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/*
** Copyright 1998 - 2009 Double Precision, Inc.
** See COPYING for distribution information.
*/
#include "lexer.h"
#include "recipe.h"
#include "varlist.h"
#include "funcs.h"
#include "tempfile.h"
#include "message.h"
#include "messageinfo.h"
#include "xconfig.h"
#include "exittrap.h"
#include "maildrop.h"
#include "config.h"
#include "setgroupid.h"
#include <sys/types.h>
#include "courierauth.h"
#if HAVE_LOCALE_H
#include <locale.h>
#endif
#if HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#include <sysexits.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <pwd.h>
#include <grp.h>
#include "../dbobj.h"
#if AUTHLIB
#include <courierauth.h>
#endif
#if HAS_GETHOSTNAME
#else
extern "C" int gethostname(const char *, size_t);
#endif
extern void setprocgroup();
static Message m1, m2;
extern char **environ;
static int errexit=EX_TEMPFAIL;
int quota_warn_percent = -1;
const char *quota_warn_message=0;
static const char *defaults_vars[]={"LOCKEXT","LOCKSLEEP","LOCKTIMEOUT",
"LOCKREFRESH", "PATH", "SENDMAIL",
"MAILDIRQUOTA"};
static const char *defaults_vals[]={LOCKEXT_DEF,LOCKSLEEP_DEF,LOCKTIMEOUT_DEF,
LOCKREFRESH_DEF, DEFAULT_PATH,
SENDMAIL_DEF, ""};
Maildrop maildrop;
Maildrop::Maildrop()
{
verbose_level=0;
isdelivery=0;
sigfpe=0;
includelevel=0;
embedded_mode=0;
msgptr= &m1;
savemsgptr= &m2;
#if AUTHLIB_TEMPREJECT
authlib_essential=1;
#else
authlib_essential=0;
#endif
}
static void help()
{
mout << "Usage: maildrop [options] [-d user] [arg] [arg] ...\n";
mout << " maildrop [options] [filterfile [arg] [arg] ...\n";
}
static void bad()
{
errexit=EX_TEMPFAIL;
throw "Bad command line arguments, -h for help.";
}
static void nouser()
{
merr << "Invalid user specified.\n";
exit(EX_NOUSER);
}
static void nochangeuidgid()
{
errexit=EX_TEMPFAIL;
throw "Cannot set my user or group id.";
}
static int trusted_user(uid_t uid)
{
static char trusted_users[]=TRUSTED_USERS;
static char buf[ sizeof(trusted_users) ];
char *p;
strcpy(buf, trusted_users);
for (p=buf; (p=strtok(p, " ")) != 0; p=0)
{
struct passwd *q=getpwnam(p);
if (q && q->pw_uid == uid)
return (1);
}
return (0);
}
static int trusted_group(gid_t gid)
{
static char trusted_groups[]=TRUSTED_GROUPS;
static char buf[ sizeof(trusted_groups) ];
char *p;
strcpy(buf, trusted_groups);
for (p=buf; (p=strtok(p, " ")) != 0; p=0)
{
struct group *q=getgrnam(p);
if (q && (gid_t)q->gr_gid == gid)
return (1);
}
return (0);
}
static int trusted_uidgid(uid_t uid, gid_t gid, gid_t gid2)
{
if (trusted_user(uid) || trusted_group(gid) ||
trusted_group(gid2))
return (1);
return (0);
}
static void sethostname(Buffer &buf)
{
char hostname[256];
hostname[0]=0;
gethostname(hostname, 256);
hostname[sizeof(hostname)-1]=0;
buf=hostname;
}
static void copyright()
{
static const char msg[]="maildrop " VERSION " Copyright 1998-2005 Double Precision, Inc."
#if CRLF_TERM
"\r\n"
#else
"\n"
#endif
#ifdef DbObj
"GDBM/DB extensions enabled."
#if CRLF_TERM
"\r\n"
#else
"\n"
#endif
#endif
#if AUTHLIB
"Courier Authentication Library extension enabled."
#if CRLF_TERM
"\r\n"
#else
"\n"
#endif
#endif
"Maildir quota extension are now always enabled."
#if CRLF_TERM
"\r\n"
#else
"\n"
#endif
"This program is distributed under the terms of the GNU General Public"
#if CRLF_TERM
"\r\n"
#else
"\n"
#endif
"License. See COPYING for additional information."
