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1 : : /**
2 : : * \file common.h
3 : : *
4 : : * \brief Utility macros for internal use in the library
5 : : */
6 : : /*
7 : : * Copyright The Mbed TLS Contributors
8 : : * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
9 : : */
10 : :
11 : : #ifndef MBEDTLS_LIBRARY_COMMON_H
12 : : #define MBEDTLS_LIBRARY_COMMON_H
13 : :
14 : : #include "mbedtls/build_info.h"
15 : : #include "alignment.h"
16 : :
17 : : #include <assert.h>
18 : : #include <stddef.h>
19 : : #include <stdint.h>
20 : : #include <stddef.h>
21 : :
22 : : #if defined(__ARM_NEON)
23 : : #include <arm_neon.h>
24 : : #define MBEDTLS_HAVE_NEON_INTRINSICS
25 : : #elif defined(MBEDTLS_PLATFORM_IS_WINDOWS_ON_ARM64)
26 : : #include <arm64_neon.h>
27 : : #define MBEDTLS_HAVE_NEON_INTRINSICS
28 : : #endif
29 : :
30 : : /** Helper to define a function as static except when building invasive tests.
31 : : *
32 : : * If a function is only used inside its own source file and should be
33 : : * declared `static` to allow the compiler to optimize for code size,
34 : : * but that function has unit tests, define it with
35 : : * ```
36 : : * MBEDTLS_STATIC_TESTABLE int mbedtls_foo(...) { ... }
37 : : * ```
38 : : * and declare it in a header in the `library/` directory with
39 : : * ```
40 : : * #if defined(MBEDTLS_TEST_HOOKS)
41 : : * int mbedtls_foo(...);
42 : : * #endif
43 : : * ```
44 : : */
45 : : #if defined(MBEDTLS_TEST_HOOKS)
46 : : #define MBEDTLS_STATIC_TESTABLE
47 : : #else
48 : : #define MBEDTLS_STATIC_TESTABLE static
49 : : #endif
50 : :
51 : : #if defined(MBEDTLS_TEST_HOOKS)
52 : : extern void (*mbedtls_test_hook_test_fail)(const char *test, int line, const char *file);
53 : : #define MBEDTLS_TEST_HOOK_TEST_ASSERT(TEST) \
54 : : do { \
55 : : if ((!(TEST)) && ((*mbedtls_test_hook_test_fail) != NULL)) \
56 : : { \
57 : : (*mbedtls_test_hook_test_fail)( #TEST, __LINE__, __FILE__); \
58 : : } \
59 : : } while (0)
60 : : #else
61 : : #define MBEDTLS_TEST_HOOK_TEST_ASSERT(TEST)
62 : : #endif /* defined(MBEDTLS_TEST_HOOKS) */
63 : :
64 : : /** \def ARRAY_LENGTH
65 : : * Return the number of elements of a static or stack array.
66 : : *
67 : : * \param array A value of array (not pointer) type.
68 : : *
69 : : * \return The number of elements of the array.
70 : : */
71 : : /* A correct implementation of ARRAY_LENGTH, but which silently gives
72 : : * a nonsensical result if called with a pointer rather than an array. */
73 : : #define ARRAY_LENGTH_UNSAFE(array) \
74 : : (sizeof(array) / sizeof(*(array)))
75 : :
76 : : #if defined(__GNUC__)
77 : : /* Test if arg and &(arg)[0] have the same type. This is true if arg is
78 : : * an array but not if it's a pointer. */
79 : : #define IS_ARRAY_NOT_POINTER(arg) \
80 : : (!__builtin_types_compatible_p(__typeof__(arg), \
81 : : __typeof__(&(arg)[0])))
82 : : /* A compile-time constant with the value 0. If `const_expr` is not a
83 : : * compile-time constant with a nonzero value, cause a compile-time error. */
84 : : #define STATIC_ASSERT_EXPR(const_expr) \
85 : : (0 && sizeof(struct { unsigned int STATIC_ASSERT : 1 - 2 * !(const_expr); }))
86 : :
87 : : /* Return the scalar value `value` (possibly promoted). This is a compile-time
88 : : * constant if `value` is. `condition` must be a compile-time constant.
