1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_FORTIFY_STRING_H_ 3 #define _LINUX_FORTIFY_STRING_H_ 4 5 #include <linux/bug.h> 6 #include <linux/const.h> 7 #include <linux/limits.h> 8 9 #define __FORTIFY_INLINE extern __always_inline __gnu_inline __overloadable 10 #define __RENAME(x) __asm__(#x) 11 12 void fortify_panic(const char *name) __noreturn __cold; 13 void __read_overflow(void) __compiletime_error("detected read beyond size of object (1st parameter)"); 14 void __read_overflow2(void) __compiletime_error("detected read beyond size of object (2nd parameter)"); 15 void __read_overflow2_field(size_t avail, size_t wanted) __compiletime_warning("detected read beyond size of field (2nd parameter); maybe use struct_group()?"); 16 void __write_overflow(void) __compiletime_error("detected write beyond size of object (1st parameter)"); 17 void __write_overflow_field(size_t avail, size_t wanted) __compiletime_warning("detected write beyond size of field (1st parameter); maybe use struct_group()?"); 18 19 #define __compiletime_strlen(p) \ 20 ({ \ 21 unsigned char *__p = (unsigned char *)(p); \ 22 size_t __ret = SIZE_MAX; \ 23 size_t __p_size = __member_size(p); \ 24 if (__p_size != SIZE_MAX && \ 25 __builtin_constant_p(*__p)) { \ 26 size_t __p_len = __p_size - 1; \ 27 if (__builtin_constant_p(__p[__p_len]) && \ 28 __p[__p_len] == '\0') \ 29 __ret = __builtin_strlen(__p); \ 30 } \ 31 __ret; \ 32 }) 33 34 #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS) 35 extern void *__underlying_memchr(const void *p, int c, __kernel_size_t size) __RENAME(memchr); 36 extern int __underlying_memcmp(const void *p, const void *q, __kernel_size_t size) __RENAME(memcmp); 37 extern void *__underlying_memcpy(void *p, const void *q, __kernel_size_t size) __RENAME(memcpy); 38 extern void *__underlying_memmove(void *p, const void *q, __kernel_size_t size) __RENAME(memmove); 39 extern void *__underlying_memset(void *p, int c, __kernel_size_t size) __RENAME(memset); 40 extern char *__underlying_strcat(char *p, const char *q) __RENAME(strcat); 41 extern char *__underlying_strcpy(char *p, const char *q) __RENAME(strcpy); 42 extern __kernel_size_t __underlying_strlen(const char *p) __RENAME(strlen); 43 extern char *__underlying_strncat(char *p, const char *q, __kernel_size_t count) __RENAME(strncat); 44 extern char *__underlying_strncpy(char *p, const char *q, __kernel_size_t size) __RENAME(strncpy); 45 #else 46 #define __underlying_memchr __builtin_memchr 47 #define __underlying_memcmp __builtin_memcmp 48 #define __underlying_memcpy __builtin_memcpy 49 #define __underlying_memmove __builtin_memmove 50 #define __underlying_memset __builtin_memset 51 #define __underlying_strcat __builtin_strcat 52 #define __underlying_strcpy __builtin_strcpy 53 #define __underlying_strlen __builtin_strlen 54 #define __underlying_strncat __builtin_strncat 55 #define __underlying_strncpy __builtin_strncpy 56 #endif 57 58 /** 59 * unsafe_memcpy - memcpy implementation with no FORTIFY bounds checking 60 * 61 * @dst: Destination memory address to write to 62 * @src: Source memory address to read from 63 * @bytes: How many bytes to write to @dst from @src 64 * @justification: Free-form text or comment describing why the use is needed 65 * 66 * This should be used for corner cases where the compiler cannot do the 67 * right thing, or during transitions between APIs, etc. It should be used 68 * very rarely, and includes a place for justification detailing where bounds 69 * checking has happened, and why existing solutions cannot be employed. 70 */ 71 #define unsafe_memcpy(dst, src, bytes, justification) \ 72 __underlying_memcpy(dst, src, bytes) 73 74 /* 75 * Clang's use of __builtin_*object_size() within inlines needs hinting via 76 * __pass_*object_size(). The preference is to only ever use type 1 (member 77 * size, rather than struct size), but there remain some stragglers using 78 * type 0 that will be converted in the future. 