sftp-server.c

OpenSSL Source code for SFTP, SSH, and many others

/*
 * Copyright (c) 2000, 2001, 2002 Markus Friedl.  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 ``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 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.
 */
#include "includes.h"
RCSID("$OpenBSD: sftp-server.c,v 1.35 2002/06/06 17:30:11 markus Exp $");

#include "buffer.h"
#include "bufaux.h"
#include "getput.h"
#include "log.h"
#include "xmalloc.h"

#include "sftp.h"
#include "sftp-common.h"

/* helper */
#define get_int64()			buffer_get_int64(&iqueue);
#define get_int()			buffer_get_int(&iqueue);
#define get_string(lenp)		buffer_get_string(&iqueue, lenp);
#define TRACE				debug

#ifdef HAVE___PROGNAME
extern char *__progname;
#else
char *__progname;
#endif

/* input and output queue */
Buffer iqueue;
Buffer oqueue;

/* Version of client */
int version;

/* portable attibutes, etc. */

typedef struct Stat Stat;

struct Stat {
	char *name;
	char *long_name;
	Attrib attrib;
};

static int
errno_to_portable(int unixerrno)
{
	int ret = 0;

	switch (unixerrno) {
	case 0:
		ret = SSH2_FX_OK;
		break;
	case ENOENT:
	case ENOTDIR:
	case EBADF:
	case ELOOP:
		ret = SSH2_FX_NO_SUCH_FILE;
		break;
	case EPERM:
	case EACCES:
	case EFAULT:
		ret = SSH2_FX_PERMISSION_DENIED;
		break;
	case ENAMETOOLONG:
	case EINVAL:
		ret = SSH2_FX_BAD_MESSAGE;
		break;
	default:
		ret = SSH2_FX_FAILURE;
		break;
	}
	return ret;
}

static int
flags_from_portable(int pflags)
{
	int flags = 0;

	if ((pflags & SSH2_FXF_READ) &&
	    (pflags & SSH2_FXF_WRITE)) {
		flags = O_RDWR;
	} else if (pflags & SSH2_FXF_READ) {
		flags = O_RDONLY;
	} else if (pflags & SSH2_FXF_WRITE) {
		flags = O_WRONLY;
	}
	if (pflags & SSH2_FXF_CREAT)
		flags |= O_CREAT;
	if (pflags & SSH2_FXF_TRUNC)
		flags |= O_TRUNC;
	if (pflags & SSH2_FXF_EXCL)
		flags |= O_EXCL;
	return flags;
}

static Attrib *
get_attrib(void)
{
	return decode_attrib(&iqueue);
}

/* handle handles */

typedef struct Handle Handle;
struct Handle {
	int use;
	DIR *dirp;
	int fd;
	char *name;
};

enum {
	HANDLE_UNUSED,
	HANDLE_DIR,
	HANDLE_FILE
};

Handle	handles[100];

static void
handle_init(void)
{
	int i;

	for (i = 0; i < sizeof(handles)/sizeof(Handle); i++)
		handles[i].use = HANDLE_UNUSED;
}

static int
handle_new(int use, char *name, int fd, DIR *dirp)
{
	int i;

	for (i = 0; i < sizeof(handles)/sizeof(Handle); i++) {
		if (handles[i].use == HANDLE_UNUSED) {
			handles[i].use = use;
			handles[i].dirp = dirp;
			handles[i].fd = fd;
			handles[i].name = name;
			return i;
		}
	}
	return -1;
}

static int
handle_is_ok(int i, int type)
{
	return i >= 0 && i < sizeof(handles)/sizeof(Handle) &&
	    handles[i].use == type;
}

static int
handle_to_string(int handle, char **stringp, int *hlenp)
{
	if (stringp == NULL || hlenp == NULL)
		return -1;
	*stringp = xmalloc(sizeof(int32_t));
	PUT_32BIT(*stringp, handle);
	*hlenp = sizeof(int32_t);
	return 0;
}

static int
handle_from_string(char *handle, u_int hlen)
{
	int val;

	if (hlen != sizeof(int32_t))
		return -1;
	val = GET_32BIT(handle);
	if (handle_is_ok(val, HANDLE_FILE) ||
	    handle_is_ok(val, HANDLE_DIR))
		return val;
	return -1;
}

static char *
handle_to_name(int handle)
{
	if (handle_is_ok(handle, HANDLE_DIR)||
	    handle_is_ok(handle, HANDLE_FILE))
		return handles[handle].name;
	return NULL;
}

static DIR *
handle_to_dir(int handle)
{
	if (handle_is_ok(handle, HANDLE_DIR))
		return handles[handle].dirp;
	return NULL;
}

