACCES Permission denied * exec_check_permissions:ENOEXEC Executable file format error * exec_check_permissions:ETXTBSY Text file busy [misuse of error code] * exec_check_permissions:??? * namei:??? * vn_rdwr:??? [anything vn_rdwr can return] * <ex_imgact>:??? [anything an imgact can return] */ static int exec_activate_image(struct image_params *imgp) { struct nameidata nd; int error; int resid; int once = 1; /* save SGUID-ness for interpreted files */ int i; int iterlimit = EAI_ITERLIMIT; proc_t p = vfs_context_proc(imgp->ip_vfs_context); error = execargs_alloc(imgp); if (error) goto bad; /* * 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, imgp->ip_user_fname, imgp->ip_seg); if (error) { goto bad_notrans; } DTRACE_PROC1(exec, uintptr_t, imgp->ip_strings); NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | AUDITVNPATH1, imgp->ip_seg, imgp->ip_user_fname, imgp->ip_vfs_context); again: error = namei(&nd); if (error) goto bad_notrans; imgp->ip_ndp = &nd; /* successful namei(); call nameidone() later */ imgp->ip_vp = nd.ni_vp; /* if set, need to vnode_put() at some point */ proc_transstart(p, 0); error = exec_check_permissions(imgp); if (error) goto bad; /* Copy; avoid invocation of an interpreter overwriting the original */ if (once) { once = 0; *imgp->ip_origvattr = *imgp->ip_vattr; } error = vn_rdwr(UIO_READ, imgp->ip_vp, imgp->ip_vdata, PAGE_SIZE, 0, UIO_SYSSPACE32, IO_NODELOCKED, vfs_context_ucred(imgp->ip_vfs_context), &resid, vfs_context_proc(imgp->ip_vfs_context)); if (error) goto bad; encapsulated_binary: /* Limit the number of iterations we will attempt on each binary */ if (--iterlimit == 0) { error = EBADEXEC; goto bad; } 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 */ #if CONFIG_MACF /* * Copy the script label for later use. Note that * the label can be different when the script is * actually read by the interpreter. */ if (imgp->ip_scriptlabelp) mac_vnode_label_free(imgp->ip_scriptlabelp); imgp->ip_scriptlabelp = mac_vnode_label_alloc(); if (imgp->ip_scriptlabelp == NULL) { error = ENOMEM; break; } mac_vnode_label_copy(imgp->ip_vp->v_label, imgp->ip_scriptlabelp); #endif 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); #ifdef IMGPF_POWERPC /* * PowerPC does not follow symlinks because the * code which sets exec_archhandler_ppc.fsid and * exec_archhandler_ppc.fileid doesn't follow them. */ if (imgp->ip_flags & IMGPF_POWERPC) nd.ni_cnd.cn_flags &= ~FOLLOW; #endif /* IMGPF_POWERPC */ nd.ni_segflg = UIO_SYSSPACE32; nd.ni_dirp = CAST_USER_ADDR_T(imgp->ip_interp_name); proc_transend(p, 0); 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(imgp->ip_vfs_context), KAUTH_FILEOP_EXEC, (uintptr_t)nd.ni_vp, 0); } bad: proc_transend(p, 0); bad_notrans: if (imgp->ip_strings) execargs_free(imgp); if (imgp->ip_ndp) nameidone(imgp->ip_ndp); return (error); } /* * exec_handle_port_actions * * Description: Go through the _posix_port_actions_t contents, * calling task_set_special_port and task_set_exception_ports * for the current task. * * Parameters: struct image_params * Image parameter block * * Returns: 0 Success * KERN_FAILURE Failure */ static int exec_handle_port_actions(struct image_params *imgp) { _posix_spawn_port_actions_t pacts = imgp->ip_px_spa; proc_t p = vfs_context_proc(imgp->ip_vfs_context); _ps_port_action_t *act = NULL; task_t task = p->task; ipc_port_t port = NULL; kern_return_t ret = KERN_SUCCESS; int i; for (i = 0; i < pacts->pspa_count; i++) { act = &pacts->pspa_actions[i]; ret = ipc_object_copyin(get_task_ipcspace(current_task()), (mach_port_name_t) act->new_port, MACH_MSG_TYPE_COPY_SEND, (ipc_object_t *) &port); if (ret) return ret; switch (act->port_type) { case PSPA_SPECIAL: ret = task_set_special_port(task, act->which, port); break; case PSPA_EXCEPTION: ret = task_set_exception_ports(task, act->mask, port, act->behavior, act->flavor); break; default: ret = KERN_FAILURE; } /* action failed, so release port resources */ if (ret) { ipc_port_release_send(port); return ret; } } return ret; } /* * exec_handle_file_actions * * Description: Go through the _posix_file_actions_t contents applying the * open, close, and dup2 operations to the open file table for * the current process. * * Parameters: struct image_params * Image parameter block * * Returns: 0 Success * ??? * * Note: Actions are applied in the order specified, with the credential * of the parent process. This