This patch is a modification of Krzysztof Dabrowski's patch from: http://members.elysium.pl/brush/qmail-smtpd-auth/dist/qmail-smtpd-auth-0.31.tar.gz It can be downloaded from: http://devsec.org/patch/qmail/qmail_smtp-auth_login+plain.tk-1.patch This patch provides LOGIN and PLAIN auth types to qmail-smtpd. It sets RELAYCLIENT and TCPREMOTEINFO after a successfull auth. With this patch, qmail-smtp will operate normally without any args, but will provide LOGIN and PLAIN auth when it has two arguments, and will not become an open relay if the 2nd argument is forgotten. -Thor Kooda 2004-03-18 diff -Naur qmail-1.03.orig/Makefile qmail-1.03/Makefile --- qmail-1.03.orig/Makefile Mon Jun 15 05:53:16 1998 +++ qmail-1.03/Makefile Wed Mar 17 22:38:24 2004 @@ -136,6 +136,10 @@ compile auto_usera.c ./compile auto_usera.c +base64.o: \ +compile base64.c base64.h stralloc.h substdio.h str.h + ./compile base64.c + binm1: \ binm1.sh conf-qmail cat binm1.sh \ @@ -1536,12 +1540,12 @@ timeoutwrite.o ip.o ipme.o ipalloc.o control.o constmap.o received.o \ date822fmt.o now.o qmail.o cdb.a fd.a wait.a datetime.a getln.a \ open.a sig.a case.a env.a stralloc.a alloc.a substdio.a error.a str.a \ -fs.a auto_qmail.o socket.lib +fs.a auto_qmail.o base64.o socket.lib ./load qmail-smtpd rcpthosts.o commands.o timeoutread.o \ timeoutwrite.o ip.o ipme.o ipalloc.o control.o constmap.o \ received.o date822fmt.o now.o qmail.o cdb.a fd.a wait.a \ datetime.a getln.a open.a sig.a case.a env.a stralloc.a \ - alloc.a substdio.a error.a str.a fs.a auto_qmail.o `cat \ + alloc.a substdio.a error.a str.a fs.a auto_qmail.o base64.o `cat \ socket.lib` qmail-smtpd.0: \ @@ -1553,7 +1557,8 @@ substdio.h alloc.h auto_qmail.h control.h received.h constmap.h \ error.h ipme.h ip.h ipalloc.h ip.h gen_alloc.h ip.h qmail.h \ substdio.h str.h fmt.h scan.h byte.h case.h env.h now.h datetime.h \ -exit.h rcpthosts.h timeoutread.h timeoutwrite.h commands.h +exit.h rcpthosts.h timeoutread.h timeoutwrite.h commands.h wait.h \ +fd.h base64.h ./compile qmail-smtpd.c qmail-start: \ diff -Naur qmail-1.03.orig/README.auth qmail-1.03/README.auth --- qmail-1.03.orig/README.auth Wed Dec 31 18:00:00 1969 +++ qmail-1.03/README.auth Wed Mar 17 22:43:18 2004 @@ -0,0 +1,129 @@ +This patch adds ESMTP AUTH authentication protocol support to +qmail-1.03. It's originally based on Mrs. Brisby's smtp-auth patch +with many enhancements from Krzysztof Dabrowski +and Eric M. Johnston . + +It has since been changed to only include LOGIN and PLAIN auth, and +handle missing args to qmail-smtp more gracefully. + +--- + +Detailed patch information: + +This patch adds the ESMTP AUTH option to qmail-1.03, allowing the +LOGIN, and PLAIN AUTH types. An appropriate checkpassword tool is +necessary to support the authentication. See +http://cr.yp.to/checkpwd.html for more information on the interface. +Note that the checkpassword tool should support all of the AUTH types +advertised by qmail-smtpd. + +As reflected in the modified qmail-smtpd(8) man page, qmail-smtpd +must be invoked with two arguments: checkprogram, and subprogram. +If either of these arguments are missing, qmail-smtpd will not +advertise availability of AUTH, and will not be able to AUTH. + +qmail-smtpd invokes checkprogram, feeding it the username and +password. If the user is permitted, checkprogram invokes subprogram, +which just has