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Message-ID: <202203272333.HjJA3Nkg-lkp@intel.com>
Date: Sun, 27 Mar 2022 23:34:20 +0800
From: kernel test robot <lkp@...el.com>
To: Kees Cook <keescook@...omium.org>
Cc: llvm@...ts.linux.dev, kbuild-all@...ts.01.org,
linux-kernel@...r.kernel.org,
Nick Desaulniers <ndesaulniers@...gle.com>
Subject: include/linux/fortify-string.h:336:4: warning: call to
__read_overflow2_field declared with 'warning' attribute: detected read
beyond size of field (2nd parameter); maybe use struct_group()?
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: 281d0c962752fb40866dd8d4cade68656f34bd1f fortify: Add Clang support
date: 6 weeks ago
config: x86_64-randconfig-a001 (https://download.01.org/0day-ci/archive/20220327/202203272333.HjJA3Nkg-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 0f6d9501cf49ce02937099350d08f20c4af86f3d)
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
# https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=281d0c962752fb40866dd8d4cade68656f34bd1f
git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
git fetch --no-tags linus master
git checkout 281d0c962752fb40866dd8d4cade68656f34bd1f
# 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=x86_64 SHELL=/bin/bash fs/cifs/
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@...el.com>
All warnings (new ones prefixed by >>):
In file included from fs/cifs/cifssmb.c:17:
In file included from include/linux/fs.h:6:
In file included from include/linux/wait_bit.h:8:
In file included from include/linux/wait.h:9:
In file included from include/linux/spinlock.h:55:
In file included from include/linux/preempt.h:78:
In file included from arch/x86/include/asm/preempt.h:7:
In file included from include/linux/thread_info.h:60:
In file included from arch/x86/include/asm/thread_info.h:53:
In file included from arch/x86/include/asm/cpufeature.h:5:
In file included from arch/x86/include/asm/processor.h:22:
In file included from arch/x86/include/asm/msr.h:11:
In file included from arch/x86/include/asm/cpumask.h:5:
In file included from include/linux/cpumask.h:12:
In file included from include/linux/bitmap.h:11:
In file included from include/linux/string.h:253:
>> include/linux/fortify-string.h:336:4: warning: call to __read_overflow2_field declared with 'warning' attribute: detected read beyond size of field (2nd parameter); maybe use struct_group()? [-Wattribute-warning]
__read_overflow2_field(q_size_field, size);
^
1 warning generated.
vim +/warning +336 include/linux/fortify-string.h
28e77cc1c06866 Kees Cook 2021-06-16 267
28e77cc1c06866 Kees Cook 2021-06-16 268 /*
28e77cc1c06866 Kees Cook 2021-06-16 269 * __builtin_object_size() must be captured here to avoid evaluating argument
28e77cc1c06866 Kees Cook 2021-06-16 270 * side-effects further into the macro layers.
28e77cc1c06866 Kees Cook 2021-06-16 271 */
28e77cc1c06866 Kees Cook 2021-06-16 272 #define memset(p, c, s) __fortify_memset_chk(p, c, s, \
28e77cc1c06866 Kees Cook 2021-06-16 273 __builtin_object_size(p, 0), __builtin_object_size(p, 1))
a28a6e860c6cf2 Francis Laniel 2021-02-25 274
f68f2ff91512c1 Kees Cook 2021-04-20 275 /*
f68f2ff91512c1 Kees Cook 2021-04-20 276 * To make sure the compiler can enforce protection against buffer overflows,
f68f2ff91512c1 Kees Cook 2021-04-20 277 * memcpy(), memmove(), and memset() must not be used beyond individual
f68f2ff91512c1 Kees Cook 2021-04-20 278 * struct members. If you need to copy across multiple members, please use
f68f2ff91512c1 Kees Cook 2021-04-20 279 * struct_group() to create a named mirror of an anonymous struct union.
f68f2ff91512c1 Kees Cook 2021-04-20 280 * (e.g. see struct sk_buff.) Read overflow checking is currently only
f68f2ff91512c1 Kees Cook 2021-04-20 281 * done when a write overflow is also present, or when building with W=1.
