Aart Bik | 1a65052 | 2015-07-08 21:20:41 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright (C) 2011 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | /* |
| 18 | * Validate and manipulate MUTF-8 encoded string data. |
| 19 | */ |
| 20 | |
| 21 | #include "DexUtf.h" |
| 22 | |
| 23 | /* Compare two '\0'-terminated modified UTF-8 strings, using Unicode |
| 24 | * code point values for comparison. This treats different encodings |
| 25 | * for the same code point as equivalent, except that only a real '\0' |
| 26 | * byte is considered the string terminator. The return value is as |
| 27 | * for strcmp(). */ |
| 28 | int dexUtf8Cmp(const char* s1, const char* s2) { |
| 29 | for (;;) { |
| 30 | if (*s1 == '\0') { |
| 31 | if (*s2 == '\0') { |
| 32 | return 0; |
| 33 | } |
| 34 | return -1; |
| 35 | } else if (*s2 == '\0') { |
| 36 | return 1; |
| 37 | } |
| 38 | |
| 39 | int utf1 = dexGetUtf16FromUtf8(&s1); |
| 40 | int utf2 = dexGetUtf16FromUtf8(&s2); |
| 41 | int diff = utf1 - utf2; |
| 42 | |
| 43 | if (diff != 0) { |
| 44 | return diff; |
| 45 | } |
| 46 | } |
| 47 | } |
| 48 | |
| 49 | /* for dexIsValidMemberNameUtf8(), a bit vector indicating valid low ascii */ |
| 50 | u4 DEX_MEMBER_VALID_LOW_ASCII[4] = { |
| 51 | 0x00000000, // 00..1f low control characters; nothing valid |
| 52 | 0x03ff2010, // 20..3f digits and symbols; valid: '0'..'9', '$', '-' |
| 53 | 0x87fffffe, // 40..5f uppercase etc.; valid: 'A'..'Z', '_' |
| 54 | 0x07fffffe // 60..7f lowercase etc.; valid: 'a'..'z' |
| 55 | }; |
| 56 | |
| 57 | /* Helper for dexIsValidMemberNameUtf8(); do not call directly. */ |
| 58 | bool dexIsValidMemberNameUtf8_0(const char** pUtf8Ptr) { |
| 59 | /* |
| 60 | * It's a multibyte encoded character. Decode it and analyze. We |
| 61 | * accept anything that isn't (a) an improperly encoded low value, |
| 62 | * (b) an improper surrogate pair, (c) an encoded '\0', (d) a high |
| 63 | * control character, or (e) a high space, layout, or special |
| 64 | * character (U+00a0, U+2000..U+200f, U+2028..U+202f, |
| 65 | * U+fff0..U+ffff). This is all specified in the dex format |
| 66 | * document. |
| 67 | */ |
| 68 | |
| 69 | u2 utf16 = dexGetUtf16FromUtf8(pUtf8Ptr); |
| 70 | |
| 71 | // Perform follow-up tests based on the high 8 bits. |
| 72 | switch (utf16 >> 8) { |
| 73 | case 0x00: { |
| 74 | // It's only valid if it's above the ISO-8859-1 high space (0xa0). |
| 75 | return (utf16 > 0x00a0); |
| 76 | } |
| 77 | case 0xd8: |
| 78 | case 0xd9: |
| 79 | case 0xda: |
| 80 | case 0xdb: { |
| 81 | /* |
| 82 | * It's a leading surrogate. Check to see that a trailing |
| 83 | * surrogate follows. |
| 84 | */ |
| 85 | utf16 = dexGetUtf16FromUtf8(pUtf8Ptr); |
| 86 | return (utf16 >= 0xdc00) && (utf16 <= 0xdfff); |
| 87 | } |
| 88 | case 0xdc: |
| 89 | case 0xdd: |
| 90 | case 0xde: |
| 91 | case 0xdf: { |
| 92 | // It's a trailing surrogate, which is not valid at this point. |
| 93 | return false; |
| 94 | } |
| 95 | case 0x20: |
| 96 | case 0xff: { |
| 97 | // It's in the range that has spaces, controls, and specials. |
| 98 | switch (utf16 & 0xfff8) { |
| 99 | case 0x2000: |
| 100 | case 0x2008: |
| 101 | case 0x2028: |