79 */ 80 #define POS __pass_object_size(1) 81 #define POS0 __pass_object_size(0) 82 #define __struct_size(p) __builtin_object_size(p, 0) 83 #define __member_size(p) __builtin_object_size(p, 1) 84 85 #define __compiletime_lessthan(bounds, length) ( \ 86 __builtin_constant_p((bounds) < (length)) && \ 87 (bounds) < (length) \ 88 ) 89 90 /** 91 * strncpy - Copy a string to memory with non-guaranteed NUL padding 92 * 93 * @p: pointer to destination of copy 94 * @q: pointer to NUL-terminated source string to copy 95 * @size: bytes to write at @p 96 * 97 * If strlen(@q) >= @size, the copy of @q will stop after @size bytes, 98 * and @p will NOT be NUL-terminated 99 * 100 * If strlen(@q) < @size, following the copy of @q, trailing NUL bytes 101 * will be written to @p until @size total bytes have been written. 102 * 103 * Do not use this function. While FORTIFY_SOURCE tries to avoid 104 * over-reads of @q, it cannot defend against writing unterminated 105 * results to @p. Using strncpy() remains ambiguous and fragile. 106 * Instead, please choose an alternative, so that the expectation 107 * of @p's contents is unambiguous: 108 * 109 * +--------------------+-----------------+------------+ 110 * | @p needs to be: | padded to @size | not padded | 111 * +====================+=================+============+ 112 * | NUL-terminated | strscpy_pad() | strscpy() | 113 * +--------------------+-----------------+------------+ 114 * | not NUL-terminated | strtomem_pad() | strtomem() | 115 * +--------------------+-----------------+------------+ 116 * 117 * Note strscpy*()'s differing return values for detecting truncation, 118 * and strtomem*()'s expectation that the destination is marked with 119 * __nonstring when it is a character array. 120 * 121 */ 122 __FORTIFY_INLINE __diagnose_as(__builtin_strncpy, 1, 2, 3) 123 char *strncpy(char * const POS p, const char *q, __kernel_size_t size) 124 { 125 size_t p_size = __member_size(p); 126 127 if (__compiletime_lessthan(p_size, size)) 128 __write_overflow(); 129 if (p_size < size) 130 fortify_panic(__func__); 131 return __underlying_strncpy(p, q, size); 132 } 133 134 __FORTIFY_INLINE __diagnose_as(__builtin_strcat, 1, 2) 135 char *strcat(char * const POS p, const char *q) 136 { 137 size_t p_size = __member_size(p); 138 139 if (p_size == SIZE_MAX) 140 return __underlying_strcat(p, q); 141 if (strlcat(p, q, p_size) >= p_size) 142 fortify_panic(__func__); 143 return p; 144 } 145 146 extern __kernel_size_t __real_strnlen(const char *, __kernel_size_t) __RENAME(strnlen); 147 __FORTIFY_INLINE __kernel_size_t strnlen(const char * const POS p, __kernel_size_t maxlen) 148 { 149 size_t p_size = __member_size(p); 150 size_t p_len = __compiletime_strlen(p); 151 size_t ret; 152 153 /* We can take compile-time actions when maxlen is const. */ 154 if (__builtin_constant_p(maxlen) && p_len != SIZE_MAX) { 155 /* If p is const, we can use its compile-time-known len. */ 156 if (maxlen >= p_size) 157 return p_len; 158 } 159 160 /* Do not check characters beyond the end of p. */ 161 ret = __real_strnlen(p, maxlen < p_size ? maxlen : p_size); 162 if (p_size <= ret && maxlen != ret) 163 fortify_panic(__func__); 164 return ret; 165 } 166 167 /* 168 * Defined after fortified strnlen to reuse it. However, it must still be 169 * possible for strlen() to be used on compile-time strings for use in 170 * static initializers (i.e. as a constant expression). 