static int tftp_send_data(struct tftp_session *spt,
u_int16_t block_nr,
struct tftp_t *recv_tp)
{
struct sockaddr_in saddr, daddr;
struct mbuf *m;
struct tftp_t *tp;
int nobytes;
if (block_nr < 1) {
return -1;
}
m = m_get(spt->slirp);
if (!m) {
return -1;
}
memset(m->m_data, 0, m->m_size);
m->m_data += IF_MAXLINKHDR;
tp = (void *)m->m_data;
m->m_data += sizeof(struct udpiphdr);
tp->tp_op = htons(TFTP_DATA);
tp->x.tp_data.tp_block_nr = htons(block_nr);
saddr.sin_addr = recv_tp->ip.ip_dst;
saddr.sin_port = recv_tp->udp.uh_dport;
daddr.sin_addr = spt->client_ip;
daddr.sin_port = spt->client_port;
nobytes = tftp_read_data(spt, block_nr - 1, tp->x.tp_data.tp_buf, 512);
if (nobytes < 0) {
m_free(m);
/* send "file not found" error back */
tftp_send_error(spt, 1, "File not found", tp);
return -1;
}
m->m_len = sizeof(struct tftp_t) - (512 - nobytes) -
sizeof(struct ip) - sizeof(struct udphdr);
udp_output2(NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
if (nobytes == 512) {
tftp_session_update(spt);
}
else {
tftp_session_terminate(spt);
}
return 0;
}
static int tftp_send_data(PNATState pData,
struct tftp_session *spt,
u_int16_t block_nr,
struct tftp_t *recv_tp)
{
struct sockaddr_in saddr, daddr;
struct mbuf *m;
struct tftp_t *tp;
int nobytes;
if (block_nr < 1)
return -1;
m = slirpTftpMbufAlloc(pData);
if (!m)
return -1;
m->m_data += if_maxlinkhdr;
m->m_pkthdr.header = mtod(m, void *);
tp = mtod(m, void *);
m->m_data += sizeof(struct udpiphdr);
tp->tp_op = RT_H2N_U16_C(TFTP_DATA);
tp->x.tp_data.tp_block_nr = RT_H2N_U16(block_nr);
saddr.sin_addr = recv_tp->ip.ip_dst;
saddr.sin_port = recv_tp->udp.uh_dport;
daddr.sin_addr = spt->client_ip;
daddr.sin_port = spt->client_port;
nobytes = tftp_read_data(pData, spt, block_nr - 1, tp->x.tp_data.tp_buf, 512);
if (nobytes < 0)
{
m_freem(pData, m);
/* send "file not found" error back */
tftp_send_error(pData, spt, 1, "File not found", tp);
return -1;
}
m->m_len = sizeof(struct tftp_t)
- (512 - nobytes)
- sizeof(struct ip)
- sizeof(struct udphdr);
udp_output2(pData, NULL, m, &saddr, &daddr, IPTOS_LOWDELAY);
if (nobytes == 512)
tftp_session_update(pData, spt);
else
tftp_session_terminate(spt);
return 0;
}
static void tftp_send_next_block(struct tftp_session *spt,
struct tftp_t *recv_tp)
{
struct mbuf *m;
struct tftp_t *tp;
int nobytes;
m = m_get(spt->slirp);
if (!m) {
return;
}
tp = tftp_prep_mbuf_data(spt, m);
tp->tp_op = htons(TFTP_DATA);
tp->x.tp_data.tp_block_nr = htons((spt->block_nr + 1) & 0xffff);
nobytes = tftp_read_data(spt, spt->block_nr, tp->x.tp_data.tp_buf,
spt->block_size);
if (nobytes < 0) {
m_free(m);
/* send "file not found" error back */
tftp_send_error(spt, 1, "File not found", tp);
return;
}
m->m_len = sizeof(struct tftp_t) - (TFTP_BLOCKSIZE_MAX - nobytes)
- sizeof(struct udphdr);
tftp_udp_output(spt, m, recv_tp);
if (nobytes == spt->block_size) {
tftp_session_update(spt);
}
else {
tftp_session_terminate(spt);
}
spt->block_nr++;
}
static void tftp_handle_rrq(Slirp *slirp, struct tftp_t *tp, int pktlen)
{
struct tftp_session *spt;
int s, k;
size_t prefix_len;
char *req_fname;
s = tftp_session_allocate(slirp, tp);
if (s < 0) {
return;
}
spt = &slirp->tftp_sessions[s];
/* unspecifed prefix means service disabled */
if (!slirp->tftp_prefix) {
tftp_send_error(spt, 2, "Access violation", tp);
return;
}
/* skip header fields */
k = 0;
pktlen -= ((uint8_t *)&tp->x.tp_buf[0] - (uint8_t *)tp);
/* prepend tftp_prefix */
prefix_len = strlen(slirp->tftp_prefix);
spt->filename = qemu_malloc(prefix_len + TFTP_FILENAME_MAX + 2);
memcpy(spt->filename, slirp->tftp_prefix, prefix_len);
spt->filename[prefix_len] = '/';
/* get name */
req_fname = spt->filename + prefix_len + 1;
while (1) {
