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/*
* Shared routines for client and server for
* secure read(), write(), getc(), and putc().
* Only one security context, thus only work on one fd at a time!
*/
#include "autoconf.h"
#ifdef GSSAPI
#include <gssapi/gssapi.h>
#include <gssapi/gssapi_generic.h>
extern gss_ctx_id_t gcontext;
#endif /* GSSAPI */
#include <secure.h> /* stuff which is specific to client or server */
#ifdef _WIN32
#undef ERROR
#endif
#include <arpa/ftp.h>
#include <stdio.h>
#include <string.h>
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <sys/types.h>
#ifdef _WIN32
#include <port-sockets.h>
#else
#include <netinet/in.h>
#endif
#include <errno.h>
#ifndef HAVE_STRERROR
#define strerror(error) (sys_errlist[error])
#ifdef NEED_SYS_ERRLIST
extern char *sys_errlist[];
#endif
#endif
#ifdef HAVE_STDINT_H
# include <stdint.h>
#endif
#ifdef HAVE_INTTYPES_H
# include <inttypes.h>
#endif
typedef uint32_t ftp_uint32;
typedef int32_t ftp_int32;
static int secure_putbuf (int, unsigned char *, unsigned int);
extern struct sockaddr_in hisaddr;
extern struct sockaddr_in myaddr;
extern int dlevel;
extern char *auth_type;
/* Some libc's (GNU libc, at least) define MAX as a macro. Forget that. */
#ifdef MAX
#undef MAX
#endif
#define MAX maxbuf
extern unsigned int maxbuf; /* maximum output buffer size */
extern unsigned char *ucbuf; /* cleartext buffer */
static unsigned int nout; /* number of chars in ucbuf,
* pointer into ucbuf */
static unsigned int smaxbuf; /* Internal saved value of maxbuf
in case changes on us */
static unsigned int smaxqueue; /* Maximum allowed to queue before
flush buffer. < smaxbuf by fudgefactor */
/* perhaps use these in general, certainly use them for GSSAPI */
#ifndef looping_write
static int
looping_write(fd, buf, len)
int fd;
register const char *buf;
int len;
{
int cc;
register int wrlen = len;
do {
cc = write(fd, buf, wrlen);
if (cc < 0) {
if (errno == EINTR)
continue;
return(cc);
}
else {
buf += cc;
wrlen -= cc;
}
} while (wrlen > 0);
return(len);
}
#endif
#ifndef looping_read
static int
looping_read(fd, buf, len)
int fd;
register char *buf;
register int len;
{
int cc, len2 = 0;
do {
cc = read(fd, buf, len);
if (cc < 0) {
if (errno == EINTR)
continue;
return(cc); /* errno is already set */
}
else if (cc == 0) {
return(len2);
} else {
buf += cc;
len2 += cc;
len -= cc;
}
} while (len > 0);
return(len2);
}
#endif
#define ERR -2
/*
* Given maxbuf as a buffer size, determine how much can we
* really transfer given the overhead of different algorithms
*
* Sets smaxbuf and smaxqueue
*/
static int secure_determine_constants()
{
smaxbuf = maxbuf;
smaxqueue = maxbuf;
#ifdef GSSAPI
if (strcmp(auth_type, "GSSAPI") == 0) {
OM_uint32 maj_stat, min_stat, mlen;
OM_uint32 msize = maxbuf;
maj_stat = gss_wrap_size_limit(&min_stat, gcontext,
(dlevel == PROT_P),
GSS_C_QOP_DEFAULT,
msize, &mlen);
if (maj_stat != GSS_S_COMPLETE) {
secure_gss_error(maj_stat, min_stat,
"GSSAPI fudge determination");
/* Return error how? */
return ERR;
}
smaxqueue = mlen;
}
#endif
return 0;
}
static int
secure_putbyte(fd, c)
int fd;
unsigned char c;
{
int ret;
if ((smaxbuf == 0) || (smaxqueue == 0) || (smaxbuf != maxbuf)) {
ret = secure_determine_constants();
if (ret) return ret;
}
ucbuf[nout++] = c;
if (nout == smaxqueue) {
nout = 0;
ret = secure_putbuf(fd, ucbuf, smaxqueue);
return(ret?ret:c);
}
return (c);
}
/* returns:
* 0 on success
* -1 on error (errno set)
* -2 on security error
*/
int secure_flush(fd)
int fd;
{
int ret;
if (dlevel == PROT_C)
return(0);
if (nout) {
ret = secure_putbuf(fd, ucbuf, nout);
if (ret)
return(ret);
}
return(secure_putbuf(fd, (unsigned char *) "", nout = 0));
}
/* returns:
* c>=0 on success
* -1 on error
* -2 on security error
*/
int secure_putc(c, stream)
int c;
FILE *stream;
{
if (dlevel == PROT_C)
return(putc(c,stream));
return(secure_putbyte(fileno(stream), (unsigned char) c));
}
/* returns:
* nbyte on success
* -1 on error (errno set)
* -2 on security error
*/
int
secure_write(fd, buf, nbyte)
int fd;
unsigned char *buf;
unsigned int nbyte;
{
unsigned int i;
int c;
if (dlevel == PROT_C)
return(write(fd,buf,nbyte));
for (i=0; nbyte>0; nbyte--)
if ((c = secure_putbyte(fd, buf[i++])) < 0)
return(c);
return(i);
}
/* returns:
* 0 on success
* -1 on error (errno set)
* -2 on security error
*/
static int
secure_putbuf(fd, buf, nbyte)
int fd;
unsigned char *buf;
unsigned int nbyte;
{
static char *outbuf; /* output ciphertext */
static unsigned int bufsize; /* size of outbuf */
ftp_int32 length = 0;
ftp_uint32 net_len;
unsigned int fudge = smaxbuf - smaxqueue; /* Difference in length
buffer lengths required */
/* Other auth types go here ... */
#ifdef GSSAPI
if (strcmp(auth_type, "GSSAPI") == 0) {
gss_buffer_desc in_buf, out_buf;
OM_uint32 maj_stat, min_stat;
int conf_state;
in_buf.value = buf;
in_buf.length = nbyte;
maj_stat = gss_seal(&min_stat, gcontext,
(dlevel == PROT_P), /* confidential */
GSS_C_QOP_DEFAULT,
&in_buf, &conf_state,
&out_buf);
if (maj_stat != GSS_S_COMPLETE) {
/* generally need to deal */
/* ie. should loop, but for now just fail */
secure_gss_error(maj_stat, min_stat,
dlevel == PROT_P?
