diff options
Diffstat (limited to 'lib/libradius/radlib.c')
-rw-r--r-- | lib/libradius/radlib.c | 864 |
1 files changed, 864 insertions, 0 deletions
diff --git a/lib/libradius/radlib.c b/lib/libradius/radlib.c new file mode 100644 index 0000000..1860fed --- /dev/null +++ b/lib/libradius/radlib.c @@ -0,0 +1,864 @@ +/*- + * Copyright 1998 Juniper Networks, Inc. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + * $FreeBSD$ + */ + +#include <sys/types.h> +#include <sys/socket.h> +#include <sys/time.h> +#include <netinet/in.h> +#include <arpa/inet.h> + +#include <errno.h> +#include <md5.h> +#include <netdb.h> +#include <stdarg.h> +#include <stddef.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +#include "radlib_private.h" + +static void clear_password(struct rad_handle *); +static void generr(struct rad_handle *, const char *, ...) + __printflike(2, 3); +static void insert_scrambled_password(struct rad_handle *, int); +static void insert_request_authenticator(struct rad_handle *, int); +static int is_valid_response(struct rad_handle *, int, + const struct sockaddr_in *); +static int put_password_attr(struct rad_handle *, int, + const void *, size_t); +static int put_raw_attr(struct rad_handle *, int, + const void *, size_t); +static int split(char *, char *[], int, char *, size_t); + +static void +clear_password(struct rad_handle *h) +{ + if (h->pass_len != 0) { + memset(h->pass, 0, h->pass_len); + h->pass_len = 0; + h->pass_pos = 0; + } +} + +static void +generr(struct rad_handle *h, const char *format, ...) +{ + va_list ap; + + va_start(ap, format); + vsnprintf(h->errmsg, ERRSIZE, format, ap); + va_end(ap); +} + +static void +insert_scrambled_password(struct rad_handle *h, int srv) +{ + MD5_CTX ctx; + unsigned char md5[16]; + const struct rad_server *srvp; + int padded_len; + int pos; + + srvp = &h->servers[srv]; + padded_len = h->pass_len == 0 ? 16 : (h->pass_len+15) & ~0xf; + + memcpy(md5, &h->request[POS_AUTH], LEN_AUTH); + for (pos = 0; pos < padded_len; pos += 16) { + int i; + + /* Calculate the new scrambler */ + MD5Init(&ctx); + MD5Update(&ctx, srvp->secret, strlen(srvp->secret)); + MD5Update(&ctx, md5, 16); + MD5Final(md5, &ctx); + + /* + * Mix in the current chunk of the password, and copy + * the result into the right place in the request. Also + * modify the scrambler in place, since we will use this + * in calculating the scrambler for next time. + */ + for (i = 0; i < 16; i++) + h->request[h->pass_pos + pos + i] = + md5[i] ^= h->pass[pos + i]; + } +} + +static void +insert_request_authenticator(struct rad_handle *h, int srv) +{ + MD5_CTX ctx; + const struct rad_server *srvp; + + srvp = &h->servers[srv]; + + /* Create the request authenticator */ + MD5Init(&ctx); + MD5Update(&ctx, &h->request[POS_CODE], POS_AUTH - POS_CODE); + MD5Update(&ctx, memset(&h->request[POS_AUTH], 0, LEN_AUTH), LEN_AUTH); + MD5Update(&ctx, &h->request[POS_ATTRS], h->req_len - POS_ATTRS); + MD5Update(&ctx, srvp->secret, strlen(srvp->secret)); + MD5Final(&h->request[POS_AUTH], &ctx); +} + +/* + * Return true if the current response is valid for a request to the + * specified server. + */ +static int +is_valid_response(struct rad_handle *h, int srv, + const struct sockaddr_in *from) +{ + MD5_CTX ctx; + unsigned char md5[16]; + const struct rad_server *srvp; + int len; + + srvp = &h->servers[srv]; + + /* Check the source address */ + if (from->sin_family != srvp->addr.sin_family || + from->sin_addr.s_addr != srvp->addr.sin_addr.s_addr || + from->sin_port != srvp->addr.sin_port) + return 0; + + /* Check the message length */ + if (h->resp_len < POS_ATTRS) + return 0; + len = h->response[POS_LENGTH] << 8 | h->response[POS_LENGTH+1]; + if (len > h->resp_len) + return 0; + + /* Check the response authenticator */ + MD5Init(&ctx); + MD5Update(&ctx, &h->response[POS_CODE], POS_AUTH - POS_CODE); + MD5Update(&ctx, &h->request[POS_AUTH], LEN_AUTH); + MD5Update(&ctx, &h->response[POS_ATTRS], len - POS_ATTRS); + MD5Update(&ctx, srvp->secret, strlen(srvp->secret)); + MD5Final(md5, &ctx); + if (memcmp(&h->response[POS_AUTH], md5, sizeof md5) != 0) + return 0; + + return 1; +} + +static int +put_password_attr(struct rad_handle *h, int type, const void *value, size_t len) +{ + int padded_len; + int pad_len; + + if (h->pass_pos != 0) { + generr(h, "Multiple User-Password attributes specified"); + return -1; + } + if (len > PASSSIZE) + len = PASSSIZE; + padded_len = len == 0 ? 