is done to permit the parent * process to utilize POSIX_SPAWN_RESETIDS to drop privilege in * the child following operations the child may in fact not be * normally permitted to perform. */ static int exec_handle_file_actions(struct image_params *imgp) { int error = 0; int action; proc_t p = vfs_context_proc(imgp->ip_vfs_context); _posix_spawn_file_actions_t px_sfap = imgp->ip_px_sfa; register_t ival[2]; /* dummy retval for system calls) */ for (action = 0; action < px_sfap->psfa_act_count; action++) { _psfa_action_t *psfa = &px_sfap->psfa_act_acts[ action]; switch(psfa->psfaa_type) { case PSFA_OPEN: { /* * Open is different, in that it requires the use of * a path argument, which is normally copied in from * user space; because of this, we have to support an * open from kernel space that passes an address space * context oof UIO_SYSSPACE, and casts the address * argument to a user_addr_t. */ struct vnode_attr va; struct nameidata nd; int mode = psfa->psfaa_openargs.psfao_mode; struct dup2_args dup2a; struct close_nocancel_args ca; int origfd; VATTR_INIT(&va); /* Mask off all but regular access permissions */ mode = ((mode &~ p->p_fd->fd_cmask) & ALLPERMS) & ~S_ISTXT; VATTR_SET(&va, va_mode, mode & ACCESSPERMS); NDINIT(&nd, LOOKUP, FOLLOW | AUDITVNPATH1, UIO_SYSSPACE, CAST_USER_ADDR_T(psfa->psfaa_openargs.psfao_path), imgp->ip_vfs_context); error = open1(imgp->ip_vfs_context, &nd, psfa->psfaa_openargs.psfao_oflag, &va, ival); /* * If there's an error, or we get the right fd by * accident, then drop out here. This is easier that * rearchitecting all the open code to preallocate fd * slots, and internally taking one as an argument. */ if (error || ival[0] == psfa->psfaa_filedes) break; origfd = ival[0]; /* * If we didn't fall out from an error, we ended up * with the wrong fd; so now we've got to try to dup2 * it to the right one. */ dup2a.from = origfd; dup2a.to = psfa->psfaa_filedes; /* * The dup2() system call implementation sets * ival to newfd in the success case, but we * can ignore that, since if we didn't get the * fd we wanted, the error will stop us. */ error = dup2(p, &dup2a, ival); if (error) break; /* * Finally, close the original fd. */ ca.fd = origfd; error = close_nocancel(p, &ca, ival); } break; case PSFA_DUP2: { struct dup2_args dup2a; dup2a.from = psfa->psfaa_filedes; dup2a.to = psfa->psfaa_openargs.psfao_oflag; /* * The dup2() system call implementation sets * ival to newfd in the success case, but we * can ignore that, since if we didn't get the * fd we wanted, the error will stop us. */ error = dup2(p, &dup2a, ival); } break; case PSFA_CLOSE: { struct close_nocancel_args ca; ca.fd = psfa->psfaa_filedes; error = close_nocancel(p, &ca, ival); } break; default: error = EINVAL; break; } /* All file actions failures are considered fatal, per POSIX */ if (error) break; } return (error); } /* * posix_spawn * * Parameters: uap->pid Pointer to pid return area * uap->fname File name to exec * uap->argp Argument list * uap->envp Environment list * * Returns: 0 Success * EINVAL Invalid argument * ENOTSUP Not supported * ENOEXEC Executable file format error * exec_activate_image:EINVAL Invalid argument * exec_activate_image:EACCES Permission denied * exec_activate_image:EINTR Interrupted function * exec_activate_image:ENOMEM Not enough space * exec_activate_image:EFAULT Bad address * exec_activate_image:ENAMETOOLONG Filename too long * exec_activate_image:ENOEXEC Executable file format error * exec_activate_image:ETXTBSY Text file busy [misuse of error code] * exec_activate_image:EBADEXEC The executable is corrupt/unknown * exec_activate_image:??? * mac_execve_enter:??? * * TODO: More gracefully handle failures after vfork * Expect to need __mac_posix_spawn() at some point... * Handle posix_spawnattr_t * Handle posix_spawn_file_actions_t */ int posix_spawn(proc_t ap, struct posix_spawn_args *uap, register_t *retval) { proc_t p = ap; /* quiet bogus GCC vfork() warning */ user_addr_t pid = uap->pid; register_t ival[2]; /* dummy retval for vfork() */ struct image_params image_params, *imgp; struct vnode_attr va; struct vnode_attr origva; struct uthread *uthread = 0; /* compiler complains if not set to 0*/ int error, sig; task_t task; int numthreads; char alt_p_comm[sizeof(p->p_comm)] = {0}; /* for PowerPC */ int is_64 = IS_64BIT_PROCESS(p); int undo_vfork = 0; struct vfs_context context; struct