#if CRLF_TERM
"\r\n"
#else
"\n"
#endif
;
mout << msg;
mout.flush();
}
void Maildrop::reset_vars()
{
int i;
Buffer name, value;
for (i=0; i<(int)(sizeof(defaults_vars)/sizeof(defaults_vars[0])); i++)
{
name=defaults_vars[i];
value=defaults_vals[i];
SetVar(name, value);
}
name="HOME";
SetVar(name, maildrop.init_home);
name="LOGNAME";
SetVar(name, maildrop.init_logname);
name="SHELL";
SetVar(name, maildrop.init_shell);
name="DEFAULT";
SetVar(name, maildrop.init_default);
name="UMASK";
value="077";
SetVar(name, value);
if (maildrop.init_quota.Length() > 0)
{
name="MAILDIRQUOTA";
SetVar(name, maildrop.init_quota);
}
}
#if AUTHLIB
// Authlib lookup
static int callback_authlib(struct authinfo *auth,
void *void_arg)
{
Maildrop &maildrop=*(Maildrop *)void_arg;
if (VerboseLevel() > 1)
{
Buffer b;
b.set(auth->sysgroupid);
b.push(0);
merr << "maildrop: authlib: groupid="
<< b << "\n";
}
setgroupid(auth->sysgroupid);
uid_t u;
if (auth->sysusername)
{
struct passwd *q=getpwnam(auth->sysusername);
if (q == NULL)
{
merr << "Cannot find system user "
<< auth->sysusername
<< "\n";
nochangeuidgid();
}
u=q->pw_uid;
}
else
u=*auth->sysuserid;
if (VerboseLevel() > 1)
{
Buffer b;
b.set(u);
b.push(0);
merr << "maildrop: authlib: userid="
<< b << "\n";
}
setuid(u);
if ( getuid() != u)
nochangeuidgid();
if (VerboseLevel() > 1)
{
merr << "maildrop: authlib: logname="
<< auth->address
<< ", home="
<< auth->homedir
<< ", mail="
<< (auth->maildir ? auth->maildir:"(default)")
<< "\n";
}
maildrop.init_home=auth->homedir;
maildrop.init_logname=auth->address;
maildrop.init_shell="/bin/sh";
maildrop.init_default=auth->maildir ? auth->maildir:
GetDefaultMailbox(auth->address);
if ( auth->quota )
maildrop.init_quota=auth->quota;
return 0;
}
int find_in_authlib(Maildrop *maildrop, const char* user)
{
int rc=auth_getuserinfo("login",
user, callback_authlib, maildrop);
if (rc == 0)
return 1;
if ((rc > 0) && (maildrop->authlib_essential == 1))
{
errexit=EX_TEMPFAIL;
throw "Temporary authentication failure.";
}
return 0;
}
#else
int find_in_authlib(Maildrop *maildrop, const char* user)
{
return 0;
}
#endif
static void tempfail(const char *msg)
{
errexit = EX_TEMPFAIL;
throw msg;
}
static int run(int argc, char **argv)
{
int argn;
const char *deliverymode=0;
char *embedded_filter=0;
const char *from=0;
int explicit_from=0;
Buffer recipe;
uid_t orig_uid;
gid_t orig_gid, orig_gid2;
Buffer extra_headers;
struct passwd *my_pw;
int found;
#if HAVE_COURIER
#if RESTRICT_TRUSTED
const char *numuidgid=0;
#endif
#endif
umask( 0007 );
for (argn=1; argn < argc; )
{
if (argv[argn][0] != '-') break;
if (strcmp(argv[argn], "--") == 0) { ++argn; break; }
char optc=argv[argn][1];
const char *optarg=argv[argn]+2;
++argn;
switch (optc) {
#if HAVE_COURIER
#if RESTRICT_TRUSTED
case 'D':
if (!*optarg && argn < argc) optarg=argv[argn++];
numuidgid=optarg;
break;
#endif
#endif
case 'd':
if (!*optarg && argn < argc) optarg=argv[argn++];
deliverymode=optarg;
break;
case 'V':
if (!*optarg && argn < argc) optarg=argv[argn++];
maildrop.verbose_level=atoi(optarg);
break;
case 'v':
copyright();
return (0);
case 'm':
maildrop.embedded_mode=1;
break;
case 'M':
if (!*optarg && argn < argc) optarg=argv[argn++];
maildrop.embedded_mode=1;
if (!deliverymode) deliverymode="";
if (!*optarg)
{
help();
return (EX_TEMPFAIL);
}
embedded_filter=(char *)malloc(strlen(optarg)+1);
if (!embedded_filter) outofmem();
strcpy(embedded_filter, optarg);
{
char *p;
for (p=embedded_filter; *p; p++)
if (*p == SLASH_CHAR || *p == '.')
