diff options
Diffstat (limited to 'nbtpd/handlers.c')
| -rw-r--r-- | nbtpd/handlers.c | 535 |
1 files changed, 535 insertions, 0 deletions
diff --git a/nbtpd/handlers.c b/nbtpd/handlers.c new file mode 100644 index 0000000..d42382e --- /dev/null +++ b/nbtpd/handlers.c @@ -0,0 +1,535 @@ +#ifdef __linux__ +#define _POSIX_C_SOURCE 200809L +#define _DEFAULT_SOURCE +#endif + +#include <stdlib.h> +#include <stdio.h> +#include <sys/socket.h> +#include <arpa/inet.h> +#include <string.h> +#include <syslog.h> +#include <limits.h> +#include <errno.h> +#include <unistd.h> +#ifdef __FreeBSD__ +#include <sys/param.h> +#endif + +#include "handlers.h" +#include "packet.h" +#include "netascii.h" + +inline nbd_opmode get_mode(char *mode) { + nbd_opmode opmode; + if (strncmp(mode, (char *)&"netascii", NBD_NBTPD_ARGS_MODE_MAX) == 0) { + opmode = NETASCII; + } else if (strncmp(mode, (char *)&"octet", NBD_NBTPD_ARGS_MODE_MAX) == 0) { + opmode = OCTET; + } else if (strncmp(mode, (char *)&"mail", NBD_NBTPD_ARGS_MODE_MAX) == 0) { + opmode = MAIL; + } else { + opmode = NOT_FOUND; + } + return opmode; +} + +int makesock(nbd_nbtpd_args *argptr) { + int s = socket(AF_INET, SOCK_DGRAM, 0); + if (s <= 0) { + syslog(LOG_ERR, "unable to define socket: %s", strerror(errno)); + return -1; + } + struct timeval timeout = { 30, 0 }; + if (setsockopt(s, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof(timeout)) < 0) { + syslog(LOG_ERR, "unable to set socket timeout: %s", strerror(errno)); + close(s); + return -1; + } + if (connect(s, (struct sockaddr *)&(argptr->client), sizeof(struct sockaddr)) < 0) { + syslog( + LOG_ERR, + "unable to connect to client %s: %s", + inet_ntoa(argptr->client.sin_addr), + strerror(errno) + ); + close(s); + return -1; + } + return s; +} + +char *checkpath(nbd_nbtpd_args *argptr, uint8_t read) { + char *fname = NULL, *wd = NULL, *path = NULL, *ptr = NULL; + char **parts = NULL; + if (!is_netascii_str((char *)&argptr->path)) { + argptr->err = 1; + goto cleanup; + } + if (read) { + fname = realpath((char *)&argptr->path, NULL); + } else { + //TODO: figure out how to canonicalize non-existent path + char *tok = NULL; + parts = malloc(sizeof(parts) * NBD_NBTPD_ARGS_PATH_MAX); + if (parts == NULL) { + goto cleanup; + } + memset(parts, '\0', sizeof(parts) * NBD_NBTPD_ARGS_PATH_MAX); + ptr = (char *)&argptr->path; + for (int i = 0; ((tok = strsep(&ptr, "/")) != NULL); i++ ) { + parts[i] = tok; + } + path = malloc(NBD_NBTPD_ARGS_PATH_MAX); + if (path == NULL) { + goto cleanup; + } + memset(path, '\0', NBD_NBTPD_ARGS_PATH_MAX); + int z = 0; + for (int i = 0; parts[i] != NULL; i++) { + if (strncmp(parts[i], "..", 2) == 0) { + continue; + } + if (strncmp(parts[i], ".", NBD_NBTPD_ARGS_PATH_MAX) == 0) { + continue; + } + for (int x = 0; parts[i][x] != '\0'; x++) { + if (z < NBD_NBTPD_ARGS_PATH_MAX) { + path[z++] = parts[i][x]; + } else { + goto cleanup; + } + } + if (z < NBD_NBTPD_ARGS_PATH_MAX) { + path[z++] = '/'; + } else { + goto cleanup; + } + } + // erase trailing slash + path[z - 1] = '\0'; + fname = strdup(path); + } + if (fname == NULL) { + syslog(LOG_ERR, "unable