user__posix_spawn_args_desc px_args; struct _posix_spawnattr px_sa; _posix_spawn_file_actions_t px_sfap = NULL; _posix_spawn_port_actions_t px_spap = NULL; struct __user_sigaction vec; imgp = &image_params; /* Initialize the common data in the image_params structure */ bzero(imgp, sizeof(*imgp)); imgp->ip_user_fname = uap->path; imgp->ip_user_argv = uap->argv; 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_p_comm = alt_p_comm; /* for PowerPC */ imgp->ip_seg = (is_64 ? UIO_USERSPACE64 : UIO_USERSPACE32); if (uap->adesc != USER_ADDR_NULL) { if(is_64) { error = copyin(uap->adesc, &px_args, sizeof(px_args)); } else { struct _posix_spawn_args_desc px_args32; error = copyin(uap->adesc, &px_args32, sizeof(px_args32)); /* * Convert arguments descriptor from external 32 bit * representation to internal 64 bit representation */ px_args.attr_size = px_args32.attr_size; px_args.attrp = CAST_USER_ADDR_T(px_args32.attrp); px_args.file_actions_size = px_args32.file_actions_size; px_args.file_actions = CAST_USER_ADDR_T(px_args32.file_actions); px_args.port_actions_size = px_args32.port_actions_size; px_args.port_actions = CAST_USER_ADDR_T(px_args32.port_actions); } if (error) goto bad; if (px_args.attr_size != 0) { /* * This could lose some of the port_actions pointer, * but we already have it from px_args. */ if ((error = copyin(px_args.attrp, &px_sa, sizeof(px_sa))) != 0) goto bad; imgp->ip_px_sa = &px_sa; } if (px_args.file_actions_size != 0) { /* Limit file_actions to allowed number of open files */ int maxfa = (p->p_limit ? p->p_rlimit[RLIMIT_NOFILE].rlim_cur : NOFILE); if (px_args.file_actions_size < PSF_ACTIONS_SIZE(1) || px_args.file_actions_size > PSF_ACTIONS_SIZE(maxfa)) { error = EINVAL; goto bad; } MALLOC(px_sfap, _posix_spawn_file_actions_t, px_args.file_actions_size, M_TEMP, M_WAITOK); if (px_sfap == NULL) { error = ENOMEM; goto bad; } imgp->ip_px_sfa = px_sfap; if ((error = copyin(px_args.file_actions, px_sfap, px_args.file_actions_size)) != 0) goto bad; } if (px_args.port_actions_size != 0) { /* Limit port_actions to one page of data */ if (px_args.port_actions_size < PS_PORT_ACTIONS_SIZE(1) || px_args.port_actions_size > PAGE_SIZE) { error = EINVAL; goto bad; } MALLOC(px_spap, _posix_spawn_port_actions_t, px_args.port_actions_size, M_TEMP, M_WAITOK); if (px_spap == NULL) { error = ENOMEM; goto bad; } imgp->ip_px_spa = px_spap; if ((error = copyin(px_args.port_actions, px_spap, px_args.port_actions_size)) != 0) goto bad; } } if (imgp->ip_px_sa == NULL || !(px_sa.psa_flags & POSIX_SPAWN_SETEXEC)){ if ((error = vfork(p, NULL, ival)) != 0) goto bad; undo_vfork = 1; } /* "reenter the kernel" on a new vfork()'ed process */ uthread = get_bsdthread_info(current_thread()); if (undo_vfork) p = uthread->uu_proc; context.vc_thread = current_thread(); context.vc_ucred = p->p_ucred; /* XXX must NOT be kauth_cred_get() */ /* * Post fdcopy(), pre exec_handle_sugid() - this is where we want * to handle the file_actions. Since vfork() also ends up setting * us into the parent process group, and saved off the signal flags, * this is also where we want to handle the spawn flags. */ /* Has spawn file actions? */ if (imgp->ip_px_sfa != NULL && (error = exec_handle_file_actions(imgp)) != 0) { goto bad; } /* Has spawn port actions? */ if (imgp->ip_px_spa != NULL) { /* Only allowed when not under vfork */ if (!(px_sa.psa_flags & POSIX_SPAWN_SETEXEC)) { error = ENOTSUP; goto bad; } if((error = exec_handle_port_actions(imgp)) != 0) goto bad; } /* Has spawn attr? */ if (imgp->ip_px_sa != NULL) { /* Set the process group ID of the child process */ if (px_sa.psa_flags & POSIX_SPAWN_SETPGROUP) { struct setpgid_args spga; spga.pid = p->p_pid; spga.pgid = px_sa.psa_pgroup; /* * Effectively, call setpgid() system call; works * because there are no pointer arguments. */ if((error = setpgid(p, &spga, ival)) != 0) goto bad; } /* * Reset UID/GID to parent's RUID/RGID; This works only * because the operation occurs *after* the vfork() and * before the call to exec_handle_sugid() by the image * activator called from exec_activate_image(). * * The use of p_ucred is safe, since we are acting on the * new process, and it has no threads other than the one * we are creating for it. */ if (px_sa.psa_flags & POSIX_SPAWN_RESETIDS) { kauth_cred_t my_cred = p->p_ucred; kauth_cred_t my_new_cred = kauth_cred_setuidgid(my_cred, my_cred->cr_ruid, my_cred->cr_rgid); if (my_new_cred != my_cred) p->p_ucred = my_new_cred; } /* * Mask a list of signals, instead of them being unmasked, if * they were unmasked in the parent; note that some signals * are not maskable. */ if (px_sa.psa_flags & POSIX_SPAWN_SETSIGMASK) uthread->uu_sigmask = (px_sa.psa_sigmask & ~sigcantmask); /* * Default a list of signals instead of ignoring them, if * they were ignored in the parent. */ if (px_sa.psa_flags & POSIX_SPAWN_SETSIGDEF) { vec.sa_handler = SIG_DFL; vec.sa_tramp = 0; vec.sa_mask = 0; vec.sa_flags = 0; for (sig = 0; sig < NSIG; sig++) if (px_sa.psa_sigdefault && 1 << sig) { error = setsigvec(p, sig, &vec); } } } /* * XXXAUDIT: Currently, we only audit the pathname of the binary. * There may also be poor interaction with dyld. */ task = current_task(); /* If we're not in vfork, don't permit a mutithreaded task to exec */ if (!(uthread->uu_flag & UT_VFORK)) { if (task != kernel_task) { numthreads = get_task_numacts(task); if (numthreads <= 0 ) { error = EINVAL; goto bad; } if (numthreads > 1) { error = ENOTSUP; goto bad; } } } #if MAC_SPAWN /* XXX */ if (uap->mac_p != USER_ADDR_NULL) { error = mac_execve_enter(uap->mac_p, imgp); if (error) goto bad; } #endif if ((error = exec_activate_image(imgp)) != 0) goto bad; bad: /* Image not claimed by any activator? */ if (error == -1) error = ENOEXEC; if (error == 0) { exec_resettextvp(p, imgp); } if (imgp->ip_vp) vnode_put(imgp->ip_vp); if (imgp->ip_strings) execargs_free(imgp); if (imgp->ip_px_sfa != NULL) FREE(imgp->ip_px_sfa, M_TEMP); if (imgp->ip_px_spa != NULL) FREE(imgp->ip_px_spa, M_TEMP); #if CONFIG_MACF if (imgp->ip_execlabelp) mac_cred_label_free(imgp->ip_execlabelp); if (imgp->ip_scriptlabelp) mac_vnode_label_free(imgp->ip_scriptlabelp); #endif if (undo_vfork) { if (error) { DTRACE_PROC1(exec__failure, int, error); vfork_exit(p, W_EXITCODE(-1, 0)); } else { DTRACE_PROC(exec__success); } /* * Returning to the parent process... * * If the parent wants the pid, copy it out */ if (pid != USER_ADDR_NULL) (void)suword(pid, p->p_pid); retval[0] = error; /* * Override inherited code signing flags with the * ones for the process that is being successfully * loaded */ proc_lock(p); p->p_csflags = imgp->ip_csflags; proc_unlock(p); vfork_return(p, NULL, error); (void)thread_resume(imgp->ip_vfork_thread); } if (!error) { /* * Override inherited code signing flags with the * ones for the process that is being successfully * loaded */ proc_lock(p); p->p_csflags = imgp->ip_csflags; proc_unlock(p); DTRACE_PROC(exec__success); } else { DTRACE_PROC1(exec__failure, int, error); } return(error); } /* * execve * * Parameters: uap->fname File name to exec * uap->argp Argument list * uap->envp Environment list * * Returns: 0 Success * __mac_execve:EINVAL Invalid argument * __mac_execve:ENOTSUP Invalid argument * __mac_execve:EACCES Permission denied * __mac_execve:EINTR Interrupted function * __mac_execve:ENOMEM Not enough space * __mac_execve:EFAULT Bad address * __mac_execve:ENAMETOOLONG Filename too long * __mac_execve:ENOEXEC Executable file format error * __mac_execve:ETXTBSY Text file busy [misuse of error code] * __mac_execve:??? * * TODO: Dynamic linker header address on stack is copied via suword() */ /* ARGSUSED */ int execve(proc_t p, struct execve_args *uap, register_t *retval) { struct __mac_execve_args muap; int err; muap.fname = uap->fname; muap.argp = uap->argp; muap.envp = uap->envp; muap.mac_p = USER_ADDR_NULL; err = __mac_execve(p, &muap, retval); return(err); } /* * __mac_execve * * Parameters: uap->fname File name to exec * uap->argp Argument list * uap->envp Environment list * uap->mac_p MAC label supplied by caller * * Returns: 0 Success * EINVAL Invalid argument * ENOTSUP Not supported * ENOEXEC Executable file format error * exec_activate_image:EINVAL Invalid argument * exec_activate_image:EACCES Permission denied * exec_activate_image:EINTR Interrupted function * exec_activate_image:ENOMEM Not enough space * exec_activate_image:EFAULT Bad address * exec_activate_image:ENAMETOOLONG Filename too long * exec_activate_image:ENOEXEC Executable file format error * exec_activate_image:ETXTBSY Text file busy [misuse of error code] * exec_activate_image:EBADEXEC The executable is corrupt/unknown * exec_activate_image:??? * mac_execve_enter:??? * * TODO: Dynamic linker header address on stack is copied via suword() */ int __mac_execve(proc_t