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Message-ID: <202112080732.rL3hdjwC-lkp@intel.com>
Date: Wed, 8 Dec 2021 08:00:24 +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
Subject: [kees:memcpy/step2/next-20211206 19/19]
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 memcpy/step2/next-20211206
head: 082faead4a3c2e5d9f541f97d8d4d5fa0f88dce0
commit: 082faead4a3c2e5d9f541f97d8d4d5fa0f88dce0 [19/19] fortify: Work around Clang inlining bugs
config: i386-randconfig-a013-20211207 (https://download.01.org/0day-ci/archive/20211208/202112080732.rL3hdjwC-lkp@intel.com/config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 097a1cb1d5ebb3a0ec4bcaed8ba3ff6a8e33c00a)
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/kees/linux.git/commit/?id=082faead4a3c2e5d9f541f97d8d4d5fa0f88dce0
git remote add kees https://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git
git fetch --no-tags kees memcpy/step2/next-20211206
git checkout 082faead4a3c2e5d9f541f97d8d4d5fa0f88dce0
# 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=i386 SHELL=/bin/bash kernel/entry/
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 kernel/entry/common.c:3:
In file included from include/linux/context_tracking.h:5:
In file included from include/linux/sched.h:14:
In file included from include/linux/pid.h:5:
In file included from include/linux/rculist.h:11:
In file included from include/linux/rcupdate.h:27:
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:12:
In file included from arch/x86/include/asm/page.h:14:
In file included from arch/x86/include/asm/page_32.h:35:
In file included from include/linux/string.h:253:
>> 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()? [-Wattribute-warning]
__read_overflow2_field(q_size_field, size);
^
>> 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()? [-Wattribute-warning]
2 warnings generated.
vim +/warning +324 include/linux/fortify-string.h
2fc46de99fed34 Kees Cook 2021-06-16 255
2fc46de99fed34 Kees Cook 2021-06-16 256 /*
2fc46de99fed34 Kees Cook 2021-06-16 257 * __builtin_object_size() must be captured here to avoid evaluating argument
2fc46de99fed34 Kees Cook 2021-06-16 258 * side-effects further into the macro layers.
2fc46de99fed34 Kees Cook 2021-06-16 259 */
2fc46de99fed34 Kees Cook 2021-06-16 260 #define memset(p, c, s) __fortify_memset_chk(p, c, s, \
2fc46de99fed34 Kees Cook 2021-06-16 261 __builtin_object_size(p, 0), __builtin_object_size(p, 1))
a28a6e860c6cf2 Francis Laniel 2021-02-25 262
a91965903a44bf Kees Cook 2021-04-20 263 /*
a91965903a44bf Kees Cook 2021-04-20 264 * To make sure the compiler can enforce protection against buffer overflows,
a91965903a44bf Kees Cook 2021-04-20 265 * memcpy(), memmove(), and memset() must not be used beyond individual
a91965903a44bf Kees Cook 2021-04-20 266 * struct members. If you need to copy across multiple members, please use
a91965903a44bf Kees Cook 2021-04-20 267 * struct_group() to create a named mirror of an anonymous struct union.
a91965903a44bf Kees Cook 2021-04-20 268 * (e.g. see struct sk_buff.)
a91965903a44bf Kees Cook 2021-04-20 269 *
a91965903a44bf Kees Cook 2021-04-20 270 * Mitigation coverage
a91965903a44bf Kees Cook 2021-04-20 271 * Bounds checking at:
a91965903a44bf Kees Cook 2021-04-20 272 * +-------+-------+-------+-------+
a91965903a44bf Kees Cook 2021-04-20 273 * | Compile time | Run time |
a91965903a44bf Kees Cook 2021-04-20 274 * memcpy() argument sizes: | write | read | write | read |
a91965903a44bf Kees Cook 2021-04-20 275 * +-------+-------+-------+-------+
a91965903a44bf Kees Cook 2021-04-20 276 * memcpy(known, known, constant) | y | y | n/a | n/a |
a91965903a44bf Kees Cook 2021-04-20 277 * memcpy(unknown, known, constant) | n | y | V | n/a |
a91965903a44bf Kees Cook 2021-04-20 278 * memcpy(known, unknown, constant) | y | n | n/a | V |
a91965903a44bf Kees Cook 2021-04-20 279 * memcpy(unknown, unknown, constant) | n | n | V | V |
a91965903a44bf Kees Cook 2021-04-20 280 * memcpy(known, known, dynamic) | n | n | b | B |
a91965903a44bf Kees Cook 2021-04-20 281 * memcpy(unknown, known, dynamic) | n | n | V | B |
a91965903a44bf Kees Cook 2021-04-20 282 * memcpy(known, unknown, dynamic) | n | n | b | V |
a91965903a44bf Kees Cook 2021-04-20 283 * memcpy(unknown, unknown, dynamic) | n | n | V | V |
a91965903a44bf Kees Cook 2021-04-20 284 * +-------+-------+-------+-------+
