1/*
2 * Copyright (c) 2008,2010 Apple Inc. All Rights Reserved.
3 *
4 * @APPLE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. Please obtain a copy of the License at
10 * http://www.opensource.apple.com/apsl/ and read it before using this
11 * file.
12 *
13 * The Original Code and all software distributed under the License are
14 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
15 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
16 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
18 * Please see the License for the specific language governing rights and
19 * limitations under the License.
20 *
21 * @APPLE_LICENSE_HEADER_END@
22 */
23
24#include <TargetConditionals.h>
25#if TARGET_OS_EMBEDDED
26
27#include "SecurityCommands.h"
28
29#include <AssertMacros.h>
30#include <mach-o/loader.h>
31#include <mach-o/fat.h>
32#include <CoreFoundation/CoreFoundation.h>
33#include <Security/SecCMS.h>
34#include <Security/SecPolicyPriv.h>
35#include <CommonCrypto/CommonDigest.h>
36#include <CommonCrypto/CommonDigestSPI.h>
37
38/*
39 * Magic numbers used by Code Signing
40 */
41enum {
42	CSMAGIC_REQUIREMENT	= 0xfade0c00,		/* single Requirement blob */
43	CSMAGIC_REQUIREMENTS = 0xfade0c01,		/* Requirements vector (internal requirements) */
44	CSMAGIC_CODEDIRECTORY = 0xfade0c02,		/* CodeDirectory blob */
45	CSMAGIC_EMBEDDED_SIGNATURE = 0xfade0cc0, /* embedded form of signature data */
46	CSMAGIC_DETACHED_SIGNATURE = 0xfade0cc1, /* multi-arch collection of embedded signatures */
47
48	CSSLOT_CODEDIRECTORY = 0,				/* slot index for CodeDirectory */
49};
50
51
52/*
53 * Structure of an embedded-signature SuperBlob
54 */
55typedef struct __BlobIndex {
56	uint32_t type;					/* type of entry */
57	uint32_t offset;				/* offset of entry */
58} CS_BlobIndex;
59
60typedef struct __SuperBlob {
61	uint32_t magic;					/* magic number */
62	uint32_t length;				/* total length of SuperBlob */
63	uint32_t count;					/* number of index entries following */
64	CS_BlobIndex index[];			/* (count) entries */
65	/* followed by Blobs in no particular order as indicated by offsets in index */
66} CS_SuperBlob;
67
68
69/*
70 * C form of a CodeDirectory.
71 */
72typedef struct __CodeDirectory {
73	uint32_t magic;					/* magic number (CSMAGIC_CODEDIRECTORY) */
74	uint32_t length;				/* total length of CodeDirectory blob */
75	uint32_t version;				/* compatibility version */
76	uint32_t flags;					/* setup and mode flags */
77	uint32_t hashOffset;			/* offset of hash slot element at index zero */
78	uint32_t identOffset;			/* offset of identifier string */
79	uint32_t nSpecialSlots;			/* number of special hash slots */
80	uint32_t nCodeSlots;			/* number of ordinary (code) hash slots */
81	uint32_t codeLimit;				/* limit to main image signature range */
82	uint8_t hashSize;				/* size of each hash in bytes */
83	uint8_t hashType;				/* type of hash (cdHashType* constants) */
84	uint8_t spare1;					/* unused (must be zero) */
85	uint8_t	pageSize;				/* log2(page size in bytes); 0 => infinite */
86	uint32_t spare2;				/* unused (must be zero) */
87	/* followed by dynamic content as located by offset fields above */
88} CS_CodeDirectory;
89
90
91	//assert(page < ntohl(cd->nCodeSlots));
92	//return base + ntohl(cd->hashOffset) + page * 20;
93
94#if 0
95static void debug_data(uint8_t *data, size_t length)
96{
97    uint32_t i, j;
98    for (i = 0; i < length; i+=16) {
99        fprintf(stderr, "%p   ", (void*)(data+i));
100        for (j = 0; (j < 16) && (j+i < length); j++) {
101            uint8_t byte = *(uint8_t*)(data+i+j);
102            fprintf(stderr, "%.02x %c|", byte, isprint(byte) ? byte : '?');
103        }
104        fprintf(stderr, "\n");
105    }
106}
107
108static void write_data(const char *path, uint8_t *data, size_t length)
109{
110    int fd = open(path, O_RDWR|O_TRUNC|O_CREAT, 0644);
111    require(fd>0, out);
112    write(fd, data, length);
113    close(fd);
114out:
115    return;
116}
117#endif
118
119static void fprint_digest(FILE *file, unsigned char *digest, size_t length) {
120    size_t ix;
121    for (ix = 0; ix < length; ++ix) {
122        fprintf(file, "%02x", digest[ix]);
123    }
124}
125
126static CFMutableDictionaryRef lc_code_sig(uint8_t *lc_code_signature, size_t lc_code_signature_len)
127{