| 102 | case 0xfff0: |
| 103 | case 0xfff8: { |
| 104 | return false; |
| 105 | } |
| 106 | } |
| 107 | break; |
| 108 | } |
| 109 | } |
| 110 | |
| 111 | return true; |
| 112 | } |
| 113 | |
| 114 | /* Return whether the given string is a valid field or method name. */ |
| 115 | bool dexIsValidMemberName(const char* s) { |
| 116 | bool angleName = false; |
| 117 | |
| 118 | switch (*s) { |
| 119 | case '\0': { |
| 120 | // The empty string is not a valid name. |
| 121 | return false; |
| 122 | } |
| 123 | case '<': { |
| 124 | /* |
| 125 | * '<' is allowed only at the start of a name, and if present, |
| 126 | * means that the name must end with '>'. |
| 127 | */ |
| 128 | angleName = true; |
| 129 | s++; |
| 130 | break; |
| 131 | } |
| 132 | } |
| 133 | |
| 134 | for (;;) { |
| 135 | switch (*s) { |
| 136 | case '\0': { |
| 137 | return !angleName; |
| 138 | } |
| 139 | case '>': { |
| 140 | return angleName && s[1] == '\0'; |
| 141 | } |
| 142 | } |
| 143 | if (!dexIsValidMemberNameUtf8(&s)) { |
| 144 | return false; |
| 145 | } |
| 146 | } |
| 147 | } |
| 148 | |
| 149 | /* Helper for validating type descriptors and class names, which is parametric |
| 150 | * with respect to type vs. class and dot vs. slash. */ |
| 151 | static bool isValidTypeDescriptorOrClassName(const char* s, bool isClassName, |
| 152 | bool dotSeparator) { |
| 153 | int arrayCount = 0; |
| 154 | |
| 155 | while (*s == '[') { |
| 156 | arrayCount++; |
| 157 | s++; |
| 158 | } |
| 159 | |
| 160 | if (arrayCount > 255) { |
| 161 | // Arrays may have no more than 255 dimensions. |
| 162 | return false; |
| 163 | } |
| 164 | |
| 165 | if (arrayCount != 0) { |
| 166 | /* |
| 167 | * If we're looking at an array of some sort, then it doesn't |
| 168 | * matter if what is being asked for is a class name; the |
| 169 | * format looks the same as a type descriptor in that case, so |
| 170 | * treat it as such. |
| 171 | */ |
| 172 | isClassName = false; |
| 173 | } |
| 174 | |
| 175 | if (!isClassName) { |
| 176 | /* |
| 177 | * We are looking for a descriptor. Either validate it as a |
| 178 | * single-character primitive type, or continue on to check the |
| 179 | * embedded class name (bracketed by "L" and ";"). |
| 180 | */ |
| 181 | switch (*(s++)) { |
| 182 | case 'B': |
| 183 | case 'C': |
| 184 | case 'D': |
| 185 | case 'F': |
| 186 | case 'I': |
| 187 | case 'J': |
| 188 | case 'S': |
| 189 | case 'Z': { |
| 190 | // These are all single-character descriptors for primitive types. |
| 191 | return (*s == '\0'); |
| 192 | } |
| 193 | case 'V': { |
| 194 | // Non-array void is valid, but you can't have an array of void. |
| 195 | return (arrayCount == 0) && (*s == '\0'); |
| 196 | } |
| 197 | case 'L': { |
| 198 | // Class name: Break out and continue below. |
| 199 | break; |
| 200 | } |
| 201 | default: { |
| 202 | // Oddball descriptor character. |
| 203 | return false; |
| 204 | } |
| 205 | } |
| 206 | } |
| 207 | |
| 208 | /* |
| 209 | * We just consumed the 'L' that introduces a class name as part |
| 210 | * of a type descriptor, or we are looking for an unadorned class |
| 211 | * name. |
| 212 | */ |
| 213 | |