to exit with a status of 0 for the user to +be authenticated. Otherwise, checkprogram exits with a non-zero +status. subprogram can usually be /usr/bin/true (or /bin/true, +depending on your flavor of OS). + +If the user is successfully authenticated, the RELAYCLIENT +environment variable is effectively set for the SMTP session, and +the TCPREMOTEINFO environment variable is set to the authenticated +username, overriding any value that tcpserver may have set. The +value of TCPREMOTEINFO is reflected in a Received header. + + +How to install it: + +Simply patch your qmail-1.03 distribution with the included patch +file and recompile & install like usual. + +From within the qmail-1.03 source dir: + + patch -p1 < ../qmail_smtp-auth_login+plain_0.1.patch + +Install qmail normally, with the exception of the new arguments +to qmail-smtpd described elsewhere in this file. + + +How to use it: + +If you're running qmail-smtpd from inetd, you'll want to do the +following: + +smtp stream tcp nowait qmaild /var/qmail/bin/tcp-env tcp-env \ +/var/qmail/bin/qmail-smtpd /usr/bin/checkpassword /bin/true + +The first argument to qmail-smtpd is your checkpassword utility. +The second argument is the executable that the checkpassword utility +execs when authentication is successful. (Note that the location of +"true" is OS dependent: you may need /usr/bin/true.) + +Invocations using tcpserver will require analagous changes. Give +your inetd a kill -HUP or restart tcpserver and away you go. + + +Caveats: + +Please note that as authentication needs vary wildly across +installations, no effort has been made to make this patch work ``out +of the box.'' You'll have to procure or develop your own +checkpassword program. + +This patch has been generated against the stock qmail 1.03 +distribution. The results of combining this patch with others are +unknown. + + +Features: + +This patch supports the following auth methods: LOGIN, and PLAIN. + + +Compatibility: + +The following MUA's are confirmed to work with this patch: + +Eudora 4.2.2 - CRAM-MD5 +Eudora 5.0.2 - CRAM-MD5 +The Bat 1.39 - LOGIN & CRAM-MD5 +Outlook Express 4 - LOGIN +Outlook Express 5 - LOGIN +Outlook 2000 - LOGIN +Netscape 4.x - LOGIN & PLAIN +Netscape 4.0x - LOGIN +Pegasus Mail 3.1x - CRAM-MD5 + + +Various compatibility issues: + +Testing with Pegasus Mail 3.1 revealed that it requires the new style +(RFC recommended) greeting message. Both styles are now enabled to +maintain the highest degree of compatibility with various clients. +This fix was suggested by David Harris , +the developer of Pegasus Mail. + + +Acknowledgments: + +This patch is based on work by Krzysztof Dabrowski at +http://members.elysium.pl/brush/qmail-smtpd-auth/ and ``Mrs. Brisby'' +at http://www.nimh.org/hacks/qmail-smtpd.c which has been further +developed by Eric M. Johnston . + +--- + +THIS SOFTWARE IS IN THE PUBLIC DOMAIN, 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. diff -Naur qmail-1.03.orig/TARGETS qmail-1.03/TARGETS --- qmail-1.03.orig/TARGETS Mon Jun 15 05:53:16 1998 +++ qmail-1.03/TARGETS Wed Mar 17 22:38:24 2004 @@ -250,6 +250,7 @@ qmail-qmtpd.o rcpthosts.o qmail-qmtpd +base64.o qmail-smtpd.o qmail-smtpd sendmail.o diff -Naur qmail-1.03.orig/base64.c qmail-1.03/base64.c --- qmail-1.03.orig/base64.c Wed Dec 31 18:00:00 1969 +++ qmail-1.03/base64.c Wed Mar 17 22:38:24 2004 @@ -0,0 +1,90 @@ +#include "base64.h" +#include "stralloc.h" +#include "substdio.h" +#include "str.h" + +static char *b64alpha = + "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; +#define B64PAD '=' + +/* returns 0 ok, 1 illegal, -1 problem */ + +int b64decode(in,l,out) +const unsigned char *in; +int l; +stralloc *out; /* not null terminated */ +{ + int i, j; + unsigned char a[4]; + unsigned char b[3]; + char *s; + + if (l == 0) + { + if (!stralloc_copys(out,"")) return -1; + return 0; + } + + if (!stralloc_ready(out,l + 2)) return -1; /* XXX generous */ + s = out->s; + + for (i = 0;i < l;i += 4) { + for (j = 0;j < 4;j++) + if ((i + j) < l && in[i + j] != B64PAD) + { + a[j] = str_chr(b64alpha,in[i + j]); + if (a[j] > 63) return 1; + } + else a[j] = 0; + + b[0] = (a[0] << 2) | (a[1] >> 4); + b[1] = (a[1] << 4) | (a[2] >> 2); + b[2] = (a[2] << 6) | (a[3]); + + *s++ = b[0]; + + if (in[i + 1] == B64PAD) break; + *s++ = b[1]; + + if (in[i + 2] == B64PAD) break; + *s++ = b[2]; + } + out->len = s - out->s; + while (out->len && !out->s[out->len - 1]) --out->len; /* XXX avoid? */ + return 0; +} + +int b64encode(in,out) +stralloc *in; +stralloc *out; /* not null terminated */ +{ + unsigned char a, b, c; + int i; + char *s; + + if (in->len == 0) + { + if (!stralloc_copys(out,"")) return -1; + return 0; + } + + if (!stralloc_ready(out,in->len / 3 * 4 + 4)) return -1; + s = out->s; + + for (i = 0;i < in->len;i += 3) { + a = in->s[i]; + b = i + 1 < in->len ? in->s[i + 1] : 0; + c = i + 2 < in->len ? in->s[i + 2] : 0; + + *s++ = b64alpha[a >> 2]; + *s++ = b64alpha[((a & 3 ) << 4) | (b >> 4)]; + + if (i + 1 >= in->len) *s++ = B64PAD; + else *s++ = b64alpha[((b & 15) << 2) | (c >> 6)]; + + if (i + 2 >= in->len) *s++ = B64PAD; + else *s++ = b64alpha[c & 63]; + } + out->len = s - out->s; + return 0; +} diff -Naur qmail-1.03.orig/base64.h qmail-1.03/base64.h --- qmail-1.03.orig/base64.h Wed Dec 31 18:00:00 1969 +++ qmail-1.03/base64.h Wed Mar 17 22:38:24 2004 @@ -0,0 +1,7 @@ +#ifndef BASE64_H +#define BASE64_H + +extern int b64decode(); +extern int b64encode(); + +#endif diff -Naur qmail-1.03.orig/qmail-smtpd.8 qmail-1.03/qmail-smtpd.8 --- qmail-1.03.orig/qmail-smtpd.8 Mon Jun 15 05:53:16 1998 +++ qmail-1.03/qmail-smtpd.8 Wed Mar 17 22:38:24 2004 @@ -3,6 +3,10 @@ qmail-smtpd \- receive mail via SMTP .SH SYNOPSIS .B qmail-smtpd +[ +.I checkprogram +.I subprogram +] .SH DESCRIPTION .B qmail-smtpd receives mail messages via the Simple Mail Transfer Protocol (SMTP) @@ -23,7 +27,26 @@ header fields. .B qmail-smtpd -supports ESMTP, including the 8BITMIME and PIPELINING options. +supports ESMTP, including the 8BITMIME, PIPELINING, and AUTH options. + +.B qmail-smtpd +can accept LOGIN, and PLAIN AUTH types. It invokes +.IR checkprogram , +which reads on file descriptor 3 the username, a 0 byte, the password, +another 0 byte, and a final 0 byte. +.I checkprogram +invokes +.I subprogram +upon successful authentication, which should in turn return 0 to +.BR qmail-smtpd , +effectively setting the environment variables RELAYCLIENT and TCPREMOTEINFO +(any supplied value replaced with the authenticated username). +.B qmail-smtpd +will reject the authentication attempt if it receives a nonzero return +value from +.I checkprogram +or +.IR subprogram . .SH TRANSPARENCY .B qmail-smtpd converts the SMTP newline convention into the UNIX newline