to get real path: %s", strerror(errno)); + argptr->err = 1; + goto cleanup; + } +/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * + * POSIX does not define what happens when getcwd() is given NULL. * + * This means that illumos libc and GNU libc both return a newly * + * malloc()'d string, while FreeBSD libc does not. Also, FreeBSD uses * + * constant MAXPATHLEN defined in <sys/param.h> rather than PATH_MAX. * + * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */ +#ifdef __FreeBSD__ + wd = malloc(MAXPATHLEN); + if (wd == NULL) { + syslog(LOG_ERR, "unable to allocate PATH_MAX memory: %s", strerror(errno)); + argptr->err = 0; + goto cleanup; + } + if (getcwd(wd, MAXPATHLEN) == NULL) { + argptr->err = 0; + goto cleanup; + } +#else + if ((wd = getcwd(NULL, PATH_MAX)) == NULL) { + argptr->err = 0; + goto cleanup; + } +#endif + syslog(LOG_DEBUG, "cwd: %s :: realpath: %s", wd, fname); + if (read) { + if (strncmp(wd, fname, strlen(wd))) { + syslog( + LOG_ERR, + "%s:%d requested invalid file %s", + inet_ntoa(argptr->client.sin_addr), + ntohs(argptr->client.sin_port), + fname + ); + argptr->err = 2; + goto cleanup; + } + } else { + strcat(wd, "/"); + strcat(wd, fname); + char *intermediate = wd; + wd = fname; + fname = intermediate; + } +cleanup: + free(wd); + free(path); + free(parts); + return fname; +} + +ssize_t senderror(int s, nbd_nbtpd_args *argptr) { + size_t buflen = 4 + strlen(nbd_tftp_error_to_message((nbd_tftp_ecode)argptr->err)); + char *buf = nbd_tftp_ser_error_from_code((nbd_tftp_ecode)argptr->err); + ssize_t sb = send(s, buf, buflen, 0); + free(buf); + return sb; +} + +void *read_req_resp(void *args) { + char *fname = NULL, *buf = NULL, *rxb = NULL; + FILE *fp = NULL; + nbd_nbtpd_args *argptr = (nbd_nbtpd_args *)args; + syslog( + LOG_DEBUG, + "%s:%d is requesting file %s", + inet_ntoa(argptr->client.sin_addr), + ntohs(argptr->client.sin_port), + argptr->path + ); + fname = checkpath(argptr, 1); + if (fname == NULL) { + goto pre_socket; + } + if (!is_netascii_str((char *)&(argptr->mode))) { + syslog( + LOG_ERR, + "%s:%d mode is invalid %s", + inet_ntoa(argptr->client.sin_addr), + ntohs(argptr->client.sin_port), + argptr->mode + ); + argptr->err = 4; + goto pre_socket; + } + nbd_opmode opmode = get_mode((char *)&(argptr->mode)); + if ((opmode != NETASCII) && (opmode != OCTET)) { + argptr->err = 4; + goto pre_socket; + } + fp = fopen(fname, "r"); + if (fp == NULL) { + syslog( + LOG_ERR, + "failed to open file for reading: %s", + strerror(errno) + ); + argptr->err = 2; + goto pre_socket; + } + buf = malloc(512); + rxb = malloc(256); + if ((buf == NULL) || (rxb == NULL)) { + syslog( + LOG_CRIT, + "failed to allocate memory: %s", + strerror(errno) + ); + argptr->err = 0; + goto pre_socket; + } + int s = makesock(argptr); + if (s <= 0) { + goto cleanup; + } + uint8_t rxon = 0, lon = 1; + uint16_t bnum = 0; + while (lon) { + memset(buf, '\0', 512); + uint8_t verif = 0; + uint8_t vcount = 0; + size_t num_read = fread(buf, 1, 512, fp); + if (((num_read < 512) && (!feof(fp))) || (vcount > 5)) { + argptr->err = 0; + senderror(s, argptr); + goto