/* * Copyright (c) 2017 Gilles Chehade <gilles@poolp.org> * * Permission to use, copy, modify, and distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ #include <sys/types.h> #include <sys/socket.h> #include <sys/un.h> #include <ctype.h> #include <err.h> #include <errno.h> #include <netdb.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sysexits.h> #include <unistd.h> enum phase { PHASE_BANNER, PHASE_HELO, PHASE_MAILFROM, PHASE_RCPTTO, PHASE_DATA, PHASE_EOM, PHASE_QUIT }; struct session { const char *lhlo; const char *mailfrom; char **rcpts; int n_rcpts; }; static FILE *lmtp_connect(const char *); static void lmtp_engine(FILE *, struct session *); static void stream_file(FILE *); int main(int argc, char *argv[]) { int ch; FILE *conn; const char *destination = "localhost"; struct session session; if (! geteuid()) errx(EX_TEMPFAIL, "mail.lmtp: may not be executed as root"); session.lhlo = "localhost"; session.mailfrom = NULL; while ((ch = getopt(argc, argv, "d:l:f:")) != -1) { switch (ch) { case 'd': destination = optarg; break; case 'l': session.lhlo = optarg; break; case 'f': session.mailfrom = optarg; break; default: break; } } argc -= optind; argv += optind; if (session.mailfrom == NULL) errx(EX_TEMPFAIL, "sender must be specified with -f"); if (argc == 0) errx(EX_TEMPFAIL, "no recipient was specified"); session.rcpts = argv; session.n_rcpts = argc; conn = lmtp_connect(destination); lmtp_engine(conn, &session); return (0); } static FILE * lmtp_connect_inet(const char *destination) { struct addrinfo hints, *res, *res0; char *destcopy = NULL; const char *hostname = NULL; const char *servname = NULL; const char *cause = NULL; char *p; int n, s = -1, save_errno; if ((destcopy = strdup(destination)) == NULL) err(EX_TEMPFAIL, NULL); servname = "25"; hostname = destcopy; p = destcopy; if (*p == '[') { if ((p = strchr(destcopy, ']')) == NULL) errx(EX_TEMPFAIL, "inet: invalid address syntax"); /* remove [ and ] */ *p = '\0'; hostname++; if (strncasecmp(hostname, "IPv6:", 5) == 0) hostname += 5; /* extract port if any */ switch (*(p+1)) { case ':': servname = p+2; break; case '\0': break; default: errx(EX_TEMPFAIL, "inet: invalid address syntax"); } } else if ((p = strchr(destcopy, ':')) != NULL) { *p++ = '\0'; servname = p; } memset(&hints, 0, sizeof hints); hints.ai_family = PF_UNSPEC; hints.ai_socktype = SOCK_STREAM; hints.ai_flags = AI_NUMERICSERV; n = getaddrinfo(hostname, servname, &hints, &res0); if (n) errx(EX_TEMPFAIL, "inet: %s", gai_strerror(n)); for (res = res0; res; res = res->ai_next) { s = socket(res->ai_family, res->ai_socktype, res->ai_protocol); if (s == -1) { cause = "socket"; continue; } if (connect(s, res->ai_addr, res->ai_addrlen) == -1) { cause = "connect"; save_errno = errno; close(s); errno = save_errno; s = -1; continue; } break; } freeaddrinfo(res0); if (s == -1) errx(EX_TEMPFAIL, "%s", cause); free(destcopy); return fdopen(s, "r+"); } static FILE * lmtp_connect_unix(const char *destination) { struct sockaddr_un addr; int s; if (*destination != '/') errx(EX_TEMPFAIL, "unix: path must be absolute"); if ((s = socket(PF_LOCAL, SOCK_STREAM, 0)) == -1) err(EX_TEMPFAIL, NULL); memset(&addr, 0, sizeof addr); addr.sun_family = AF_UNIX; if (strlcpy(addr.sun_path, destination, sizeof addr.sun_path) >= sizeof addr.sun_path) errx(EX_TEMPFAIL, "unix: socket path is too long"); if (connect(s, (struct sockaddr *)&addr, sizeof addr) == -1) err(EX_TEMPFAIL, "connect"); return fdopen(s, "r+"); } static FILE * lmtp_connect(const char *destination) { if (destination[0] == '/') return lmtp_connect_unix(destination); return lmtp_connect_inet(destination); } static void lmtp_engine(FILE *conn, struct session *session) { char *line = NULL; size_t linesize = 0; ssize_t linelen; enum phase phase = PHASE_BANNER; do { fflush(conn); if ((linelen = getline(&line, &linesize, conn)) == -1) { if (ferror(conn)) err(EX_TEMPFAIL, "getline"); else errx(EX_TEMPFAIL, "unexpected EOF from LMTP server"); } line[strcspn(line, "\n")] = '\0'; line[strcspn(line, "\r")] = '\0'; if (linelen < 4 || !isdigit(line[0]) || !isdigit(line[1]) || !isdigit(line[2]) || (line[3] != ' ' && line[3] != '-')) errx(EX_TEMPFAIL, "LMTP server sent an invalid line"); if (line[0] != (phase == PHASE_DATA ? '3' : '2')) errx(EX_TEMPFAIL, "LMTP server error: %s", line); if (line[3] == '-') continue; switch (phase) { case PHASE_BANNER: fprintf(conn, "LHLO %s\r\n", session->lhlo); phase++; break; case PHASE_HELO: fprintf(conn, "MAIL FROM:<%s>\r\n", session->mailfrom); phase++; break; case PHASE_MAILFROM: fprintf(conn, "RCPT TO:<%s>\r\n", session->rcpts[session->n_rcpts - 1]); if (session->n_rcpts - 1 == 0) { phase++; break; } session->n_rcpts--; break; case PHASE_RCPTTO: fprintf(conn, "DATA\r\n"); phase++; break; case PHASE_DATA: stream_file(conn); fprintf(conn, ".\r\n"); phase++; break; case PHASE_EOM: fprintf(conn, "QUIT\r\n"); phase++; break; case PHASE_QUIT: exit(0); } } while (1); } static void stream_file(FILE *conn) { char *line = NULL; size_t linesize = 0; ssize_t linelen; while ((linelen = getline(&line, &linesize, stdin)) != -1) { line[strcspn(line, "\n")] = '\0'; if (line[0] == '.') fprintf(conn, "."); fprintf(conn, "%s\r\n", line); } free(line); if (ferror(stdin)) err(EX_TEMPFAIL, "getline"); }