From 798fe42a149cb39158136001d10781007188b7d9 Mon Sep 17 00:00:00 2001 From: John Carr Date: Sun, 23 Feb 1992 12:13:59 +0000 Subject: [PATCH] Major rewrite for a more portable data format git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@2223 dc483132-0cff-0310-8789-dd5450dbe970 --- src/lib/krb5/keytab/file/ktf_util.c | 392 ++++++++++++++++++---------- 1 file changed, 249 insertions(+), 143 deletions(-) diff --git a/src/lib/krb5/keytab/file/ktf_util.c b/src/lib/krb5/keytab/file/ktf_util.c index 3bfbfd8e1..dcc503f41 100644 --- a/src/lib/krb5/keytab/file/ktf_util.c +++ b/src/lib/krb5/keytab/file/ktf_util.c @@ -67,16 +67,9 @@ static char rcsid_ktf_util_c[] = #include "ktfile.h" #include -#ifdef KRB5_USE_INET -#include -#else - #error find some way to use net-byte-order file version numbers. -#endif - -#define KRB5_KT_VNO 0x0501 /* krb5, keytab v 1 */ - -#define xfwrite(a, b, c, d) fwrite((char *)a, b, c, d) -#define xfread(a, b, c, d) fread((char *)a, b, c, d) +/* keytab version 1 didn't do byte swapping correctly; call this version 2 + so old files will be recognized as old instead of badly formatted. */ +#define KRB5_KT_VNO 0x0502 /* krb5, keytab v 2 */ extern int errno; @@ -85,71 +78,87 @@ krb5_ktfileint_open(id, mode) krb5_keytab id; int mode; { + register FILE *fp; krb5_error_code kerror; - krb5_int16 kt_vno = htons(KRB5_KT_VNO); int writevno = 0; +#ifdef POSIX_TYPES + mode_t omask; +#else + int omask; +#endif -#if defined(__STDC__) - KTFILEP(id) = fopen(KTFILENAME(id), - (mode == KRB5_LOCKMODE_EXCLUSIVE) ? "rb+" : "rb"); + /* Make sure nobody else can read the new file. It might be better + to use open with mode 600 followed by fdopen on UNIX systems. */ + omask = umask(066); + +#ifdef ANSI_STDIO + fp = fopen(KTFILENAME(id), + (mode == KRB5_LOCKMODE_EXCLUSIVE) ? "rb+" : "rb"); #else - KTFILEP(id) = fopen(KTFILENAME(id), - (mode == KRB5_LOCKMODE_EXCLUSIVE) ? "r+" : "r"); + fp = fopen(KTFILENAME(id), + (mode == KRB5_LOCKMODE_EXCLUSIVE) ? "r+" : "r"); #endif - if (!KTFILEP(id)) { + if (!fp) { if ((mode == KRB5_LOCKMODE_EXCLUSIVE) && (errno == ENOENT)) { /* try making it first time around */ -#if defined(__STDC__) - KTFILEP(id) = fopen(KTFILENAME(id), "ab+"); +#ifdef ANSI_STDIO + fp = fopen(KTFILENAME(id), "ab+"); #else - KTFILEP(id) = fopen(KTFILENAME(id), "a+"); + fp = fopen(KTFILENAME(id), "a+"); #endif - if (!KTFILEP(id)) + if (!fp) { + (void) umask (omask); return errno; + } writevno = 1; - } else /* some other error */ + } else { /* some other error */ + (void) umask (omask); return errno; + } } - if (kerror = krb5_lock_file(KTFILEP(id), KTFILENAME(id), - mode)) { - (void) fclose(KTFILEP(id)); - KTFILEP(id) = 0; + (void) umask (omask); + + if (kerror = krb5_lock_file(fp, KTFILENAME(id), mode)) { + (void) fclose(fp); return kerror; } - /* assume ANSI or BSD-style stdio */ - setbuf(KTFILEP(id), NULL); /* get the vno and verify it */ if (writevno) { - if (!xfwrite(&kt_vno, sizeof(kt_vno), 1, KTFILEP(id))) { - kerror = errno; - (void) krb5_unlock_file(KTFILEP(id), KTFILENAME(id)); - (void) fclose(KTFILEP(id)); - return kerror; + /* Write a version number, MSB first. */ + if (putc((KRB5_KT_VNO >> 8), fp) == EOF || putc(KRB5_KT_VNO, fp) == EOF) { + (void) krb5_unlock_file(fp, KTFILENAME(id)); + (void) fclose(fp); + return KRB5_KT_IOERR; } } else { - /* gotta verify it instead... */ - if (!xfread(&kt_vno, sizeof(kt_vno), 1, KTFILEP(id))) { - kerror = errno; - (void) krb5_unlock_file(KTFILEP(id), KTFILENAME(id)); - (void) fclose(KTFILEP(id)); + int c1, c2; + + /* Verify version number. */ + c1 = getc(fp); + c2 = getc(fp); + + if (c1 == EOF || c2 == EOF) { + kerror = feof(fp) ? KRB5_KT_END : KRB5_KT_IOERR; + (void) krb5_unlock_file(fp, KTFILENAME(id)); + (void) fclose(fp); return kerror; } - if (kt_vno != ntohs(KRB5_KT_VNO)) { - (void) krb5_unlock_file(KTFILEP(id), KTFILENAME(id)); - (void) fclose(KTFILEP(id)); + if ((c1 << 8) + c2 != KRB5_KT_VNO) { + (void) krb5_unlock_file(fp, KTFILENAME(id)); + (void) fclose(fp); return KRB5_KEYTAB_BADVNO; } } /* seek to the end for writers */ if (mode == KRB5_LOCKMODE_EXCLUSIVE) { - if (fseek(KTFILEP(id), 0, 2)) { - kerror = errno; - (void) krb5_unlock_file(KTFILEP(id), KTFILENAME(id)); - (void) fclose(KTFILEP(id)); - return kerror; + if (fseek(fp, 0, 2)) { + (void) krb5_unlock_file(fp, KTFILENAME(id)); + (void) fclose(fp); + return KRB5_KT_IOERR; } } + KTFILEP(id) = fp; return 0; } @@ -181,65 +190,151 @@ krb5_keytab id; return kerror; } +/* Keytab file format. This is not documented anywhere and is not known + outside this file. + + Each entry in the file contains: + + prinicipal name: + 2 byte count of number of components in name + component: + 2 byte count of number of bytes + data + 1 byte key version number + 2 byte key type + 4 byte key length + key data + + The write file function could do range checking on 2 byte quantities, + but doesn't. Values greater than 2 ^ 15 are unlikely. +*/ + krb5_error_code -krb5_ktfileint_read_entry(id, entrypp) +krb5_ktfileint_read_entry(id, entryp) krb5_keytab id; -krb5_keytab_entry **entrypp; +krb5_keytab_entry **entryp; { - register krb5_keytab_entry *ret_entry; - krb5_int16 count; - krb5_int16 princ_size; - register int i; - - if (!(ret_entry = (krb5_keytab_entry *)calloc(1, sizeof(*ret_entry)))) - return ENOMEM; - - - /* deal with guts of parsing... */ - - /* first, int16 with #princ components */ - if (!xfread(&count, sizeof(count), 1, KTFILEP(id))) - return KRB5_KT_END; - if (!count || (count < 0)) - return KRB5_KT_END; - if (!(ret_entry->principal = (krb5_data **)calloc(count+1, sizeof(krb5_data *)))) - return ENOMEM; - for (i = 0; i < count; i++) { - if (!xfread(&princ_size, sizeof(princ_size), 1, KTFILEP(id))) - return KRB5_KT_END; - if (!princ_size || (princ_size < 0)) - return KRB5_KT_END; - - if (!(ret_entry->principal[i] = (krb5_data *)malloc(sizeof(krb5_data)))) - return ENOMEM; - ret_entry->principal[i]->length = princ_size; - ret_entry->principal[i]->data = malloc(princ_size); - if (!ret_entry->principal[i]->data) - return ENOMEM; - if (!xfread(ret_entry->principal[i]->data, sizeof(char), princ_size, - KTFILEP(id))) - return KRB5_KT_END; + krb5_keytab_entry *entry; + register FILE *fp = KTFILEP(id); + int i; /* index into principal component array; failure cleanup + code uses this to determine how much to free */ + + int count; + int size; + int c1, c2; + krb5_error_code error; + + entry = (krb5_keytab_entry *)malloc (sizeof (krb5_keytab_entry)); + if (entry == 0) + return ENOMEM; + + /* Read a character at a time to avoid any problems with byte order. */ + c1 = getc(fp); + c2 = getc(fp); + if (c1 == EOF || c2 == EOF) + return KRB5_KT_END; + + count = (c1 << 8) + c2; + + if (!(entry->principal = (krb5_data **)malloc((count+1) * sizeof(krb5_data *)))) + return ENOMEM; + + for (i = 0; i < count; i++) + { + krb5_data *princ; + + princ = (krb5_data *)malloc(sizeof (krb5_data)); + if (princ == 0) + { + error = ENOMEM; + goto fail; + } + + c1 = getc(fp); + c2 = getc(fp); + if (c1 == EOF || c2 == EOF) + { + free(princ); + error = KRB5_KT_END; + goto fail; + } + + size = (c1 << 8) + c2; + + princ->length = size; + if ((princ->data = malloc (size)) == 0) + { + free (princ); + error = ENOMEM; + goto fail; + } + if (fread(princ->data, 1, size, fp) != size) + { + free (princ); + free (princ->data); + error = KRB5_KT_END; + goto fail; + } + entry->principal[i] = princ; } - if (!xfread(&ret_entry->vno, sizeof(ret_entry->vno), 1, KTFILEP(id))) - return KRB5_KT_END; - /* key type */ - if (!xfread(&ret_entry->key.keytype, sizeof(ret_entry->key.keytype), 1, - KTFILEP(id))) - return KRB5_KT_END; - /* key contents */ - if (!xfread(&count, sizeof(count), 1, KTFILEP(id))) - return KRB5_KT_END; - if (!count || (count < 0)) - return KRB5_KT_END; - ret_entry->key.length = count; - if (!