/* * Copyright (c) 2000-2010 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) 1988, 1989, NeXT, Inc. * * File: kern/mach_loader.c * Author: Avadis Tevanian, Jr. * * Mach object file loader (kernel version, for now). * * 21-Jul-88 Avadis Tevanian, Jr. (avie) at NeXT * Started. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* vm_allocate() */ #include /* mach_vm_allocate() */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* for kIOReturnNotPrivileged */ /* * XXX vm/pmap.h should not treat these prototypes as MACH_KERNEL_PRIVATE * when KERNEL is defined. */ extern pmap_t pmap_create(ledger_t ledger, vm_map_size_t size, boolean_t is_64bit); /* XXX should have prototypes in a shared header file */ extern int get_map_nentries(vm_map_t); extern kern_return_t memory_object_signed(memory_object_control_t control, boolean_t is_signed); /* An empty load_result_t */ static load_result_t load_result_null = { .mach_header = MACH_VM_MIN_ADDRESS, .entry_point = MACH_VM_MIN_ADDRESS, .user_stack = MACH_VM_MIN_ADDRESS, .user_stack_size = 0, .all_image_info_addr = MACH_VM_MIN_ADDRESS, .all_image_info_size = 0, .thread_count = 0, .unixproc = 0, .dynlinker = 0, .needs_dynlinker = 0, .prog_allocated_stack = 0, .prog_stack_size = 0, .validentry = 0, .csflags = 0, .uuid = { 0 }, .min_vm_addr = MACH_VM_MAX_ADDRESS, .max_vm_addr = MACH_VM_MIN_ADDRESS }; /* * Prototypes of static functions. */ static load_return_t parse_machfile( struct vnode *vp, vm_map_t map, thread_t thread, struct mach_header *header, off_t file_offset, off_t macho_size, int depth, int64_t slide, int64_t dyld_slide, load_result_t *result ); static load_return_t load_segment( struct load_command *lcp, uint32_t filetype, void *control, off_t pager_offset, off_t macho_size, struct vnode *vp, vm_map_t map, int64_t slide, load_result_t *result ); static load_return_t load_uuid( struct uuid_command *uulp, char *command_end, load_result_t *result ); static load_return_t load_code_signature( struct linkedit_data_command *lcp, struct vnode *vp, off_t macho_offset, off_t macho_size, cpu_type_t cputype, load_result_t *result); #if CONFIG_CODE_DECRYPTION static load_return_t set_code_unprotect( struct encryption_info_command *lcp, caddr_t addr, vm_map_t map, int64_t slide, struct vnode *vp, cpu_type_t cputype, cpu_subtype_t cpusubtype); #endif static load_return_t load_main( struct entry_point_command *epc, thread_t thread, int64_t slide, load_result_t *result ); static load_return_t load_unixthread( struct thread_command *tcp, thread_t thread, int64_t slide, load_result_t *result ); static load_return_t load_threadstate( thread_t thread, uint32_t *ts, uint32_t total_size ); static load_return_t load_threadstack( thread_t thread, uint32_t *ts, uint32_t total_size, mach_vm_offset_t *user_stack, int *customstack ); static load_return_t load_threadentry( thread_t thread, uint32_t *ts, uint32_t total_size, mach_vm_offset_t *entry_point ); static load_return_t load_dylinker( struct dylinker_command *lcp, integer_t archbits, vm_map_t map, thread_t thread, int depth, int64_t slide, load_result_t *result ); struct macho_data; static load_return_t get_macho_vnode( char *path, integer_t archbits, struct mach_header *mach_header, off_t *file_offset, off_t *macho_size, struct macho_data *macho_data, struct vnode **vpp ); static inline void widen_segment_command(const struct segment_command *scp32, struct segment_command_64 *scp) { scp->cmd = scp32->cmd; scp->cmdsize = scp32->cmdsize; bcopy(scp32->segname, scp->segname, sizeof(scp->segname)); scp->vmaddr = scp32->vmaddr; scp->vmsize = scp32->vmsize; scp->fileoff = scp32->fileoff; scp->filesize = scp32->filesize; scp->maxprot = scp32->maxprot; scp->initprot = scp32->initprot; scp->nsects = scp32->nsects; scp->flags = scp32->flags; } static void note_all_image_info_section(const struct segment_command_64 *scp, boolean_t is64, size_t section_size, const void *sections, int64_t slide, load_result_t *result) { const union { struct section s32; struct section_64 s64; } *sectionp; unsigned int i; if (strncmp(scp->segname, "__DATA", sizeof(scp->segname)) != 0) return; for (i = 0; i < scp->nsects; ++i) { sectionp = (const void *) ((const char *)sections + section_size * i); if (0 == strncmp(sectionp->s64.sectname, "__all_image_info", sizeof(sectionp->s64.sectname))) { result->all_image_info_addr = is64 ? sectionp->s64.addr : sectionp->s32.addr; result->all_image_info_addr += slide; result->all_image_info_size = is64 ? sectionp->s64.size : sectionp->s32.size; return; } } } load_return_t load_machfile( struct image_params *imgp, struct mach_header *header, thread_t thread, vm_map_t new_map, load_result_t *result ) { struct vnode *vp = imgp->ip_vp; off_t file_offset = imgp->ip_arch_offset; off_t macho_size = imgp->ip_arch_size; off_t file_size = imgp->ip_vattr->va_data_size; pmap_t pmap = 0; /* protected by create_map */ vm_map_t map; vm_map_t old_map; task_t old_task = TASK_NULL; /* protected by create_map */ load_result_t myresult; load_return_t lret; boolean_t create_map = FALSE; boolean_t enforce_hard_pagezero = TRUE; int spawn = (imgp->ip_flags & IMGPF_SPAWN); task_t task = current_task(); proc_t p = current_proc(); mach_vm_offset_t aslr_offset = 0; mach_vm_offset_t dyld_aslr_offset = 0; kern_return_t