f68f2ff91512c1 Kees Cook 2021-04-20 282 *
f68f2ff91512c1 Kees Cook 2021-04-20 283 * Mitigation coverage matrix
f68f2ff91512c1 Kees Cook 2021-04-20 284 * Bounds checking at:
f68f2ff91512c1 Kees Cook 2021-04-20 285 * +-------+-------+-------+-------+
f68f2ff91512c1 Kees Cook 2021-04-20 286 * | Compile time | Run time |
f68f2ff91512c1 Kees Cook 2021-04-20 287 * memcpy() argument sizes: | write | read | write | read |
f68f2ff91512c1 Kees Cook 2021-04-20 288 * dest source length +-------+-------+-------+-------+
f68f2ff91512c1 Kees Cook 2021-04-20 289 * memcpy(known, known, constant) | y | y | n/a | n/a |
f68f2ff91512c1 Kees Cook 2021-04-20 290 * memcpy(known, unknown, constant) | y | n | n/a | V |
f68f2ff91512c1 Kees Cook 2021-04-20 291 * memcpy(known, known, dynamic) | n | n | B | B |
f68f2ff91512c1 Kees Cook 2021-04-20 292 * memcpy(known, unknown, dynamic) | n | n | B | V |
f68f2ff91512c1 Kees Cook 2021-04-20 293 * memcpy(unknown, known, constant) | n | y | V | n/a |
f68f2ff91512c1 Kees Cook 2021-04-20 294 * memcpy(unknown, unknown, constant) | n | n | V | V |
f68f2ff91512c1 Kees Cook 2021-04-20 295 * memcpy(unknown, known, dynamic) | n | n | V | B |
f68f2ff91512c1 Kees Cook 2021-04-20 296 * memcpy(unknown, unknown, dynamic) | n | n | V | V |
f68f2ff91512c1 Kees Cook 2021-04-20 297 * +-------+-------+-------+-------+
f68f2ff91512c1 Kees Cook 2021-04-20 298 *
f68f2ff91512c1 Kees Cook 2021-04-20 299 * y = perform deterministic compile-time bounds checking
f68f2ff91512c1 Kees Cook 2021-04-20 300 * n = cannot perform deterministic compile-time bounds checking
f68f2ff91512c1 Kees Cook 2021-04-20 301 * n/a = no run-time bounds checking needed since compile-time deterministic
f68f2ff91512c1 Kees Cook 2021-04-20 302 * B = can perform run-time bounds checking (currently unimplemented)
f68f2ff91512c1 Kees Cook 2021-04-20 303 * V = vulnerable to run-time overflow (will need refactoring to solve)
f68f2ff91512c1 Kees Cook 2021-04-20 304 *
f68f2ff91512c1 Kees Cook 2021-04-20 305 */
f68f2ff91512c1 Kees Cook 2021-04-20 306 __FORTIFY_INLINE void fortify_memcpy_chk(__kernel_size_t size,
f68f2ff91512c1 Kees Cook 2021-04-20 307 const size_t p_size,
f68f2ff91512c1 Kees Cook 2021-04-20 308 const size_t q_size,
f68f2ff91512c1 Kees Cook 2021-04-20 309 const size_t p_size_field,
f68f2ff91512c1 Kees Cook 2021-04-20 310 const size_t q_size_field,
f68f2ff91512c1 Kees Cook 2021-04-20 311 const char *func)
a28a6e860c6cf2 Francis Laniel 2021-02-25 312 {
a28a6e860c6cf2 Francis Laniel 2021-02-25 313 if (__builtin_constant_p(size)) {
f68f2ff91512c1 Kees Cook 2021-04-20 314 /*
f68f2ff91512c1 Kees Cook 2021-04-20 315 * Length argument is a constant expression, so we
f68f2ff91512c1 Kees Cook 2021-04-20 316 * can perform compile-time bounds checking where
f68f2ff91512c1 Kees Cook 2021-04-20 317 * buffer sizes are known.