171 */ 172 #define strlen(p) \ 173 __builtin_choose_expr(__is_constexpr(__builtin_strlen(p)), \ 174 __builtin_strlen(p), __fortify_strlen(p)) 175 __FORTIFY_INLINE __diagnose_as(__builtin_strlen, 1) 176 __kernel_size_t __fortify_strlen(const char * const POS p) 177 { 178 __kernel_size_t ret; 179 size_t p_size = __member_size(p); 180 181 /* Give up if we don't know how large p is. */ 182 if (p_size == SIZE_MAX) 183 return __underlying_strlen(p); 184 ret = strnlen(p, p_size); 185 if (p_size <= ret) 186 fortify_panic(__func__); 187 return ret; 188 } 189 190 /* defined after fortified strlen to reuse it */ 191 extern size_t __real_strlcpy(char *, const char *, size_t) __RENAME(strlcpy); 192 __FORTIFY_INLINE size_t strlcpy(char * const POS p, const char * const POS q, size_t size) 193 { 194 size_t p_size = __member_size(p); 195 size_t q_size = __member_size(q); 196 size_t q_len; /* Full count of source string length. */ 197 size_t len; /* Count of characters going into destination. */ 198 199 if (p_size == SIZE_MAX && q_size == SIZE_MAX) 200 return __real_strlcpy(p, q, size); 201 q_len = strlen(q); 202 len = (q_len >= size) ? size - 1 : q_len; 203 if (__builtin_constant_p(size) && __builtin_constant_p(q_len) && size) { 204 /* Write size is always larger than destination. */ 205 if (len >= p_size) 206 __write_overflow(); 207 } 208 if (size) { 209 if (len >= p_size) 210 fortify_panic(__func__); 211 __underlying_memcpy(p, q, len); 212 p[len] = '\0'; 213 } 214 return q_len; 215 } 216 217 /* defined after fortified strnlen to reuse it */ 218 extern ssize_t __real_strscpy(char *, const char *, size_t) __RENAME(strscpy); 219 __FORTIFY_INLINE ssize_t strscpy(char * const POS p, const char * const POS q, size_t size) 220 { 221 size_t len; 222 /* Use string size rather than possible enclosing struct size. */ 223 size_t p_size = __member_size(p); 224 size_t q_size = __member_size(q); 225 226 /* If we cannot get size of p and q default to call strscpy. */ 227 if (p_size == SIZE_MAX && q_size == SIZE_MAX) 228 return __real_strscpy(p, q, size); 229 230 /* 231 * If size can be known at compile time and is greater than 232 * p_size, generate a compile time write overflow error. 233 */ 234 if (__compiletime_lessthan(p_size, size)) 235 __write_overflow(); 236 237 /* 238 * This call protects from read overflow, because len will default to q 239 * length if it smaller than size. 240 */ 241 len = strnlen(q, size); 242 /* 243 * If len equals size, we will copy only size bytes which leads to 244 * -E2BIG being returned. 245 * Otherwise we will copy len + 1 because of the final '\O'. 246 */ 247 len = len == size ? size : len + 1; 248 249 /* 250 * Generate a runtime write overflow error if len is greater than 251 * p_size. 252 */ 253 if (len > p_size) 254 fortify_panic(__func__); 255 256 /* 257 * We can now safely call vanilla strscpy because we are protected from: 258 * 1. Read overflow thanks to call to strnlen(). 259 * 2. Write overflow thanks to above ifs. 260 */ 261 return __real_strscpy(p, q, len); 262 } 263 264 /* defined after fortified strlen and strnlen to reuse them */ 265 __FORTIFY_INLINE __diagnose_as(__builtin_strncat, 1, 2, 3) 266 char *strncat(char * const POS p, const char * const POS q, __kernel_size_t count) 267 { 268 size_t p_len, copy_len; 269 size_t p_size = __member_size(p); 270 size_t q_size = __member_size(q); 271 272 if (p_size == SIZE_MAX && q_size == SIZE_MAX) 273 return __underlying_strncat(p, q, count); 274 p_len = strlen(p); 275 copy_len = strnlen(q, count); 276 if (p_size < p_len + copy_len + 1) 277 fortify_panic(__func__); 278 __underlying_memcpy(p + p_len, q, copy_len); 279 p[p_len + copy_len] = '\0'; 280 return p; 281 } 282 283 __FORTIFY_INLINE void fortify_memset_chk(__kernel_size_t size, 284 const size_t p_size, 285 const size_t p_size_field) 286 { 287 if (__builtin_constant_p(size)) { 288 /* 289 * Length argument is a constant expression, so we 290 * can perform compile-time bounds checking where 