if (k >= TFTP_FILENAME_MAX || k >= pktlen) {
tftp_send_error(spt, 2, "Access violation", tp);
return;
}
req_fname[k] = (char)tp->x.tp_buf[k];
if (req_fname[k++] == '\0') {
break;
}
}
/* check mode */
if ((pktlen - k) < 6) {
tftp_send_error(spt, 2, "Access violation", tp);
return;
}
if (memcmp(&tp->x.tp_buf[k], "octet\0", 6) != 0) {
tftp_send_error(spt, 4, "Unsupported transfer mode", tp);
return;
}
k += 6; /* skipping octet */
/* do sanity checks on the filename */
if (!strncmp(req_fname, "../", 3) ||
req_fname[strlen(req_fname) - 1] == '/' ||
strstr(req_fname, "/../")) {
tftp_send_error(spt, 2, "Access violation", tp);
return;
}
/* check if the file exists */
if (tftp_read_data(spt, 0, NULL, 0) < 0) {
tftp_send_error(spt, 1, "File not found", tp);
return;
}
if (tp->x.tp_buf[pktlen - 1] != 0) {
tftp_send_error(spt, 2, "Access violation", tp);
return;
}
while (k < pktlen) {
const char *key, *value;
key = (const char *)&tp->x.tp_buf[k];
k += strlen(key) + 1;
if (k >= pktlen) {
tftp_send_error(spt, 2, "Access violation", tp);
return;
}
value = (const char *)&tp->x.tp_buf[k];
k += strlen(value) + 1;
if (strcmp(key, "tsize") == 0) {
int tsize = atoi(value);
struct stat stat_p;
if (tsize == 0) {
if (stat(spt->filename, &stat_p) == 0)
tsize = stat_p.st_size;
else {
tftp_send_error(spt, 1, "File not found", tp);
return;
}
}
tftp_send_oack(spt, "tsize", tsize, tp);
}
}
tftp_send_data(spt, 1, tp);
}
static void tftp_handle_rrq(struct tftp_t *tp, int pktlen)
{
struct tftp_session *spt;
int s, k, n;
u_int8_t *src, *dst;
s = tftp_session_allocate(tp);
if (s < 0) {
return;
}
spt = &tftp_sessions[s];
src = tp->x.tp_buf;
dst = spt->filename;
n = pktlen - ((uint8_t *)&tp->x.tp_buf[0] - (uint8_t *)tp);
/* get name */
for (k = 0; k < n; k++) {
if (k < TFTP_FILENAME_MAX) {
dst[k] = src[k];
}
else {
return;
}
if (src[k] == '\0') {
break;
}
}
if (k >= n) {
return;
}
k++;
/* check mode */
if ((n - k) < 6) {
return;
}
if (memcmp(&src[k], "octet\0", 6) != 0) {
tftp_send_error(spt, 4, "Unsupported transfer mode", tp);
return;
}
k += 6; /* skipping octet */
/* do sanity checks on the filename */
if ((spt->filename[0] != '/')
|| (spt->filename[strlen((char *)spt->filename) - 1] == '/')
|| strstr((char *)spt->filename, "/../")) {
tftp_send_error(spt, 2, "Access violation", tp);
return;
}
/* only allow exported prefixes */
if (!tftp_prefix) {
tftp_send_error(spt, 2, "Access violation", tp);
return;
}
/* check if the file exists */
if (tftp_read_data(spt, 0, spt->filename, 0) < 0) {
tftp_send_error(spt, 1, "File not found", tp);
return;
}
if (src[n - 1] != 0) {
tftp_send_error(spt, 2, "Access violation", tp);
return;
}
while (k < n) {
const char *key, *value;
key = (char *)src + k;
k += strlen(key) + 1;
if (k >= n) {
tftp_send_error(spt, 2, "Access violation", tp);
return;
}
value = (char *)src + k;
k += strlen(value) + 1;
if (strcmp(key, "tsize") == 0) {
int tsize = atoi(value);
struct stat stat_p;
if (tsize == 0 && tftp_prefix) {
char buffer[1024];
int len;
len = snprintf(buffer, sizeof(buffer), "%s/%s",
tftp_prefix, spt->filename);
if (stat(buffer, &stat_p) == 0)
tsize = stat_p.st_size;
else {
tftp_send_error(spt, 1, "File not found", tp);
return;
}
}
tftp_send_oack(spt, "tsize", tsize, tp);
}
}
tftp_send_data(spt, 1, tp);
}
static void tftp_handle_rrq(Slirp *slirp, struct tftp_t *tp, int pktlen)
{
struct tftp_session *spt;
int s, k;
size_t prefix_len;
char *req_fname;
const char *option_name[2];
uint32_t option_value[2];
int nb_options = 0;
/* check if a session already exists and if so terminate it */
s = tftp_session_find(slirp, tp);
if (s >= 0) {
tftp_session_terminate(&slirp->tftp_sessions[s]);
}
s = tftp_session_allocate(slirp, tp);
if (s < 0) {
return;
}