a91965903a44bf Kees Cook 2021-04-20 285 *
a91965903a44bf Kees Cook 2021-04-20 286 * y = deterministic compile-time bounds checking
a91965903a44bf Kees Cook 2021-04-20 287 * n = cannot do deterministic compile-time bounds checking
a91965903a44bf Kees Cook 2021-04-20 288 * n/a = no run-time bounds checking needed since compile-time deterministic
a91965903a44bf Kees Cook 2021-04-20 289 * b = perform run-time bounds checking
a91965903a44bf Kees Cook 2021-04-20 290 * B = can perform run-time bounds checking, but current unenforced
a91965903a44bf Kees Cook 2021-04-20 291 * V = vulnerable to run-time overflow
a91965903a44bf Kees Cook 2021-04-20 292 *
a91965903a44bf Kees Cook 2021-04-20 293 */
a91965903a44bf Kees Cook 2021-04-20 294 __FORTIFY_INLINE void fortify_memcpy_chk(__kernel_size_t size,
a91965903a44bf Kees Cook 2021-04-20 295 const size_t p_size,
a91965903a44bf Kees Cook 2021-04-20 296 const size_t q_size,
a91965903a44bf Kees Cook 2021-04-20 297 const size_t p_size_field,
a91965903a44bf Kees Cook 2021-04-20 298 const size_t q_size_field,
a91965903a44bf 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)) {
a91965903a44bf Kees Cook 2021-04-20 302 /*
a91965903a44bf Kees Cook 2021-04-20 303 * Length argument is a constant expression, so we
a91965903a44bf Kees Cook 2021-04-20 304 * can perform compile-time bounds checking where
a91965903a44bf Kees Cook 2021-04-20 305 * buffer sizes are known.
a91965903a44bf Kees Cook 2021-04-20 306 */
a91965903a44bf Kees Cook 2021-04-20 307
a91965903a44bf Kees Cook 2021-04-20 308 /* Error when size is larger than enclosing struct. */
a91965903a44bf Kees Cook 2021-04-20 309 if (p_size > p_size_field && p_size < size)
a28a6e860c6cf2 Francis Laniel 2021-02-25 310 __write_overflow();
a91965903a44bf Kees Cook 2021-04-20 311 if (q_size > q_size_field && q_size < size)
a28a6e860c6cf2 Francis Laniel 2021-02-25 312 __read_overflow2();
a91965903a44bf Kees Cook 2021-04-20 313
a91965903a44bf Kees Cook 2021-04-20 314 /* Warn when write size argument larger than dest field. */
a91965903a44bf Kees Cook 2021-04-20 315 if (p_size_field < size)
a91965903a44bf Kees Cook 2021-04-20 316 __write_overflow_field(p_size_field, size);
a91965903a44bf Kees Cook 2021-04-20 317 /*
a91965903a44bf Kees Cook 2021-04-20 318 * Warn for source field over-read when building with W=1
a91965903a44bf Kees Cook 2021-04-20 319 * or when an over-write happened, so both can be fixed at
a91965903a44bf Kees Cook 2021-04-20 320 * the same time.
a91965903a44bf Kees Cook 2021-04-20 321 */
a91965903a44bf Kees Cook 2021-04-20 322 if ((IS_ENABLED(KBUILD_EXTRA_WARN1) || p_size_field < size) &&
a91965903a44bf Kees Cook 2021-04-20 323 q_size_field < size)
a91965903a44bf Kees Cook 2021-04-20 @324 __read_overflow2_field(q_size_field, size);
a28a6e860c6cf2 Francis Laniel 2021-02-25 325 }
a91965903a44bf Kees Cook 2021-04-20 326 /*
a91965903a44bf Kees Cook 2021-04-20 327 * At this point, length argument may not be a constant expression,
a91965903a44bf Kees Cook 2021-04-20 328 * so run-time bounds checking can be done where buffer sizes are
a91965903a44bf Kees Cook 2021-04-20 329 * known. (This is not an "else" because the above checks may only
a91965903a44bf Kees Cook 2021-04-20 330 * be compile-time warnings, and we want to still warn for run-time
a91965903a44bf Kees Cook 2021-04-20 331 * overflows.)
a91965903a44bf Kees Cook 2021-04-20 332 */
a91965903a44bf Kees Cook 2021-04-20 333
a91965903a44bf Kees Cook 2021-04-20 334 /*
a91965903a44bf Kees Cook 2021-04-20 335 * Always stop accesses beyond the struct that contains the
a91965903a44bf Kees Cook 2021-04-20 336 * field, when the buffer's remaining size is known.
a91965903a44bf Kees Cook 2021-04-20 337 * (The -1 test is to optimize away checks where the buffer
a91965903a44bf Kees Cook 2021-04-20 338 * lengths are unknown.)
a91965903a44bf Kees Cook 2021-04-20 339 */
a91965903a44bf Kees Cook 2021-04-20 340 if ((p_size != (size_t)(-1) && p_size < size) ||
a91965903a44bf Kees Cook 2021-04-20 341 (q_size != (size_t)(-1) && q_size < size))
a91965903a44bf 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
:::::: a91965903a44bf236856efc7e20c6334c4e07388 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, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
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