cleanup; + } + if ((opmode == NETASCII) && (!is_netascii_buf(buf, num_read))) { + syslog( + LOG_ERR, + "%s:%d: requested file is not netascii compliant.", + inet_ntoa(argptr->client.sin_addr), + ntohs(argptr->client.sin_port) + ); + argptr->err = 5; + senderror(s, argptr); + goto cleanup; + } + char *packet = nbd_tftp_ser_data_from_parts(++bnum, buf, num_read); + while (!verif) { + syslog(LOG_DEBUG, "sending block number %d to %s:%d", + bnum, + inet_ntoa(argptr->client.sin_addr), + htons(argptr->client.sin_port) + ); + if (send(s, packet, num_read + 4, 0) < 0) { + syslog( + LOG_ERR, + "unable to send data to %s: %s", + inet_ntoa(argptr->client.sin_addr), + strerror(errno) + ); + continue; + } + rxon = 1; + uint8_t rxcount = 0; + while (rxon) { + syslog(LOG_DEBUG, "waiting for ack %d from %s:%d", + bnum, + inet_ntoa(argptr->client.sin_addr), + htons(argptr->client.sin_port) + ); + memset(rxb, '\0', 256); + ssize_t rcv = recv(s, rxb, 256, 0); + syslog(LOG_DEBUG, "recv'd %ld bytes from %s:%d", + rcv, + inet_ntoa(argptr->client.sin_addr), + htons(argptr->client.sin_port) + ); + if (rcv == 4) { + nbd_tftp_packet_ack ack = nbd_tftp_de_ack(rxb, rcv); + if (ack.opcode == 5) { + goto socket_clean; + } + syslog(LOG_DEBUG, "%s:%d ack'd with block number: %d (expect %d)", + inet_ntoa(argptr->client.sin_addr), + htons(argptr->client.sin_port), + ack.block_num, + bnum + ); + if (ack.block_num == bnum) { + rxon = 0; + verif = 1; + break; + } + if (ack.block_num == (bnum - 1)) { + rxon = 0; + vcount++; + break; + } + } + if (++rxcount > 30) { + argptr->err = 0; + senderror(s, argptr); + goto cleanup; + } + if (rcv > 4) { + if ((((uint16_t)buf[0] << 8) + buf[1]) == 5) { + goto socket_clean; + } + } + } + } + free(packet); + if (num_read < 512) { + lon = 0; + } + } +socket_clean: + close(s); +cleanup: + fclose(fp); + free(buf); + free(rxb); + free(fname); + free(args); + return (void *)NULL; +pre_socket: + if (fp != NULL) { + fclose(fp); + } + free(buf); + free(rxb); + free(fname); + return nbd_nbtpd_resp_error(args); +} + +void *write_req_resp(void *args) { + char *fname = NULL, *rxb = NULL; + FILE *fp = NULL; + nbd_nbtpd_args *argptr = (nbd_nbtpd_args *)args; + syslog( + LOG_DEBUG, + "%s:%d is trying to write file %s", + inet_ntoa(argptr->client.sin_addr), + ntohs(argptr->client.sin_port), + argptr->path + ); + fname = checkpath(argptr, 0); + if (fname == NULL) { + syslog(LOG_ERR, "fname is NULL"); + goto pre_socket; + } + if (!is_netascii_str((char *)&(argptr->mode))) { + syslog( + LOG_ERR, + "%s:%d mode is invalid %s", + inet_ntoa(argptr->client.sin_addr), + ntohs(argptr->client.sin_port), + argptr->mode + ); + argptr->err = 4; + goto pre_socket; + } + nbd_opmode opmode = get_mode((char *)&(argptr->mode)); + if ((opmode != NETASCII) && (opmode != OCTET)) { + syslog(LOG_ERR, "%s:%d mode is not supported.", inet_ntoa(argptr->client.sin_addr), ntohs(argptr->client.sin_port)); + argptr->err = 4; + goto pre_socket; + } + fp = fopen(fname, "w"); + if (fp == NULL) { + syslog( + LOG_ERR, + "failed to open file for writing: %s", + strerror(errno) + ); + argptr->err = 