/* * Copyright (c) 2010 Philip Guenther * * Public domain. * * Verify that mkstemp() and mkstemps() doesn't overrun or underrun * the template buffer and that it can generate names that don't * contain any X's */ #include #include #include #include #include #include #include #include #include #include #define MAX_TEMPLATE_LEN 10 #define MAX_TRIES 100 #define MIN_Xs 6 #define SUFFIX ".suff" #define SLEN (sizeof SUFFIX - 1) long pg; /* * verify that a path generated by mkstemp() or mkstemp() looks like a * reasonable expansion of the template and matches the fd. Returns true * if all the X's were replaced with non-X's */ int check(int fd, char const *path, char const *prefix, size_t plen, char const *suffix, size_t slen, int tlen) { struct stat sb, fsb; char const *p; if (tlen < MIN_Xs) { if (fd >= 0) errx(1, "mkstemp(%s) succeed with too few Xs", path); if (errno != EINVAL) err(1, "mkstemp(%s) failed with wrong errno", path); return 1; } if (fd < 0) err(1, "mkstemp(%s)", path); if (stat(path, &sb)) err(1, "stat(%s)", path); if (fstat(fd, &fsb)) err(1, "fstat(%d==%s)", fd, path); if (sb.st_dev != fsb.st_dev || sb.st_ino != fsb.st_ino) errx(1, "stat mismatch"); close(fd); if (memcmp(path, prefix, plen) != 0) errx(1, "prefix changed! %s vs %s", prefix, path); if (memcmp(path + plen + tlen, suffix, slen + 1) != 0) errx(1, "suffix changed! %s vs %s", suffix, path); for (p = path + plen; p < path + plen + tlen; p++) if (*p == '\0') errx(1, "unexpected truncation"); else if (*p == 'X') return 0; return 1; } void try_mkstemp(char *p, char const *prefix, int len) { char *q; size_t plen = strlen(prefix); int tries, fd; for (tries = 0; tries < MAX_TRIES; tries++) { memcpy(p, prefix, plen); memset(p + plen, 'X', len); p[plen + len] = '\0'; fd = mkstemp(p); if (check(fd, p, prefix, plen, "", 0, len)) return; } errx(1, "exceeded MAX_TRIES"); } void try_mkstemps(char *p, char const *prefix, int len, char const *suffix) { char *q; size_t plen = strlen(prefix); size_t slen = strlen(suffix); int tries, fd; for (tries = 0; tries < MAX_TRIES; tries++) { memcpy(p, prefix, plen); memset(p + plen, 'X', len); memcpy(p + plen + len, suffix, slen + 1); fd = mkstemps(p, slen); if (check(fd, p, prefix, plen, suffix, slen, len)) return; } errx(1, "exceeded MAX_TRIES"); } int main(void) { struct stat sb, fsb; char cwd[PATH_MAX + 1]; char *p; size_t clen; int i; pg = sysconf(_SC_PAGESIZE); if (getcwd(cwd, sizeof cwd - 1) == NULL) err(1, "getcwd"); clen = strlen(cwd); cwd[clen++] = '/'; cwd[clen] = '\0'; p = mmap(NULL, pg * 3, PROT_READ | PROT_WRITE, MAP_ANON, -1, 0); if (p == MAP_FAILED) err(1, "mmap"); if (mprotect(p, pg, PROT_NONE) || mprotect(p + pg * 2, pg, PROT_NONE)) err(1, "mprotect"); p += pg; i = MAX_TEMPLATE_LEN + 1; while (i-- > 0) { /* try first at the start of a page, no prefix */ try_mkstemp(p, "", i); /* now at the end of the page, no prefix */ try_mkstemp(p + pg - i - 1, "", i); /* start of the page, prefixed with the cwd */ try_mkstemp(p, cwd, i); /* how about at the end of the page, prefixed with cwd? */ try_mkstemp(p + pg - clen - i - 1, cwd, i); /* again, with mkstemps() and an empty suffix */ /* try first at the start of a page, no prefix */ try_mkstemps(p, "", i, ""); /* now at the end of the page, no prefix */ try_mkstemps(p + pg - i - 1, "", i, ""); /* start of the page, prefixed with the cwd */ try_mkstemps(p, cwd, i, ""); /* how about at the end of the page, prefixed with cwd? */ try_mkstemps(p + pg - clen - i - 1, cwd, i, ""); /* mkstemps() and a non-empty suffix */ /* try first at the start of a page, no prefix */ try_mkstemps(p, "", i, SUFFIX); /* now at the end of the page, no prefix */ try_mkstemps(p + pg - i - SLEN - 1, "", i, SUFFIX); /* start of the page, prefixed with the cwd */ try_mkstemps(p, cwd, i, SUFFIX); /* how about at the end of the page, prefixed with cwd? */ try_mkstemps(p + pg - clen - i - SLEN - 1, cwd, i, SUFFIX); } return 0; }