89 : : * If `condition` is false, arrange to cause a compile-time error. */
90 : : #define STATIC_ASSERT_THEN_RETURN(condition, value) \
91 : : (STATIC_ASSERT_EXPR(condition) ? 0 : (value))
92 : :
93 : : #define ARRAY_LENGTH(array) \
94 : : (STATIC_ASSERT_THEN_RETURN(IS_ARRAY_NOT_POINTER(array), \
95 : : ARRAY_LENGTH_UNSAFE(array)))
96 : :
97 : : #else
98 : : /* If we aren't sure the compiler supports our non-standard tricks,
99 : : * fall back to the unsafe implementation. */
100 : : #define ARRAY_LENGTH(array) ARRAY_LENGTH_UNSAFE(array)
101 : : #endif
102 : : /** Allow library to access its structs' private members.
103 : : *
104 : : * Although structs defined in header files are publicly available,
105 : : * their members are private and should not be accessed by the user.
106 : : */
107 : : #define MBEDTLS_ALLOW_PRIVATE_ACCESS
108 : :
109 : : /**
110 : : * \brief Securely zeroize a buffer then free it.
111 : : *
112 : : * Similar to making consecutive calls to
113 : : * \c mbedtls_platform_zeroize() and \c mbedtls_free(), but has
114 : : * code size savings, and potential for optimisation in the future.
115 : : *
116 : : * Guaranteed to be a no-op if \p buf is \c NULL and \p len is 0.
117 : : *
118 : : * \param buf Buffer to be zeroized then freed.
119 : : * \param len Length of the buffer in bytes
120 : : */
121 : : void mbedtls_zeroize_and_free(void *buf, size_t len);
122 : :
123 : : /** Return an offset into a buffer.
124 : : *
125 : : * This is just the addition of an offset to a pointer, except that this
126 : : * function also accepts an offset of 0 into a buffer whose pointer is null.
127 : : * (`p + n` has undefined behavior when `p` is null, even when `n == 0`.
128 : : * A null pointer is a valid buffer pointer when the size is 0, for example
129 : : * as the result of `malloc(0)` on some platforms.)
130 : : *
131 : : * \param p Pointer to a buffer of at least n bytes.
132 : : * This may be \p NULL if \p n is zero.
133 : : * \param n An offset in bytes.
134 : : * \return Pointer to offset \p n in the buffer \p p.
135 : : * Note that this is only a valid pointer if the size of the
136 : : * buffer is at least \p n + 1.
137 : : */
138 : 0 : static inline unsigned char *mbedtls_buffer_offset(
139 : : unsigned char *p, size_t n)
140 : : {
141 [ # # ]: 0 : return p == NULL ? NULL : p + n;
142 : : }
143 : :
144 : : /** Return an offset into a read-only buffer.
145 : : *
146 : : * Similar to mbedtls_buffer_offset(), but for const pointers.
147 : : *
148 : : * \param p Pointer to a buffer of at least n bytes.
149 : : * This may be \p NULL if \p n is zero.
150 : : * \param n An offset in bytes.
151 : : * \return Pointer to offset \p n in the buffer \p p.
152 : : * Note that this is only a valid pointer if the size of the
153 : : * buffer is at least \p n + 1.
154 : : */
155 : 0 : static inline const unsigned char *mbedtls_buffer_offset_const(
156 : : const unsigned char *p, size_t n)
157 : : {
158 [ # # ]: 0 : return p == NULL ? NULL : p + n;
159 : : }
160 : :
161 : : /* Always inline mbedtls_xor() for similar reasons as mbedtls_xor_no_simd(). */
162 : : #if defined(__IAR_SYSTEMS_ICC__)
163 : : #pragma inline = forced
164 : : #elif defined(__GNUC__)
165 : : __attribute__((always_inline))
166 : : #endif
167 : : /**
168 : : * Perform a fast block XOR operation, such that
169 : : * r[i] = a[i] ^ b[i] where 0 <= i < n
170 : : *
171 : : * \param r Pointer to result (buffer of at least \p n bytes). \p r
172 : : * may be equal to either \p a or \p b, but behaviour when
173 : : * it overlaps in other ways is undefined.
