1 /* 2 * Copyright (c) 2010 Philip Guenther <guenther@openbsd.org> 3 * 4 * Public domain. 5 * 6 * Verify that mkstemp() and mkstemps() doesn't overrun or underrun 7 * the template buffer and that it can generate names that don't 8 * contain any X's 9 */ 10 11 #include <sys/param.h> 12 13 #include <err.h> 14 #include <stdio.h> 15 #include <stdlib.h> 16 #include <string.h> 17 #include <sys/mman.h> 18 #include <sys/stat.h> 19 #include <unistd.h> 20 21 #define MAX_TEMPLATE_LEN 10 22 #define MAX_TRIES 100 23 24 #define SUFFIX ".suff" 25 #define SLEN (sizeof SUFFIX - 1) 26 27 long pg; 28 29 /* 30 * verify that a path generated by mkstemp() or mkstemp() looks like a 31 * reasonable expansion of the template and matches the fd. Returns true 32 * if all the X's were replaced with non-X's 33 */ 34 int 35 check(int fd, char const *path, char const *prefix, size_t plen, 36 char const *suffix, size_t slen, int tlen) 37 { 38 struct stat sb, fsb; 39 char const *p; 40 41 if (fd < 0) 42 err(1, "mkstemp"); 43 if (stat(path, &sb)) 44 err(1, "stat(%s)", path); 45 if (fstat(fd, &fsb)) 46 err(1, "fstat(%d==%s)", fd, path); 47 if (sb.st_dev != fsb.st_dev || sb.st_ino != fsb.st_ino) 48 errx(1, "stat mismatch"); 49 close(fd); 50 if (memcmp(path, prefix, plen) != 0) 51 errx(1, "prefix changed! %s vs %s", prefix, path); 52 if (memcmp(path + plen + tlen, suffix, slen + 1) != 0) 53 errx(1, "suffix changed! %s vs %s", suffix, path); 54 for (p = path + plen; p < path + plen + tlen; p++) 55 if (*p == '\0') 56 errx(1, "unexpected truncation"); 57 else if (*p == 'X') 58 return 0; 59 return 1; 60 } 61 62 63 void 64 try_mkstemp(char *p, char const *prefix, int len) 65 { 66 char *q; 67 size_t plen = strlen(prefix); 68 int tries, fd; 69 70 for (tries = 0; tries < MAX_TRIES; tries++) { 71 memcpy(p, prefix, plen); 72 memset(p + plen, 'X', len); 73 p[plen + len] = '\0'; 74 fd = mkstemp(p); 75 if (check(fd, p, prefix, plen, "", 0, len)) 76 return; 77 } 78 errx(1, "exceeded MAX_TRIES"); 79 } 80 81 void 82 try_mkstemps(char *p, char const *prefix, int len, char const *suffix) 83 { 84 char *q; 85 size_t plen = strlen(prefix); 86 size_t slen = strlen(suffix); 87 int tries, fd; 88 89 for (tries = 0; tries < MAX_TRIES; tries++) { 90 memcpy(p, prefix, plen); 91 memset(p + plen, 'X', len); 92 memcpy(p + plen + len, suffix, slen + 1); 93 fd = mkstemps(p, slen); 94 if (check(fd, p, prefix, plen, suffix, slen, len)) 95 return; 96 } 97 errx(1, "exceeded MAX_TRIES"); 98 } 99 100 int 101 main(void) 102 { 103 struct stat sb, fsb; 104 char cwd[MAXPATHLEN + 1]; 105 char *p; 106 size_t clen; 107 int i; 108 109 pg = sysconf(_SC_PAGESIZE); 110 if (getcwd(cwd, sizeof cwd - 1) == NULL) 111 err(1, "getcwd"); 112 clen = strlen(cwd); 113 cwd[clen++] = '/'; 114 cwd[clen] = '\0'; 115 p = mmap(NULL, pg * 3, PROT_READ | PROT_WRITE, MAP_ANON, -1, 0); 116 if (p == NULL) 117 err(1, "mmap"); 118 if (mprotect(p, pg, PROT_NONE) || mprotect(p + pg * 2, pg, PROT_NONE)) 119 err(1, "mprotect"); 120 p += pg; 121 122 i = MAX_TEMPLATE_LEN + 1; 123 while (i-- > 1) { 124 /* try first at the start of a page, no prefix */ 125 try_mkstemp(p, "", i); 126 /* now at the end of the page, no prefix */ 127 try_mkstemp(p + pg - i - 1, "", i); 128 /* start of the page, prefixed with the cwd */ 129 try_mkstemp(p, cwd, i); 130 /* how about at the end of the page, prefixed with cwd? */ 131 try_mkstemp(p + pg - clen - i - 1, cwd, i); 132 133 /* again, with mkstemps() and an empty suffix */ 134 /* try first at the start of a page, no prefix */ 135 try_mkstemps(p, "", i, ""); 136 /* now at the end of the page, no prefix */ 137 try_mkstemps(p + pg - i - 1, "", i, ""); 138 /* start of the page, prefixed with the cwd */ 139 try_mkstemps(p, cwd, i, ""); 140 /* how about at the end of the page, prefixed with cwd? */ 141 try_mkstemps(p + pg - clen - i - 1, cwd, i, ""); 142 143 /* mkstemps() and a non-empty suffix */ 144 /* try first at the start of a page, no prefix */ 145 try_mkstemps(p, "", i, SUFFIX); 146 /* now at the end of the page, no prefix */ 147 try_mkstemps(p + pg - i - SLEN - 1, "", i, SUFFIX); 148 /* start of the page, prefixed with the cwd */ 149 try_mkstemps(p, cwd, i, SUFFIX); 150 /* how about at the end of the page, prefixed with cwd? */ 151 try_mkstemps(p + pg - clen - i - SLEN - 1, cwd, i, SUFFIX); 152 153 } 154 155 return 0; 156 } 157