291 * buffer sizes are also known at compile time. 292 */ 293 294 /* Error when size is larger than enclosing struct. */ 295 if (__compiletime_lessthan(p_size_field, p_size) && 296 __compiletime_lessthan(p_size, size)) 297 __write_overflow(); 298 299 /* Warn when write size is larger than dest field. */ 300 if (__compiletime_lessthan(p_size_field, size)) 301 __write_overflow_field(p_size_field, size); 302 } 303 /* 304 * At this point, length argument may not be a constant expression, 305 * so run-time bounds checking can be done where buffer sizes are 306 * known. (This is not an "else" because the above checks may only 307 * be compile-time warnings, and we want to still warn for run-time 308 * overflows.) 309 */ 310 311 /* 312 * Always stop accesses beyond the struct that contains the 313 * field, when the buffer's remaining size is known. 314 * (The SIZE_MAX test is to optimize away checks where the buffer 315 * lengths are unknown.) 316 */ 317 if (p_size != SIZE_MAX && p_size < size) 318 fortify_panic("memset"); 319 } 320 321 #define __fortify_memset_chk(p, c, size, p_size, p_size_field) ({ \ 322 size_t __fortify_size = (size_t)(size); \ 323 fortify_memset_chk(__fortify_size, p_size, p_size_field), \ 324 __underlying_memset(p, c, __fortify_size); \ 325 }) 326 327 /* 328 * __struct_size() vs __member_size() must be captured here to avoid 329 * evaluating argument side-effects further into the macro layers. 330 */ 331 #ifndef CONFIG_KMSAN 332 #define memset(p, c, s) __fortify_memset_chk(p, c, s, \ 333 __struct_size(p), __member_size(p)) 334 #endif 335 336 /* 337 * To make sure the compiler can enforce protection against buffer overflows, 338 * memcpy(), memmove(), and memset() must not be used beyond individual 339 * struct members. If you need to copy across multiple members, please use 340 * struct_group() to create a named mirror of an anonymous struct union. 341 * (e.g. see struct sk_buff.) Read overflow checking is currently only 342 * done when a write overflow is also present, or when building with W=1. 343 * 344 * Mitigation coverage matrix 345 * Bounds checking at: 346 * +-------+-------+-------+-------+ 347 * | Compile time | Run time | 348 * memcpy() argument sizes: | write | read | write | read | 349 * dest source length +-------+-------+-------+-------+ 350 * memcpy(known, known, constant) | y | y | n/a | n/a | 351 * memcpy(known, unknown, constant) | y | n | n/a | V | 352 * memcpy(known, known, dynamic) | n | n | B | B | 353 * memcpy(known, unknown, dynamic) | n | n | B | V | 354 * memcpy(unknown, known, constant) | n | y | V | n/a | 355 * memcpy(unknown, unknown, constant) | n | n | V | V | 356 * memcpy(unknown, known, dynamic) | n | n | V | B | 357 * memcpy(unknown, unknown, dynamic) | n | n | V | V | 358 * +-------+-------+-------+-------+ 359 * 360 * y = perform deterministic compile-time bounds checking 361 * n = cannot perform deterministic compile-time bounds checking 362 * n/a = no run-time bounds checking needed since compile-time deterministic 363 * B = can perform run-time bounds checking (currently unimplemented) 364 * V = vulnerable to run-time overflow (will need refactoring to solve) 365 * 366 */ 367 __FORTIFY_INLINE bool fortify_memcpy_chk(__kernel_size_t size, 368 const size_t p_size, 369 const size_t q_size, 370 const size_t p_size_field, 371 const size_t q_size_field, 372 const char *func) 373 { 374 if (__builtin_constant_p(size)) { 375 /* 376 * Length argument is a constant expression, so we 377 * can perform compile-time bounds checking where 378 * buffer sizes are also known at compile time. 379 */ 380 381 /* Error when size is larger than enclosing struct. */ 382 if (__compiletime_lessthan(p_size_field, p_size) && 383 __compiletime_lessthan(p_size, size)) 384 __write_overflow(); 