174 : : * \param a Pointer to input (buffer of at least \p n bytes)
175 : : * \param b Pointer to input (buffer of at least \p n bytes)
176 : : * \param n Number of bytes to process.
177 : : *
178 : : * \note Depending on the situation, it may be faster to use either mbedtls_xor() or
179 : : * mbedtls_xor_no_simd() (these are functionally equivalent).
180 : : * If the result is used immediately after the xor operation in non-SIMD code (e.g, in
181 : : * AES-CBC), there may be additional latency to transfer the data from SIMD to scalar
182 : : * registers, and in this case, mbedtls_xor_no_simd() may be faster. In other cases where
183 : : * the result is not used immediately (e.g., in AES-CTR), mbedtls_xor() may be faster.
184 : : * For targets without SIMD support, they will behave the same.
185 : : */
186 : 319 : static inline void mbedtls_xor(unsigned char *r,
187 : : const unsigned char *a,
188 : : const unsigned char *b,
189 : : size_t n)
190 : : {
191 : 319 : size_t i = 0;
192 : : #if defined(MBEDTLS_EFFICIENT_UNALIGNED_ACCESS)
193 : : #if defined(MBEDTLS_HAVE_NEON_INTRINSICS) && \
194 : : (!(defined(MBEDTLS_COMPILER_IS_GCC) && MBEDTLS_GCC_VERSION < 70300))
195 : : /* Old GCC versions generate a warning here, so disable the NEON path for these compilers */
196 : : for (; (i + 16) <= n; i += 16) {
197 : : uint8x16_t v1 = vld1q_u8(a + i);
198 : : uint8x16_t v2 = vld1q_u8(b + i);
199 : : uint8x16_t x = veorq_u8(v1, v2);
200 : : vst1q_u8(r + i, x);
201 : : }
202 : : #if defined(__IAR_SYSTEMS_ICC__)
203 : : /* This if statement helps some compilers (e.g., IAR) optimise out the byte-by-byte tail case
204 : : * where n is a constant multiple of 16.
205 : : * For other compilers (e.g. recent gcc and clang) it makes no difference if n is a compile-time
206 : : * constant, and is a very small perf regression if n is not a compile-time constant. */
207 : : if (n % 16 == 0) {
208 : : return;
209 : : }
210 : : #endif
211 : : #elif defined(MBEDTLS_ARCH_IS_X64) || defined(MBEDTLS_ARCH_IS_ARM64)
212 : : /* This codepath probably only makes sense on architectures with 64-bit registers */
213 : : for (; (i + 8) <= n; i += 8) {
214 : : uint64_t x = mbedtls_get_unaligned_uint64(a + i) ^ mbedtls_get_unaligned_uint64(b + i);
215 : : mbedtls_put_unaligned_uint64(r + i, x);
216 : : }
217 : : #if defined(__IAR_SYSTEMS_ICC__)
218 : : if (n % 8 == 0) {
219 : : return;
220 : : }
221 : : #endif
222 : : #else
223 [ + + + + : 1546 : for (; (i + 4) <= n; i += 4) {
+ + + + ]
224 : 1212 : uint32_t x = mbedtls_get_unaligned_uint32(a + i) ^ mbedtls_get_unaligned_uint32(b + i);
225 : 1212 : mbedtls_put_unaligned_uint32(r + i, x);
226 : : }
227 : : #if defined(__IAR_SYSTEMS_ICC__)
228 : : if (n % 4 == 0) {
229 : : return;
230 : : }
231 : : #endif
232 : : #endif
233 : : #endif
234 [ + + + + : 601 : for (; i < n; i++) {
+ + + + ]
235 : 267 : r[i] = a[i] ^ b[i];
236 : : }
237 : : }
238 : :
239 : : /* Always inline mbedtls_xor_no_simd() as we see significant perf regressions when it does not get
240 : : * inlined (e.g., observed about 3x perf difference in gcm_mult_largetable with gcc 7 - 12) */
241 : : #if defined(__IAR_SYSTEMS_ICC__)
242 : : #pragma inline = forced
243 : : #elif defined(__GNUC__)
244 : : __attribute__((always_inline))
245 : : #endif
246 : : /**
247 : : * Perform a fast block XOR operation, such that
248 : : * r[i] = a[i] ^ b[i] where 0 <= i < n
249 : : *
250 : : * In some situations, this can perform better than mbedtls_xor() (e.g., it's about 5%
251 : : * better in AES-CBC).
