/* * popsbr.c -- POP client subroutines * * This code is Copyright (c) 2002, by the authors of nmh. See the * COPYRIGHT file in the root directory of the nmh distribution for * complete copyright information. */ #include #include #ifdef CYRUS_SASL # include # include #endif /* CYRUS_SASL */ #include #include #include #include #define TRM "." #define TRMLEN (sizeof TRM - 1) static int poprint = 0; static int pophack = 0; char response[BUFSIZ]; static FILE *input; static FILE *output; #ifdef CYRUS_SASL static sasl_conn_t *conn; /* SASL connection state */ static int sasl_complete = 0; /* Has sasl authentication succeeded? */ static int maxoutbuf; /* Maximum output buffer size */ static sasl_ssf_t sasl_ssf = 0; /* Security strength factor */ static int sasl_get_user(void *, int, const char **, unsigned *); static int sasl_get_pass(sasl_conn_t *, void *, int, sasl_secret_t **); struct pass_context { char *user; char *host; }; static sasl_callback_t callbacks[] = { { SASL_CB_USER, sasl_get_user, NULL }, #define POP_SASL_CB_N_USER 0 { SASL_CB_PASS, sasl_get_pass, NULL }, #define POP_SASL_CB_N_PASS 1 { SASL_CB_LOG, NULL, NULL }, { SASL_CB_LIST_END, NULL, NULL }, #define SASL_BUFFER_SIZE 262144 }; #else /* CYRUS_SASL */ # define sasl_fgetc fgetc #endif /* CYRUS_SASL */ /* * static prototypes */ static int command(const char *, ...); static int multiline(void); #ifdef CYRUS_SASL static int pop_auth_sasl(char *, char *, char *); static int sasl_fgetc(FILE *); #endif /* CYRUS_SASL */ static int traverse (int (*)(char *), const char *, ...); static int vcommand(const char *, va_list); static int sasl_getline (char *, int, FILE *); static int putline (char *, FILE *); #ifdef CYRUS_SASL /* * This function implements the AUTH command for various SASL mechanisms * * We do the whole SASL dialog here. If this completes, then we've * authenticated successfully and have (possibly) negotiated a security * layer. */ int pop_auth_sasl(char *user, char *host, char *mech) { int result, status, sasl_capability = 0; unsigned int buflen, outlen; char server_mechs[256], *buf, outbuf[BUFSIZ]; const char *chosen_mech; sasl_security_properties_t secprops; struct pass_context p_context; sasl_ssf_t *ssf; int *moutbuf; /* * First off, we're going to send the CAPA command to see if we can * even support the AUTH command, and if we do, then we'll get a * list of mechanisms the server supports. If we don't support * the CAPA command, then it's unlikely that we will support * SASL */ if (command("CAPA") == NOTOK) { snprintf(response, sizeof(response), "The POP CAPA command failed; POP server does not " "support SASL"); return NOTOK; } while ((status = multiline()) != DONE) switch (status) { case NOTOK: return NOTOK; break; case DONE: /* Shouldn't be possible, but just in case */ break; case OK: if (strncasecmp(response, "SASL ", 5) == 0) { /* * We've seen the SASL capability. Grab the mech list */ sasl_capability++; strncpy(server_mechs, response + 5, sizeof(server_mechs)); } break; } if (!sasl_capability) { snprintf(response, sizeof(response), "POP server does not support " "SASL"); return NOTOK; } /* * If we received a preferred mechanism, see if the server supports it. */ if (mech && stringdex(mech, server_mechs) == -1) { snprintf(response, sizeof(response), "Requested SASL mech \"%s\" is " "not in list of supported mechanisms:\n%s", mech, server_mechs); return NOTOK; } /* * Start the SASL process. First off, initialize the SASL library. */ callbacks[POP_SASL_CB_N_USER].context = user; p_context.user = user; p_context.host = host; callbacks[POP_SASL_CB_N_PASS].context = &p_context; result = sasl_client_init(callbacks); if (result != SASL_OK) { snprintf(response, sizeof(response), "SASL library initialization " "failed: %s", sasl_errstring(result, NULL, NULL)); return NOTOK; } result = sasl_client_new("pop", host, NULL, NULL, NULL, 0, &conn); if (result != SASL_OK) { snprintf(response, sizeof(response), "SASL client initialization " "failed: %s", sasl_errstring(result, NULL, NULL)); return NOTOK; } /* * Initialize the security properties */ memset(&secprops, 0, sizeof(secprops)); secprops.maxbufsize = SASL_BUFFER_SIZE; secprops.max_ssf = UINT_MAX; result = sasl_setprop(conn, SASL_SEC_PROPS, &secprops); if (result != SASL_OK) { snprintf(response, sizeof(response), "SASL security property " "initialization failed: %s", sasl_errdetail(conn)); return NOTOK; } /* * Start the actual protocol. Feed the mech list into the library * and get out a possible initial challenge */ result = sasl_client_start(conn, (const char *) (mech ? mech : server_mechs), NULL, (const char **) &buf, &buflen, &chosen_mech); if (result != SASL_OK && result != SASL_CONTINUE) { snprintf(response, sizeof(response), "SASL client start failed: %s", sasl_errdetail(conn)); return NOTOK; } if (buflen) { status = sasl_encode64(buf, buflen, outbuf, sizeof(outbuf), NULL); if (status != SASL_OK) { snprintf(response, sizeof(response), "SASL base64 encode " "failed: %s", sasl_errstring(status, NULL, NULL)); return NOTOK; } status = command("AUTH %s %s", chosen_mech, outbuf); } else status = command("AUTH %s", chosen_mech); while (result == SASL_CONTINUE) { if (status == NOTOK) return NOTOK; /* * If we get a "+OK" prefix to our response, then we should * exit out of this exchange now (because authenticated should * have succeeded) */ if (strncmp(response, "+OK", 3) == 0) break; /* * Otherwise, make sure the server challenge is correctly formatted */ if (strncmp(response, "+ ", 2) != 0) { command("*"); snprintf(response, sizeof(response), "Malformed authentication message from server"); return NOTOK; } result = sasl_decode64(response + 2, strlen(response + 2), outbuf, sizeof(outbuf), &outlen); if (result != SASL_OK) { command("*"); snprintf(response, sizeof(response), "SASL base64 decode " "failed: %s", sasl_errstring(result, NULL, NULL)); return NOTOK; } result = sasl_client_step(conn, outbuf, outlen, NULL, (const char **) &buf, &buflen); if (result != SASL_OK && result != SASL_CONTINUE) { command("*"); snprintf(response, sizeof(response), "SASL client negotiaton " "failed: %s", sasl_errdetail(conn)); return NOTOK; } status = sasl_encode64(buf, buflen, outbuf, sizeof(outbuf), NULL); if (status != SASL_OK) { command("*"); snprintf(response, sizeof(response), "SASL base64 encode " "failed: %s", sasl_errstring(status, NULL, NULL)); return NOTOK; } status = command(outbuf); } /* * If we didn't get a positive final response, then error out * (that probably means we failed an authorization check). */ if (status != OK) return NOTOK; /* * We _should_ be okay now. Get a few properties now that negotiation * has completed. */ result = sasl_getprop(conn, SASL_MAXOUTBUF, (const void **) &moutbuf); if (result != SASL_OK) { snprintf(response, sizeof(response), "Cannot retrieve SASL negotiated " "output buffer size: %s", sasl_errdetail(conn)); return NOTOK; } maxoutbuf = *moutbuf; result = sasl_getprop(conn, SASL_SSF, (const void **) &ssf); sasl_ssf = *ssf; if (result != SASL_OK) { snprintf(response, sizeof(response), "Cannot retrieve SASL negotiated " "security strength factor: %s", sasl_errdetail(conn)); return NOTOK; } /* * Limit this to what we can deal with. Shouldn't matter much because * this is only outgoing data (which should be small) */ if (maxoutbuf == 0 || maxoutbuf > BUFSIZ) maxoutbuf = BUFSIZ; sasl_complete = 1; return status; } /* * Callback to return the userid sent down via the user parameter */ static int sasl_get_user(void *context, int id, const char **result, unsigned *len) { char *user = (char *) context; if (! result || id != SASL_CB_USER) return SASL_BADPARAM; *result = user; if (len) *len = strlen(user); return SASL_OK; } /* * Callback to return the password (we call ruserpass, which can get it * out of the .netrc */ static int sasl_get_pass(sasl_conn_t *conn, void *context, int id, sasl_secret_t **psecret) { NMH_UNUSED (conn); struct pass_context *p_context = (struct pass_context *) context; char *pass = NULL; int len; if (! psecret || id != SASL_CB_PASS) return SASL_BADPARAM; ruserpass(p_context->user, &(p_context->host), &pass); len = strlen(pass); *psecret = (sasl_secret_t *) mh_xmalloc(sizeof(sasl_secret_t) + len); (*psecret)->len = len; strcpy((char *) (*psecret)->data, pass); return SASL_OK; } #endif /* CYRUS_SASL */ /* * Split string containing proxy command into an array of arguments * suitable for passing to exec. Returned array must be freed. Shouldn't * be possible to call this with host set to NULL. */ char ** parse_proxy(char *proxy, char *host) { char **pargv, **p; int pargc = 2; int hlen = strlen(host); int plen = 1; unsigned char *cur, *pro; char *c; /* skip any initial space */ for (pro = (unsigned char *) proxy; isspace(*pro); pro++) continue; /* calculate required size for argument array */ for (cur = pro; *cur; cur++) { if (isspace(*cur) && cur[1] && !isspace(cur[1])) plen++, pargc++; else if (*cur == '%' && cur[1] == 'h') { plen += hlen; cur++; } else if (!isspace(*cur)) plen++; } /* put together list of arguments */ p = pargv = mh_xmalloc(pargc * sizeof(char *)); c = *pargv = mh_xmalloc(plen * sizeof(char)); for (cur = pro; *cur; cur++) { if (isspace(*cur) && cur[1] && !isspace(cur[1])) { *c++ = '\0'; *++p = c; } else if (*cur == '%' && cur[1] == 'h') { strcpy (c, host); c += hlen; cur++; } else if (!isspace(*cur)) *c++ = *cur; } *++p = NULL; return pargv; } int pop_init (char *host, char *port, char *user, char *pass, char *proxy, int snoop, int sasl, char *mech) { #ifndef CYRUS_SASL NMH_UNUSED (sasl); NMH_UNUSED (mech); #endif /* ! CYRUS_SASL */ int fd1, fd2; char buffer[BUFSIZ]; if (proxy && *proxy) { int pid; int inpipe[2]; /* for reading from the server */ int outpipe[2]; /* for sending to the server */ /* first give up any root priviledges we may have for rpop */ setuid(getuid()); pipe(inpipe); pipe(outpipe); pid=fork(); if (pid==0) { char **argv; /* in child */ close(0); close(1); dup2(outpipe[0],0); /* connect read end of connection */ dup2(inpipe[1], 1); /* connect write end of connection */ if(inpipe[0]>1) close(inpipe[0]); if(inpipe[1]>1) close(inpipe[1]); if(outpipe[0]>1) close(outpipe[0]); if(outpipe[1]>1) close(outpipe[1]); /* run the proxy command */ argv=parse_proxy(proxy, host); execvp(argv[0],argv); perror(argv[0]); close(0); close(1); free(*argv); free(argv); exit(10); } /* okay in the parent we do some stuff */ close(inpipe[1]); /* child uses this */ close(outpipe[0]); /* child uses this */ /* we read on fd1 */ fd1=inpipe[0]; /* and write on fd2 */ fd2=outpipe[1]; } else { if ((fd1 = client (host, port ? port : "pop3", response, sizeof(response), snoop)) == NOTOK) { return NOTOK; } if ((fd2 = dup (fd1)) == NOTOK) { char *s; if ((s = strerror(errno))) snprintf (response, sizeof(response), "unable to dup connection descriptor: %s", s); else snprintf (response, sizeof(response), "unable to dup connection descriptor: unknown error"); close (fd1); return NOTOK; } } if (pop_set (fd1, fd2, snoop) == NOTOK) return NOTOK; SIGNAL (SIGPIPE, SIG_IGN); switch (sasl_getline (response, sizeof response, input)) { case OK: if (poprint) fprintf (stderr, "<--- %s\n", response); if (*response == '+') { # ifdef CYRUS_SASL if (sasl) { if (pop_auth_sasl(user, host, mech) != NOTOK) return OK; } else # endif /* CYRUS_SASL */ if (command ("USER %s", user) != NOTOK && command ("%s %s", (pophack++, "PASS"), pass) != NOTOK) return OK; } strncpy (buffer, response, sizeof(buffer)); command ("QUIT"); strncpy (response, buffer, sizeof(response)); /* and fall */ case NOTOK: case DONE: if (poprint) fprintf (stderr, "%s\n", response); fclose (input); fclose (output); return NOTOK; } return NOTOK; /* NOTREACHED */ } int pop_set (int in, int out, int snoop) { if ((input = fdopen (in, "r")) == NULL || (output = fdopen (out, "w")) == NULL) { strncpy (response, "fdopen failed on connection descriptor", sizeof(response)); if (input) fclose (input); else close (in); close (out); return NOTOK; } poprint = snoop; return OK; } int pop_fd (char *in, int inlen, char *out, int outlen) { snprintf (in, inlen, "%d", fileno (input)); snprintf (out, outlen, "%d", fileno (output)); return OK; } /* * Find out number of messages available * and their total size. */ int pop_stat (int *nmsgs, int *nbytes) { if (command ("STAT") == NOTOK) return NOTOK; *nmsgs = *nbytes = 0; sscanf (response, "+OK %d %d", nmsgs, nbytes); return OK; } int pop_list (int msgno, int *nmsgs, int *msgs, int *bytes) { int i; int *ids = NULL; if (msgno) { if (command ("LIST %d", msgno) == NOTOK) return NOTOK; *msgs = *bytes = 0; if (ids) { *ids = 0; sscanf (response, "+OK %d %d %d", msgs, bytes, ids); } else sscanf (response, "+OK %d %d", msgs, bytes); return OK; } if (command ("LIST") == NOTOK) return NOTOK; for (i = 0; i < *nmsgs; i++) switch (multiline ()) { case NOTOK: return NOTOK; case DONE: *nmsgs = ++i; return OK; case OK: *msgs = *bytes = 0; if (ids) { *ids = 0; sscanf (response, "%d %d %d", msgs++, bytes++, ids++); } else sscanf (response, "%d %d", msgs++, bytes++); break; } for (;;) switch (multiline ()) { case NOTOK: return NOTOK; case DONE: return OK; case OK: break; } } int pop_retr (int msgno, int (*action)(char *)) { return traverse (action, "RETR %d", msgno); } static int traverse (int (*action)(char *), const char *fmt, ...) { int result; va_list ap; char buffer[sizeof(response)]; va_start(ap, fmt); result = vcommand (fmt, ap); va_end(ap); if (result == NOTOK) return NOTOK; strncpy (buffer, response, sizeof(buffer)); for (;;) switch (multiline ()) { case NOTOK: return NOTOK; case DONE: strncpy (response, buffer, sizeof(response)); return OK; case OK: (*action) (response); break; } } int pop_dele (int msgno) { return command ("DELE %d", msgno); } int pop_noop (void) { return command ("NOOP"); } int pop_rset (void) { return command ("RSET"); } int pop_top (int msgno, int lines, int (*action)(char *)) { return traverse (action, "TOP %d %d", msgno, lines); } int pop_quit (void) { int i; i = command ("QUIT"); pop_done (); return i; } int pop_done (void) { #ifdef CYRUS_SASL if (conn) sasl_dispose(&conn); #endif /* CYRUS_SASL */ fclose (input); fclose (output); return OK; } int command(const char *fmt, ...) { va_list ap; int result; va_start(ap, fmt); result = vcommand(fmt, ap); va_end(ap); return result; } static int vcommand (const char *fmt, va_list ap) { char *cp, buffer[BUFSIZ]; vsnprintf (buffer, sizeof(buffer), fmt, ap); if (poprint) { #ifdef CYRUS_SASL if (sasl_ssf) fprintf(stderr, "(encrypted) "); #endif /* CYRUS_SASL */ if (pophack) { if ((cp = strchr (buffer, ' '))) *cp = 0; fprintf (stderr, "---> %s ********\n", buffer); if (cp) *cp = ' '; pophack = 0; } else fprintf (stderr, "---> %s\n", buffer); } if (putline (buffer, output) == NOTOK) return NOTOK; #ifdef CYRUS_SASL if (poprint && sasl_ssf) fprintf(stderr, "(decrypted) "); #endif /* CYRUS_SASL */ switch (sasl_getline (response, sizeof response, input)) { case OK: if (poprint) fprintf (stderr, "<--- %s\n", response); return (*response == '+' ? OK : NOTOK); case NOTOK: case DONE: if (poprint) fprintf (stderr, "%s\n", response); return NOTOK; } return NOTOK; /* NOTREACHED */ } int multiline (void) { char buffer[BUFSIZ + TRMLEN]; if (sasl_getline (buffer, sizeof buffer, input) != OK) return NOTOK; #ifdef DEBUG if (poprint) { #ifdef CYRUS_SASL if (sasl_ssf) fprintf(stderr, "(decrypted) "); #endif /* CYRUS_SASL */ fprintf (stderr, "<--- %s\n", response); } #endif /* DEBUG */ if (strncmp (buffer, TRM, TRMLEN) == 0) { if (buffer[TRMLEN] == 0) return DONE; else strncpy (response, buffer + TRMLEN, sizeof(response)); } else strncpy (response, buffer, sizeof(response)); return OK; } /* * Note that these functions have been modified to deal with layer encryption * in the SASL case */ static int sasl_getline (char *s, int n, FILE *iop) { int c = -2; char *p; p = s; while (--n > 0 && (c = sasl_fgetc (iop)) != EOF && c != -2) if ((*p++ = c) == '\n') break; if (c == -2) return NOTOK; if (ferror (iop) && c != EOF) { strncpy (response, "error on connection", sizeof(response)); return NOTOK; } if (c == EOF && p == s) { strncpy (response, "connection closed by foreign host", sizeof(response)); return DONE; } *p = 0; if (*--p == '\n') *p = 0; if (*--p == '\r') *p = 0; return OK; } static int putline (char *s, FILE *iop) { #ifdef CYRUS_SASL char outbuf[BUFSIZ], *buf; int result; unsigned int buflen; if (!sasl_complete) { #endif /* CYRUS_SASL */ fprintf (iop, "%s\r\n", s); #ifdef CYRUS_SASL } else { /* * Build an output buffer, encrypt it using sasl_encode, and * squirt out the results. */ strncpy(outbuf, s, sizeof(outbuf) - 3); outbuf[sizeof(outbuf) - 3] = '\0'; /* Just in case */ strcat(outbuf, "\r\n"); result = sasl_encode(conn, outbuf, strlen(outbuf), (const char **) &buf, &buflen); if (result != SASL_OK) { snprintf(response, sizeof(response), "SASL encoding error: %s", sasl_errdetail(conn)); return NOTOK; } fwrite(buf, buflen, 1, iop); } #endif /* CYRUS_SASL */ fflush (iop); if (ferror (iop)) { strncpy (response, "lost connection", sizeof(response)); return NOTOK; } return OK; } #ifdef CYRUS_SASL /* * Okay, our little fgetc replacement. Hopefully this is a little more * efficient than the last one. */ static int sasl_fgetc(FILE *f) { static unsigned char *buffer = NULL, *ptr; static unsigned int size = 0; static int cnt = 0; unsigned int retbufsize = 0; int cc, result; char *retbuf, tmpbuf[SASL_BUFFER_SIZE]; /* * If we have some leftover data, return that */ if (cnt) { cnt--; return (int) *ptr++; } /* * Otherwise, fill our buffer until we have some data to return. */ while (retbufsize == 0) { cc = read(fileno(f), tmpbuf, sizeof(tmpbuf)); if (cc == 0) return EOF; if (cc < 0) { snprintf(response, sizeof(response), "Error during read from " "network: %s", strerror(errno)); return -2; } /* * We're not allowed to call sasl_decode until sasl_complete is * true, so we do these gyrations ... */ if (!sasl_complete) { retbuf = tmpbuf; retbufsize = cc; } else { result = sasl_decode(conn, tmpbuf, cc, (const char **) &retbuf, &retbufsize); if (result != SASL_OK) { snprintf(response, sizeof(response), "Error during SASL " "decoding: %s", sasl_errdetail(conn)); return -2; } } } if (retbufsize > size) { buffer = mh_xrealloc(buffer, retbufsize); size = retbufsize; } memcpy(buffer, retbuf, retbufsize); ptr = buffer + 1; cnt = retbufsize - 1; return (int) buffer[0]; } #endif /* CYRUS_SASL */