| 214 | bool sepOrFirst = true; // first character or just encountered a separator. |
| 215 | for (;;) { |
| 216 | u1 c = (u1) *s; |
| 217 | switch (c) { |
| 218 | case '\0': { |
| 219 | /* |
| 220 | * Premature end for a type descriptor, but valid for |
| 221 | * a class name as long as we haven't encountered an |
| 222 | * empty component (including the degenerate case of |
| 223 | * the empty string ""). |
| 224 | */ |
| 225 | return isClassName && !sepOrFirst; |
| 226 | } |
| 227 | case ';': { |
| 228 | /* |
| 229 | * Invalid character for a class name, but the |
| 230 | * legitimate end of a type descriptor. In the latter |
| 231 | * case, make sure that this is the end of the string |
| 232 | * and that it doesn't end with an empty component |
| 233 | * (including the degenerate case of "L;"). |
| 234 | */ |
| 235 | return !isClassName && !sepOrFirst && (s[1] == '\0'); |
| 236 | } |
| 237 | case '/': |
| 238 | case '.': { |
| 239 | if (dotSeparator != (c == '.')) { |
| 240 | // The wrong separator character. |
| 241 | return false; |
| 242 | } |
| 243 | if (sepOrFirst) { |
| 244 | // Separator at start or two separators in a row. |
| 245 | return false; |
| 246 | } |
| 247 | sepOrFirst = true; |
| 248 | s++; |
| 249 | break; |
| 250 | } |
| 251 | default: { |
| 252 | if (!dexIsValidMemberNameUtf8(&s)) { |
| 253 | return false; |
| 254 | } |
| 255 | sepOrFirst = false; |
| 256 | break; |
| 257 | } |
| 258 | } |
| 259 | } |
| 260 | } |
| 261 | |
| 262 | /* Return whether the given string is a valid type descriptor. */ |
| 263 | bool dexIsValidTypeDescriptor(const char* s) { |
| 264 | return isValidTypeDescriptorOrClassName(s, false, false); |
| 265 | } |
| 266 | |
| 267 | /* (documented in header) */ |
| 268 | bool dexIsValidClassName(const char* s, bool dotSeparator) { |
| 269 | return isValidTypeDescriptorOrClassName(s, true, dotSeparator); |
| 270 | } |
| 271 | |
| 272 | /* Return whether the given string is a valid reference descriptor. This |
| 273 | * is true if dexIsValidTypeDescriptor() returns true and the descriptor |
| 274 | * is for a class or array and not a primitive type. */ |
| 275 | bool dexIsReferenceDescriptor(const char* s) { |
| 276 | if (!dexIsValidTypeDescriptor(s)) { |
| 277 | return false; |
| 278 | } |
| 279 | |
| 280 | return (s[0] == 'L') || (s[0] == '['); |
| 281 | } |
| 282 | |
| 283 | /* Return whether the given string is a valid class descriptor. This |
| 284 | * is true if dexIsValidTypeDescriptor() returns true and the descriptor |
| 285 | * is for a class and not an array or primitive type. */ |
| 286 | bool dexIsClassDescriptor(const char* s) { |
| 287 | if (!dexIsValidTypeDescriptor(s)) { |
| 288 | return false; |
| 289 | } |
| 290 | |
| 291 | return s[0] == 'L'; |
| 292 | } |
| 293 | |
| 294 | /* Return whether the given string is a valid field type descriptor. This |
| 295 | * is true if dexIsValidTypeDescriptor() returns true and the descriptor |
| 296 | * is for anything but "void". */ |
| 297 | bool dexIsFieldDescriptor(const char* s) { |
| 298 | if (!dexIsValidTypeDescriptor(s)) { |
| 299 | return false; |
| 300 | } |
| 301 | |
| 302 | return s[0] != 'V'; |
| 303 | } |
| 304 | |