252 : : *
253 : : * \param r Pointer to result (buffer of at least \p n bytes). \p r
254 : : * may be equal to either \p a or \p b, but behaviour when
255 : : * it overlaps in other ways is undefined.
256 : : * \param a Pointer to input (buffer of at least \p n bytes)
257 : : * \param b Pointer to input (buffer of at least \p n bytes)
258 : : * \param n Number of bytes to process.
259 : : *
260 : : * \note Depending on the situation, it may be faster to use either mbedtls_xor() or
261 : : * mbedtls_xor_no_simd() (these are functionally equivalent).
262 : : * If the result is used immediately after the xor operation in non-SIMD code (e.g, in
263 : : * AES-CBC), there may be additional latency to transfer the data from SIMD to scalar
264 : : * registers, and in this case, mbedtls_xor_no_simd() may be faster. In other cases where
265 : : * the result is not used immediately (e.g., in AES-CTR), mbedtls_xor() may be faster.
266 : : * For targets without SIMD support, they will behave the same.
267 : : */
268 : : static inline void mbedtls_xor_no_simd(unsigned char *r,
269 : : const unsigned char *a,
270 : : const unsigned char *b,
271 : : size_t n)
272 : : {
273 : : size_t i = 0;
274 : : #if defined(MBEDTLS_EFFICIENT_UNALIGNED_ACCESS)
275 : : #if defined(MBEDTLS_ARCH_IS_X64) || defined(MBEDTLS_ARCH_IS_ARM64)
276 : : /* This codepath probably only makes sense on architectures with 64-bit registers */
277 : : for (; (i + 8) <= n; i += 8) {
278 : : uint64_t x = mbedtls_get_unaligned_uint64(a + i) ^ mbedtls_get_unaligned_uint64(b + i);
279 : : mbedtls_put_unaligned_uint64(r + i, x);
280 : : }
281 : : #if defined(__IAR_SYSTEMS_ICC__)
282 : : /* This if statement helps some compilers (e.g., IAR) optimise out the byte-by-byte tail case
283 : : * where n is a constant multiple of 8.
284 : : * For other compilers (e.g. recent gcc and clang) it makes no difference if n is a compile-time
285 : : * constant, and is a very small perf regression if n is not a compile-time constant. */
286 : : if (n % 8 == 0) {
287 : : return;
288 : : }
289 : : #endif
290 : : #else
291 : : for (; (i + 4) <= n; i += 4) {
292 : : uint32_t x = mbedtls_get_unaligned_uint32(a + i) ^ mbedtls_get_unaligned_uint32(b + i);
293 : : mbedtls_put_unaligned_uint32(r + i, x);
294 : : }
295 : : #if defined(__IAR_SYSTEMS_ICC__)
296 : : if (n % 4 == 0) {
297 : : return;
298 : : }
299 : : #endif
300 : : #endif
301 : : #endif
302 : : for (; i < n; i++) {
303 : : r[i] = a[i] ^ b[i];
304 : : }
305 : : }
306 : :
307 : : /* Fix MSVC C99 compatible issue
308 : : * MSVC support __func__ from visual studio 2015( 1900 )
309 : : * Use MSVC predefine macro to avoid name check fail.
