Messages in this thread | | | Date | Mon, 28 Mar 2022 00:46:04 +0800 | From | kernel test robot <> | Subject | include/linux/fortify-string.h:275:4: warning: call to '__read_overflow2_field' declared with attribute warning: detected read beyond size of field (2nd parameter); maybe use struct_group()? |
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Hi Kees,
FYI, the error/warning still remains.
tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: f022814633e1c600507b3a99691b4d624c2813f0 commit: f68f2ff91512c199ec24883001245912afc17873 fortify: Detect struct member overflows in memcpy() at compile-time date: 6 weeks ago config: i386-randconfig-a003 (https://download.01.org/0day-ci/archive/20220328/202203280039.25eZrV5Z-lkp@intel.com/config) compiler: gcc-9 (Ubuntu 9.4.0-1ubuntu1~20.04.1) 9.4.0 reproduce (this is a W=1 build): # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f68f2ff91512c199ec24883001245912afc17873 git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git git fetch --no-tags linus master git checkout f68f2ff91512c199ec24883001245912afc17873 # save the config file to linux build tree mkdir build_dir make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash net/
If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp@intel.com>
All warnings (new ones prefixed by >>):
In file included from include/linux/string.h:253, from arch/x86/include/asm/page_32.h:22, from arch/x86/include/asm/page.h:14, from arch/x86/include/asm/processor.h:19, from arch/x86/include/asm/timex.h:5, from include/linux/timex.h:65, from include/linux/time32.h:13, from include/linux/time.h:60, from include/linux/skbuff.h:15, from net/core/flow_dissector.c:3: In function 'fortify_memcpy_chk', inlined from '__skb_flow_dissect' at net/core/flow_dissector.c:1034:3: >> include/linux/fortify-string.h:275:4: warning: call to '__read_overflow2_field' declared with attribute warning: detected read beyond size of field (2nd parameter); maybe use struct_group()? [-Wattribute-warning] 275 | __read_overflow2_field(q_size_field, size); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
vim +/__read_overflow2_field +275 include/linux/fortify-string.h
213 214 /* 215 * To make sure the compiler can enforce protection against buffer overflows, 216 * memcpy(), memmove(), and memset() must not be used beyond individual 217 * struct members. If you need to copy across multiple members, please use 218 * struct_group() to create a named mirror of an anonymous struct union. 219 * (e.g. see struct sk_buff.) Read overflow checking is currently only 220 * done when a write overflow is also present, or when building with W=1. 221 * 222 * Mitigation coverage matrix 223 * Bounds checking at: 224 * +-------+-------+-------+-------+ 225 * | Compile time | Run time | 226 * memcpy() argument sizes: | write | read | write | read | 227 * dest source length +-------+-------+-------+-------+ 228 * memcpy(known, known, constant) | y | y | n/a | n/a | 229 * memcpy(known, unknown, constant) | y | n | n/a | V | 230 * memcpy(known, known, dynamic) | n | n | B | B | 231 * memcpy(known, unknown, dynamic) | n | n | B | V | 232 * memcpy(unknown, known, constant) | n | y | V | n/a | 233 * memcpy(unknown, unknown, constant) | n | n | V | V | 234 * memcpy(unknown, known, dynamic) | n | n | V | B | 235 * memcpy(unknown, unknown, dynamic) | n | n | V | V | 236 * +-------+-------+-------+-------+ 237 * 238 * y = perform deterministic compile-time bounds checking 239 * n = cannot perform deterministic compile-time bounds checking 240 * n/a = no run-time bounds checking needed since compile-time deterministic 241 * B = can perform run-time bounds checking (currently unimplemented) 242 * V = vulnerable to run-time overflow (will need refactoring to solve) 243 * 244 */ 245 __FORTIFY_INLINE void fortify_memcpy_chk(__kernel_size_t size, 246 const size_t p_size, 247 const size_t q_size, 248 const size_t p_size_field, 249 const size_t q_size_field, 250 const char *func) 251 { 252 if (__builtin_constant_p(size)) { 253 /* 254 * Length argument is a constant expression, so we 255 * can perform compile-time bounds checking where 256 * buffer sizes are known. 257 */ 258 259 /* Error when size is larger than enclosing struct. */ 260 if (p_size > p_size_field && p_size < size) 261 __write_overflow(); 262 if (q_size > q_size_field && q_size < size) 263 __read_overflow2(); 264 265 /* Warn when write size argument larger than dest field. */ 266 if (p_size_field < size) 267 __write_overflow_field(p_size_field, size); 268 /* 269 * Warn for source field over-read when building with W=1 270 * or when an over-write happened, so both can be fixed at 271 * the same time. 272 */ 273 if ((IS_ENABLED(KBUILD_EXTRA_WARN1) || p_size_field < size) && 274 q_size_field < size) > 275 __read_overflow2_field(q_size_field, size); 276 } 277 /* 278 * At this point, length argument may not be a constant expression, 279 * so run-time bounds checking can be done where buffer sizes are 280 * known. (This is not an "else" because the above checks may only 281 * be compile-time warnings, and we want to still warn for run-time 282 * overflows.) 283 */ 284 285 /* 286 * Always stop accesses beyond the struct that contains the 287 * field, when the buffer's remaining size is known. 288 * (The -1 test is to optimize away checks where the buffer 289 * lengths are unknown.) 290 */ 291 if ((p_size != (size_t)(-1) && p_size < size) || 292 (q_size != (size_t)(-1) && q_size < size)) 293 fortify_panic(func); 294 } 295
-- 0-DAY CI Kernel Test Service https://01.org/lkp
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