diff options
Diffstat (limited to 'eBones/lib/libkrb/rd_priv.c')
| -rw-r--r-- | eBones/lib/libkrb/rd_priv.c | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/eBones/lib/libkrb/rd_priv.c b/eBones/lib/libkrb/rd_priv.c new file mode 100644 index 0000000..9adefec --- /dev/null +++ b/eBones/lib/libkrb/rd_priv.c @@ -0,0 +1,204 @@ +/* + * Copyright 1986, 1987, 1988 by the Massachusetts Institute + * of Technology. + * For copying and distribution information, please see the file + * <Copyright.MIT>. + * + * This routine dissects a a Kerberos 'private msg', decrypting it, + * checking its integrity, and returning a pointer to the application + * data contained and its length. + * + * Returns 0 (RD_AP_OK) for success or an error code (RD_AP_...). If + * the return value is RD_AP_TIME, then either the times are too far + * out of synch, OR the packet was modified. + * + * Steve Miller Project Athena MIT/DEC + * + * from: rd_priv.c,v 4.14 89/04/28 11:59:42 jtkohl Exp $ + * $Id: rd_priv.c,v 1.2 1994/07/19 19:26:11 g89r4222 Exp $ + */ + +#ifndef lint +static char rcsid[]= +"$Id: rd_priv.c,v 1.2 1994/07/19 19:26:11 g89r4222 Exp $"; +#endif /* lint */ + +/* system include files */ +#include <stdio.h> +#include <errno.h> +#include <sys/types.h> +#include <netinet/in.h> +#include <sys/time.h> + +/* application include files */ +#include <des.h> +#include <krb.h> +#include <prot.h> +#include "lsb_addr_comp.h" + +extern char *errmsg(); +extern int errno; +extern int krb_debug; + +/* static storage */ + +static u_long c_length; +static int swap_bytes; +static struct timeval local_time; +static long delta_t; +int private_msg_ver = KRB_PROT_VERSION; + +/* +#ifdef NOENCRPYTION + * krb_rd_priv() checks the integrity of an +#else + * krb_rd_priv() decrypts and checks the integrity of an +#endif + * AUTH_MSG_PRIVATE message. Given the message received, "in", + * the length of that message, "in_length", the key "schedule" + * and "key", and the network addresses of the + * "sender" and "receiver" of the message, krb_rd_safe() returns + * RD_AP_OK if the message is okay, otherwise some error code. + * + * The message data retrieved from "in" are returned in the structure + * "m_data". The pointer to the application data + * (m_data->app_data) refers back to the appropriate place in "in". + * + * See the file "mk_priv.c" for the format of the AUTH_MSG_PRIVATE + * message. The structure containing the extracted message + * information, MSG_DAT, is defined in "krb.h". + */ + +long krb_rd_priv(in,in_length,schedule,key,sender,receiver,m_data) + u_char *in; /* pointer to the msg received */ + u_long in_length; /* length of "in" msg */ + Key_schedule schedule; /* precomputed key schedule */ + C_Block key; /* encryption key for seed and ivec */ + struct sockaddr_in *sender; + struct sockaddr_in *receiver; + MSG_DAT *m_data; /*various input/output data from msg */ +{ + register u_char *p,*q; + static u_long src_addr; /* Can't send structs since no + * guarantees on size */ + + if (gettimeofday(&local_time,(struct timezone *)0)) + return -1; + + p = in; /* beginning of message */ + swap_bytes = 0; + + if (*p++ != KRB_PROT_VERSION && *(p-1) != 3) + return RD_AP_VERSION; + private_msg_ver = *(p-1); + if (((*p) & ~1) != AUTH_MSG_PRIVATE) + return RD_AP_MSG_TYPE; + if ((*p++ & 1) != HOST_BYTE_ORDER) + swap_bytes++; + + /* get cipher length */ + bcopy((char *)p,(char *)&c_length,sizeof(c_length)); + if (swap_bytes) + swap_u_long(c_length); + p += sizeof(c_length); + /* check for rational length so we don't go comatose */ + if (VERSION_SZ + MSG_TYPE_SZ + c_length > in_length) + return RD_AP_MODIFIED; + + + q = p; /* mark start of encrypted stuff */ + +#ifndef NOENCRYPTION + pcbc_encrypt((C_Block *)q,(C_Block *)q,(long)c_length,schedule,key,DECRYPT); +#endif + + /* safely get application data length */ + bcopy((char *) p,(char *)&(m_data->app_length), + sizeof(m_data->app_length)); + if (swap_bytes) + swap_u_long(m_data->app_length); + p += sizeof(m_data->app_length); /* skip over */ + + if (m_data->app_length + sizeof(c_length) + sizeof(in_length) + + sizeof(m_data->time_sec) + sizeof(m_data->time_5ms) + + sizeof(src_addr) + VERSION_SZ + MSG_TYPE_SZ + > in_length) + return RD_AP_MODIFIED; + +#ifndef NOENCRYPTION + /* we're now at the decrypted application data */ +#endif + m_data->app_data = p; + + p += m_data->app_length; + + /* safely get time_5ms */ + bcopy((char *) p, (char *)&(m_data->time_5ms), + sizeof(m_data->time_5ms)); + /* don't need to swap-- one byte for now */ + p += sizeof(m_data->time_5ms); + + /* safely get src address */ + bcopy((char *) p,(char *)&src_addr,sizeof(src_addr)); + /* don't swap, net order always */ + p += sizeof(src_addr); + + if (src_addr != (u_long) sender->sin_addr.s_addr) + return RD_AP_MODIFIED; + + /* safely get time_sec */ + bcopy((char *) p, (char *)&(m_data->time_sec), + sizeof(m_data->time_sec)); + if (swap_bytes) swap_u_long(m_data->time_sec); + + p += sizeof(m_data->time_sec); + + /* check direction bit is the sign bit */ + /* For compatibility with broken old code, compares are done in VAX + byte order (LSBFIRST) */ + if (lsb_net_ulong_less(sender->sin_addr.s_addr, + receiver->sin_addr.s_addr)==-1) + /* src < recv */ + m_data->time_sec = - m_data->time_sec; + else if (lsb_net_ulong_less(sender->sin_addr.s_addr, + receiver->sin_addr.s_addr)==0) + if (lsb_net_ushort_less(sender->sin_port,receiver->sin_port)==-1) + /* src < recv */ + m_data->time_sec = - m_data->time_sec; + /* + * all that for one tiny bit! + * Heaven help those that talk to themselves. + */ + + /* check the time integrity of the msg */ + delta_t = abs((int)((long) local_time.tv_sec + - m_data->time_sec)); + if (delta_t > CLOCK_SKEW) + return RD_AP_TIME; + if (krb_debug) + printf("\ndelta_t = %d",delta_t); + + /* + * caller must check timestamps for proper order and + * replays, since server might have multiple clients + * each with its own timestamps and we don't assume + * tightly synchronized clocks. + */ + +#ifdef notdef + bcopy((char *) p,(char *)&cksum,sizeof(cksum)); + if (swap_bytes) swap_u_long(cksum) + /* + * calculate the checksum of the length, sequence, + * and input data, on the sending byte order!! + */ + calc_cksum = quad_cksum(q,NULL,p-q,0,key); + + if (krb_debug) + printf("\ncalc_cksum = %u, received cksum = %u", + calc_cksum, cksum); + if (cksum != calc_cksum) + return RD_AP_MODIFIED; +#endif + return RD_AP_OK; /* OK == 0 */ +} |