kret; if (macho_size > file_size) { return(LOAD_BADMACHO); } if (new_map == VM_MAP_NULL) { create_map = TRUE; old_task = current_task(); } /* * If we are spawning, we have created backing objects for the process * already, which include non-lazily creating the task map. So we * are going to switch out the task map with one appropriate for the * bitness of the image being loaded. */ if (spawn) { create_map = TRUE; old_task = get_threadtask(thread); } if (create_map) { task_t ledger_task; if (imgp->ip_new_thread) { ledger_task = get_threadtask(imgp->ip_new_thread); } else { ledger_task = task; } pmap = pmap_create(get_task_ledger(ledger_task), (vm_map_size_t) 0, (imgp->ip_flags & IMGPF_IS_64BIT)); pal_switch_pmap(thread, pmap, imgp->ip_flags & IMGPF_IS_64BIT); map = vm_map_create(pmap, 0, vm_compute_max_offset((imgp->ip_flags & IMGPF_IS_64BIT)), TRUE); } else map = new_map; #ifndef CONFIG_ENFORCE_SIGNED_CODE /* This turns off faulting for executable pages, which allows * to circumvent Code Signing Enforcement. The per process * flag (CS_ENFORCEMENT) is not set yet, but we can use the * global flag. */ if ( !cs_enforcement(NULL) && (header->flags & MH_ALLOW_STACK_EXECUTION) ) vm_map_disable_NX(map); #endif /* Forcibly disallow execution from data pages on even if the arch * normally permits it. */ if ((header->flags & MH_NO_HEAP_EXECUTION) && !(imgp->ip_flags & IMGPF_ALLOW_DATA_EXEC)) vm_map_disallow_data_exec(map); /* * Compute a random offset for ASLR, and an independent random offset for dyld. */ if (!(imgp->ip_flags & IMGPF_DISABLE_ASLR)) { uint64_t max_slide_pages; max_slide_pages = vm_map_get_max_aslr_slide_pages(map); aslr_offset = random(); aslr_offset %= max_slide_pages; aslr_offset <<= vm_map_page_shift(map); dyld_aslr_offset = random(); dyld_aslr_offset %= max_slide_pages; dyld_aslr_offset <<= vm_map_page_shift(map); } if (!result) result = &myresult; *result = load_result_null; lret = parse_machfile(vp, map, thread, header, file_offset, macho_size, 0, (int64_t)aslr_offset, (int64_t)dyld_aslr_offset, result); if (lret != LOAD_SUCCESS) { if (create_map) { vm_map_deallocate(map); /* will lose pmap reference too */ } return(lret); } #if __x86_64__ /* * On x86, for compatibility, don't enforce the hard page-zero restriction for 32-bit binaries. */ if ((imgp->ip_flags & IMGPF_IS_64BIT) == 0) { enforce_hard_pagezero = FALSE; } #endif /* * Check to see if the page zero is enforced by the map->min_offset. */ if (enforce_hard_pagezero && (vm_map_has_hard_pagezero(map, 0x1000) == FALSE)) { if (create_map) { vm_map_deallocate(map); /* will lose pmap reference too */ } printf("Cannot enforce a hard page-zero for %s\n", imgp->ip_strings); return (LOAD_BADMACHO); } /* * Commit to new map. * * Swap the new map for the old, which consumes our new map * reference but each leaves us responsible for the old_map reference. * That lets us get off the pmap associated with it, and * then we can release it. */ if (create_map) { /* * If this is an exec, then we are going to destroy the old * task, and it's correct to halt it; if it's spawn, the * task is not yet running, and it makes no sense. */ if (!spawn) { /* * Mark the task as halting and start the other * threads towards terminating themselves. Then * make sure any threads waiting for a process * transition get informed that we are committed to * this transition, and then finally complete the * task halting (wait for threads and then cleanup * task resources). * * NOTE: task_start_halt() makes sure that no new * threads are created in the task during the transition. * We need to mark the workqueue as exiting before we * wait for threads to terminate (at the end of which * we no longer have a prohibition on thread creation). * * Finally, clean up any lingering workqueue data structures * that may have been left behind by the workqueue threads * as they exited (and then clean up the work queue itself). */ kret = task_start_halt(task); if (kret != KERN_SUCCESS) { vm_map_deallocate(map); /* will lose pmap reference too */ return (LOAD_FAILURE); } proc_transcommit(p, 0); workqueue_mark_exiting(p); task_complete_halt(task); workqueue_exit(p); } old_map = swap_task_map(old_task, thread, map, !spawn); vm_map_deallocate(old_map); } return(LOAD_SUCCESS); } /* * The file size of a mach-o file is limited to 32 bits; this is because * this is the limit on the kalloc() of enough bytes for a mach_header and * the contents of its sizeofcmds, which is currently constrained to 32 * bits in the file format itself. We read into the kernel buffer the * commands section, and then parse it in order to parse the mach-o file * format load_command segment(s). We are only interested in a subset of * the total set of possible commands. If "map"==VM_MAP_NULL or * "thread"==THREAD_NULL, do not make permament VM modifications, * just preflight the parse. */ static load_return_t parse_machfile( struct vnode *vp, vm_map_t map, thread_t thread, struct mach_header *header, off_t file_offset, off_t macho_size, int depth, int64_t aslr_offset, int64_t dyld_aslr_offset, load_result_t *result ) { uint32_t ncmds; struct load_command *lcp; struct dylinker_command *dlp = 0; integer_t dlarchbits = 0; void * control; load_return_t ret = LOAD_SUCCESS; caddr_t addr; void * kl_addr; vm_size_t size,kl_size; size_t offset; size_t oldoffset; /* for overflow check */ int pass; proc_t p = current_proc(); /* XXXX */ int error; int resid=0; size_t mach_header_sz = sizeof(struct mach_header); boolean_t abi64; boolean_t got_code_signatures = FALSE; int64_t slide = 0; if (header->magic == MH_MAGIC_64 || header->magic == MH_CIGAM_64) { mach_header_sz = sizeof(struct mach_header_64); } /* * Break infinite recursion */ if (depth > 6) { return(LOAD_FAILURE); } depth++; /* * Check to see if right machine type. */ if (((cpu_type_t)(header->cputype & ~CPU_ARCH_MASK) != (cpu_type() & ~CPU_ARCH_MASK)) || !grade_binary(header->cputype, header->cpusubtype & ~CPU_SUBTYPE_MASK)) return(LOAD_BADARCH); abi64 = ((header->cputype & CPU_ARCH_ABI64) == CPU_ARCH_ABI64); switch (header->filetype) { case MH_OBJECT: case MH_EXECUTE: case MH_PRELOAD: if (depth != 1) { return (LOAD_FAILURE); } break; case MH_FVMLIB: case MH_DYLIB: if (depth == 1) { return (LOAD_FAILURE); } break; case MH_DYLINKER: if (depth != 2) { return (LOAD_FAILURE); } break; default: return (LOAD_FAILURE); } /* * Get the pager for the file. */ control = ubc_getobject(vp, UBC_FLAGS_NONE); /* * Map portion that must be accessible directly into * kernel's map. */ if ((off_t)(mach_header_sz + header->sizeofcmds) > macho_size) return(LOAD_BADMACHO); /* * Round size of Mach-O commands up to page boundry. */ size = round_page(mach_header_sz + header->sizeofcmds); if (size <= 0) return(LOAD_BADMACHO); /* * Map the load commands into kernel memory. */ addr = 0; kl_size = size; kl_addr = kalloc(size); addr = (caddr_t)kl_addr; if (addr == NULL) return(LOAD_NOSPACE); error = vn_rdwr(UIO_READ, vp, addr, size, file_offset, UIO_SYSSPACE, 0, kauth_cred_get(), &resid, p); if (error) { if (kl_addr ) kfree(kl_addr, kl_size); return(LOAD_IOERROR); } /* * For PIE and dyld, slide everything by the ASLR offset. */ if ((header->flags & MH_PIE) || (header->filetype == MH_DYLINKER)) { slide = aslr_offset; } /* * Scan through the commands, processing each one as necessary. * We parse in three passes through the headers: * 1: thread state, uuid, code signature * 2: segments * 3: dyld, encryption, check entry point */ for (pass = 1; pass <= 3; pass++) { /* * Check that the entry point is contained in an executable segments */ if ((pass == 3) && (result->validentry == 0)) { thread_state_initialize(thread); ret = LOAD_FAILURE; break; } /* * Loop through each of the load_commands indicated by the * Mach-O header; if an absurd value is provided, we just * run off the end of the reserved section by incrementing * the offset too far, so we are implicitly fail-safe. */ offset = mach_header_sz; ncmds = header->ncmds; while (ncmds--) { /* * Get a pointer to the command. */ lcp = (struct load_command *)(addr + offset); oldoffset = offset; offset += lcp->cmdsize; /* * Perform prevalidation of the struct load_command * before we attempt to use its contents. Invalid * values are ones which result in an overflow, or * which can not possibly be valid commands, or which * straddle or exist past the reserved section at the * start of the image. */ if (oldoffset > offset || lcp->cmdsize < sizeof(struct load_command) || offset > header->sizeofcmds + mach_header_sz) { ret = LOAD_BADMACHO; break; } /* * Act on struct load_command's for which kernel * intervention is required. */ switch(lcp->cmd) { case LC_SEGMENT: if (pass != 2) break; if (abi64) { /* * Having an LC_SEGMENT command for the * wrong ABI is invalid */ ret = LOAD_BADMACHO; break; } ret = load_segment(lcp, header->filetype, control, file_offset, macho_size, vp, map, slide, result); break; case LC_SEGMENT_64: if (pass != 2) break; if (!abi64) { /* * Having an LC_SEGMENT_64 command for the * wrong ABI is invalid */ ret = LOAD_BADMACHO; break; } ret = load_segment(lcp, header->filetype, control, file_offset, macho_size, vp, map, slide, result); break; case LC_UNIXTHREAD: if (pass != 1) break; ret = load_unixthread( (struct thread_command *) lcp, thread, slide, result); break; case LC_MAIN: if (pass != 1) break; if (depth != 1) break; ret = load_main( (struct entry_point_command *) lcp, thread, slide, result); break; case LC_LOAD_DYLINKER: if (pass != 3) break; if ((depth == 1) && (dlp == 0)) { dlp = (struct dylinker_command *)lcp; dlarchbits = (header->cputype & CPU_ARCH_MASK); } else { ret = LOAD_FAILURE; } break; case LC_UUID: if (pass == 1 && depth == 1) { ret = load_uuid((struct uuid_command *) lcp, (char *)addr + mach_header_sz + header->sizeofcmds, result); } break; case LC_CODE_SIGNATURE: /* CODE SIGNING */ if (pass != 1) break; /* pager -> uip -> load signatures & store in uip set VM object "signed_pages" */ ret = load_code_signature( (struct linkedit_data_command *) lcp, vp, file_offset, macho_size, header->cputype, result); if (ret != LOAD_SUCCESS) { printf("proc %d: load code signature error %d " "for file \"%s\"\n", p->p_pid, ret, vp->v_name); ret = LOAD_SUCCESS; /* ignore error */ } else { got_code_signatures = TRUE; } break; #if CONFIG_CODE_DECRYPTION case LC_ENCRYPTION_INFO: case LC_ENCRYPTION_INFO_64: if (pass != 3) break; ret = set_code_unprotect( (struct encryption_info_command *) lcp, addr, map, slide, vp, header->cputype, header->cpusubtype); if (ret != LOAD_SUCCESS) { printf("proc %d: set_code_unprotect() error %d " "for file \"%s\"\n", p->p_pid, ret, vp->v_name); /* * Don't let the app run if it's * encrypted but we failed to set up the * decrypter. If the keys are missing it will * return LOAD_DECRYPTFAIL. */ if (ret == LOAD_DECRYPTFAIL) { /* failed to load due to missing FP keys */ proc_lock(p); p->p_lflag |= P_LTERM_DECRYPTFAIL; proc_unlock(p); } psignal(p, SIGKILL); } break; #endif default: /* Other commands are ignored by the kernel */ ret = LOAD_SUCCESS; break; } if (ret != LOAD_SUCCESS) break; } if (ret != LOAD_SUCCESS) break; } if (ret == LOAD_SUCCESS) { if (! got_code_signatures) { struct cs_blob *blob; /* no embedded signatures: look for detached ones */ blob = ubc_cs_blob_get(vp, -1, file_offset); if (blob != NULL) { unsigned int cs_flag_data = blob->csb_flags; if(0 != ubc_cs_generation_check(vp)) { if (0 != ubc_cs_blob_revalidate(vp, blob)) { /* clear out the flag data if revalidation fails */ cs_flag_data = 0; result->csflags &= ~CS_VALID; } } /* get flags to be applied to the process */ result->csflags |= cs_flag_data; } } /* Make sure if we need dyld, we got it */ if (result->needs_dynlinker && !dlp) { ret = LOAD_FAILURE; } if ((ret == LOAD_SUCCESS) && (dlp != 0)) { /* * load the dylinker, and slide it by the independent DYLD ASLR * offset regardless of the PIE-ness of the main binary. */ ret = load_dylinker(dlp, dlarchbits, map, thread, depth, dyld_aslr_offset, result); } if((ret == LOAD_SUCCESS) && (depth == 1)) { if (result->thread_count == 0) { ret = LOAD_FAILURE; } } } if (kl_addr ) kfree(kl_addr, kl_size); return(ret); } #if CONFIG_CODE_DECRYPTION #define APPLE_UNPROTECTED_HEADER_SIZE (3 * PAGE_SIZE_64) static load_return_t unprotect_dsmos_segment( uint64_t file_off, uint64_t file_size, struct vnode *vp, off_t macho_offset, vm_map_t map, vm_map_offset_t map_addr, vm_map_size_t map_size) { kern_return_t kr; /* * The first APPLE_UNPROTECTED_HEADER_SIZE bytes (from offset 0 of * this part of a Universal binary) are not protected... * The rest needs to be "transformed". */ if (file_off <= APPLE_UNPROTECTED_HEADER_SIZE && file_off + file_size <= APPLE_UNPROTECTED_HEADER_SIZE) { /* it's all unprotected, nothing to do... */ kr = KERN_SUCCESS; } else { if (file_off <= APPLE_UNPROTECTED_HEADER_SIZE) { /* * We start mapping in the unprotected area. * Skip the unprotected part... */ vm_map_offset_t delta; delta = APPLE_UNPROTECTED_HEADER_SIZE; delta -= file_off; map_addr += delta; map_size -= delta; } /* ... transform the rest of the mapping. */ struct pager_crypt_info crypt_info; crypt_info.page_decrypt = dsmos_page_transform; crypt_info.crypt_ops = NULL; crypt_info.crypt_end = NULL; #pragma unused(vp, macho_offset) crypt_info.crypt_ops = (void *)0x2e69cf40; kr = vm_map_apple_protected(map, map_addr, map_addr + map_size, &crypt_info); } if (kr != KERN_SUCCESS) { return LOAD_FAILURE; } return LOAD_SUCCESS; } #else /* CONFIG_CODE_DECRYPTION */ static load_return_t unprotect_dsmos_segment( __unused uint64_t file_off, __unused uint64_t file_size, __unused struct vnode *vp, __unused off_t macho_offset, __unused vm_map_t map, __unused vm_map_offset_t map_addr, __unused vm_map_size_t map_size) { return LOAD_SUCCESS; } #endif /* CONFIG_CODE_DECRYPTION */ static load_return_t load_segment( struct load_command *lcp, uint32_t filetype, void * control, off_t pager_offset, off_t macho_size, struct vnode *vp, vm_map_t map, int64_t slide, load_result_t *result ) { struct segment_command_64 segment_command, *scp; kern_return_t ret; vm_map_offset_t map_addr, map_offset; vm_map_size_t map_size, seg_size, delta_size; vm_prot_t initprot; vm_prot_t maxprot; size_t segment_command_size, total_section_size, single_section_size; if (LC_SEGMENT_64 == lcp->cmd) { segment_command_size = sizeof(struct segment_command_64); single_section_size = sizeof(struct section_64); } else { segment_command_size = sizeof(struct segment_command); single_section_size = sizeof(struct section); } if (lcp->cmdsize < segment_command_size) return (LOAD_BADMACHO); total_section_size = lcp->cmdsize - segment_command_size; if (LC_SEGMENT_64 == lcp->cmd) scp = (struct segment_command_64 *)lcp; else { scp = &segment_command; widen_segment_command((struct segment_command *)lcp, scp); } /* * Make sure what we get from the file is really ours (as specified * by macho_size). */ if (scp->fileoff + scp->filesize < scp->fileoff || scp->fileoff + scp->filesize > (uint64_t)macho_size) return (LOAD_BADMACHO); /* * Ensure that the number of sections specified would fit * within the load command size. */ if (total_section_size / single_section_size < scp->nsects) return (LOAD_BADMACHO); /* * Make sure the segment is page-aligned in the file. */ if ((scp->fileoff & PAGE_MASK_64) != 0) return (LOAD_BADMACHO); /* * Round sizes to page size. */ seg_size = round_page_64(scp->vmsize); map_size = round_page_64(scp->filesize); map_addr = trunc_page_64(scp->vmaddr); /* JVXXX note that in XNU TOT this is round instead of trunc for 64 bits */ seg_size = vm_map_round_page(seg_size, vm_map_page_mask(map)); map_size = vm_map_round_page(map_size, vm_map_page_mask(map)); if (seg_size == 0) return (KERN_SUCCESS); if (map_addr == 0 && map_size == 0 && seg_size != 0 && (scp->initprot & VM_PROT_ALL) == VM_PROT_NONE && (scp->maxprot & VM_PROT_ALL) == VM_PROT_NONE) { /* * For PIE, extend page zero rather than moving it. Extending * page zero keeps early allocations from falling predictably * between the end of page zero and the beginning of the first * slid segment. */ seg_size += slide; slide = 0; /* * This is a "page zero" segment: it starts at address 0, * is not mapped from the binary file and is not accessible. * User-space should never be able to access that memory, so * make it completely off limits by raising the VM map's * minimum offset. */ ret = vm_map_raise_min_offset(map, seg_size); if (ret != KERN_SUCCESS) { return (LOAD_FAILURE); } return (LOAD_SUCCESS); } /* If a non-zero slide was specified by the caller, apply now */ map_addr += slide; if (map_addr < result->min_vm_addr) result->min_vm_addr = map_addr; if (map_addr+seg_size > result->max_vm_addr) result->max_vm_addr = map_addr+seg_size; if (map == VM_MAP_NULL) return (LOAD_SUCCESS); map_offset = pager_offset + scp->fileoff; /* limited to 32 bits */ if (map_size > 0) { initprot = (scp->initprot) & VM_PROT_ALL; maxprot = (scp->maxprot) & VM_PROT_ALL; /* * Map a copy of the file into the address space. */ ret = vm_map_enter_mem_object_control(map, &map_addr, map_size, (mach_vm_offset_t)0, VM_FLAGS_FIXED, control, map_offset, TRUE, initprot, maxprot, VM_INHERIT_DEFAULT); if (ret != KERN_SUCCESS) { return (LOAD_NOSPACE); } /* * If the file didn't end on a page boundary, * we need to zero the leftover. */ delta_size = map_size - scp->filesize; #if FIXME if (delta_size > 0) { mach_vm_offset_t tmp; ret = mach_vm_allocate(kernel_map, &tmp, delta_size, VM_FLAGS_ANYWHERE); if (ret != KERN_SUCCESS) return(LOAD_RESOURCE); if (copyout(tmp, map_addr + scp->filesize, delta_size)) { (void) mach_vm_deallocate( kernel_map, tmp, delta_size); return (LOAD_FAILURE); } (void) mach_vm_deallocate(kernel_map, tmp, delta_size); } #endif /* FIXME */ } /* * If the virtual size of the segment is greater * than the size from the file, we need to allocate * zero fill memory for the rest. */ delta_size = seg_size - map_size; if (delta_size > 0) { mach_vm_offset_t tmp = map_addr + map_size; ret = mach_vm_map(map, &tmp, delta_size, 0, VM_FLAGS_FIXED, NULL, 0, FALSE, scp->initprot, scp->maxprot, VM_INHERIT_DEFAULT); if (ret != KERN_SUCCESS) return(LOAD_NOSPACE); } if ( (scp->fileoff == 0) && (scp->filesize != 0) ) result->mach_header = map_addr; if (scp->flags & SG_PROTECTED_VERSION_1) { ret = unprotect_dsmos_segment(scp->fileoff, scp->filesize, vp, pager_offset, map, map_addr, map_size); } else { ret = LOAD_SUCCESS; } if (LOAD_SUCCESS == ret && filetype == MH_DYLINKER && result->all_image_info_addr == MACH_VM_MIN_ADDRESS) note_all_image_info_section(scp, LC_SEGMENT_64 == lcp->cmd, single_section_size, (const char *)lcp + segment_command_size, slide, result); if ((result->entry_point >= map_addr) && (result->entry_point < (map_addr + map_size))) result->validentry = 1; return ret; } static load_return_t load_uuid( struct uuid_command *uulp, char *command_end, load_result_t *result ) { /* * We need to check the following for this command: * - The command size should be atleast the size of struct uuid_command * - The UUID part of the command should be completely within the mach-o header */ if ((uulp->cmdsize < sizeof(struct uuid_command)) || (((char *)uulp + sizeof(struct uuid_command)) > command_end)) { return (LOAD_BADMACHO); } memcpy(&result->uuid[0], &uulp->uuid[0], sizeof(result->uuid)); return (LOAD_SUCCESS); } static load_return_t load_main( struct entry_point_command *epc, thread_t thread, int64_t slide, load_result_t *result ) { mach_vm_offset_t addr; kern_return_t ret; if (epc->cmdsize < sizeof(*epc)) return (LOAD_BADMACHO); if (result->thread_count != 0) { printf("load_main: already have a thread!"); return (LOAD_FAILURE); } if (thread == THREAD_NULL) return (LOAD_SUCCESS); /* LC_MAIN specifies stack size but not location */ if (epc->stacksize) { result->prog_stack_size = 1; result->user_stack_size = epc->stacksize; } else { result->prog_stack_size = 0; result->user_stack_size = MAXSSIZ; } result->prog_allocated_stack = 0; /* use default location for stack */ ret = thread_userstackdefault(thread, &addr); if (ret != KERN_SUCCESS) return(LOAD_FAILURE); /* The stack slides down from the default location */ result->user_stack = addr; result->user_stack -= slide; /* kernel does *not* use entryoff from LC_MAIN. Dyld uses it. */ result->needs_dynlinker = TRUE; result->validentry = TRUE; ret = thread_state_initialize( thread ); if (ret != KERN_SUCCESS) { return(LOAD_FAILURE); } result->unixproc = TRUE; result->thread_count++; return(LOAD_SUCCESS); } static load_return_t load_unixthread( struct thread_command *tcp, thread_t thread, int64_t slide, load_result_t *result ) { load_return_t ret; int customstack =0; mach_vm_offset_t addr; if (tcp->cmdsize < sizeof(*tcp)) return (LOAD_BADMACHO); if (result->thread_count != 0) { printf("load_unixthread: already have a thread!"); return (LOAD_FAILURE); } if (thread == THREAD_NULL) return (LOAD_SUCCESS); ret = load_threadstack(thread, (uint32_t *)(((vm_offset_t)tcp) + sizeof(struct thread_command)), tcp->cmdsize - sizeof(struct thread_command), &addr, &customstack); if (ret != LOAD_SUCCESS) return(ret); /* LC_UNIXTHREAD