*p=':';
}
break;
case 'A':
if (!*optarg && argn < argc) optarg=argv[argn++];
if (*optarg)
{
extra_headers += optarg;
extra_headers += '\n';
}
break;
case 'f':
if (!*optarg && argn < argc) optarg=argv[argn++];
if (*optarg)
{
from=optarg;
explicit_from=1;
}
break;
case 'w':
if (!*optarg && argn < argc) optarg=argv[argn++];
if (*optarg)
quota_warn_percent=atoi(optarg);
break;
case 'W':
if (!*optarg && argn < argc) optarg=argv[argn++];
if (*optarg)
quota_warn_message=optarg;
break;
case 'a':
maildrop.authlib_essential=1;
break;
case 'h':
help();
return (EX_TEMPFAIL);
default:
bad();
}
}
my_pw=0;
found=0;
orig_uid=getuid();
orig_gid=getgid();
orig_gid2=getegid();
if (!deliverymode && argn < argc)
recipe=argv[argn++];
else
{
if (!deliverymode) deliverymode="";
if (*deliverymode)
{
found = find_in_authlib(&maildrop, deliverymode);
if ( !found )
{
my_pw=getpwnam(deliverymode);
if (!my_pw)
nouser();
#if RESET_GID
setgroupid(my_pw->pw_gid);
#else
setgroupid(getegid());
#endif
setuid(my_pw->pw_uid);
if (getuid() != my_pw->pw_uid)
nochangeuidgid(); // Security violation.
maildrop.init_home=my_pw->pw_dir;
maildrop.init_logname=my_pw->pw_name;
maildrop.init_shell=
my_pw->pw_shell && *my_pw->pw_shell
? my_pw->pw_shell:"/bin/sh";
maildrop.init_default=
GetDefaultMailbox(my_pw->pw_name);
found=1;
}
}
maildrop.isdelivery=1;
#if RESTRICT_TRUSTED
if ( getuid() != orig_uid && !trusted_uidgid(orig_uid,
orig_gid, orig_gid2))
{
errexit=EX_TEMPFAIL;
throw "You are not a trusted user.";
// Security violation
}
#endif
}
#if HAVE_COURIER
#if RESTRICT_TRUSTED
if (numuidgid)
{
uid_t un=0;
gid_t gn=getgid();
if (deliverymode && *deliverymode)
{
errexit=EX_TEMPFAIL;
throw "Cannot use both -d and -D options.";
}
if ( !trusted_uidgid(orig_uid, orig_gid, orig_gid2))
{
errexit=EX_TEMPFAIL;
throw "You are not authorized to use the -D option.";
}
if (!isdigit( (int)(unsigned char)*numuidgid))
{
errexit=EX_TEMPFAIL;
throw "Invalid -D option.";
}
do
{
un=un * 10 + (*numuidgid++ - '0');
} while (isdigit( (int)(unsigned char)*numuidgid));
if ( *numuidgid )
{
if ( *numuidgid++ != '/' ||
!isdigit( (int)(unsigned char)*numuidgid))
{
errexit=EX_TEMPFAIL;
throw "Invalid -D option.";
}
gn=0;
do
{
gn=gn * 10 + (*numuidgid++ - '0');
} while (isdigit( (int)(unsigned char)*numuidgid));
if ( *numuidgid )
{
errexit=EX_TEMPFAIL;
throw "Invalid -D option.";
}
}
setgroupid(gn);
setuid(un);
deliverymode="";
orig_uid=un; /* See below for another Courier hook */
}
#endif
#endif
#if RESET_GID
setgroupid(getgid());
#endif
uid_t my_u=getuid();
setuid(my_u); // Drop any setuid privileges.