310 : : */
311 : : #if (defined(_MSC_VER) && (_MSC_VER <= 1900))
312 : : #define /*no-check-names*/ __func__ __FUNCTION__
313 : : #endif
314 : :
315 : : /* Define `asm` for compilers which don't define it. */
316 : : /* *INDENT-OFF* */
317 : : #ifndef asm
318 : : #if defined(__IAR_SYSTEMS_ICC__)
319 : : #define asm __asm
320 : : #else
321 : : #define asm __asm__
322 : : #endif
323 : : #endif
324 : : /* *INDENT-ON* */
325 : :
326 : : /*
327 : : * Define the constraint used for read-only pointer operands to aarch64 asm.
328 : : *
329 : : * This is normally the usual "r", but for aarch64_32 (aka ILP32,
330 : : * as found in watchos), "p" is required to avoid warnings from clang.
331 : : *
332 : : * Note that clang does not recognise '+p' or '=p', and armclang
333 : : * does not recognise 'p' at all. Therefore, to update a pointer from
334 : : * aarch64 assembly, it is necessary to use something like:
335 : : *
336 : : * uintptr_t uptr = (uintptr_t) ptr;
337 : : * asm( "ldr x4, [%x0], #8" ... : "+r" (uptr) : : )
338 : : * ptr = (void*) uptr;
339 : : *
340 : : * Note that the "x" in "%x0" is neccessary; writing "%0" will cause warnings.
341 : : */
342 : : #if defined(__aarch64__) && defined(MBEDTLS_HAVE_ASM)
343 : : #if UINTPTR_MAX == 0xfffffffful
344 : : /* ILP32: Specify the pointer operand slightly differently, as per #7787. */
345 : : #define MBEDTLS_ASM_AARCH64_PTR_CONSTRAINT "p"
346 : : #elif UINTPTR_MAX == 0xfffffffffffffffful
347 : : /* Normal case (64-bit pointers): use "r" as the constraint for pointer operands to asm */
348 : : #define MBEDTLS_ASM_AARCH64_PTR_CONSTRAINT "r"
349 : : #else
350 : : #error "Unrecognised pointer size for aarch64"
351 : : #endif
352 : : #endif
353 : :
354 : : /* Always provide a static assert macro, so it can be used unconditionally.
355 : : * It does nothing on systems where we don't know how to define a static assert.
356 : : */
357 : : /* Can't use the C11-style `defined(static_assert)` on FreeBSD, since it
358 : : * defines static_assert even with -std=c99, but then complains about it.
359 : : */
360 : : #if defined(static_assert) && !defined(__FreeBSD__)
361 : : #define MBEDTLS_STATIC_ASSERT(expr, msg) static_assert(expr, msg)
362 : : #else
363 : : /* Make sure `MBEDTLS_STATIC_ASSERT(expr, msg);` is valid both inside and
364 : : * outside a function. We choose a struct declaration, which can be repeated
365 : : * any number of times and does not need a matching definition. */
366 : : #define MBEDTLS_STATIC_ASSERT(expr, msg) \
367 : : struct ISO_C_does_not_allow_extra_semicolon_outside_of_a_function
368 : : #endif
369 : :
370 : : #if defined(__has_builtin)
371 : : #define MBEDTLS_HAS_BUILTIN(x) __has_builtin(x)
372 : : #else
373 : : #define MBEDTLS_HAS_BUILTIN(x) 0
374 : : #endif
375 : :
376 : : /* Define compiler branch hints */
377 : : #if MBEDTLS_HAS_BUILTIN(__builtin_expect)
378 : : #define MBEDTLS_LIKELY(x) __builtin_expect(!!(x), 1)
379 : : #define MBEDTLS_UNLIKELY(x) __builtin_expect(!!(x), 0)
380 : : #else
381 : : #define MBEDTLS_LIKELY(x) x
382 : : #define MBEDTLS_UNLIKELY(x) x
383 : : #endif
384 : :
385 : : /* MBEDTLS_ASSUME may be used to provide additional information to the compiler
386 : : * which can result in smaller code-size. */
387 : : #if MBEDTLS_HAS_BUILTIN(__builtin_assume)
388 : : /* clang provides __builtin_assume */
389 : : #define MBEDTLS_ASSUME(x) __builtin_assume(x)
390 : : #elif MBEDTLS_HAS_BUILTIN(__builtin_unreachable)
391 : : /* gcc and IAR can use __builtin_unreachable */
392 : : #define MBEDTLS_ASSUME(x) do { if (!(x)) __builtin_unreachable(); } while (0)
393 : : #elif defined(_MSC_VER)
394 : : /* Supported by MSVC since VS 2005 */
395 : : #define MBEDTLS_ASSUME(x) __assume(x)
396 : : #else
397 : : #define MBEDTLS_ASSUME(x) do { } while (0)
398 : : #endif
399 : :
400 : : /* For gcc -Os, override with -O2 for a given function.