p, struct __mac_execve_args *uap, register_t *retval) { struct image_params image_params, *imgp; struct vnode_attr va; struct vnode_attr origva; struct uthread *uthread; int error; task_t task; int numthreads; char alt_p_comm[sizeof(p->p_comm)] = {0}; /* for PowerPC */ int is_64 = IS_64BIT_PROCESS(p); struct vfs_context context; context.vc_thread = current_thread(); context.vc_ucred = kauth_cred_proc_ref(p); /* 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_p_comm = alt_p_comm; /* for PowerPC */ imgp->ip_seg = (is_64 ? UIO_USERSPACE64 : UIO_USERSPACE32); /* * 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 we're not in vfork, don't permit a mutithreaded task to exec */ if (!(uthread->uu_flag & UT_VFORK)) { if (task != kernel_task) { proc_lock(p); numthreads = get_task_numactivethreads(task); if (numthreads <= 0 ) { proc_unlock(p); kauth_cred_unref(&context.vc_ucred); return(EINVAL); } if (numthreads > 1) { proc_unlock(p); kauth_cred_unref(&context.vc_ucred); return(ENOTSUP); } proc_unlock(p); } } #if CONFIG_MACF if (uap->mac_p != USER_ADDR_NULL) { error = mac_execve_enter(uap->mac_p, imgp); if (error) { kauth_cred_unref(&context.vc_ucred); return (error); } } #endif error = exec_activate_image(imgp); kauth_cred_unref(&context.vc_ucred); /* Image not claimed by any activator? */ if (error == -1) error = ENOEXEC; if (error == 0) { exec_resettextvp(p, imgp); } if (imgp->ip_vp != NULLVP) vnode_put(imgp->ip_vp); if (imgp->ip_strings) execargs_free(imgp); #if CONFIG_MACF if (imgp->ip_execlabelp) mac_cred_label_free(imgp->ip_execlabelp); if (imgp->ip_scriptlabelp) mac_vnode_label_free(imgp->ip_scriptlabelp); #endif if (!error) { /* * Override inherited code signing flags with the * ones for the process that is being successfully * loaded */ proc_lock(p); p->p_csflags = imgp->ip_csflags; proc_unlock(p); DTRACE_PROC(exec__success); if (uthread->uu_flag & UT_VFORK) { vfork_return(p, retval, p->p_pid); (void)thread_resume(imgp->ip_vfork_thread); } } else { DTRACE_PROC1(exec__failure, int, error); } return(error); } /* * copyinptr * * Description: Copy a pointer in from user space to a user_addr_t in kernel * space, based on 32/64 bitness of the user space * * Parameters: froma User space address * toptr Address of kernel space user_addr_t * ptr_size 4/8, based on 'froma' address space * * Returns: 0 Success * EFAULT Bad 'froma' * * Implicit returns: * *ptr_size Modified */ 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); } /* * copyoutptr * * Description: Copy a pointer out from a user_addr_t in kernel space to * user space, based on 32/64 bitness of the user space * * Parameters: ua User space address to copy to * ptr Address of kernel space user_addr_t * ptr_size 4/8, based on 'ua' address space * * Returns: 0 Success * EFAULT Bad 'ua' * * Implicit returns: * *ptr_size Modified */ 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) { proc_t 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; unsigned patharea_len = imgp->ip_argv - imgp->ip_strings; int envc_add = 0; /* * 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 - ((patharea_len + ptr_size-1) & ~(ptr_size-1)); ptr_area = path_area - ((imgp->ip_argc + imgp->ip_envc + 4 + envc_add) * 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. */ proc_lock(p); p->p_argc = imgp->ip_argc; p->p_argslen = (int)(stack - path_area); proc_unlock(p); /* * 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, patharea_len, (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); } #if CONFIG_DTRACE p->p_dtrace_argv = ptr_area; /* user_addr_t &argv[0] for dtrace convenience */ #endif /* CONFIG_DTRACE */ /* * 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 CONFIG_DTRACE p->p_dtrace_envp = ptr_area; /* user_addr_t &env[0] for dtrace convenience */ #endif /* CONFIG_DTRACE */ } 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 * * * Note: 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; 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; /* * If the argument vector is NULL, this is the system startup * bootstrap from load_init_program(), and there's nothing to do */ if (imgp->ip_user_argv == 0LL) goto bad; /* 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); 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); 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); if (error) goto bad; imgp->ip_envc++; } bad: return