convention @@ -177,3 +200,6 @@ qmail-newmrh(8), qmail-queue(8), qmail-remote(8) +.SH "HISTORY" +The patch enabling the ESMTP AUTH option is not part of the standard +qmail-1.03 distribution. diff -Naur qmail-1.03.orig/qmail-smtpd.c qmail-1.03/qmail-smtpd.c --- qmail-1.03.orig/qmail-smtpd.c Mon Jun 15 05:53:16 1998 +++ qmail-1.03/qmail-smtpd.c Wed Mar 17 22:38:24 2004 @@ -23,6 +23,8 @@ #include "timeoutread.h" #include "timeoutwrite.h" #include "commands.h" +#include "wait.h" +#include "fd.h" #define MAXHOPS 100 unsigned int databytes = 0; @@ -59,6 +61,15 @@ void err_vrfy() { out("252 send some mail, i'll try my best\r\n"); } void err_qqt() { out("451 qqt failure (#4.3.0)\r\n"); } +int err_child() { out("454 oops, problem with child and I can't auth (#4.3.0)\r\n"); return -1; } +int err_fork() { out("454 oops, child won't start and I can't auth (#4.3.0)\r\n"); return -1; } +int err_pipe() { out("454 oops, unable to open pipe and I can't auth (#4.3.0)\r\n"); return -1; } +int err_write() { out("454 oops, unable to write pipe and I can't auth (#4.3.0)\r\n"); return -1; } +void err_authd() { out("503 you're already authenticated (#5.5.0)\r\n"); } +void err_authmail() { out("503 no auth during mail transaction (#5.5.0)\r\n"); } +int err_noauth() { out("504 auth type unimplemented (#5.5.1)\r\n"); return -1; } +int err_authabrt() { out("501 auth exchange cancelled (#5.0.0)\r\n"); return -1; } +int err_input() { out("501 malformed auth input (#5.5.4)\r\n"); return -1; } stralloc greeting = {0}; @@ -221,6 +232,8 @@ int flagbarf; /* defined if seenmail */ stralloc mailfrom = {0}; stralloc rcptto = {0}; +char **childargs; +int haschildargs = 0; void smtp_helo(arg) char *arg; { @@ -229,7 +242,13 @@ } void smtp_ehlo(arg) char *arg; { - smtp_greet("250-"); out("\r\n250-PIPELINING\r\n250 8BITMIME\r\n"); + smtp_greet("250-"); + if (haschildargs) + { + out("\r\n250-AUTH LOGIN PLAIN"); + out("\r\n250-AUTH=LOGIN PLAIN"); + } + out("\r\n250-PIPELINING\r\n250 8BITMIME\r\n"); seenmail = 0; dohelo(arg); } void smtp_rset() @@ -394,10 +413,180 @@ out("\r\n"); } + +char unique[FMT_ULONG + FMT_ULONG + 3]; +static stralloc authin = {0}; +static stralloc user = {0}; +static stralloc pass = {0}; +static stralloc resp = {0}; +static stralloc slop = {0}; +substdio ssup; +char upbuf[128]; +int authd = 0; + +int authgetl(void) { + int i; + + if (!stralloc_copys(&authin, "")) die_nomem(); + + for (;;) { + if (!stralloc_readyplus(&authin,1)) die_nomem(); /* XXX */ + i = substdio_get(&ssin,authin.s + authin.len,1); + if (i != 1) die_read(); + if (authin.s[authin.len] == '\n') break; + ++authin.len; + } + + if (authin.len > 0) if (authin.s[authin.len - 1] == '\r') --authin.len; + authin.s[authin.len] = 0; + + if (*authin.s == '*' && *(authin.s + 1) == 0) { return err_authabrt(); } + if (authin.len == 0) { return err_input(); } + return authin.len; +} + +int authenticate(void) +{ + int child; + int wstat; + int pi[2]; + + if (!stralloc_0(&user)) die_nomem(); + if (!stralloc_0(&pass)) die_nomem(); + if (!stralloc_0(&resp)) die_nomem(); + + if (fd_copy(2,1) == -1) return err_pipe(); + close(3); + if (pipe(pi) == -1) return err_pipe(); + if (pi[0] != 3) return err_pipe(); + switch(child = fork()) { + case -1: + return err_fork(); + case 0: + close(pi[1]); + sig_pipedefault(); + execvp(*childargs, childargs); + _exit(1); + } + close(pi[0]); + + substdio_fdbuf(&ssup,write,pi[1],upbuf,sizeof