2; + goto pre_socket; + } + rxb = malloc(768); // 768 is 1.5x expected block size + if (rxb == NULL) { + syslog( + LOG_CRIT, + "failed to allocate memory: %s", + strerror(errno) + ); + argptr->err = 0; + goto pre_socket; + } + int s = makesock(argptr); + if (s <= 0) { + goto cleanup; + } + uint8_t rxon = 0, lon = 1; + uint16_t bnum = 0; + ssize_t rcv = 516; + while (lon) { + uint8_t verif = 0; + uint8_t vcount = 0; + char *packet = nbd_tftp_ser_ack_from_block_num(bnum++); + while (!verif) { + syslog(LOG_DEBUG, "sending ack number %d to %s:%d", + bnum, + inet_ntoa(argptr->client.sin_addr), + htons(argptr->client.sin_port) + ); + if (send(s, packet, 4, 0) < 0) { + syslog( + LOG_ERR, + "unable to send ack to %s:%d: %s", + inet_ntoa(argptr->client.sin_addr), + htons(argptr->client.sin_port), + strerror(errno) + ); + continue; + } + if ((rcv < 516) || (vcount > 5)) { + lon = 0; + break; + } + rxon = 1; + uint8_t rxcount = 0; + while (rxon) { + syslog(LOG_DEBUG, "waiting for data from %s:%d", + inet_ntoa(argptr->client.sin_addr), + htons(argptr->client.sin_port) + ); + memset(rxb, '\0', 768); + rcv = recv(s, rxb, 768, 0); + syslog(LOG_DEBUG, "recv'd %ld bytes from %s:%d", + rcv, + inet_ntoa(argptr->client.sin_addr), + htons(argptr->client.sin_port) + ); + if (rcv >= 4) { + nbd_tftp_packet_data data = nbd_tftp_de_data(rxb, rcv); + if (data.opcode == 5) { + free(data.data); + goto cleanup; + } + syslog( + LOG_DEBUG, + "%s:%d sent block number: %d (expect %d)", + inet_ntoa(argptr->client.sin_addr), + htons(argptr->client.sin_port), + data.block_num, + bnum + ); + if (data.block_num == bnum) { + rxon = 0; + verif = 1; + if (data.datalen > 0) { + if ((opmode == NETASCII) && (!is_netascii_buf(data.data, data.datalen))) { + syslog( + LOG_ERR, + "%s:%d: requested file is not netascii compliant.", + inet_ntoa(argptr->client.sin_addr), + ntohs(argptr->client.sin_port) + ); + argptr->err = 5; + senderror(s, argptr); + free(data.data); + goto cleanup; + } + if (fwrite(data.data, 1, data.datalen, fp) < data.datalen) { + syslog(LOG_ERR, "filewrite failed for %s: %s", fname, strerror(errno)); + argptr->err = 0; + senderror(s, argptr); + free(data.data); + goto clean_socket; + } + } + free(data.data); + break; + } + if (data.block_num == (bnum - 1)) { + rxon = 0; + vcount++; + free(data.data); + break; + } + free(data.data); + } + if (++rxcount > 30) { + syslog(LOG_ERR, "retry count exceeded"); + argptr->err = 0; + senderror(s, argptr); + goto clean_socket; + } + } + } + free(packet); + } +clean_socket: + close(s); +cleanup: + fclose(fp); + free(rxb); + free(fname); + free(args); + return (void *)NULL; +pre_socket: + if (fp != NULL) { + fclose(fp); + } + free(rxb); + free(fname); + return nbd_nbtpd_resp_error(args); +} + +void *nbd_nbtpd_resp_error(void *args) { + nbd_nbtpd_args *argptr = (nbd_nbtpd_args *)args; + int s = makesock(argptr); + if (s <= 0) { + syslog( + LOG_ERR, + "cannot send error to %s:%d", + inet_ntoa(argptr->client.sin_addr), + ntohs(argptr->client.sin_port) + ); + goto cleanup; + } + senderror(s, argptr); +cleanup: + free(args); + return (void *)NULL; +} + |