if (!found)
{
#if HAVE_COURIER
if (!deliverymode)
#endif
{
my_pw=getpwuid(my_u);
if (!my_pw)
{
errexit=EX_TEMPFAIL;
throw "Cannot determine my username.";
}
maildrop.init_home=my_pw->pw_dir;
maildrop.init_logname=my_pw->pw_name;
maildrop.init_shell=
my_pw->pw_shell && *my_pw->pw_shell
? my_pw->pw_shell:"/bin/sh";
maildrop.init_default=
GetDefaultMailbox(my_pw->pw_name);
}
}
int i;
Buffer name;
Buffer value;
for (i=0; environ[i]; i++)
{
name=environ[i];
char *p=strchr(environ[i], '=');
value= p ? (name.Length(p - environ[i]), p+1):"";
if (maildrop.isdelivery)
{
if (name == "LANG" ||
name == "LANGUAGE" ||
strncmp(name, "LC_", 3) == 0)
;
else
continue;
}
SetVar(name, value);
}
i=1;
while (argn < argc)
{
name="";
name.append( (unsigned long)i);
value=argv[argn++];
SetVar(name, value);
++i;
}
#if HAVE_COURIER
if (deliverymode && orig_uid == getuid())
{
const char *p;
if ((p=getenv("HOME")) && *p)
maildrop.init_home=p;
if ((p=getenv("LOGNAME")) && *p)
maildrop.init_logname=p;
if ((p=getenv("SHELL")) && *p)
maildrop.init_shell=p;
p=getenv("MAILDROPDEFAULT");
if (!p || !*p)
{
p=getenv("LOCAL");
if (p && *p)
p=GetDefaultMailbox(p);
else
p="./Maildir";
}
maildrop.init_default=p;
if ((p=getenv("MAILDIRQUOTA")) && *p)
maildrop.init_quota=p;
}
#endif
if (deliverymode)
{
struct stat buf;
Buffer b;
b=maildrop.init_home;
b += '\0';
const char *h=b;
if (VerboseLevel() > 1)
merr << "maildrop: Changing to " << h << "\n";
if (chdir(h) < 0)
{
errexit=EX_TEMPFAIL;
throw "Unable to change to home directory.";
}
recipe=".mailfilter";
if ( stat(".", &buf) < 0)
tempfail("Cannot stat() home directory.");
if ( !S_ISDIR(buf.st_mode))
tempfail("Home directory is not a directory.");
if ( buf.st_mode & S_IWOTH)
tempfail("Invalid home directory permissions - world writable.");
if ( buf.st_uid != getuid())
tempfail("Home directory owned by wrong user.");
// Quietly terminate if the sticky bit is set on the homedir
if ( buf.st_mode & S_ISVTX)
return (EX_TEMPFAIL);
if (embedded_filter)
{
i=stat(".mailfilters", &buf);
if ( i < 0 && errno != ENOENT)
tempfail("Unable to read $HOME/.mailfilters.");
else if ( i >= 0)
{
if ( !S_ISDIR(buf.st_mode))
tempfail("$HOME/.mailfilters should be a directory.");
if ( buf.st_mode & (S_IRWXO|S_IRWXG))
tempfail("Invalid permissions on $HOME/.mailfilters - remove world and group perms.");
if ( buf.st_uid != getuid())
tempfail("Invalid user ownership of $HOME/.mailfilters.");
}
recipe = embedded_filter;
}
}
#if SHARED_TEMPDIR
#else
maildrop.tempdir=maildrop.init_home;
maildrop.tempdir += "/" TEMPDIR;
maildrop.tempdir += '\0';
mkdir( (const char *)maildrop.tempdir, 0700 );
#endif
maildrop.reset_vars();
Buffer msg;
maildrop.global_timer.Set(GLOBAL_TIMEOUT);
maildrop.msgptr->Init(0); // Read message from standard input.
maildrop.msginfo.info( *maildrop.msgptr );
maildrop.msgptr->ExtraHeaders(extra_headers);
maildrop.msgptr->setmsgsize();
if (!from) from="";
if (*from) maildrop.msginfo.fromname=from;
// If invoking user is trusted, trust the From line, else set it to invoking
// user.
if (
#if KEEP_FROMLINE
// The original From_ line is kept, if necessary
#else
// If invoking user is trusted, trust the From line, else set it to invoking
// user.