16 : (len+15) & ~0xf; + pad_len = padded_len - len; + + /* + * Put in a place-holder attribute containing all zeros, and + * remember where it is so we can fill it in later. + */ + clear_password(h); + put_raw_attr(h, type, h->pass, padded_len); + h->pass_pos = h->req_len - padded_len; + + /* Save the cleartext password, padded as necessary */ + memcpy(h->pass, value, len); + h->pass_len = len; + memset(h->pass + len, 0, pad_len); + return 0; +} + +static int +put_raw_attr(struct rad_handle *h, int type, const void *value, size_t len) +{ + if (len > 253) { + generr(h, "Attribute too long"); + return -1; + } + if (h->req_len + 2 + len > MSGSIZE) { + generr(h, "Maximum message length exceeded"); + return -1; + } + h->request[h->req_len++] = type; + h->request[h->req_len++] = len + 2; + memcpy(&h->request[h->req_len], value, len); + h->req_len += len; + return 0; +} + +int +rad_add_server(struct rad_handle *h, const char *host, int port, + const char *secret, int timeout, int tries) +{ + struct rad_server *srvp; + + if (h->num_servers >= MAXSERVERS) { + generr(h, "Too many RADIUS servers specified"); + return -1; + } + srvp = &h->servers[h->num_servers]; + + memset(&srvp->addr, 0, sizeof srvp->addr); + srvp->addr.sin_len = sizeof srvp->addr; + srvp->addr.sin_family = AF_INET; + if (!inet_aton(host, &srvp->addr.sin_addr)) { + struct hostent *hent; + + if ((hent = gethostbyname(host)) == NULL) { + generr(h, "%s: host not found", host); + return -1; + } + memcpy(&srvp->addr.sin_addr, hent->h_addr, + sizeof srvp->addr.sin_addr); + } + if (port != 0) + srvp->addr.sin_port = htons(port); + else { + struct servent *sent; + + if (h->type == RADIUS_AUTH) + srvp->addr.sin_port = + (sent = getservbyname("radius", "udp")) != NULL ? + sent->s_port : htons(RADIUS_PORT); + else + srvp->addr.sin_port = + (sent = getservbyname("radacct", "udp")) != NULL ? + sent->s_port : htons(RADACCT_PORT); + } + if ((srvp->secret = strdup(secret)) == NULL) { + generr(h, "Out of memory"); + return -1; + } + srvp->timeout = timeout; + srvp->max_tries = tries; + srvp->num_tries = 0; + h->num_servers++; + return 0; +} + +void +rad_close(struct rad_handle *h) +{ + int srv; + + if (h->fd != -1) + close(h->fd); + for (srv = 0; srv < h->num_servers; srv++) { + memset(h->servers[srv].secret, 0, + strlen(h->servers[srv].secret)); + free(h->servers[srv].secret); + } + clear_password(h); + free(h); +} + +int +rad_config(struct rad_handle *h, const char *path) +{ + FILE *fp; + char buf[MAXCONFLINE]; + int linenum; + int retval; + + if (path == NULL) + path = PATH_RADIUS_CONF; + if ((fp = fopen(path, "r")) == NULL) { + generr(h, "Cannot open \"%s\": %s", path, strerror(errno)); + return -1; + } + retval = 0; + linenum = 0; + while (fgets(buf, sizeof buf, fp) != NULL) { + int len; + char *fields[5]; + int nfields; + char msg[ERRSIZE]; + char *type; + char *host; + char *port_str; + char *secret; + char *timeout_str; + char *maxtries_str; + char *end; + char *wanttype; + unsigned long timeout; + unsigned long maxtries; + int port; + int i; + + linenum++; + len = strlen(buf); + /* We know len > 0, else fgets would have returned NULL. */ + if (buf[len - 1] != '\n') { + if (len == sizeof buf - 1) + generr(h, "%s:%d: line too long", path, + linenum); + else + generr(h, "%s:%d: missing newline", path, + linenum); + retval = -1; + break; + } + buf[len - 1] = '\0'; + + /* Extract the fields from the line. */ + nfields = split(buf, fields, 5, msg, sizeof msg); + if (nfields == -1) { + generr(h, "%s:%d: %s", path, linenum, msg); + retval = -1; + break; + } + if (nfields == 0) + continue; + /* + * The first field should contain "auth" or "acct" for + * authentication or accounting, respectively. But older + * versions of the file didn't have that field. Default + * it to "auth" for backward compatibility. + */ + if (strcmp(fields[0], "auth") != 0 && + strcmp(fields[0], "acct") != 0) { + if (nfields >= 5) { + generr(h, "%s:%d: invalid service type", path, + linenum); + retval = -1; + break; + } + nfields++; + for (i = nfields; --i > 0; ) + fields[i] = fields[i - 1]; + fields[0] = "auth"; + } + if (nfields < 3) { + generr(h, "%s:%d: missing shared secret", path, + linenum); + retval = -1; + break; + } + type = fields[0]; + host = fields[1]; + secret = fields[2]; + timeout_str = fields[3]; + maxtries_str = fields[4]; + + /* Ignore the line if it is for the wrong service type. */ + wanttype = h->type == RADIUS_AUTH ? "auth" : "acct"; + if (strcmp(type, wanttype) != 0) + continue; + + /* Parse and validate the fields. */ + host = strtok(host, ":"); + port_str = strtok(NULL, ":"); + if (port_str != NULL) { + port = strtoul(port_str, &end, 10); + if (*end != '\0') { + generr(h, "%s:%d: invalid port", path, + linenum); + retval = -1; + break; + } + } else + port = 0; + if (timeout_str != NULL) { + timeout = strtoul(timeout_str, &end, 10); + if (*end != '\0') { + generr(h, "%s:%d: invalid timeout", path, + linenum); + retval = -1; + break; + } + } else + timeout = TIMEOUT; + if (maxtries_str != NULL) { + maxtries = strtoul(maxtries_str, &end, 10); + if (*end != '\0') { + generr(h, "%s:%d: invalid maxtries", path, + linenum); + retval = -1; + break; + } + } else + maxtries = MAXTRIES; + + if (rad_add_server(h, host, port, secret, timeout, maxtries) == + -1) { + strcpy(msg, h->errmsg); + generr(h, "%s:%d: %s", path, linenum, msg); + retval = -1; + break; + } + } + /* Clear out the buffer to wipe a possible copy of a shared secret */ + memset(buf, 0, sizeof buf); + fclose(fp); + return retval; +} + +/* + * rad_init_send_request() must have previously been called. + * Returns: + * 0 The application should select on *fd with a timeout of tv before + * calling rad_continue_send_request again. + * < 0 Failure + * > 0 Success + */ +int +rad_continue_send_request(struct rad_handle *h, int selected, int *fd, + struct timeval *tv) +{ + int n; + + if (selected) { + struct sockaddr_in from; + int fromlen; + + fromlen = sizeof from; + h->resp_len = recvfrom(h->fd, h->response, + MSGSIZE, MSG_WAITALL, (struct sockaddr *)&from, &fromlen); + if (h->resp_len == -1) { + generr(h, "recvfrom: %s", strerror(errno)); + return -1; + } + if (is_valid_response(h, h->srv, &from)) { + h->resp_len = h->response[POS_LENGTH] << 8 | + h->response[POS_LENGTH+1]; + h->resp_pos = POS_ATTRS; + return h->response[POS_CODE]; + } + } + + if (h->try == h->total_tries) { + generr(h, "No valid RADIUS responses received"); + return -1; + } + + /* + * Scan round-robin to the next server that has some + * tries left. There is guaranteed to be one, or we + * would have exited this loop by now. + */ + while (h->servers[h->srv].num_tries >= h->servers[h->srv].max_tries) + if (++h->srv >= h->num_servers) + h->srv = 0; + + if (h->request[POS_CODE] == RAD_ACCOUNTING_REQUEST) + /* Insert the request authenticator into the request */ + insert_request_authenticator(h, h->srv); + else + /* Insert the scrambled password into the request */ + if (h->pass_pos != 0) + insert_scrambled_password(h, h->srv); + + /* Send the request */ + n = sendto(h->fd, h->request, h->req_len, 0, + (const struct sockaddr *)&h->servers[h->srv].addr, + sizeof h->servers[h->srv].addr); + if (n != h->req_len) { + if (n == -1) + generr(h, "sendto: %s", strerror(errno)); + else + generr(h, "sendto: short write"); + return -1; + } + + h->try++; + h->servers[h->srv].num_tries++; + tv->tv_sec = h->servers[h->srv].timeout; + tv->tv_usec = 0; + *fd = h->fd; + + return 0; +} + +int +rad_create_request(struct rad_handle *h, int code) +{ + int i; + + h->request[POS_CODE] = code; + h->request[POS_IDENT] = ++h->ident; + /* Create a random authenticator */ + for (i = 0; i < LEN_AUTH; i += 2) { + long r; + r = random(); + h->request[POS_AUTH+i] = r; + h->request[POS_AUTH+i+1] = r >> 8; + } + h->req_len = POS_ATTRS; + clear_password(h); + return 0; +} + +struct in_addr +rad_cvt_addr(const void *data) +{ + struct in_addr value; + + memcpy(&value.s_addr, data, sizeof value.s_addr); + return value; +} + +u_int32_t +rad_cvt_int(const void *data) +{ + u_int32_t value; + + memcpy(&value, data, sizeof value); + return ntohl(value); +} + +char * +rad_cvt_string(const void *data, size_t len) +{ + char *s; + + s = malloc(len + 1); + if (s != NULL) { + memcpy(s, data, len); + s[len] = '\0'; + } + return s; +} + +/* + * Returns the attribute type. If none are left, returns 0. On failure, + * returns -1. + */ +int +rad_get_attr(struct rad_handle *h, const void **value, size_t *len) +{ + int type; + + if (h->resp_pos >= h->resp_len) + return 0; + if (h->resp_pos + 2 > h->resp_len) { + generr(h, "Malformed attribute in response"); + return -1; + } + type = h->response[h->resp_pos++]; + *len = h->response[h->resp_pos++] - 2; + if (h->resp_pos + *len > h->resp_len) { + generr(h, "Malformed attribute in response"); + return -1; + } + *value = &h->response[h->resp_pos]; + h->resp_pos += *len; + return type; +} + +/* + * Returns -1 on error, 0 to indicate no event and >0 for success + */ +int +rad_init_send_request(struct rad_handle *h, int *fd, struct timeval *tv) +{ + int srv; + + /* Make sure we have a socket to use */ + if (h->fd == -1) { + struct sockaddr_in sin; + + if ((h->fd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1) { + generr(h, "Cannot create socket: %s", strerror(errno)); + return -1; + } + memset(&sin, 0, sizeof sin); + sin.sin_len = sizeof sin; + sin.sin_family = AF_INET; + sin.sin_addr.s_addr = INADDR_ANY; + sin.sin_port = htons(0); + if (bind(h->fd, (const struct sockaddr *)&sin, + sizeof sin) == -1) { + generr(h, "bind: %s", strerror(errno)); + close(h->fd); + h->fd = -1; + return -1; + } + } + + if (h->request[POS_CODE] == RAD_ACCOUNTING_REQUEST) { + /* Make sure no password given */ + if (h->pass_pos || h->chap_pass) { + generr(h, "User or Chap Password in accounting request"); + return -1; + } + } else { + /* Make sure the user gave us a password */ + if (h->pass_pos == 0 && !h->chap_pass) { + generr(h, "No User or Chap Password attributes given"); + return -1; + } + if (h->pass_pos != 0 && h->chap_pass) { + generr(h, "Both User and Chap Password attributes given"); + return -1; + } + } + + /* Fill in the length field in the message */ + h->request[POS_LENGTH] = h->req_len >> 8; + h->request[POS_LENGTH+1] = h->req_len; + + /* + * Count the total number of tries we will make, and zero the + * counter for each server. + */ + h->total_tries = 0; + for (srv = 0; srv < h->num_servers; srv++) { + h->total_tries += h->servers[srv].max_tries; + h->servers[srv].num_tries = 0; + } + if (h->total_tries == 0) { + generr(h, "No RADIUS servers specified"); + return -1; + } + + h->try = h->srv = 0; + + return rad_continue_send_request(h, 0, fd, tv); +} + +/* + * Create and initialize a rad_handle structure, and return it to the + * caller. Can fail only if the necessary memory cannot be allocated. + * In that case, it returns NULL. + */ +struct rad_handle * +rad_auth_open(void) +{ + struct rad_handle *h; + + h = (struct rad_handle *)malloc(sizeof(struct rad_handle)); + if (h != NULL) { + srandomdev(); + h->fd = -1; + h->num_servers = 0; + h->ident = random(); + h->errmsg[0] = '\0'; + memset(h->pass, 