static int
handle_to_fd(int handle)
{
	if (handle_is_ok(handle, HANDLE_FILE))
		return handles[handle].fd;
	return -1;
}

static int
handle_close(int handle)
{
	int ret = -1;

	if (handle_is_ok(handle, HANDLE_FILE)) {
		ret = close(handles[handle].fd);
		handles[handle].use = HANDLE_UNUSED;
	} else if (handle_is_ok(handle, HANDLE_DIR)) {
		ret = closedir(handles[handle].dirp);
		handles[handle].use = HANDLE_UNUSED;
	} else {
		errno = ENOENT;
	}
	return ret;
}

static int
get_handle(void)
{
	char *handle;
	int val = -1;
	u_int hlen;

	handle = get_string(&hlen);
	if (hlen < 256)
		val = handle_from_string(handle, hlen);
	xfree(handle);
	return val;
}

/* send replies */

static void
send_msg(Buffer *m)
{
	int mlen = buffer_len(m);

	buffer_put_int(&oqueue, mlen);
	buffer_append(&oqueue, buffer_ptr(m), mlen);
	buffer_consume(m, mlen);
}

static void
send_status(u_int32_t id, u_int32_t error)
{
	Buffer msg;
	const char *status_messages[] = {
		"Success",			/* SSH_FX_OK */
		"End of file",			/* SSH_FX_EOF */
		"No such file",			/* SSH_FX_NO_SUCH_FILE */
		"Permission denied",		/* SSH_FX_PERMISSION_DENIED */
		"Failure",			/* SSH_FX_FAILURE */
		"Bad message",			/* SSH_FX_BAD_MESSAGE */
		"No connection",		/* SSH_FX_NO_CONNECTION */
		"Connection lost",		/* SSH_FX_CONNECTION_LOST */
		"Operation unsupported",	/* SSH_FX_OP_UNSUPPORTED */
		"Unknown error"			/* Others */
	};

	TRACE("sent status id %d error %d", id, error);
	buffer_init(&msg);
	buffer_put_char(&msg, SSH2_FXP_STATUS);
	buffer_put_int(&msg, id);
	buffer_put_int(&msg, error);
	if (version >= 3) {
		buffer_put_cstring(&msg,
		    status_messages[MIN(error,SSH2_FX_MAX)]);
		buffer_put_cstring(&msg, "");
	}
	send_msg(&msg);
	buffer_free(&msg);
}
static void
send_data_or_handle(char type, u_int32_t id, char *data, int dlen)
{
	Buffer msg;

	buffer_init(&msg);
	buffer_put_char(&msg, type);
	buffer_put_int(&msg, id);
	buffer_put_string(&msg, data, dlen);
	send_msg(&msg);
	buffer_free(&msg);
}

static void
send_data(u_int32_t id, char *data, int dlen)
{
	TRACE("sent data id %d len %d", id, dlen);
	send_data_or_handle(SSH2_FXP_DATA, id, data, dlen);
}

static void
send_handle(u_int32_t id, int handle)
{
	char *string;
	int hlen;

	handle_to_string(handle, &string, &hlen);
	TRACE("sent handle id %d handle %d", id, handle);
	send_data_or_handle(SSH2_FXP_HANDLE, id, string, hlen);
	xfree(string);
}

static void
send_names(u_int32_t id, int count, Stat *stats)
{
	Buffer msg;
	int i;

	buffer_init(&msg);
	buffer_put_char(&msg, SSH2_FXP_NAME);
	buffer_put_int(&msg, id);
	buffer_put_int(&msg, count);
	TRACE("sent names id %d count %d", id, count);
	for (i = 0; i < count; i++) {
		buffer_put_cstring(&msg, stats[i].name);
		buffer_put_cstring(&msg, stats[i].long_name);
		encode_attrib(&msg, &stats[i].attrib);
	}
	send_msg(&msg);
	buffer_free(&msg);
}

static void
send_attrib(u_int32_t id, Attrib *a)
{
	Buffer msg;

	TRACE("sent attrib id %d have 0x%x", id, a->flags);
	buffer_init(&msg);
	buffer_put_char(&msg, SSH2_FXP_ATTRS);
	buffer_put_int(&msg, id);
	encode_attrib(&msg, a);
	send_msg(&msg);
	buffer_free(&msg);
}

