[kbuild-all] [kees:for-next/memcpy 9/9] include/linux/fortify-string.h:324:4: warning: call to __read_overflow2_field declared with 'warning' attribute: detected read beyond size of field (2nd parameter); maybe use struct_group()?

tree: https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git for-next/memcpy head: 6303361147fc8984dd259b54c189592cd0551ab6 commit: 6303361147fc8984dd259b54c189592cd0551ab6 [9/9] fortify: Work around Clang inlining bugs config: arm-randconfig-c002-20220124 (https://download.01.org/0day-ci/archive/20220125/202201251831.4t5TPp18-lk...) compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 997e128e2a78f5a5434fc75997441ae1ee76f8a4) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # install arm cross compiling tool for clang build # apt-get install binutils-arm-linux-gnueabi # https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git/commit/?id... git remote add kees https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git git fetch --no-tags kees for-next/memcpy git checkout 6303361147fc8984dd259b54c189592cd0551ab6 # save the config file to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash drivers/net/wireless/ath/ath9k/ If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): In file included from drivers/net/wireless/ath/ath9k/xmit.c:17: In file included from include/linux/dma-mapping.h:6: In file included from include/linux/string.h:253: __read_overflow2_field(q_size_field, size); ^ 2 warnings generated. vim +/warning +324 include/linux/fortify-string.h 6f6f253efa1346 Kees Cook 2021-06-16 255 6f6f253efa1346 Kees Cook 2021-06-16 256 /* 6f6f253efa1346 Kees Cook 2021-06-16 257 * __builtin_object_size() must be captured here to avoid evaluating argument 6f6f253efa1346 Kees Cook 2021-06-16 258 * side-effects further into the macro layers. 6f6f253efa1346 Kees Cook 2021-06-16 259 */ 6f6f253efa1346 Kees Cook 2021-06-16 260 #define memset(p, c, s) __fortify_memset_chk(p, c, s, \ 6f6f253efa1346 Kees Cook 2021-06-16 261 __builtin_object_size(p, 0), __builtin_object_size(p, 1)) a28a6e860c6cf2 Francis Laniel 2021-02-25 262 602670289b69b2 Kees Cook 2021-04-20 263 /* 602670289b69b2 Kees Cook 2021-04-20 264 * To make sure the compiler can enforce protection against buffer overflows, 602670289b69b2 Kees Cook 2021-04-20 265 * memcpy(), memmove(), and memset() must not be used beyond individual 602670289b69b2 Kees Cook 2021-04-20 266 * struct members. If you need to copy across multiple members, please use 602670289b69b2 Kees Cook 2021-04-20 267 * struct_group() to create a named mirror of an anonymous struct union. 602670289b69b2 Kees Cook 2021-04-20 268 * (e.g. see struct sk_buff.) 602670289b69b2 Kees Cook 2021-04-20 269 * 602670289b69b2 Kees Cook 2021-04-20 270 * Mitigation coverage 602670289b69b2 Kees Cook 2021-04-20 271 * Bounds checking at: 602670289b69b2 Kees Cook 2021-04-20 272 * +-------+-------+-------+-------+ 602670289b69b2 Kees Cook 2021-04-20 273 * | Compile time | Run time | 602670289b69b2 Kees Cook 2021-04-20 274 * memcpy() argument sizes: | write | read | write | read | 602670289b69b2 Kees Cook 2021-04-20 275 * +-------+-------+-------+-------+ 602670289b69b2 Kees Cook 2021-04-20 276 * memcpy(known, known, constant) | y | y | n/a | n/a | 602670289b69b2 Kees Cook 2021-04-20 277 * memcpy(unknown, known, constant) | n | y | V | n/a | 602670289b69b2 Kees Cook 2021-04-20 278 * memcpy(known, unknown, constant) | y | n | n/a | V | 602670289b69b2 Kees Cook 2021-04-20 279 * memcpy(unknown, unknown, constant) | n | n | V | V | 602670289b69b2 Kees Cook 2021-04-20 280 * memcpy(known, known, dynamic) | n | n | b | B | 602670289b69b2 Kees Cook 2021-04-20 281 * memcpy(unknown, known, dynamic) | n | n | V | B | 602670289b69b2 Kees Cook 2021-04-20 282 * memcpy(known, unknown, dynamic) | n | n | b | V | 602670289b69b2 Kees Cook 2021-04-20 283 * memcpy(unknown, unknown, dynamic) | n | n | V | V | 602670289b69b2 Kees Cook 2021-04-20 284 * +-------+-------+-------+-------+ 602670289b69b2 Kees Cook 2021-04-20 285 * 602670289b69b2 Kees Cook 2021-04-20 286 * y = deterministic compile-time bounds checking 602670289b69b2 Kees Cook 2021-04-20 287 * n = cannot do deterministic compile-time bounds checking 602670289b69b2 Kees Cook 2021-04-20 288 * n/a = no run-time bounds checking needed since