128    CFMutableDictionaryRef code_signature =
129        CFDictionaryCreateMutable(kCFAllocatorDefault, 0,
130                &kCFTypeDictionaryKeyCallBacks,
131                &kCFTypeDictionaryValueCallBacks);
132    require(code_signature, out);
133
134    CS_SuperBlob *sb = (CS_SuperBlob*)lc_code_signature;
135    require(ntohl(sb->magic) == CSMAGIC_EMBEDDED_SIGNATURE, out);
136    uint32_t count;
137    for (count = 0; count < ntohl(sb->count); count++) {
138        //uint32_t type = ntohl(sb->index[count].type);
139        uint32_t offset = ntohl(sb->index[count].offset);
140        uint8_t *bytes = lc_code_signature + offset;
141        //fprintf(stderr, "blob[%d]: (type: 0x%.08x, offset: %p)\n", count, type, (void*)offset);
142        uint32_t magic = ntohl(*(uint32_t*)bytes);
143        uint32_t length = ntohl(*(uint32_t*)(bytes+4));
144        //fprintf(stderr, "    magic: 0x%.08x length: %d\n", magic, length);
145        switch(magic) {
146            case 0xfade0c01: //write_data("requirements", bytes, length);
147                break;
148            case 0xfade0c02: //write_data("codedir", bytes, length);
149            {
150                const CS_CodeDirectory *cd = (const CS_CodeDirectory *)bytes;
151                CFDataRef codedir = CFDataCreate(kCFAllocatorDefault, bytes, length);
152                require(codedir, out);
153                CFDictionarySetValue(code_signature, CFSTR("CodeDirectory"), codedir);
154                CFRelease(codedir);
155                require_string(ntohl(cd->version) >= 0x20001, out, "incompatible version");
156                require_string(ntohl(cd->version) <= 0x2F000, out, "incompatible version");
157                require_string(cd->hashSize == 20, out, "unexpected hash size");
158                require_string(cd->hashType == 1, out, "unexpected hash type");
159
160                uint32_t hash_offset = ntohl(cd->hashOffset);
161                uint32_t entitlement_slot = 5;
162
163                if (ntohl(cd->nSpecialSlots) >= entitlement_slot) {
164                    CFDataRef message = CFDataCreate(kCFAllocatorDefault, bytes+hash_offset-entitlement_slot*cd->hashSize, cd->hashSize);
165                    require(message, out);
166                    CFDictionarySetValue(code_signature, CFSTR("EntitlementsCDHash"), message);
167                    CFRelease(message);
168                } else
169                    fprintf(stderr, "no entitlements slot yet\n");
170            }
171                break;
172            case 0xfade0b01:  //write_data("signed", lc_code_signature, bytes-lc_code_signature);
173                if (length != 8) {
174                    CFDataRef message = CFDataCreate(kCFAllocatorDefault, bytes+8, length-8);
175                    require(message, out);
176                    CFDictionarySetValue(code_signature, CFSTR("SignedData"), message);
177                    CFRelease(message);
178                }
179                break;
180            case 0xfade7171:
181            {
182                unsigned char digest[CC_SHA1_DIGEST_LENGTH];
183                CCDigest(kCCDigestSHA1, bytes, length, digest);
184
185                CFDataRef message = CFDataCreate(kCFAllocatorDefault, digest, sizeof(digest));
186                require(message, out);
187                CFDictionarySetValue(code_signature, CFSTR("EntitlementsHash"), message);
188                CFRelease(message);
189                message = CFDataCreate(kCFAllocatorDefault, bytes+8, length-8);
190                require(message, out);
191                CFDictionarySetValue(code_signature, CFSTR("Entitlements"), message);
192                CFRelease(message);
193                break;
194            }
195            default:
196                fprintf(stderr, "Skipping block with magic: 0x%x\n", magic);
197                break;
198        }
199    }
200    return code_signature;
201out:
202    if (code_signature) CFRelease(code_signature);
203    return NULL;
204}
205
206static FILE *
207open_bundle(const char * path, const char * mode)
208{
209    char full_path[1024] = {};
210    CFStringRef path_cfstring = NULL;
211    CFURLRef path_url = NULL;
212    CFBundleRef bundle = NULL;
213
214    path_cfstring = CFStringCreateWithFileSystemRepresentation(kCFAllocatorDefault, path);