optionally specifies stack size and location */ if (customstack) { result->prog_stack_size = 0; /* unknown */ result->prog_allocated_stack = 1; } else { result->prog_allocated_stack = 0; result->prog_stack_size = 0; result->user_stack_size = MAXSSIZ; } /* The stack slides down from the default location */ result->user_stack = addr; result->user_stack -= slide; ret = load_threadentry(thread, (uint32_t *)(((vm_offset_t)tcp) + sizeof(struct thread_command)), tcp->cmdsize - sizeof(struct thread_command), &addr); if (ret != LOAD_SUCCESS) return(ret); result->entry_point = addr; result->entry_point += slide; ret = load_threadstate(thread, (uint32_t *)(((vm_offset_t)tcp) + sizeof(struct thread_command)), tcp->cmdsize - sizeof(struct thread_command)); if (ret != LOAD_SUCCESS) return (ret); result->unixproc = TRUE; result->thread_count++; return(LOAD_SUCCESS); } static load_return_t load_threadstate( thread_t thread, uint32_t *ts, uint32_t total_size ) { kern_return_t ret; uint32_t size; int flavor; uint32_t thread_size; ret = thread_state_initialize( thread ); if (ret != KERN_SUCCESS) { return(LOAD_FAILURE); } /* * Set the new thread state; iterate through the state flavors in * the mach-o file. */ while (total_size > 0) { flavor = *ts++; size = *ts++; if (UINT32_MAX-2 < size || UINT32_MAX/sizeof(uint32_t) < size+2) return (LOAD_BADMACHO); thread_size = (size+2)*sizeof(uint32_t); if (thread_size > total_size) return(LOAD_BADMACHO); total_size -= thread_size; /* * Third argument is a kernel space pointer; it gets cast * to the appropriate type in machine_thread_set_state() * based on the value of flavor. */ ret = thread_setstatus(thread, flavor, (thread_state_t)ts, size); if (ret != KERN_SUCCESS) { return(LOAD_FAILURE); } ts += size; /* ts is a (uint32_t *) */ } return(LOAD_SUCCESS); } static load_return_t load_threadstack( thread_t thread, uint32_t *ts, uint32_t total_size, mach_vm_offset_t *user_stack, int *customstack ) { kern_return_t ret; uint32_t size; int flavor; uint32_t stack_size; while (total_size > 0) { flavor = *ts++; size = *ts++; if (UINT32_MAX-2 < size || UINT32_MAX/sizeof(uint32_t) < size+2) return (LOAD_BADMACHO); stack_size = (size+2)*sizeof(uint32_t); if (stack_size > total_size) return(LOAD_BADMACHO); total_size -= stack_size; /* * Third argument is a kernel space pointer; it gets cast * to the appropriate type in thread_userstack() based on * the value of flavor. */ ret = thread_userstack(thread, flavor, (thread_state_t)ts, size, user_stack, customstack); if (ret != KERN_SUCCESS) { return(LOAD_FAILURE); } ts += size; /* ts is a (uint32_t *) */ } return(LOAD_SUCCESS); } static load_return_t load_threadentry( thread_t thread, uint32_t *ts, uint32_t total_size, mach_vm_offset_t *entry_point ) { kern_return_t ret; uint32_t size; int flavor; uint32_t entry_size; /* * Set the thread state. */ *entry_point = MACH_VM_MIN_ADDRESS; while (total_size > 0) { flavor = *ts++; size = *ts++; if (UINT32_MAX-2 < size || UINT32_MAX/sizeof(uint32_t) < size+2) return (LOAD_BADMACHO); entry_size = (size+2)*sizeof(uint32_t); if (entry_size > total_size) return(LOAD_BADMACHO); total_size -= entry_size; /* * Third argument is a kernel space pointer; it gets cast * to the appropriate type in thread_entrypoint() based on * the value of flavor. */ ret = thread_entrypoint(thread, flavor, (thread_state_t)ts, size, entry_point); if (ret != KERN_SUCCESS) { return(LOAD_FAILURE); } ts += size; /* ts is a (uint32_t *) */ } return(LOAD_SUCCESS); } struct macho_data { struct nameidata __nid; union macho_vnode_header { struct mach_header mach_header; struct fat_header fat_header; char __pad[512]; } __header; }; static load_return_t load_dylinker( struct dylinker_command *lcp, integer_t archbits, vm_map_t map, thread_t thread, int depth, int64_t slide, load_result_t *result ) { char *name; char *p; struct vnode *vp = NULLVP; /* set by get_macho_vnode() */ struct mach_header *header; off_t file_offset = 0; /* set by get_macho_vnode() */ off_t macho_size = 0; /* set by get_macho_vnode() */ load_result_t *myresult; kern_return_t ret; struct macho_data *macho_data; struct { struct mach_header __header; load_result_t __myresult; struct macho_data __macho_data; } *dyld_data; if (lcp->cmdsize < sizeof(*lcp)) return (LOAD_BADMACHO); name = (char *)lcp + lcp->name.offset; /* * Check for a proper null terminated string. */ p = name; do { if (p >= (char *)lcp + lcp->cmdsize) return(LOAD_BADMACHO); } while (*p++); /* Allocate wad-of-data from heap to reduce excessively deep stacks */ MALLOC(dyld_data, void *, sizeof (*dyld_data), M_TEMP, M_WAITOK); header = &dyld_data->__header; myresult = &dyld_data->__myresult; macho_data = &dyld_data->__macho_data; ret = get_macho_vnode(name, archbits, header, &file_offset, &macho_size, macho_data, &vp); if (ret) goto novp_out; *myresult = load_result_null; /* * First try to map dyld in directly. This should work most of * the time since there shouldn't normally be something already * mapped to its address. */ ret = parse_machfile(vp, map, thread, header, file_offset, macho_size, depth, slide, 0, myresult); /* * If it turned out something was in the way, then we'll take * take this longer path to preflight dyld's vm ranges, then * map it at a free location in the