error; } #define unix_stack_size(p) (p->p_rlimit[RLIMIT_STACK].rlim_cur) /* * exec_check_permissions * * Decription: Verify that the file that is being attempted to be executed * is in fact allowed to be executed based on it POSIX file * permissions and other access control criteria * * Parameters: struct image_params * the image parameter block * * Returns: 0 Success * EACCES Permission denied * ENOEXEC Executable file format error * ETXTBSY Text file busy [misuse of error code] * vnode_getattr:??? * vnode_authorize:??? */ static int exec_check_permissions(struct image_params *imgp) { struct vnode *vp = imgp->ip_vp; struct vnode_attr *vap = imgp->ip_vattr; proc_t 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_lflag & P_LTRACED)) { vap->va_mode &= ~(VSUID | VSGID); #if CONFIG_MACF imgp->ip_no_trans = 1; #endif } #if CONFIG_MACF error = mac_vnode_check_exec(imgp->ip_vfs_context, vp, imgp); if (error) return (error); #endif /* Check for execute permission */ action = KAUTH_VNODE_EXECUTE; /* Traced images must also be readable */ if (p->p_lflag & P_LTRACED) action |= KAUTH_VNODE_READ_DATA; if ((error = vnode_authorize(vp, NULL, action, imgp->ip_vfs_context)) != 0) return (error); #if 0 /* Don't let it run if anyone had it open for writing */ vnode_lock(vp); if (vp->v_writecount) { panic("going to return ETXTBSY %x", vp); vnode_unlock(vp); return (ETXTBSY); } vnode_unlock(vp); #endif #ifdef IMGPF_POWERPC /* * If the file we are about to attempt to load is the exec_handler_ppc, * which is determined by matching the vattr fields against previously * cached values, then we set the PowerPC environment flag. */ if (vap->va_fsid == exec_archhandler_ppc.fsid && vap->va_fileid == (uint64_t)((u_long)exec_archhandler_ppc.fileid)) { imgp->ip_flags |= IMGPF_POWERPC; } #endif /* IMGPF_POWERPC */ /* 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 SUGID, 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: * <process credential> Potentially modified/replaced * <task port> Potentially revoked * <process flags> P_SUGID bit potentially modified * <security token> Potentially modified */ static int exec_handle_sugid(struct image_params *imgp) { kauth_cred_t cred = vfs_context_ucred(imgp->ip_vfs_context); proc_t p = vfs_context_proc(imgp->ip_vfs_context); int i; int leave_sugid_clear = 0; int error = 0; struct vnode *dev_null = NULLVP; #if CONFIG_MACF int mac_transition; /* * Determine whether a call to update the MAC label will result in the * credential changing. * * Note: MAC policies which do not actually end up modifying * the label subsequently are strongly encouraged to * return 0 for this check, since a non-zero answer will * slow down the exec fast path for normal binaries. */ mac_transition = mac_cred_check_label_update_execve( imgp->ip_vfs_context, imgp->ip_vp, imgp->ip_scriptlabelp, imgp->ip_execlabelp, p); #endif OSBitAndAtomic(~((uint32_t)P_SUGID), (UInt32 *)&p->p_flag); /* * Order of the following is important; group checks must go last, * as we use the success of the 'ismember' check combined with the * failure of the explicit match to indicate that we will be setting * the egid of the process even though the new process did not * require VSUID/VSGID bits in order for it to set the new group as * its egid. * * Note: Technically, by this we are implying a call to * setegid() in the new process, rather than implying * it used its VSGID bit to set the effective group, * even though there is no code in that process to make * such a call. */ if (((imgp->ip_origvattr->va_mode & VSUID) != 0 && kauth_cred_getuid(cred) != imgp->ip_origvattr->va_uid) || ((imgp->ip_origvattr->va_mode & VSGID) != 0 && ((kauth_cred_ismember_gid(cred, imgp->ip_origvattr->va_gid, &leave_sugid_clear) || !leave_sugid_clear) || (cred->cr_gid != imgp->ip_origvattr->va_gid)))) { #if CONFIG_MACF /* label for MAC transition and neither VSUID nor VSGID */ handle_mac_transition: #endif /* * Replace the credential with a copy of itself if euid or * egid change. * * Note: setuid binaries will automatically opt out of * group resolver participation as a side effect * of this operation. This is an intentional * part of the security model, which requires a * participating credential be established by * escalating privilege, setting up all other * aspects of the credential including whether * or not to participate in external group * membership resolution, then