215    require_quiet(path_cfstring, out);
216    path_url = CFURLCreateWithFileSystemPath(kCFAllocatorDefault, path_cfstring, kCFURLPOSIXPathStyle, true);
217    require_quiet(path_url, out);
218	bundle =  CFBundleCreate(kCFAllocatorDefault, path_url);
219    require_quiet(bundle, out);
220    CFURLRef exec = CFBundleCopyExecutableURL(bundle);
221    require(exec, out);
222    require(CFURLGetFileSystemRepresentation(exec, true, (uint8_t*)full_path, sizeof(full_path)), out);
223out:
224    if (path_cfstring) CFRelease(path_cfstring);
225    if (path_url) CFRelease(path_url);
226    if (bundle) CFRelease(bundle);
227
228    return fopen(full_path, "r");
229}
230
231static CFMutableDictionaryRef load_code_signature(FILE *binary, size_t slice_offset)
232{
233    bool signature_found = false;
234    CFMutableDictionaryRef result = NULL;
235    struct load_command lc;
236    do {
237        require(1 == fread(&lc, sizeof(lc), 1, binary), out);
238        if (lc.cmd == LC_CODE_SIGNATURE) {
239            struct { uint32_t offset; uint32_t size; } sig;
240            require(1 == fread(&sig, sizeof(sig), 1, binary), out);
241            require_noerr(fseek(binary, slice_offset+sig.offset, SEEK_SET), out);
242            size_t length = sig.size;
243            uint8_t *data = malloc(length);
244            require(length && data, out);
245            require(1 == fread(data, length, 1, binary), out);
246            signature_found = true;
247            result = lc_code_sig(data, length);
248            free(data);
249            break;
250        }
251        require_noerr(fseek(binary, lc.cmdsize-sizeof(lc), SEEK_CUR), out);
252    } while(lc.cmd || lc.cmdsize); /* count lc */
253out:
254    if (!signature_found)
255        fprintf(stderr, "No LC_CODE_SIGNATURE segment found\n");
256    return result;
257}
258
259static CFArrayRef load_code_signatures(const char *path)
260{
261    bool fully_parsed_binary = false;
262    CFMutableDictionaryRef result = NULL;
263    CFMutableArrayRef results = CFArrayCreateMutable(kCFAllocatorDefault, 0, &kCFTypeArrayCallBacks);
264
265    FILE *binary = open_bundle(path, "r");
266    if (!binary) binary = fopen(path, "r");
267    require(binary, out);
268
269    struct mach_header header;
270    require(1 == fread(&header, sizeof(header), 1, binary), out);
271    if ((header.magic == MH_MAGIC) || (header.magic == MH_MAGIC_64)) {
272	if (header.magic == MH_MAGIC_64)
273		fseek(binary, sizeof(struct mach_header_64) - sizeof(struct mach_header), SEEK_CUR);
274        result = load_code_signature(binary, 0 /*non fat*/);
275        require(result, out);
276        CFStringRef type = CFStringCreateWithFormat(kCFAllocatorDefault, NULL, CFSTR("CPU type: (%d,%d)"), header.cputype, header.cpusubtype);
277        CFDictionarySetValue(result, CFSTR("ARCH"), type);
278        CFRelease(type);
279        CFArrayAppendValue(results, result);
280    }
281    else
282    {
283        struct fat_header fat;
284        require(!fseek(binary, 0L, SEEK_SET), out);
285        require(1 == fread(&fat, sizeof(fat), 1, binary), out);
286        require(ntohl(fat.magic) == FAT_MAGIC, out);
287        uint32_t slice, slices = ntohl(fat.nfat_arch);
288        struct fat_arch *archs = calloc(slices, sizeof(struct fat_arch));
289        require(slices == fread(archs, sizeof(struct fat_arch), slices, binary), out);
290        for (slice = 0; slice < slices; slice++) {
291            uint32_t slice_offset = ntohl(archs[slice].offset);
292            require(!fseek(binary, slice_offset, SEEK_SET), out);
293            require(1 == fread(&header, sizeof(header), 1, binary), out);
294	    require((header.magic == MH_MAGIC) || (header.magic == MH_MAGIC_64), out);
295	    if (header.magic == MH_MAGIC_64)
296		    fseek(binary, sizeof(struct mach_header_64) - sizeof(struct mach_header), SEEK_CUR);
297            result = load_code_signature(binary, slice_offset);
298            require(result, out);
299            CFStringRef type = CFStringCreateWithFormat(kCFAllocatorDefault, NULL, CFSTR("CPU type: (%d,%d)"), header.cputype, header.cpusubtype);
300            CFDictionarySetValue(result, CFSTR("ARCH"), type);
301            CFRelease(type);
302            CFArrayAppendValue(results, result);
303            CFRelease(result);