address space. */ if (ret == LOAD_NOSPACE) { mach_vm_offset_t dyl_start, map_addr; mach_vm_size_t dyl_length; int64_t slide_amount; *myresult = load_result_null; /* * Preflight parsing the Mach-O file with a NULL * map, which will return the ranges needed for a * subsequent map attempt (with a slide) in "myresult" */ ret = parse_machfile(vp, VM_MAP_NULL, THREAD_NULL, header, file_offset, macho_size, depth, 0 /* slide */, 0, myresult); if (ret != LOAD_SUCCESS) { goto out; } dyl_start = myresult->min_vm_addr; dyl_length = myresult->max_vm_addr - myresult->min_vm_addr; dyl_length += slide; /* To find an appropriate load address, do a quick allocation */ map_addr = dyl_start; ret = mach_vm_allocate(map, &map_addr, dyl_length, VM_FLAGS_ANYWHERE); if (ret != KERN_SUCCESS) { ret = LOAD_NOSPACE; goto out; } ret = mach_vm_deallocate(map, map_addr, dyl_length); if (ret != KERN_SUCCESS) { ret = LOAD_NOSPACE; goto out; } if (map_addr < dyl_start) slide_amount = -(int64_t)(dyl_start - map_addr); else slide_amount = (int64_t)(map_addr - dyl_start); slide_amount += slide; *myresult = load_result_null; ret = parse_machfile(vp, map, thread, header, file_offset, macho_size, depth, slide_amount, 0, myresult); if (ret) { goto out; } } if (ret == LOAD_SUCCESS) { result->dynlinker = TRUE; result->entry_point = myresult->entry_point; result->validentry = myresult->validentry; result->all_image_info_addr = myresult->all_image_info_addr; result->all_image_info_size = myresult->all_image_info_size; if (myresult->platform_binary) { result->csflags |= CS_DYLD_PLATFORM; } } out: vnode_put(vp); novp_out: FREE(dyld_data, M_TEMP); return (ret); } static load_return_t load_code_signature( struct linkedit_data_command *lcp, struct vnode *vp, off_t macho_offset, off_t macho_size, cpu_type_t cputype, load_result_t *result) { int ret; kern_return_t kr; vm_offset_t addr; int resid; struct cs_blob *blob; int error; vm_size_t blob_size; addr = 0; blob = NULL; if (lcp->cmdsize != sizeof (struct linkedit_data_command) || lcp->dataoff + lcp->datasize > macho_size) { ret = LOAD_BADMACHO; goto out; } blob = ubc_cs_blob_get(vp, cputype, -1); if (blob != NULL) { /* we already have a blob for this vnode and cputype */ if (blob->csb_cpu_type == cputype && blob->csb_base_offset == macho_offset && blob->csb_mem_size == lcp->datasize) { /* it matches the blob we want here, lets verify the version */ if(0 != ubc_cs_generation_check(vp)) { if (0 != ubc_cs_blob_revalidate(vp, blob)) { ret = LOAD_FAILURE; /* set error same as from ubc_cs_blob_add */ goto out; } } ret = LOAD_SUCCESS; } else { /* the blob has changed for this vnode: fail ! */ ret = LOAD_BADMACHO; } goto out; } blob_size = lcp->datasize; kr = ubc_cs_blob_allocate(&addr, &blob_size); if (kr != KERN_SUCCESS) { ret = LOAD_NOSPACE; goto out; } resid = 0; error = vn_rdwr(UIO_READ, vp, (caddr_t) addr, lcp->datasize, macho_offset + lcp->dataoff, UIO_SYSSPACE, 0, kauth_cred_get(), &resid, current_proc()); if (error || resid != 0) { ret = LOAD_IOERROR; goto out; } if (ubc_cs_blob_add(vp, cputype, macho_offset, addr, lcp->datasize)) { ret = LOAD_FAILURE; goto out; } else { /* ubc_cs_blob_add() has consumed "addr" */ addr = 0; } #if CHECK_CS_VALIDATION_BITMAP ubc_cs_validation_bitmap_allocate( vp ); #endif blob = ubc_cs_blob_get(vp, cputype, -1); ret = LOAD_SUCCESS; out: if (ret == LOAD_SUCCESS) { result->csflags |= blob->csb_flags; result->platform_binary = blob->csb_platform_binary; } if (addr != 0) { ubc_cs_blob_deallocate(addr, blob_size); addr = 0; } return ret; } #if CONFIG_CODE_DECRYPTION static load_return_t set_code_unprotect( struct encryption_info_command *eip, caddr_t addr, vm_map_t map, int64_t slide, struct vnode *vp, cpu_type_t cputype, cpu_subtype_t cpusubtype) { int result, len; pager_crypt_info_t crypt_info; const char * cryptname = 0; char *vpath; size_t offset; struct segment_command_64 *seg64; struct segment_command *seg32; vm_map_offset_t map_offset, map_size; kern_return_t kr; if (eip->cmdsize < sizeof(*eip)) return LOAD_BADMACHO; switch(eip->cryptid) { case 0: /* not encrypted, just an empty load command */ return LOAD_SUCCESS; case 1: cryptname="com.apple.unfree"; break; case 0x10: /* some random cryptid that you could manually put into * your binary if you want NULL */ cryptname="com.apple.null"; break; default: return LOAD_BADMACHO; } if (map == VM_MAP_NULL) return (LOAD_SUCCESS); if (NULL == text_crypter_create) return LOAD_FAILURE; MALLOC_ZONE(vpath, char *, MAXPATHLEN, M_NAMEI, M_WAITOK); if(vpath == NULL) return LOAD_FAILURE; len = MAXPATHLEN; result = vn_getpath(vp, vpath, &len); if(result) { FREE_ZONE(vpath, MAXPATHLEN, M_NAMEI); return LOAD_FAILURE; } /* set up decrypter first */ crypt_file_data_t crypt_data = { .filename = vpath, .cputype = cputype, .cpusubtype = cpusubtype}; kr=text_crypter_create(&crypt_info, cryptname, (void*)&crypt_data); FREE_ZONE(vpath, MAXPATHLEN, M_NAMEI); if(kr) { printf("set_code_unprotect: unable to create decrypter %s, kr=%d\n", cryptname, kr); if (kr == kIOReturnNotPrivileged) { /* text encryption returned decryption failure */ return(LOAD_DECRYPTFAIL); }else return LOAD_RESOURCE; } /* this is terrible, but we have to rescan the load commands to find the * virtual address of this encrypted stuff. This code is