/* SPDX-License-Identifier: MIT */ /* SPDX-FileCopyrightText: 2022, 2023 Leah Rowe <leah@libreboot.org> */ #include <sys/stat.h> #include <dirent.h> #include <err.h> #include <errno.h> #include <fcntl.h> #include <stdint.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> void openFiles(const char *path); void readGbeFile(void); void cmd_setmac(void); int invalidMacAddress(const char *strMac, uint16_t *mac); uint8_t hextonum(char chs); uint8_t rhex(void); void cmd_dump(void); void showmac(int partnum); void hexdump(int partnum); void cmd_setchecksum(void); void cmd_brick(void); void cmd_copy(void); int validChecksum(int partnum); void xorswap_buf(int partnum); void writeGbeFile(void); #define COMMAND argv[2] #define MAC_ADDRESS argv[3] #define PARTNUM argv[3] #define SIZE_4KB 0x1000 uint16_t buf16[SIZE_4KB], mac[3] = {0, 0, 0}; uint8_t *buf = (uint8_t *) &buf16; size_t nf = 128, gbe[2]; uint8_t nvmPartModified[2] = {0, 0}, skipread[2] = {0, 0}; int endian = 1, flags = O_RDWR, rfd, fd, part, gbeFileModified = 0; const char *strMac = NULL, *strRMac = "??:??:??:??:??:??", *filename = NULL; typedef struct op { char *str; void (*cmd)(void); int args; } op_t; op_t op[] = { { .str = "dump", .cmd = cmd_dump, .args = 3}, { .str = "setmac", .cmd = cmd_setmac, .args = 3}, { .str = "swap", .cmd = writeGbeFile, .args = 3}, { .str = "copy", .cmd = cmd_copy, .args = 4}, { .str = "brick", .cmd = cmd_brick, .args = 4}, { .str = "setchecksum", .cmd = cmd_setchecksum, .args = 4}, }; void (*cmd)(void) = NULL; #define ERR() errno = errno ? errno : ECANCELED #define err_if(x) if (x) err(ERR(), "%s", filename) #define xopen(f,l,p) if (opendir(l) != NULL) err(errno = EISDIR, "%s", l); \ if ((f = open(l, p)) == -1) err(ERR(), "%s", l); \ if (fstat(f, &st) == -1) err(ERR(), "%s", l) #define handle_endianness(r) if (((uint8_t *) &endian)[0] ^ 1) xorswap_buf(r) #define word(pos16, partnum) buf16[pos16 + (partnum << 11)] #define setWord(pos16, p, val16) if ((gbeFileModified = 1) && \ word(pos16, p) != val16) nvmPartModified[p] = 1 | (word(pos16, p) = val16) int main(int argc, char *argv[]) { if (argc < 3) err(errno = ECANCELED, "Too few arguments"); flags = (strcmp(COMMAND, "dump") == 0) ? O_RDONLY : flags; filename = argv[1]; #ifdef __OpenBSD__ err_if(unveil("/dev/urandom", "r") == -1); err_if(unveil(filename, flags == O_RDONLY ? "r" : "rw") == -1); err_if(pledge(flags == O_RDONLY ? "stdio rpath" : "stdio rpath wpath", NULL) == -1); #endif openFiles(filename); #ifdef __OpenBSD__ err_if(pledge("stdio", NULL) == -1); #endif for (int i = 0; i < 6; i++) if (strcmp(COMMAND, op[i].str) == 0) if ((cmd = argc >= op[i].args ? op[i].cmd : NULL)) break; if (cmd == cmd_setmac) strMac = (argc > 3) ? MAC_ADDRESS : strRMac; else if ((cmd != NULL) && (argc > 3)) err_if((errno = (!((part = PARTNUM[0] - '0') == 0 || part == 1)) || PARTNUM[1] ? EINVAL : errno)); err_if((errno = (cmd == NULL) ? EINVAL : errno)); readGbeFile(); (*cmd)(); if ((gbeFileModified) && (flags != O_RDONLY) && (cmd != writeGbeFile)) writeGbeFile(); err_if((errno != 0) && (cmd != cmd_dump)); return errno; } void openFiles(const char *path) { struct stat st; xopen(fd, path, flags); if ((st.st_size != (SIZE_4KB << 1))) err(errno = ECANCELED, "File `%s` not 8KiB", path); xopen(rfd, "/dev/urandom", O_RDONLY); errno = errno != ENOTDIR ? errno : 0; } void readGbeFile(void) { nf = ((cmd == writeGbeFile) || (cmd == cmd_copy)) ? SIZE_4KB : nf; skipread[part ^ 1] = (cmd == cmd_copy) | (cmd == cmd_setchecksum) | (cmd == cmd_brick); gbe[1] = (gbe[0] = (size_t) buf) + SIZE_4KB; for (int p = 0; p < 2; p++) { if (skipread[p]) continue; err_if(pread(fd, (uint8_t *) gbe[p], nf, p << 12) == -1); handle_endianness(p); } } void cmd_setmac(void) { if (invalidMacAddress(strMac, mac)) err(errno = ECANCELED, "Bad MAC address"); for (int partnum = 0; partnum < 2; partnum++) { if (!validChecksum(part = partnum)) continue; for (int w = 0; w < 3; w++) setWord(w, partnum, mac[w]); cmd_setchecksum(); } } int invalidMacAddress(const char *strMac, uint16_t *mac) { uint64_t total = 0; if (strnlen(strMac, 20) == 17) { for (uint8_t h, i = 0; i < 16; i += 3) { if (i != 15) if (strMac[i + 2] != ':') return 1; int byte = i / 3; for (int nib = 0; nib < 2; nib++, total += h) { if ((h = hextonum(strMac[i + nib])) > 15) return 1; if ((byte == 0) && (nib == 1)) if (strMac[i + nib] == '?') h = (h & 0xE) | 2; /* local, unicast */ mac[byte >> 1] |= ((uint16_t ) h) << ((8 * (byte % 2)) + (4 * (nib ^ 1))); } }} return ((total == 0) | (mac[0] & 1)); /* multicast/all-zero banned */ } uint8_t hextonum(char ch) { if ((ch >= '0') && (ch <= '9')) return ch - '0'; else if ((ch >= 'A') && (ch <= 'F')) return ch - 'A' + 10; else if ((ch >= 'a') && (ch <= 'f')) return ch - 'a' + 10; return (ch == '?') ? rhex() : 16; } uint8_t rhex(void) { static uint8_t n = 0, rnum[16]; if (!n) err_if(pread(rfd, (uint8_t *) &rnum, (n = 15) + 1, 0) == -1); return rnum[n--] & 0xf; } void cmd_dump(void) { for (int partnum = 0, numInvalid = 0; partnum < 2; partnum++) { if (!validChecksum(partnum)) ++numInvalid; printf("MAC (part %d): ", partnum); showmac(partnum), hexdump(partnum); errno = ((numInvalid < 2) && (partnum)) ? 0 : errno; } } void showmac(int partnum) { for (int c = 0; c < 3; c++) { uint16_t val16 = word(c, partnum); printf("%02x:%02x", val16 & 0xff, val16 >> 8); printf(c == 2 ? "\n" : ":"); } } void hexdump(int partnum) { for (int row = 0; row < 8; row++) { printf("%07x", row << 4); for (int c = 0; c < 8; c++) { uint16_t val16 = word((row << 3) + c, partnum); printf(" %02x%02x", val16 >> 8, val16 & 0xff); } printf("\n"); } } void cmd_setchecksum(void) { uint16_t val16 = 0; for (int c = 0; c < 0x3F; c++) val16 += word(c, part); setWord(0x3F, part, 0xBABA - val16); } void cmd_brick(void) { if (validChecksum(part)) setWord(0x3F, part, ((word(0x3F, part)) ^ 0xFF)); } void cmd_copy(void) { if ((gbeFileModified = nvmPartModified[part ^ 1] = validChecksum(part))) gbe[part ^ 1] = gbe[part]; /* speedhack: copy ptr, not words */ } int validChecksum(int partnum) { uint16_t total = 0; for(int w = 0; w <= 0x3F; w++) total += word(w, partnum); if (total == 0xBABA) return 1; fprintf(stderr, "WARNING: BAD checksum in part %d\n", partnum); return (errno = ECANCELED) & 0; } void xorswap_buf(int partnum) { uint8_t *n = (uint8_t *) gbe[partnum]; for (size_t w = 0, x = 1; w < nf; w += 2, x += 2) n[w] ^= n[x], n[x] ^= n[w], n[w] ^= n[x]; } void writeGbeFile(void) { errno = 0; err_if((cmd == writeGbeFile) && !(validChecksum(0) || validChecksum(1))); for (int p = 0, x = (cmd == writeGbeFile) ? 1 : 0; p < 2; p++) { if ((!nvmPartModified[p]) && (cmd != writeGbeFile)) continue; handle_endianness(p^x); err_if(pwrite(fd, (uint8_t *) gbe[p^x], nf, p << 12) == -1); } err_if(close(fd) == -1); }