304        }
305    }
306    fully_parsed_binary = true;
307out:
308    if (!fully_parsed_binary) {
309        if (results) {
310            CFRelease(results);
311            results = NULL;
312        }
313    }
314    if (binary)
315        fclose(binary);
316    return results;
317}
318
319
320extern int codesign_util(int argc, char * const *argv)
321{
322    int             result = 1, verbose = 0;
323    char            ch;
324
325    while ((ch = getopt(argc, argv, "v")) != -1)
326    {
327        switch (ch)
328        {
329        case 'v':
330            verbose++;
331            break;
332        default:
333            return 2; /* Trigger usage message. */
334        }
335    }
336
337	argc -= optind;
338	argv += optind;
339
340    if (argc != 1)
341        return 2; /* Trigger usage message. */
342
343    CFArrayRef sigs = load_code_signatures(argv[0]);
344    require(sigs, out);
345
346    if (verbose >= 2)
347        CFShow(sigs);
348
349    CFIndex i, count = CFArrayGetCount(sigs);
350
351    for (i = 0; i < count; i++) {
352        CFDictionaryRef signature = CFArrayGetValueAtIndex(sigs, i);
353
354        CFDataRef code_dir = CFDictionaryGetValue(signature, CFSTR("CodeDirectory"));
355        const CS_CodeDirectory *cd = (CS_CodeDirectory *)CFDataGetBytePtr(code_dir);
356
357        CFDataRef signed_data = CFDictionaryGetValue(signature, CFSTR("SignedData"));
358
359        CFDataRef entitlements = CFDictionaryGetValue(signature, CFSTR("Entitlements"));
360        CFDataRef entitlements_cd_hash = CFDictionaryGetValue(signature, CFSTR("EntitlementsCDHash"));
361        CFDataRef entitlements_hash = CFDictionaryGetValue(signature, CFSTR("EntitlementsHash"));
362
363        CFStringRef arch = CFDictionaryGetValue(signature, CFSTR("ARCH"));
364
365        CFShow(arch);
366
367        SecPolicyRef policy = SecPolicyCreateiPhoneApplicationSigning();
368
369        if (signed_data) {
370            if (SecCMSVerify(signed_data, code_dir, policy, NULL, NULL)) {
371                fprintf(stderr, "Failed to verify signature\n");
372                result = -1;
373            } else
374                fprintf(stderr, "Signature ok\n");
375
376        } else
377            fprintf(stderr, "Ad-hoc signed binary\n");
378
379        if (entitlements_cd_hash) {
380            if (entitlements_hash && entitlements_cd_hash && CFEqual(entitlements_hash, entitlements_cd_hash))
381                fprintf(stderr, "Entitlements ok\n");
382            else
383                fprintf(stderr, "Entitlements modified\n");
384        }
385
386        if (verbose >= 2) {
387            fprintf(stderr, "magic: 0x%x length: %u(%lu)\n", ntohl(cd->magic), ntohl(cd->length), CFDataGetLength(code_dir));
388            fprintf(stderr, "code directory version/flags: 0x%x/0x%x special/code hash slots: %u/%u\n"
389                "codelimit: %u hash size/type: %u/%u hash/ident offset: %u/%u\n",
390                ntohl(cd->version), ntohl(cd->flags), ntohl(cd->nSpecialSlots), ntohl(cd->nCodeSlots),
391                ntohl(cd->codeLimit), cd->hashSize, cd->hashType, ntohl(cd->hashOffset), ntohl(cd->identOffset));
392            fprintf(stderr, "ident: '%s'\n", CFDataGetBytePtr(code_dir) + ntohl(cd->identOffset));
393
394            uint32_t ix;
395            uint8_t *hashes = (uint8_t *)CFDataGetBytePtr(code_dir) + ntohl(cd->hashOffset);
396            for (ix = 0; ix < ntohl(cd->nSpecialSlots); ++ix) {
397                fprint_digest(stderr, hashes, cd->hashSize);
398                fprintf(stderr, "\n");
399                hashes += cd->hashSize;
400            }
401        }
402
403        if (verbose >= 1) {
404            if (entitlements)
405                fprintf(stderr, "Entitlements\n%.*s", (int)CFDataGetLength(entitlements)-8, CFDataGetBytePtr(entitlements)+8);
406        }
407
408        if (verbose >= 2) {
409            if (entitlements_hash) {
410                fprintf(stderr, "digest: ");
411                fprint_digest(stderr, (uint8_t *)CFDataGetBytePtr(entitlements_hash), CC_SHA1_DIGEST_LENGTH);
412                fprintf(stderr, "\n");
413            }
414        }
415    }
416
417    CFRelease(sigs);
418
419    return result;
420out:
421    return -1;
422}
423
424#endif // TARGET_OS_EMBEDDED
425