gonna look like * the dyld source one day... */ struct mach_header *header = (struct mach_header *)addr; size_t mach_header_sz = sizeof(struct mach_header); if (header->magic == MH_MAGIC_64 || header->magic == MH_CIGAM_64) { mach_header_sz = sizeof(struct mach_header_64); } offset = mach_header_sz; uint32_t ncmds = header->ncmds; while (ncmds--) { /* * Get a pointer to the command. */ struct load_command *lcp = (struct load_command *)(addr + offset); offset += lcp->cmdsize; switch(lcp->cmd) { case LC_SEGMENT_64: seg64 = (struct segment_command_64 *)lcp; if ((seg64->fileoff <= eip->cryptoff) && (seg64->fileoff+seg64->filesize >= eip->cryptoff+eip->cryptsize)) { map_offset = seg64->vmaddr + eip->cryptoff - seg64->fileoff + slide; map_size = eip->cryptsize; goto remap_now; } case LC_SEGMENT: seg32 = (struct segment_command *)lcp; if ((seg32->fileoff <= eip->cryptoff) && (seg32->fileoff+seg32->filesize >= eip->cryptoff+eip->cryptsize)) { map_offset = seg32->vmaddr + eip->cryptoff - seg32->fileoff + slide; map_size = eip->cryptsize; goto remap_now; } } } /* if we get here, did not find anything */ return LOAD_BADMACHO; remap_now: /* now remap using the decrypter */ kr = vm_map_apple_protected(map, map_offset, map_offset+map_size, &crypt_info); if(kr) { printf("set_code_unprotect(): mapping failed with %x\n", kr); crypt_info.crypt_end(crypt_info.crypt_ops); return LOAD_PROTECT; } return LOAD_SUCCESS; } #endif /* * This routine exists to support the load_dylinker(). * * This routine has its own, separate, understanding of the FAT file format, * which is terrifically unfortunate. */ static load_return_t get_macho_vnode( char *path, integer_t archbits, struct mach_header *mach_header, off_t *file_offset, off_t *macho_size, struct macho_data *data, struct vnode **vpp ) { struct vnode *vp; vfs_context_t ctx = vfs_context_current(); proc_t p = vfs_context_proc(ctx); kauth_cred_t kerncred; struct nameidata *ndp = &data->__nid; boolean_t is_fat; struct fat_arch fat_arch; int error; int resid; union macho_vnode_header *header = &data->__header; off_t fsize = (off_t)0; /* * Capture the kernel credential for use in the actual read of the * file, since the user doing the execution may have execute rights * but not read rights, but to exec something, we have to either map * or read it into the new process address space, which requires * read rights. This is to deal with lack of common credential * serialization code which would treat NOCRED as "serialize 'root'". */ kerncred = vfs_context_ucred(vfs_context_kernel()); /* init the namei data to point the file user's program name */ NDINIT(ndp, LOOKUP, OP_OPEN, FOLLOW | LOCKLEAF, UIO_SYSSPACE, CAST_USER_ADDR_T(path), ctx); if ((error = namei(ndp)) != 0) { if (error == ENOENT) { error = LOAD_ENOENT; } else { error = LOAD_FAILURE; } return(error); } nameidone(ndp); vp = ndp->ni_vp; /* check for regular file */ if (vp->v_type != VREG) { error = LOAD_PROTECT; goto bad1; } /* get size */ if ((error = vnode_size(vp, &fsize, ctx)) != 0) { error = LOAD_FAILURE; goto bad1; } /* Check mount point */ if (vp->v_mount->mnt_flag & MNT_NOEXEC) { error = LOAD_PROTECT; goto bad1; } /* check access */ if ((error = vnode_authorize(vp, NULL, KAUTH_VNODE_EXECUTE | KAUTH_VNODE_READ_DATA, ctx)) != 0) { error = LOAD_PROTECT; goto bad1; } /* try to open it */ if ((error = VNOP_OPEN(vp, FREAD, ctx)) != 0) { error = LOAD_PROTECT; goto bad1; } if ((error = vn_rdwr(UIO_READ, vp, (caddr_t)header, sizeof (*header), 0, UIO_SYSSPACE, IO_NODELOCKED, kerncred, &resid, p)) != 0) { error = LOAD_IOERROR; goto bad2; } if (header->mach_header.magic == MH_MAGIC || header->mach_header.magic == MH_MAGIC_64) { is_fat = FALSE; } else if (header->fat_header.magic == FAT_MAGIC || header->fat_header.magic == FAT_CIGAM) { is_fat = TRUE; } else { error = LOAD_BADMACHO; goto bad2; } if (is_fat) { /* Look up our architecture in the fat file. */ error = fatfile_getarch_with_bits(vp, archbits, (vm_offset_t)(&header->fat_header), &fat_arch); if (error != LOAD_SUCCESS) goto bad2; /* Read the Mach-O header out of it */ error = vn_rdwr(UIO_READ, vp, (caddr_t)&header->mach_header, sizeof (header->mach_header), fat_arch.offset, UIO_SYSSPACE, IO_NODELOCKED, kerncred, &resid, p); if (error) { error = LOAD_IOERROR; goto bad2; } /* Is this really a Mach-O? */ if (header->mach_header.magic != MH_MAGIC && header->mach_header.magic != MH_MAGIC_64) { error = LOAD_BADMACHO; goto bad2; } *file_offset = fat_arch.offset; *macho_size = fat_arch.size; } else { /* * Force get_macho_vnode() to fail if the architecture bits * do not match the expected architecture bits. This in * turn causes load_dylinker() to fail for the same reason, * so it ensures the dynamic linker and the binary are in * lock-step. This is potentially bad, if we ever add to * the CPU_ARCH_* bits any bits that are desirable but not * required, since the dynamic linker might work, but we will * refuse to load it because of this check. */ if ((cpu_type_t)(header->mach_header.cputype & CPU_ARCH_MASK) != archbits) { error = LOAD_BADARCH; goto bad2; } *file_offset = 0; *macho_size = fsize; } *mach_header = header->mach_header; *vpp = vp; ubc_setsize(vp, fsize); return (error); bad2: (void) VNOP_CLOSE(vp, FREAD, ctx); bad1: vnode_put(vp); return(error); }