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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 | #ifndef _PKEYS_HELPER_H #define _PKEYS_HELPER_H #define _GNU_SOURCE #include <string.h> #include <stdarg.h> #include <stdio.h> #include <stdint.h> #include <stdbool.h> #include <signal.h> #include <assert.h> #include <stdlib.h> #include <ucontext.h> #include <sys/mman.h> #define NR_PKEYS 16 #define PKRU_BITS_PER_PKEY 2 #ifndef DEBUG_LEVEL #define DEBUG_LEVEL 0 #endif #define DPRINT_IN_SIGNAL_BUF_SIZE 4096 extern int dprint_in_signal; extern char dprint_in_signal_buffer[DPRINT_IN_SIGNAL_BUF_SIZE]; static inline void sigsafe_printf(const char *format, ...) { va_list ap; va_start(ap, format); if (!dprint_in_signal) { vprintf(format, ap); } else { int len = vsnprintf(dprint_in_signal_buffer, DPRINT_IN_SIGNAL_BUF_SIZE, format, ap); /* * len is amount that would have been printed, * but actual write is truncated at BUF_SIZE. */ if (len > DPRINT_IN_SIGNAL_BUF_SIZE) len = DPRINT_IN_SIGNAL_BUF_SIZE; write(1, dprint_in_signal_buffer, len); } va_end(ap); } #define dprintf_level(level, args...) do { \ if (level <= DEBUG_LEVEL) \ sigsafe_printf(args); \ fflush(NULL); \ } while (0) #define dprintf0(args...) dprintf_level(0, args) #define dprintf1(args...) dprintf_level(1, args) #define dprintf2(args...) dprintf_level(2, args) #define dprintf3(args...) dprintf_level(3, args) #define dprintf4(args...) dprintf_level(4, args) extern unsigned int shadow_pkru; static inline unsigned int __rdpkru(void) { unsigned int eax, edx; unsigned int ecx = 0; unsigned int pkru; asm volatile(".byte 0x0f,0x01,0xee\n\t" : "=a" (eax), "=d" (edx) : "c" (ecx)); pkru = eax; return pkru; } static inline unsigned int _rdpkru(int line) { unsigned int pkru = __rdpkru(); dprintf4("rdpkru(line=%d) pkru: %x shadow: %x\n", line, pkru, shadow_pkru); assert(pkru == shadow_pkru); return pkru; } #define rdpkru() _rdpkru(__LINE__) static inline void __wrpkru(unsigned int pkru) { unsigned int eax = pkru; unsigned int ecx = 0; unsigned int edx = 0; dprintf4("%s() changing %08x to %08x\n", __func__, __rdpkru(), pkru); asm volatile(".byte 0x0f,0x01,0xef\n\t" : : "a" (eax), "c" (ecx), "d" (edx)); assert(pkru == __rdpkru()); } static inline void wrpkru(unsigned int pkru) { dprintf4("%s() changing %08x to %08x\n", __func__, __rdpkru(), pkru); /* will do the shadow check for us: */ rdpkru(); __wrpkru(pkru); shadow_pkru = pkru; dprintf4("%s(%08x) pkru: %08x\n", __func__, pkru, __rdpkru()); } /* * These are technically racy. since something could * change PKRU between the read and the write. */ static inline void __pkey_access_allow(int pkey, int do_allow) { unsigned int pkru = rdpkru(); int bit = pkey * 2; if (do_allow) pkru &= (1<<bit); else pkru |= (1<<bit); dprintf4("pkru now: %08x\n", rdpkru()); wrpkru(pkru); } static inline void __pkey_write_allow(int pkey, int do_allow_write) { long pkru = rdpkru(); int bit = pkey * 2 + 1; if (do_allow_write) pkru &= (1<<bit); else pkru |= (1<<bit); wrpkru(pkru); dprintf4("pkru now: %08x\n", rdpkru()); } #define PROT_PKEY0 0x10 /* protection key value (bit 0) */ #define PROT_PKEY1 0x20 /* protection key value (bit 1) */ #define PROT_PKEY2 0x40 /* protection key value (bit 2) */ #define PROT_PKEY3 0x80 /* protection key value (bit 3) */ #define PAGE_SIZE 4096 #define MB (1<<20) static inline void __cpuid(unsigned int *eax, unsigned int *ebx, unsigned int *ecx, unsigned int *edx) { /* ecx is often an input as well as an output. */ asm volatile( "cpuid;" : "=a" (*eax), "=b" (*ebx), "=c" (*ecx), "=d" (*edx) : "0" (*eax), "2" (*ecx)); } /* Intel-defined CPU features, CPUID level 0x00000007:0 (ecx) */ #define X86_FEATURE_PKU (1<<3) /* Protection Keys for Userspace */ #define X86_FEATURE_OSPKE (1<<4) /* OS Protection Keys Enable */ static inline int cpu_has_pku(void) { unsigned int eax; unsigned int ebx; unsigned int ecx; unsigned int edx; eax = 0x7; ecx = 0x0; __cpuid(&eax, &ebx, &ecx, &edx); if (!(ecx & X86_FEATURE_PKU)) { dprintf2("cpu does not have PKU\n"); return 0; } if (!(ecx & X86_FEATURE_OSPKE)) { dprintf2("cpu does not have OSPKE\n"); return 0; } return 1; } #define XSTATE_PKRU_BIT (9) #define XSTATE_PKRU 0x200 int pkru_xstate_offset(void) { unsigned int eax; unsigned int ebx; unsigned int ecx; unsigned int edx; int xstate_offset; int xstate_size; unsigned long XSTATE_CPUID = 0xd; int leaf; /* assume that XSTATE_PKRU is set in XCR0 */ leaf = XSTATE_PKRU_BIT; { eax = XSTATE_CPUID; ecx = leaf; __cpuid(&eax, &ebx, &ecx, &edx); if (leaf == XSTATE_PKRU_BIT) { xstate_offset = ebx; xstate_size = eax; } } if (xstate_size == 0) { printf("could not find size/offset of PKRU in xsave state\n"); return 0; } return xstate_offset; } #endif /* _PKEYS_HELPER_H */ |