1 #include <darwintest.h> 2 #include <stdio.h> 3 #include <stdlib.h> 4 #include <string.h> 5 #include <sys/mman.h> 6 #include <mach/machine/vm_param.h> 7 8 static inline unsigned char * 9 get_guarded_page(void) 10 { 11 unsigned char *p = mmap(NULL, 3 * PAGE_SIZE, PROT_NONE, MAP_SHARED | MAP_ANON, 0, 0); 12 p += PAGE_SIZE; 13 mprotect(p, PAGE_SIZE, PROT_READ | PROT_WRITE); 14 return p; 15 } 16 17 static inline void 18 free_guarded_page(unsigned char *p) 19 { 20 munmap(p - PAGE_SIZE, 3 * PAGE_SIZE); 21 } 22 23 /* memcmp_zero_ptr_aligned() checks string s of n bytes contains all zeros. 24 * Address and size of the string s must be pointer-aligned. 25 * Return 0 if true, 1 otherwise. Also return 0 if n is 0. 26 */ 27 extern int 28 memcmp_zero_ptr_aligned(const void *s, size_t n); 29 30 T_DECL(memcmp_zero, "memcmp_zero") 31 { 32 // the assembly version is for the kernel and doesn't support arm64_32 33 #if defined(__arm64__) && __LP64__ 34 unsigned char *buffer = get_guarded_page(); 35 unsigned char *right = buffer + PAGE_SIZE - 512; 36 const int ptr_size = sizeof(buffer); 37 38 for (size_t i = 0; i < 256; i += ptr_size) { 39 for (size_t j = i; j < 256; ++j) { 40 for (size_t k = 0; k < 256; ++k) { 41 if (k < i) { 42 buffer[k] = (unsigned char)rand(); 43 } else if (k < j) { 44 buffer[k] = '\0'; 45 } else if (k == j) { 46 do { 47 buffer[k] = (unsigned char)rand(); 48 } while (!buffer[k]); 49 } else { 50 buffer[k] = '\0'; 51 } 52 } 53 for (size_t m = 0; m < 128; m += ptr_size) { 54 int result = memcmp_zero_ptr_aligned(&buffer[i], m); 55 int ref = j - i < m ? 1 : 0; 56 T_QUIET; T_ASSERT_EQ(result, ref, "expected %d, saw %d\n" 57 "memcmp_zero_ptr_aligned(buf[%zd], %zd)\n", 58 ref, result, i, m); 59 } 60 61 62 for (size_t k = 0; k < 256; ++k) { 63 if (k < i) { 64 right[k] = (unsigned char)rand(); 65 } else if (k < j) { 66 right[k] = '\0'; 67 } else if (k == j) { 68 do { 69 right[k] = (unsigned char)rand(); 70 } while (!right[k]); 71 } else { 72 right[k] = '\0'; 73 } 74 } 75 for (size_t m = 0; m < 256; m += ptr_size) { 76 int result = memcmp_zero_ptr_aligned(&right[i], m); 77 int ref = j - i < m ? 1 : 0; 78 T_QUIET; T_ASSERT_EQ(result, ref, "expected %d, saw %d\n" 79 "memcmp_zero_ptr_aligned(buf[%zd], %zd)\n", 80 ref, result, i, m); 81 } 82 } 83 } 84 85 T_PASS("success"); 86 87 free_guarded_page(buffer); 88 #else 89 T_SKIP("no optimized version to test"); 90 #endif 91 } 92