dropping their * effective privilege to that of the desired * final credential state. */ if (imgp->ip_origvattr->va_mode & VSUID) { p->p_ucred = kauth_cred_setresuid(p->p_ucred, KAUTH_UID_NONE, imgp->ip_origvattr->va_uid, imgp->ip_origvattr->va_uid, KAUTH_UID_NONE); } if (imgp->ip_origvattr->va_mode & VSGID) { p->p_ucred = kauth_cred_setresgid(p->p_ucred, KAUTH_GID_NONE, imgp->ip_origvattr->va_gid, imgp->ip_origvattr->va_gid); } #if CONFIG_MACF /* * If a policy has indicated that it will transition the label, * before making the call into the MAC policies, get a new * duplicate credential, so they can modify it without * modifying any others sharing it. */ if (mac_transition) { kauth_cred_t my_cred; if (kauth_proc_label_update_execve(p, imgp->ip_vfs_context, imgp->ip_vp, imgp->ip_scriptlabelp, imgp->ip_execlabelp)) { /* * If updating the MAC label resulted in a * disjoint credential, flag that we need to * set the P_SUGID bit. This protects * against debuggers being attached by an * insufficiently privileged process onto the * result of a transition to a more privileged * credential. */ leave_sugid_clear = 0; } my_cred = kauth_cred_proc_ref(p); mac_task_label_update_cred(my_cred, p->task); kauth_cred_unref(&my_cred); } #endif /* CONFIG_MACF */ /* * Have mach reset the task and thread ports. * We don't want anyone who had the ports before * a setuid exec to be able to access/control the * task/thread after. */ if (current_task() == p->task) { ipc_task_reset(p->task); ipc_thread_reset(current_thread()); } /* * If 'leave_sugid_clear' is non-zero, then we passed the * VSUID and MACF checks, and successfully determined that * the previous cred was a member of the VSGID group, but * that it was not the default at the time of the execve, * and that the post-labelling credential was not disjoint. * So we don't set the P_SUGID on the basis of simply * running this code. */ if (!leave_sugid_clear) OSBitOrAtomic(P_SUGID, (UInt32 *)&p->p_flag); /* 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, imgp->ip_vfs_context)) != 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); procfdtbl_releasefd(p, indx, NULL); 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; } } #if CONFIG_MACF else { /* * We are here because we were told that the MAC label will * be transitioned, and the binary is not VSUID or VSGID; to * deal with this case, we could either duplicate a lot of * code, or we can indicate we want to default the P_SUGID * bit clear and jump back up. */ if (mac_transition) { leave_sugid_clear = 1; goto handle_mac_transition; } } #endif /* CONFIG_MACF */ /* * 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); /* Update the process' identity version and set the security token */ p->p_idversion++; set_security_token(p); return(error); } /* * create_unix_stack * * Description: Set the user stack address for the process to the provided * address. If a custom stack was not set as a result of the * load process (i.e. as specified by the image file for the * executable), then allocate the stack in the provided map and * set up appropriate guard pages for enforcing administrative * limits on stack growth, if they end up being needed. * * Parameters: p Process to set stack on * user_stack Address to set stack for process to * customstack FALSE if no custom stack in binary * map Address map in which to allocate the * new stack, if 'customstack' is FALSE * * Returns: KERN_SUCCESS Stack successfully created * !KERN_SUCCESS Mach failure code */ static kern_return_t create_unix_stack(vm_map_t map, user_addr_t user_stack, int customstack, proc_t p) { mach_vm_size_t size, prot_size; mach_vm_offset_t addr, prot_addr; kern_return_t kr; proc_lock(p); p->user_stack = user_stack; proc_unlock(p); if (!customstack) { /* * Allocate enough space for the maximum stack size we * will ever authorize and an extra page to act as * a guard page for stack overflows. */ size = mach_vm_round_page(MAXSSIZ); #if STACK_GROWTH_UP addr = mach_vm_trunc_page(user_stack); #else /* STACK_GROWTH_UP */ addr = mach_vm_trunc_page(user_stack - size); #endif /* STACK_GROWTH_UP */ kr = mach_vm_allocate(map, &addr, size, VM_MAKE_TAG(VM_MEMORY_STACK) | VM_FLAGS_FIXED); if (kr != KERN_SUCCESS) { return kr; } /* * And prevent access to what's above the current stack * size limit for this process. */ prot_addr = addr; #if STACK_GROWTH_UP prot_addr += unix_stack_size(p); #endif /* STACK_GROWTH_UP */ prot_addr = mach_vm_round_page(prot_addr); prot_size = mach_vm_trunc_page(size - unix_stack_size(p)); kr = mach_vm_protect(map, prot_addr, prot_size, FALSE, VM_PROT_NONE); if (kr != KERN_SUCCESS) { (void) mach_vm_deallocate(map, addr, size); return kr; } } return KERN_SUCCESS; } #include <sys/reboot.h> static char init_program_name[128] = "/sbin/launchd"; struct execve_args init_exec_args; /* * load_init_program * * Description: Load the "init" program; in most cases, this will be "launchd" * * Parameters: p Process to call execve() to create * the "init" program * * Returns: (void) * * Notes: The process that is passed in is the first manufactured * process on the system, and gets here via bsd_ast() firing * for the first time. This is done to ensure that bsd_init() * has run to completion. */ void load_init_program(proc_t p) { vm_offset_t init_addr; int argc = 0; char *argv[3]; int error; register_t retval[2]; /* * 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[argc++] = (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. */ if (boothowto & RB_SINGLE) { const char *init_args = "-s"; copyout(init_args, CAST_USER_ADDR_T(init_addr), strlen(init_args)); argv[argc++] = (char *)init_addr; init_addr += strlen(init_args); init_addr = (vm_offset_t)ROUND_PTR(char, init_addr); } /* * Null-end the argument list */ argv[argc] = NULL; /* * 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); if (error) panic("Process 1 exec of %s failed, errno %d\n", init_program_name, error); } /* * load_return_to_errno * * Description: Convert a load_return_t (Mach error) to an errno (BSD error) * * Parameters: lrtn Mach error number * * Returns: (int) BSD error number * 0 Success * EBADARCH Bad architecture * EBADMACHO Bad Mach object file * ESHLIBVERS Bad shared library version * ENOMEM Out of memory/resource shortage * EACCES Access denied * ENOENT Entry not found (usually "file does * does not exist") * EIO An I/O error occurred * EBADEXEC The executable is corrupt/unknown */ 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 <mach/mach_types.h> #include <mach/vm_prot.h> #include <mach/semaphore.h> #include <mach/sync_policy.h> #include <kern/clock.h> #include <mach/kern_return.h> extern semaphore_t execve_semaphore; /* * execargs_alloc * * Description: Allocate 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. * * Parameters: struct image_params * the image parameter block * * Returns: 0 Success * EINVAL Invalid argument * EACCES Permission denied * EINTR Interrupted function * ENOMEM Not enough space * * Notes: This is a temporary allocation into the kernel address space * to enable us to copy arguments in from user space. This is * necessitated by not mapping the process calling execve() into * the kernel address space during the execve() system call. * * We assemble the argument and environment, etc., into this * region before copying it as a single block into the child * process address space (at the top or bottom of the stack, * depending on which way the stack grows; see the function * exec_copyout_strings() for details). * * This ends up with a second (possibly unnecessary) copy compared * with assembing the data directly into the child address space, * instead, but since we cannot be guaranteed that the parent has * not modified its environment, we can't really know that it's * really a block there as well. */ 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); } /* * execargs_free * * Description: Free the block of memory used by the execve arguments and the * first page of the executable by a previous call to the function * execargs_alloc(). * * Parameters: struct image_params * the image parameter block * * Returns: 0 Success * EINVAL Invalid argument * EINTR Oeration interrupted */ 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); } } static void exec_resettextvp(proc_t p, struct image_params *imgp) { vnode_t vp; off_t offset; vnode_t tvp = p->p_textvp; int ret; vp = imgp->ip_vp; offset = imgp->ip_arch_offset; if (vp == NULLVP) panic("exec_resettextvp: expected valid vp"); ret = vnode_ref(vp); proc_lock(p); if (ret == 0) { p->p_textvp = vp; p->p_textoff = offset; } else { p->p_textvp = NULLVP; /* this is paranoia */ p->p_textoff = 0; } proc_unlock(p); if ( tvp != NULLVP) { if (vnode_getwithref(tvp) == 0) { vnode_rele(tvp); vnode_put(tvp); } } }