f68f2ff91512c1 Kees Cook 2021-04-20 318 */
f68f2ff91512c1 Kees Cook 2021-04-20 319
f68f2ff91512c1 Kees Cook 2021-04-20 320 /* Error when size is larger than enclosing struct. */
f68f2ff91512c1 Kees Cook 2021-04-20 321 if (p_size > p_size_field && p_size < size)
a28a6e860c6cf2 Francis Laniel 2021-02-25 322 __write_overflow();
f68f2ff91512c1 Kees Cook 2021-04-20 323 if (q_size > q_size_field && q_size < size)
a28a6e860c6cf2 Francis Laniel 2021-02-25 324 __read_overflow2();
f68f2ff91512c1 Kees Cook 2021-04-20 325
f68f2ff91512c1 Kees Cook 2021-04-20 326 /* Warn when write size argument larger than dest field. */
f68f2ff91512c1 Kees Cook 2021-04-20 327 if (p_size_field < size)
f68f2ff91512c1 Kees Cook 2021-04-20 328 __write_overflow_field(p_size_field, size);
f68f2ff91512c1 Kees Cook 2021-04-20 329 /*
f68f2ff91512c1 Kees Cook 2021-04-20 330 * Warn for source field over-read when building with W=1
f68f2ff91512c1 Kees Cook 2021-04-20 331 * or when an over-write happened, so both can be fixed at
f68f2ff91512c1 Kees Cook 2021-04-20 332 * the same time.
f68f2ff91512c1 Kees Cook 2021-04-20 333 */
f68f2ff91512c1 Kees Cook 2021-04-20 334 if ((IS_ENABLED(KBUILD_EXTRA_WARN1) || p_size_field < size) &&
f68f2ff91512c1 Kees Cook 2021-04-20 335 q_size_field < size)
f68f2ff91512c1 Kees Cook 2021-04-20 @336 __read_overflow2_field(q_size_field, size);
a28a6e860c6cf2 Francis Laniel 2021-02-25 337 }
f68f2ff91512c1 Kees Cook 2021-04-20 338 /*
f68f2ff91512c1 Kees Cook 2021-04-20 339 * At this point, length argument may not be a constant expression,
f68f2ff91512c1 Kees Cook 2021-04-20 340 * so run-time bounds checking can be done where buffer sizes are
f68f2ff91512c1 Kees Cook 2021-04-20 341 * known. (This is not an "else" because the above checks may only
f68f2ff91512c1 Kees Cook 2021-04-20 342 * be compile-time warnings, and we want to still warn for run-time
f68f2ff91512c1 Kees Cook 2021-04-20 343 * overflows.)
f68f2ff91512c1 Kees Cook 2021-04-20 344 */
f68f2ff91512c1 Kees Cook 2021-04-20 345
f68f2ff91512c1 Kees Cook 2021-04-20 346 /*
f68f2ff91512c1 Kees Cook 2021-04-20 347 * Always stop accesses beyond the struct that contains the
f68f2ff91512c1 Kees Cook 2021-04-20 348 * field, when the buffer's remaining size is known.
f68f2ff91512c1 Kees Cook 2021-04-20 349 * (The -1 test is to optimize away checks where the buffer
f68f2ff91512c1 Kees Cook 2021-04-20 350 * lengths are unknown.)
f68f2ff91512c1 Kees Cook 2021-04-20 351 */
f68f2ff91512c1 Kees Cook 2021-04-20 352 if ((p_size != (size_t)(-1) && p_size < size) ||
f68f2ff91512c1 Kees Cook 2021-04-20 353 (q_size != (size_t)(-1) && q_size < size))
f68f2ff91512c1 Kees Cook 2021-04-20 354 fortify_panic(func);
a28a6e860c6cf2 Francis Laniel 2021-02-25 355 }
a28a6e860c6cf2 Francis Laniel 2021-02-25 356
:::::: The code at line 336 was first introduced by commit
:::::: f68f2ff91512c199ec24883001245912afc17873 fortify: Detect struct member overflows in memcpy() at compile-time
:::::: TO: Kees Cook <keescook@...omium.org>
:::::: CC: Kees Cook <keescook@...omium.org>
--
0-DAY CI Kernel Test Service
https://01.org/lkp
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