!trusted_uidgid(orig_uid, orig_gid, orig_gid2) ||
#endif
maildrop.msginfo.fromname.Length() == 0)
{
maildrop.msginfo.fromname=maildrop.init_logname;
}
if (explicit_from)
maildrop.msginfo.fromname=from;
name="FROM";
value=maildrop.msginfo.fromname;
SetVar(name, value);
if (VerboseLevel() > 1)
{
msg.reset();
msg.append("Message start at ");
msg.append((unsigned long)maildrop.msginfo.msgoffset);
msg.append(" bytes, envelope sender=");
if (maildrop.msginfo.fromname.Length() > 0)
msg += maildrop.msginfo.fromname;
msg.append("\n");
msg += '\0';
merr.write(msg);
}
name="HOSTNAME";
sethostname(value);
SetVar(name, value);
int fd;
//
//
if (!embedded_filter && deliverymode)
{
Recipe r;
Lexer in;
fd=in.Open(ETCDIR "/maildroprc");
if (fd < 0)
{
if (errno != ENOENT)
{
errexit=EX_TEMPFAIL;
throw "Error opening " ETCDIR "/maildroprc.";
}
}
else
{
if (r.ParseRecipe(in) < 0)
return (EX_TEMPFAIL);
r.ExecuteRecipe();
}
}
Recipe r;
Lexer in;
#ifdef DEFAULTEXT
int firstdefault=1;
#endif
name="MAILFILTER";
value=recipe;
SetVar(name, value);
for (;;)
{
if (embedded_filter)
{
msg=".mailfilters/";
msg += recipe;
if (VerboseLevel() > 1)
merr << "maildrop: Attempting " << msg << "\n";
msg += '\0';
fd=in.Open((const char *)msg);
}
else
{
msg=recipe;
if (VerboseLevel() > 1)
merr << "maildrop: Attempting " << msg << "\n";
msg += '\0';
fd=in.Open((const char *)msg);
break;
}
#ifndef DEFAULTEXT
break;
#else
if (fd >= 0) break;
if (errno != ENOENT) break;
if (firstdefault)
{
recipe += DEFAULTEXT;
firstdefault=0;
continue;
}
// Pop DEFAULTEXT bytes from end of recipe name
for (fd=sizeof(DEFAULTEXT)-1; fd; --fd)
recipe.pop();
while (recipe.Length())
{
if (recipe.pop() == '-')
{
recipe += DEFAULTEXT;
break;
}
}
if (recipe.Length() == 0)
{
msg=".mailfilters/";
msg += DEFAULTEXT+1;
if (VerboseLevel() > 1)
merr << "maildrop: Attempting " << msg << "\n";
msg += '\0';
fd=in.Open((const char *)msg);
break;
}
#endif
}
if (fd < 0)
{
//
// If we are operating in delivery mode, it's ok if
// .mailfilter does not exist.
//
if (!deliverymode || errno != ENOENT)
{
static char buf[80];
sprintf(buf, "Unable to open filter file, errno=%d.",
errno);
errexit=EX_TEMPFAIL;
throw buf;
}
}
else
{
struct stat stat_buf;
setprocgroup();
if (fstat( fd, &stat_buf) != 0)
tempfail("stat() failed.");
if (!S_ISREG(stat_buf.st_mode))
tempfail("mailfilter file isn't a regular file.");
if (stat_buf.st_mode & (S_IRWXO | S_IRWXG))
tempfail("Cannot have world/group permissions on the filter file - for your own good.");
if (stat_buf.st_uid != getuid())
tempfail("mailfilter file is owned by the wrong user.");
if (r.ParseRecipe(in) < 0)
return (EX_TEMPFAIL);
// if (maildrop.msgptr->MessageSize() > 0)
r.ExecuteRecipe();
}
//
// If a message is succesfully delivered, an exception is thrown.
// If we're here, we should deliver to the default mailbox.
//
if (!maildrop.embedded_mode)
{
name="DEFAULT";
const char *v=GetVarStr(name);
if (!v)
{
errexit=EX_TEMPFAIL;
throw "DEFAULT mailbox not defined.";
}
value=v;
value += '\0';
if (delivery((const char *)value) < 0)
return (EX_TEMPFAIL);
}
value="EXITCODE";
return ( GetVar(value)->Int("0") );
}
int main(int argc, char **argv)
{
#if HAVE_SETLOCALE
setlocale(LC_ALL, "C");
#endif
_exit(Maildrop::trap(run, argc, argv));
}
const char *GetDefaultMailbox(const char *username)
{
static Buffer buf;
int isfile=0;
buf="";
const char *p=DEFAULT_DEF;
if (*p != SLASH_CHAR) // Relative to home directory
{
buf=maildrop.init_home;
buf.push(SLASH_CHAR);
isfile=1;
}
while (*p)
{
if (*p != '=')
{
buf.push(*p);
++p;
}
const char *q=username;
while (*p == '=')
{
buf.push (*q ? *q:'.');
if (*q) q++;
p++;
}
}
if (!isfile)
{
buf.push(SLASH_CHAR);
buf += username;
}
buf += '\0';
return (buf);
}
#if SHARED_TEMPDIR
#else
const char *TempName()
{
Buffer t;
t=(const char *)maildrop.tempdir;
t += "/tmp.";
t += '\0';
return (TempName((const char *)t, 0));
}
#endif