385 if (__compiletime_lessthan(q_size_field, q_size) && 386 __compiletime_lessthan(q_size, size)) 387 __read_overflow2(); 388 389 /* Warn when write size argument larger than dest field. */ 390 if (__compiletime_lessthan(p_size_field, size)) 391 __write_overflow_field(p_size_field, size); 392 /* 393 * Warn for source field over-read when building with W=1 394 * or when an over-write happened, so both can be fixed at 395 * the same time. 396 */ 397 if ((IS_ENABLED(KBUILD_EXTRA_WARN1) || 398 __compiletime_lessthan(p_size_field, size)) && 399 __compiletime_lessthan(q_size_field, size)) 400 __read_overflow2_field(q_size_field, size); 401 } 402 /* 403 * At this point, length argument may not be a constant expression, 404 * so run-time bounds checking can be done where buffer sizes are 405 * known. (This is not an "else" because the above checks may only 406 * be compile-time warnings, and we want to still warn for run-time 407 * overflows.) 408 */ 409 410 /* 411 * Always stop accesses beyond the struct that contains the 412 * field, when the buffer's remaining size is known. 413 * (The SIZE_MAX test is to optimize away checks where the buffer 414 * lengths are unknown.) 415 */ 416 if ((p_size != SIZE_MAX && p_size < size) || 417 (q_size != SIZE_MAX && q_size < size)) 418 fortify_panic(func); 419 420 /* 421 * Warn when writing beyond destination field size. 422 * 423 * We must ignore p_size_field == 0 for existing 0-element 424 * fake flexible arrays, until they are all converted to 425 * proper flexible arrays. 426 * 427 * The implementation of __builtin_*object_size() behaves 428 * like sizeof() when not directly referencing a flexible 429 * array member, which means there will be many bounds checks 430 * that will appear at run-time, without a way for them to be 431 * detected at compile-time (as can be done when the destination 432 * is specifically the flexible array member). 433 * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101832 434 */ 435 if (p_size_field != 0 && p_size_field != SIZE_MAX && 436 p_size != p_size_field && p_size_field < size) 437 return true; 438 439 return false; 440 } 441 442 #define __fortify_memcpy_chk(p, q, size, p_size, q_size, \ 443 p_size_field, q_size_field, op) ({ \ 444 size_t __fortify_size = (size_t)(size); \ 445 WARN_ONCE(fortify_memcpy_chk(__fortify_size, p_size, q_size, \ 446 p_size_field, q_size_field, #op), \ 447 #op ": detected field-spanning write (size %zu) of single %s (size %zu)\n", \ 448 __fortify_size, \ 449 "field \"" #p "\" at " __FILE__ ":" __stringify(__LINE__), \ 450 p_size_field); \ 451 __underlying_##op(p, q, __fortify_size); \ 452 }) 453 454 /* 455 * Notes about compile-time buffer size detection: 456 * 457 * With these types... 458 * 459 * struct middle { 460 * u16 a; 461 * u8 middle_buf[16]; 462 * int b; 463 * }; 464 * struct end { 465 * u16 a; 466 * u8 end_buf[16]; 467 * }; 468 * struct flex { 469 * int a; 470 * u8 flex_buf[]; 471 * }; 472 * 473 * void func(TYPE *ptr) { ... } 474 * 475 * Cases where destination size cannot be currently detected: 476 * - the size of ptr's object (seemingly by design, gcc & clang fail): 477 * __builtin_object_size(ptr, 1) == SIZE_MAX 478 * - the size of flexible arrays in ptr's obj (by design, dynamic size): 479 * __builtin_object_size(ptr->flex_buf, 1) == SIZE_MAX 480 * - the size of ANY array at the end of ptr's obj (gcc and clang bug): 481 * __builtin_object_size(ptr->end_buf, 1) == SIZE_MAX 482 * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101836 483 * 484 * Cases where destination size is currently detected: 485 * - the size of non-array members within ptr's object: 486 * __builtin_object_size(ptr->a, 1) == 2 487 * - the size of non-flexible-array in the middle of ptr's obj: 488 * __builtin_object_size(ptr->middle_buf, 1) == 16 489 * 490 */ 491 492 /* 493 * __struct_size() vs __member_size() must be captured here to avoid 494 * evaluating argument side-effects further into the macro layers. 