401 : : *
402 : : * This will not affect behaviour for other optimisation settings, e.g. -O0.
403 : : */
404 : : #if defined(MBEDTLS_COMPILER_IS_GCC) && defined(__OPTIMIZE_SIZE__)
405 : : #define MBEDTLS_OPTIMIZE_FOR_PERFORMANCE __attribute__((optimize("-O2")))
406 : : #else
407 : : #define MBEDTLS_OPTIMIZE_FOR_PERFORMANCE
408 : : #endif
409 : :
410 : : /* Suppress compiler warnings for unused functions and variables. */
411 : : #if !defined(MBEDTLS_MAYBE_UNUSED) && defined(__has_attribute)
412 : : # if __has_attribute(unused)
413 : : # define MBEDTLS_MAYBE_UNUSED __attribute__((unused))
414 : : # endif
415 : : #endif
416 : : #if !defined(MBEDTLS_MAYBE_UNUSED) && defined(__GNUC__)
417 : : # define MBEDTLS_MAYBE_UNUSED __attribute__((unused))
418 : : #endif
419 : : #if !defined(MBEDTLS_MAYBE_UNUSED) && defined(__IAR_SYSTEMS_ICC__) && defined(__VER__)
420 : : /* IAR does support __attribute__((unused)), but only if the -e flag (extended language support)
421 : : * is given; the pragma always works.
422 : : * Unfortunately the pragma affects the rest of the file where it is used, but this is harmless.
423 : : * Check for version 5.2 or later - this pragma may be supported by earlier versions, but I wasn't
424 : : * able to find documentation).
425 : : */
426 : : # if (__VER__ >= 5020000)
427 : : # define MBEDTLS_MAYBE_UNUSED _Pragma("diag_suppress=Pe177")
428 : : # endif
429 : : #endif
430 : : #if !defined(MBEDTLS_MAYBE_UNUSED) && defined(_MSC_VER)
431 : : # define MBEDTLS_MAYBE_UNUSED __pragma(warning(suppress:4189))
432 : : #endif
433 : : #if !defined(MBEDTLS_MAYBE_UNUSED)
434 : : # define MBEDTLS_MAYBE_UNUSED
435 : : #endif
436 : :
437 : : /* GCC >= 15 has a warning 'unterminated-string-initialization' which complains if you initialize
438 : : * a string into an array without space for a terminating NULL character. In some places in the
439 : : * codebase this behaviour is intended, so we add the macro MBEDTLS_ATTRIBUTE_UNTERMINATED_STRING
440 : : * to suppress the warning in these places.
441 : : */
442 : : #if defined(__has_attribute)
443 : : #if __has_attribute(nonstring)
444 : : #define MBEDTLS_HAS_ATTRIBUTE_NONSTRING
445 : : #endif /* __has_attribute(nonstring) */
446 : : #endif /* __has_attribute */
447 : : #if defined(MBEDTLS_HAS_ATTRIBUTE_NONSTRING)
448 : : #define MBEDTLS_ATTRIBUTE_UNTERMINATED_STRING __attribute__((nonstring))
449 : : #else
450 : : #define MBEDTLS_ATTRIBUTE_UNTERMINATED_STRING
451 : : #endif /* MBEDTLS_HAS_ATTRIBUTE_NONSTRING */
452 : :
453 : : #endif /* MBEDTLS_LIBRARY_COMMON_H */
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