upbuf); + if (substdio_put(&ssup,user.s,user.len) == -1) return err_write(); + if (substdio_put(&ssup,pass.s,pass.len) == -1) return err_write(); + if (substdio_put(&ssup,resp.s,resp.len) == -1) return err_write(); + if (substdio_flush(&ssup) == -1) return err_write(); + + close(pi[1]); + byte_zero(pass.s,pass.len); + byte_zero(upbuf,sizeof upbuf); + if (wait_pid(&wstat,child) == -1) return err_child(); + if (wait_crashed(wstat)) return err_child(); + if (wait_exitcode(wstat)) { sleep(5); return 1; } /* no */ + return 0; /* yes */ +} + +int auth_login(arg) char *arg; +{ + int r; + + if (*arg) { + if (r = b64decode(arg,str_len(arg),&user) == 1) return err_input(); + } + else { + out("334 VXNlcm5hbWU6\r\n"); flush(); /* Username: */ + if (authgetl() < 0) return -1; + if (r = b64decode(authin.s,authin.len,&user) == 1) return err_input(); + } + if (r == -1) die_nomem(); + + out("334 UGFzc3dvcmQ6\r\n"); flush(); /* Password: */ + + if (authgetl() < 0) return -1; + if (r = b64decode(authin.s,authin.len,&pass) == 1) return err_input(); + if (r == -1) die_nomem(); + + if (!user.len || !pass.len) return err_input(); + return authenticate(); +} + +int auth_plain(arg) char *arg; +{ + int r, id = 0; + + if (*arg) { + if (r = b64decode(arg,str_len(arg),&slop) == 1) return err_input(); + } + else { + out("334 \r\n"); flush(); + if (authgetl() < 0) return -1; + if (r = b64decode(authin.s,authin.len,&slop) == 1) return err_input(); + } + if (r == -1 || !stralloc_0(&slop)) die_nomem(); + while (slop.s[id]) id++; /* ignore authorize-id */ + + if (slop.len > id + 1) + if (!stralloc_copys(&user,slop.s + id + 1)) die_nomem(); + if (slop.len > id + user.len + 2) + if (!stralloc_copys(&pass,slop.s + id + user.len + 2)) die_nomem(); + + if (!user.len || !pass.len) return err_input(); + return authenticate(); +} + +struct authcmd { + char *text; + int (*fun)(); +} authcmds[] = { + { "login", auth_login } +, { "plain", auth_plain } +, { 0, err_noauth } +}; + +void smtp_auth(arg) +char *arg; +{ + int i; + char *cmd = arg; + + if (!haschildargs) + { + out("503 auth not available (#5.3.3)\r\n"); + return; + } + if (authd) { err_authd(); return; } + if (seenmail) { err_authmail(); return; } + + if (!stralloc_copys(&user,"")) die_nomem(); + if (!stralloc_copys(&pass,"")) die_nomem(); + if (!stralloc_copys(&resp,"")) die_nomem(); + + i = str_chr(cmd,' '); + arg = cmd + i; + while (*arg == ' ') ++arg; + cmd[i] = 0; + + for (i = 0;authcmds[i].text;++i) + if (case_equals(authcmds[i].text,cmd)) break; + + switch (authcmds[i].fun(arg)) { + case 0: + authd = 1; + relayclient = ""; + remoteinfo = user.s; + if (!env_unset("TCPREMOTEINFO")) die_read(); + if (!env_put2("TCPREMOTEINFO",remoteinfo)) die_nomem(); + out("235 ok, go ahead (#2.0.0)\r\n"); + break; + case 1: + out("535 authorization failed (#5.7.0)\r\n"); + } +} + struct commands smtpcommands[] = { { "rcpt", smtp_rcpt, 0 } , { "mail", smtp_mail, 0 } , { "data", smtp_data, flush } +, { "auth", smtp_auth, flush } , { "quit", smtp_quit, flush } , { "helo", smtp_helo, flush } , { "ehlo", smtp_ehlo, flush } @@ -408,8 +597,16 @@ , { 0, err_unimpl, flush } } ; -void main() -{ +void main(argc,argv) +int argc; +char **argv; +{ + if (argc == 3) + { + haschildargs = 1; + childargs = argv + 1; + } + sig_pipeignore(); if (chdir(auto_qmail) == -1) die_control(); setup();