(ret_entry->key.contents = (krb5_octet *)malloc(count))) - return ENOMEM; - if (!xfread(ret_entry->key.contents, sizeof(krb5_octet), count, - KTFILEP(id))) - return KRB5_KT_END; - - *entrypp = ret_entry; - return 0; + + entry->principal[count] = 0; + + /* key version number: 1 byte */ + c1 = getc(fp); + if (c1 == EOF) + { + error = KRB5_KT_END; + goto fail; + } + entry->vno = c1; + /* keyblock: keytype (2), length (4), contents */ + c1 = getc(fp); + c2 = getc(fp); + if (c1 == EOF || c2 == EOF) + { + error = KRB5_KT_END; + goto fail; + } + entry->key.keytype = (c1 << 8) | c2; + c1 = getc(fp); + c2 = getc(fp); + if (c1 == EOF || c2 == EOF) + { + error = KRB5_KT_END; + goto fail; + } + size = (c1 << 24) + (c2 << 16); + c1 = getc(fp); + c2 = getc(fp); + if (c1 == EOF || c2 == EOF) + { + error = KRB5_KT_END; + goto fail; + } + size += (c1 << 8) + c2; + + entry->key.length = size; + if ((entry->key.contents = (krb5_octet *)malloc(size)) == 0) + { + error = ENOMEM; + goto fail; + } + + if (fread((char *)entry->key.contents, 1, size, fp) != size) + { + free(entry->key.contents); + error = KRB5_KT_END; + goto fail; + } + *entryp = entry; + return 0; + + fail: + while(--i >= 0) + free(entry->principal[i]); + free(entry->principal); + return error; } krb5_error_code @@ -247,51 +342,62 @@ krb5_ktfileint_write_entry(id, entry) krb5_keytab id; krb5_keytab_entry *entry; { - krb5_data **princp; - krb5_int16 count, size; - krb5_error_code retval = 0; - char iobuf[BUFSIZ]; + register FILE *fp = KTFILEP(id); + int count, size; + krb5_error_code retval = 0; + krb5_data **princp; + char c1, c2; - setbuf(KTFILEP(id), iobuf); + /* Do all I/O and check for error once at the end. This function isn't + expensive, and errors should be rare. */ - /* count up principal components */ - for (count = 0, princp = entry->principal; *princp; princp++, count++); + /* count up principal components */ + for (count = 0, princp = entry->principal; *princp; princp++, count++); - if (!xfwrite(&count, sizeof(count), 1, KTFILEP(id))) { - abend: - setbuf(KTFILEP(id), 0); - return KRB5_KT_IOERR; - } + /* 2 byte count of number of components in name, MSB first. */ - for (princp = entry->principal; *princp; princp++) { - size = (*princp)->length; - if (!xfwrite(&size, sizeof(size), 1, KTFILEP(id))) { - goto abend; - } - if (!xfwrite((*princp)->data, sizeof(char), size, KTFILEP(id))) { - goto abend; - } - } - if (!xfwrite(&entry->vno, sizeof(entry->vno), 1, KTFILEP(id))) { - goto abend; - } - if (!xfwrite(&entry->key.keytype, sizeof(entry->key.keytype), 1, - KTFILEP(id))) { - goto abend; - } - size = entry->key.length; - if (!xfwrite(&size, sizeof(size), 1, KTFILEP(id))) { - goto abend; + c2 = count; + c1 = count >> 8; + + putc(c1, fp); + putc(c2, fp); + + for (princp = entry->principal; *princp; princp++) + { + size = (*princp)->length; + + c2 = size; + c1 = size >> 8; + + putc(c1, fp); + putc(c2, fp); + + fwrite((*princp)->data, 1, size, fp); } - if (!xfwrite(entry->key.contents, sizeof(krb5_octet), size, KTFILEP(id))) { - memset(iobuf, 0, sizeof(iobuf)); - setbuf(KTFILEP(id), 0); - return KRB5_KT_IOERR; - } - if (fflush(KTFILEP(id)) == EOF) - retval = errno; - - (void) memset(iobuf, 0, sizeof(iobuf)); - setbuf(KTFILEP(id), 0); - return retval; + /* Version number is one byte. */ + putc(entry->vno, fp); + + /* Key type is 2 bytes. */ + c2 = entry->key.keytype; + c1 = entry->key.keytype >> 8; + + putc(c1, fp); + putc(c2, fp); + + size = entry->key.length; + + c1 = size >> 24; + c2 = size >> 16; + putc(c1, fp); + putc(c2, fp); + c1 = size >> 8; + c2 = size; + putc(c1, fp); + putc(c2, fp); + + fwrite((char *)entry->key.contents, 1, size, fp); + + if (fflush(fp) == EOF || ferror(fp)) + return KRB5_KT_IOERR; + return 0; } -- 2.26.2