compile-time deterministic 602670289b69b2 Kees Cook 2021-04-20 289 * b = perform run-time bounds checking 602670289b69b2 Kees Cook 2021-04-20 290 * B = can perform run-time bounds checking, but current unenforced 602670289b69b2 Kees Cook 2021-04-20 291 * V = vulnerable to run-time overflow 602670289b69b2 Kees Cook 2021-04-20 292 * 602670289b69b2 Kees Cook 2021-04-20 293 */ 602670289b69b2 Kees Cook 2021-04-20 294 __FORTIFY_INLINE void fortify_memcpy_chk(__kernel_size_t size, 602670289b69b2 Kees Cook 2021-04-20 295 const size_t p_size, 602670289b69b2 Kees Cook 2021-04-20 296 const size_t q_size, 602670289b69b2 Kees Cook 2021-04-20 297 const size_t p_size_field, 602670289b69b2 Kees Cook 2021-04-20 298 const size_t q_size_field, 602670289b69b2 Kees Cook 2021-04-20 299 const char *func) a28a6e860c6cf2 Francis Laniel 2021-02-25 300 { a28a6e860c6cf2 Francis Laniel 2021-02-25 301 if (__builtin_constant_p(size)) { 602670289b69b2 Kees Cook 2021-04-20 302 /* 602670289b69b2 Kees Cook 2021-04-20 303 * Length argument is a constant expression, so we 602670289b69b2 Kees Cook 2021-04-20 304 * can perform compile-time bounds checking where 602670289b69b2 Kees Cook 2021-04-20 305 * buffer sizes are known. 602670289b69b2 Kees Cook 2021-04-20 306 */ 602670289b69b2 Kees Cook 2021-04-20 307 602670289b69b2 Kees Cook 2021-04-20 308 /* Error when size is larger than enclosing struct. */ 602670289b69b2 Kees Cook 2021-04-20 309 if (p_size > p_size_field && p_size < size) a28a6e860c6cf2 Francis Laniel 2021-02-25 310 __write_overflow(); 602670289b69b2 Kees Cook 2021-04-20 311 if (q_size > q_size_field && q_size < size) a28a6e860c6cf2 Francis Laniel 2021-02-25 312 __read_overflow2(); 602670289b69b2 Kees Cook 2021-04-20 313 602670289b69b2 Kees Cook 2021-04-20 314 /* Warn when write size argument larger than dest field. */ 602670289b69b2 Kees Cook 2021-04-20 315 if (p_size_field < size) 602670289b69b2 Kees Cook 2021-04-20 316 __write_overflow_field(p_size_field, size); 602670289b69b2 Kees Cook 2021-04-20 317 /* 602670289b69b2 Kees Cook 2021-04-20 318 * Warn for source field over-read when building with W=1 602670289b69b2 Kees Cook 2021-04-20 319 * or when an over-write happened, so both can be fixed at 602670289b69b2 Kees Cook 2021-04-20 320 * the same time. 602670289b69b2 Kees Cook 2021-04-20 321 */ 602670289b69b2 Kees Cook 2021-04-20 322 if ((IS_ENABLED(KBUILD_EXTRA_WARN1) || p_size_field < size) && 602670289b69b2 Kees Cook 2021-04-20 323 q_size_field < size) 602670289b69b2 Kees Cook 2021-04-20 @324 __read_overflow2_field(q_size_field, size); a28a6e860c6cf2 Francis Laniel 2021-02-25 325 } 602670289b69b2 Kees Cook 2021-04-20 326 /* 602670289b69b2 Kees Cook 2021-04-20 327 * At this point, length argument may not be a constant expression, 602670289b69b2 Kees Cook 2021-04-20 328 * so run-time bounds checking can be done where buffer sizes are 602670289b69b2 Kees Cook 2021-04-20 329 * known. (This is not an "else" because the above checks may only 602670289b69b2 Kees Cook 2021-04-20 330 * be compile-time warnings, and we want to still warn for run-time 602670289b69b2 Kees Cook 2021-04-20 331 * overflows.) 602670289b69b2 Kees Cook 2021-04-20 332 */ 602670289b69b2 Kees Cook 2021-04-20 333 602670289b69b2 Kees Cook 2021-04-20 334 /* 602670289b69b2 Kees Cook 2021-04-20 335 * Always stop accesses beyond the struct that contains the 602670289b69b2 Kees Cook 2021-04-20 336 * field, when the buffer's remaining size is known. 602670289b69b2 Kees Cook 2021-04-20 337 * (The -1 test is to optimize away checks where the buffer 602670289b69b2 Kees Cook 2021-04-20 338 * lengths are unknown.) 602670289b69b2 Kees Cook 2021-04-20 339 */ 602670289b69b2 Kees Cook 2021-04-20 340 if ((p_size != (size_t)(-1) && p_size < size) || 602670289b69b2 Kees Cook 2021-04-20 341 (q_size != (size_t)(-1) && q_size < size)) 602670289b69b2 Kees Cook 2021-04-20 342 fortify_panic(func); a28a6e860c6cf2 Francis Laniel 2021-02-25 343 } a28a6e860c6cf2 Francis Laniel 2021-02-25 344 :::::: The code at line 324 was first introduced by commit :::::: 602670289b69b2fded3a0b2240c4877e3a015ac6 fortify: Detect struct member overflows in memcpy() at compile-time :::::: TO: Kees Cook <keescook(a)chromium.org&gt; :::::: CC: Kees Cook <keescook(a)chromium.org&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org