495 */ 496 #define memcpy(p, q, s) __fortify_memcpy_chk(p, q, s, \ 497 __struct_size(p), __struct_size(q), \ 498 __member_size(p), __member_size(q), \ 499 memcpy) 500 #define memmove(p, q, s) __fortify_memcpy_chk(p, q, s, \ 501 __struct_size(p), __struct_size(q), \ 502 __member_size(p), __member_size(q), \ 503 memmove) 504 505 extern void *__real_memscan(void *, int, __kernel_size_t) __RENAME(memscan); 506 __FORTIFY_INLINE void *memscan(void * const POS0 p, int c, __kernel_size_t size) 507 { 508 size_t p_size = __struct_size(p); 509 510 if (__compiletime_lessthan(p_size, size)) 511 __read_overflow(); 512 if (p_size < size) 513 fortify_panic(__func__); 514 return __real_memscan(p, c, size); 515 } 516 517 __FORTIFY_INLINE __diagnose_as(__builtin_memcmp, 1, 2, 3) 518 int memcmp(const void * const POS0 p, const void * const POS0 q, __kernel_size_t size) 519 { 520 size_t p_size = __struct_size(p); 521 size_t q_size = __struct_size(q); 522 523 if (__builtin_constant_p(size)) { 524 if (__compiletime_lessthan(p_size, size)) 525 __read_overflow(); 526 if (__compiletime_lessthan(q_size, size)) 527 __read_overflow2(); 528 } 529 if (p_size < size || q_size < size) 530 fortify_panic(__func__); 531 return __underlying_memcmp(p, q, size); 532 } 533 534 __FORTIFY_INLINE __diagnose_as(__builtin_memchr, 1, 2, 3) 535 void *memchr(const void * const POS0 p, int c, __kernel_size_t size) 536 { 537 size_t p_size = __struct_size(p); 538 539 if (__compiletime_lessthan(p_size, size)) 540 __read_overflow(); 541 if (p_size < size) 542 fortify_panic(__func__); 543 return __underlying_memchr(p, c, size); 544 } 545 546 void *__real_memchr_inv(const void *s, int c, size_t n) __RENAME(memchr_inv); 547 __FORTIFY_INLINE void *memchr_inv(const void * const POS0 p, int c, size_t size) 548 { 549 size_t p_size = __struct_size(p); 550 551 if (__compiletime_lessthan(p_size, size)) 552 __read_overflow(); 553 if (p_size < size) 554 fortify_panic(__func__); 555 return __real_memchr_inv(p, c, size); 556 } 557 558 extern void *__real_kmemdup(const void *src, size_t len, gfp_t gfp) __RENAME(kmemdup); 559 __FORTIFY_INLINE void *kmemdup(const void * const POS0 p, size_t size, gfp_t gfp) 560 { 561 size_t p_size = __struct_size(p); 562 563 if (__compiletime_lessthan(p_size, size)) 564 __read_overflow(); 565 if (p_size < size) 566 fortify_panic(__func__); 567 return __real_kmemdup(p, size, gfp); 568 } 569 570 /* Defined after fortified strlen to reuse it. */ 571 __FORTIFY_INLINE __diagnose_as(__builtin_strcpy, 1, 2) 572 char *strcpy(char * const POS p, const char * const POS q) 573 { 574 size_t p_size = __member_size(p); 575 size_t q_size = __member_size(q); 576 size_t size; 577 578 /* If neither buffer size is known, immediately give up. */ 579 if (__builtin_constant_p(p_size) && 580 __builtin_constant_p(q_size) && 581 p_size == SIZE_MAX && q_size == SIZE_MAX) 582 return __underlying_strcpy(p, q); 583 size = strlen(q) + 1; 584 /* Compile-time check for const size overflow. */ 585 if (__compiletime_lessthan(p_size, size)) 586 __write_overflow(); 587 /* Run-time check for dynamic size overflow. */ 588 if (p_size < size) 589 fortify_panic(__func__); 590 __underlying_memcpy(p, q, size); 591 return p; 592 } 593 594 /* Don't use these outside the FORITFY_SOURCE implementation */ 595 #undef __underlying_memchr 596 #undef __underlying_memcmp 597 #undef __underlying_strcat 598 #undef __underlying_strcpy 599 #undef __underlying_strlen 600 #undef __underlying_strncat 601 #undef __underlying_strncpy 602 603 #undef POS 604 #undef POS0 605 606 #endif /* _LINUX_FORTIFY_STRING_H_ */ 607