"GSSAPI seal failed":
"GSSAPI sign failed");
return(ERR);
}
if (bufsize < out_buf.length) {
if (outbuf?
(outbuf = realloc(outbuf, (unsigned) out_buf.length)):
(outbuf = malloc((unsigned) out_buf.length))) {
bufsize = out_buf.length;
} else {
bufsize = 0;
secure_error("%s (in malloc of PROT buffer)",
strerror(errno));
return(ERR);
}
}
length=out_buf.length;
memcpy(outbuf, out_buf.value, out_buf.length);
gss_release_buffer(&min_stat, &out_buf);
}
#endif /* GSSAPI */
net_len = htonl((u_long) length);
if (looping_write(fd, (char *) &net_len, 4) == -1) return(-1);
if (looping_write(fd, outbuf, length) != length) return(-1);
return(0);
}
static int
secure_getbyte(fd)
int fd;
{
/* number of chars in ucbuf, pointer into ucbuf */
static unsigned int nin, bufp;
int kerror;
ftp_uint32 length;
if (nin == 0) {
if ((kerror = looping_read(fd, (char *) &length,
sizeof(length)))
!= sizeof(length)) {
secure_error("Couldn't read PROT buffer length: %d/%s",
kerror,
kerror == -1 ? strerror(errno)
: "premature EOF");
return(ERR);
}
if ((length = (u_long) ntohl(length)) > MAX) {
secure_error("Length (%d) of PROT buffer > PBSZ=%u",
length, MAX);
return(ERR);
}
if ((kerror = looping_read(fd, (char *) ucbuf, (int) length)) != length) {
secure_error("Couldn't read %u byte PROT buffer: %s",
length, kerror == -1 ?
strerror(errno) : "premature EOF");
return(ERR);
}
/* Other auth types go here ... */
#ifdef GSSAPI
if (strcmp(auth_type, "GSSAPI") == 0) {
gss_buffer_desc xmit_buf, msg_buf;
OM_uint32 maj_stat, min_stat;
int conf_state;
xmit_buf.value = ucbuf;
xmit_buf.length = length;
conf_state = (dlevel == PROT_P);
/* decrypt/verify the message */
maj_stat = gss_unseal(&min_stat, gcontext, &xmit_buf,
&msg_buf, &conf_state, NULL);
if (maj_stat != GSS_S_COMPLETE) {
secure_gss_error(maj_stat, min_stat,
(dlevel == PROT_P)?
"failed unsealing ENC message":
"failed unsealing MIC message");
return ERR;
}
memcpy(ucbuf, msg_buf.value, nin = bufp = msg_buf.length);
gss_release_buffer(&min_stat, &msg_buf);
}
#endif /* GSSAPI */
/* Other auth types go here ... */
}
if (nin == 0)
return(EOF);
else return(ucbuf[bufp - nin--]);
}
/* returns:
* c>=0 on success
* -1 on EOF
* -2 on security error
*/
int secure_getc(stream)
FILE *stream;
{
if (dlevel == PROT_C)
return(getc(stream));
return(secure_getbyte(fileno(stream)));
}
/* returns:
* n>0 on success (n == # of bytes read)
* 0 on EOF
* -1 on error (errno set), only for PROT_C
* -2 on security error
*/
int secure_read(fd, buf, nbyte)
int fd;
char *buf;
unsigned int nbyte;
{
static int c;
int i;
if (dlevel == PROT_C)
return(read(fd,buf,nbyte));
if (c == EOF)
return(c = 0);
for (i=0; nbyte>0; nbyte--)
switch (c = secure_getbyte(fd)) {
case ERR: return(c);
case EOF: if (!i) c = 0;
return(i);
default: buf[i++] = c;
}
return(i);
}
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