0, sizeof h->pass); + h->pass_len = 0; + h->pass_pos = 0; + h->chap_pass = 0; + h->type = RADIUS_AUTH; + } + return h; +} + +struct rad_handle * +rad_acct_open(void) +{ + struct rad_handle *h; + + h = rad_open(); + if (h != NULL) + h->type = RADIUS_ACCT; + return h; +} + +struct rad_handle * +rad_open(void) +{ + return rad_auth_open(); +} + +int +rad_put_addr(struct rad_handle *h, int type, struct in_addr addr) +{ + return rad_put_attr(h, type, &addr.s_addr, sizeof addr.s_addr); +} + +int +rad_put_attr(struct rad_handle *h, int type, const void *value, size_t len) +{ + int result; + + if (type == RAD_USER_PASSWORD) + result = put_password_attr(h, type, value, len); + else { + result = put_raw_attr(h, type, value, len); + if (result == 0 && type == RAD_CHAP_PASSWORD) + h->chap_pass = 1; + } + + return result; +} + +int +rad_put_int(struct rad_handle *h, int type, u_int32_t value) +{ + u_int32_t nvalue; + + nvalue = htonl(value); + return rad_put_attr(h, type, &nvalue, sizeof nvalue); +} + +int +rad_put_string(struct rad_handle *h, int type, const char *str) +{ + return rad_put_attr(h, type, str, strlen(str)); +} + +/* + * Returns the response type code on success, or -1 on failure. + */ +int +rad_send_request(struct rad_handle *h) +{ + struct timeval timelimit; + struct timeval tv; + int fd; + int n; + + n = rad_init_send_request(h, &fd, &tv); + + if (n != 0) + return n; + + gettimeofday(&timelimit, NULL); + timeradd(&tv, &timelimit, &timelimit); + + for ( ; ; ) { + fd_set readfds; + + FD_ZERO(&readfds); + FD_SET(fd, &readfds); + + n = select(fd + 1, &readfds, NULL, NULL, &tv); + + if (n == -1) { + generr(h, "select: %s", strerror(errno)); + return -1; + } + + if (!FD_ISSET(fd, &readfds)) { + /* Compute a new timeout */ + gettimeofday(&tv, NULL); + timersub(&timelimit, &tv, &tv); + if (tv.tv_sec > 0 || (tv.tv_sec == 0 && tv.tv_usec > 0)) + /* Continue the select */ + continue; + } + + n = rad_continue_send_request(h, n, &fd, &tv); + + if (n != 0) + return n; + + gettimeofday(&timelimit, NULL); + timeradd(&tv, &timelimit, &timelimit); + } +} + +const char * +rad_strerror(struct rad_handle *h) +{ + return h->errmsg; +} + +/* + * Destructively split a string into fields separated by white space. + * `#' at the beginning of a field begins a comment that extends to the + * end of the string. Fields may be quoted with `"'. Inside quoted + * strings, the backslash escapes `\"' and `\\' are honored. + * + * Pointers to up to the first maxfields fields are stored in the fields + * array. Missing fields get NULL pointers. + * + * The return value is the actual number of fields parsed, and is always + * <= maxfields. + * + * On a syntax error, places a message in the msg string, and returns -1. + */ +static int +split(char *str, char *fields[], int maxfields, char *msg, size_t msglen) +{ + char *p; + int i; + static const char ws[] = " \t"; + + for (i = 0; i < maxfields; i++) + fields[i] = NULL; + p = str; + i = 0; + while (*p != '\0') { + p += strspn(p, ws); + if (*p == '#' || *p == '\0') + break; + if (i >= maxfields) { + snprintf(msg, msglen, "line has too many fields"); + return -1; + } + if (*p == '"') { + char *dst; + + dst = ++p; + fields[i] = dst; + while (*p != '"') { + if (*p == '\\') { + p++; + if (*p != '"' && *p != '\\' && + *p != '\0') { + snprintf(msg, msglen, + "invalid `\\' escape"); + return -1; + } + } + if (*p == '\0') { + snprintf(msg, msglen, + "unterminated quoted string"); + return -1; + } + *dst++ = *p++; + } + *dst = '\0'; + p++; + if (*fields[i] == '\0') { + snprintf(msg, msglen, + "empty quoted string not permitted"); + return -1; + } + if (*p != '\0' && strspn(p, ws) == 0) { + snprintf(msg, msglen, "quoted string not" + " followed by white space"); + return -1; + } + } else { + fields[i] = p; + p += strcspn(p, ws); + if (*p != '\0') + *p++ = '\0'; + } + i++; + } + return i; +} |