/* parse incoming */

static void
process_init(void)
{
	Buffer msg;

	version = get_int();
	TRACE("client version %d", version);
	buffer_init(&msg);
	buffer_put_char(&msg, SSH2_FXP_VERSION);
	buffer_put_int(&msg, SSH2_FILEXFER_VERSION);
	send_msg(&msg);
	buffer_free(&msg);
}

static void
process_open(void)
{
	u_int32_t id, pflags;
	Attrib *a;
	char *name;
	int handle, fd, flags, mode, status = SSH2_FX_FAILURE;

	id = get_int();
	name = get_string(NULL);
	pflags = get_int();		/* portable flags */
	a = get_attrib();
	flags = flags_from_portable(pflags);
	mode = (a->flags & SSH2_FILEXFER_ATTR_PERMISSIONS) ? a->perm : 0666;
	TRACE("open id %d name %s flags %d mode 0%o", id, name, pflags, mode);
	fd = open(name, flags, mode);
	if (fd < 0) {
		status = errno_to_portable(errno);
	} else {
		handle = handle_new(HANDLE_FILE, xstrdup(name), fd, NULL);
		if (handle < 0) {
			close(fd);
		} else {
			send_handle(id, handle);
			status = SSH2_FX_OK;
		}
	}
	if (status != SSH2_FX_OK)
		send_status(id, status);
	xfree(name);
}

static void
process_close(void)
{
	u_int32_t id;
	int handle, ret, status = SSH2_FX_FAILURE;

	id = get_int();
	handle = get_handle();
	TRACE("close id %d handle %d", id, handle);
	ret = handle_close(handle);
	status = (ret == -1) ? errno_to_portable(errno) : SSH2_FX_OK;
	send_status(id, status);
}

static void
process_read(void)
{
	char buf[64*1024];
	u_int32_t id, len;
	int handle, fd, ret, status = SSH2_FX_FAILURE;
	u_int64_t off;

	id = get_int();
	handle = get_handle();
	off = get_int64();
	len = get_int();

	TRACE("read id %d handle %d off %llu len %d", id, handle,
	    (u_int64_t)off, len);
	if (len > sizeof buf) {
		len = sizeof buf;
		log("read change len %d", len);
	}
	fd = handle_to_fd(handle);
	if (fd >= 0) {
		if (lseek(fd, off, SEEK_SET) < 0) {
			error("process_read: seek failed");
			status = errno_to_portable(errno);
		} else {
			ret = read(fd, buf, len);
			if (ret < 0) {
				status = errno_to_portable(errno);
			} else if (ret == 0) {
				status = SSH2_FX_EOF;
			} else {
				send_data(id, buf, ret);
				status = SSH2_FX_OK;
			}
		}
	}
	if (status != SSH2_FX_OK)
		send_status(id, status);
}

static void
process_write(void)
{
	u_int32_t id;
	u_int64_t off;
	u_int len;
	int handle, fd, ret, status = SSH2_FX_FAILURE;
	char *data;

	id = get_int();
	handle = get_handle();
	off = get_int64();
	data = get_string(&len);

	TRACE("write id %d handle %d off %llu len %d", id, handle,
	    (u_int64_t)off, len);
	fd = handle_to_fd(handle);
	if (fd >= 0) {
		if (lseek(fd, off, SEEK_SET) < 0) {
			status = errno_to_portable(errno);
			error("process_write: seek failed");
		} else {
/* XXX ATOMICIO ? */
			ret = write(fd, data, len);
			if (ret == -1) {
				error("process_write: write failed");
				status = errno_to_portable(errno);
			} else if (ret == len) {
				status = SSH2_FX_OK;
			} else {
				log("nothing at all written");
			}
		}
	}
	send_status(id, status);
	xfree(data);
}

static void
process_do_stat(int do_lstat)
{
	Attrib a;
	struct stat st;
	u_int32_t id;
	char *name;
	int ret, status = SSH2_FX_FAILURE;

	id = get_int();
	name = get_string(NULL);
	TRACE("%sstat id %d name %s", do_lstat ? "l" : "", id, name);
	ret = do_lstat ? lstat(name, &st) : stat(name, &st);
	if (ret < 0) {
		status = errno_to_portable(errno);
	} else {
		stat_to_attrib(&st, &a);
		send_attrib(id, &a);
		status = SSH2_FX_OK;
	}
	if (status != SSH2_FX_OK)
		send_status(id, status);
	xfree(name);
}

static void
process_stat(void)
{
	process_do_stat(0);
}

static void
process_lstat(void)
{
	process_do_stat(1);
}

static void
process_fstat(void)
{
	Attrib a;
	struct stat st;
	u_int32_t id;
	int fd, ret, handle, status = SSH2_FX_FAILURE;

	id = get_int();
	handle = get_handle();
	TRACE("fstat id %d handle %d", id, handle);
	fd = handle_to_fd(handle);
	if (fd  >= 0) {
		ret = fstat(fd, &st);
		if (ret < 0) {
			status = errno_to_portable(errno);
		} else {
			stat_to_attrib(&st, &a);
			send_attrib(id, &a);
			status = SSH2_FX_OK;
		}
	}
	if (status != SSH2_FX_OK)
		send_status(id, status);
}

static struct timeval *