spt = &slirp->tftp_sessions[s];
/* unspecified prefix means service disabled */
if (!slirp->tftp_prefix) {
tftp_send_error(spt, 2, "Access violation", tp);
return;
}
/* skip header fields */
k = 0;
pktlen -= offsetof(struct tftp_t, x.tp_buf);
/* prepend tftp_prefix */
prefix_len = strlen(slirp->tftp_prefix);
spt->filename = g_malloc(prefix_len + TFTP_FILENAME_MAX + 2);
memcpy(spt->filename, slirp->tftp_prefix, prefix_len);
spt->filename[prefix_len] = '/';
/* get name */
req_fname = spt->filename + prefix_len + 1;
while (1) {
if (k >= TFTP_FILENAME_MAX || k >= pktlen) {
tftp_send_error(spt, 2, "Access violation", tp);
return;
}
req_fname[k] = tp->x.tp_buf[k];
if (req_fname[k++] == '\0') {
break;
}
}
/* check mode */
if ((pktlen - k) < 6) {
tftp_send_error(spt, 2, "Access violation", tp);
return;
}
if (strcasecmp(&tp->x.tp_buf[k], "octet") != 0) {
tftp_send_error(spt, 4, "Unsupported transfer mode", tp);
return;
}
k += 6; /* skipping octet */
/* do sanity checks on the filename */
if (!strncmp(req_fname, "../", 3) ||
req_fname[strlen(req_fname) - 1] == '/' ||
strstr(req_fname, "/../")) {
tftp_send_error(spt, 2, "Access violation", tp);
return;
}
/* check if the file exists */
if (tftp_read_data(spt, 0, NULL, 0) < 0) {
tftp_send_error(spt, 1, "File not found", tp);
return;
}
if (tp->x.tp_buf[pktlen - 1] != 0) {
tftp_send_error(spt, 2, "Access violation", tp);
return;
}
while (k < pktlen && nb_options < ARRAY_SIZE(option_name)) {
const char *key, *value;
key = &tp->x.tp_buf[k];
k += strlen(key) + 1;
if (k >= pktlen) {
tftp_send_error(spt, 2, "Access violation", tp);
return;
}
value = &tp->x.tp_buf[k];
k += strlen(value) + 1;
if (strcasecmp(key, "tsize") == 0) {
int tsize = atoi(value);
struct stat stat_p;
if (tsize == 0) {
if (stat(spt->filename, &stat_p) == 0)
tsize = stat_p.st_size;
else {
tftp_send_error(spt, 1, "File not found", tp);
return;
}
}
option_name[nb_options] = "tsize";
option_value[nb_options] = tsize;
nb_options++;
} else if (strcasecmp(key, "blksize") == 0) {
int blksize = atoi(value);
/* If blksize option is bigger than what we will
* emit, accept the option with our packet size.
* Otherwise, simply do as we didn't see the option.
*/
if (blksize >= 512) {
option_name[nb_options] = "blksize";
option_value[nb_options] = 512;
nb_options++;
}
}
}
if (nb_options > 0) {
assert(nb_options <= ARRAY_SIZE(option_name));
tftp_send_oack(spt, option_name, option_value, nb_options, tp);
return;
}
spt->block_nr = 0;
tftp_send_next_block(spt, tp);
}
static void tftp_handle_rrq(struct tftp_t *tp, int pktlen)
{
struct tftp_session *spt;
int s, k, n;
u_int8_t *src, *dst;
s = tftp_session_allocate(tp);
if (s < 0) {
return;
}
spt = &tftp_sessions[s];
src = tp->x.tp_buf;
dst = (u_int8_t *)spt->filename;
n = pktlen - ((uint8_t *)&tp->x.tp_buf[0] - (uint8_t *)tp);
/* get name */
for (k = 0; k < n; k++) {
if (k < TFTP_FILENAME_MAX) {
dst[k] = src[k];
}
else {
return;
}
if (src[k] == '\0') {
break;
}
}
if (k >= n) {
return;
}
k++;
/* check mode */
if ((n - k) < 6) {
return;
}
if (memcmp(&src[k], "octet\0", 6) != 0) {
tftp_send_error(spt, 4, "Unsupported transfer mode", tp);
return;
}
/* do sanity checks on the filename */
if ((spt->filename[0] != '/')
|| (spt->filename[strlen(spt->filename) - 1] == '/')
|| strstr(spt->filename, "/../")) {
tftp_send_error(spt, 2, "Access violation", tp);
return;
}
/* only allow exported prefixes */
if (!tftp_prefix
|| (strncmp(spt->filename, tftp_prefix, strlen(tftp_prefix)) != 0)) {
tftp_send_error(spt, 2, "Access violation", tp);
return;
}
/* check if the file exists */
if (tftp_read_data(spt, 0, (u_int8_t *)spt->filename, 0) < 0) {
tftp_send_error(spt, 1, "File not found", tp);
return;
}
tftp_send_data(spt, 1, tp);
}
