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ngircd-tor
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Implement asynchronous user authentication using PAM 

For each client connection a child process is forked which handles the
actual PAM authentication and reports the result back to the master
process using a pipe for communication.

While the PAM authentication is in process the daemon does not block.
This commit is contained in:
Alexander Barton 2010-07-12 12:56:33 +02:00
parent fb4b5acfb8
commit 808d4f6e85
1 changed files with 102 additions and 6 deletions
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108
src/ngircd/irc-login.c
View File

@ -20,13 +20,16 @@
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <unistd.h>
#include "ngircd.h"
#include "conn-func.h"
#include "conf.h"
#include "channel.h"
#include "io.h"
#include "log.h"
#include "messages.h"
#include "pam.h"
#include "parse.h"
#include "irc.h"
#include "irc-info.h"
@ -37,11 +40,17 @@
static bool Hello_User PARAMS(( CLIENT *Client ));
static bool Hello_User_PostAuth PARAMS(( CLIENT *Client ));
static void Kill_Nick PARAMS(( char *Nick, char *Reason ));
static void Introduce_Client PARAMS((CLIENT *To, CLIENT *Client, int Type));
static void Reject_Client PARAMS((CLIENT *Client));
static void cb_introduceClient PARAMS((CLIENT *Client, CLIENT *Prefix,
void *i));
#ifdef PAM
static void cb_Read_Auth_Result PARAMS((int r_fd, UNUSED short events));
#endif
/**
* Handler for the IRC command "PASS".
@ -760,18 +769,105 @@ IRC_PONG(CLIENT *Client, REQUEST *Req)
static bool
Hello_User(CLIENT * Client)
{
#ifdef PAM
int pipefd[2], result;
CONN_ID conn;
pid_t pid;
assert(Client != NULL);
conn = Client_Conn(Client);
pid = Proc_Fork(Conn_GetProcStat(conn), pipefd, cb_Read_Auth_Result);
if (pid > 0) {
LogDebug("Authenticator for connection %d created (PID %d).",
conn, pid);
return CONNECTED;
} else {
/* Sub process */
signal(SIGTERM, Proc_GenericSignalHandler);
Log_Init_Subprocess("Auth");
result = PAM_Authenticate(Client);
write(pipefd[1], &result, sizeof(result));
Log_Exit_Subprocess("Auth");
exit(0);
}
#else
assert(Client != NULL);
/* Check password ... */
/* Check global server password ... */
if (strcmp(Client_Password(Client), Conf_ServerPwd) != 0) {
/* Bad password! */
Log(LOG_ERR,
"Client \"%s\" rejected (connection %d): Bad password!",
Client_Mask(Client), Client_Conn(Client));
Conn_Close(Client_Conn(Client), NULL, "Bad password", true);
Reject_Client(Client);
return DISCONNECTED;
}
return Hello_User_PostAuth(Client);
#endif
}
#ifdef PAM
/**
* Read result of the authenticatior sub-process from pipe
*/
static void
cb_Read_Auth_Result(int r_fd, UNUSED short events)
{
CONN_ID conn;
CLIENT *client;
int result;
size_t len;
PROC_STAT *proc;
LogDebug("Auth: Got callback on fd %d, events %d", r_fd, events);
conn = Conn_GetFromProc(r_fd);
if (conn == NONE) {
/* Ops, none found? Probably the connection has already
* been closed!? We'll ignore that ... */
io_close(r_fd);
LogDebug("Auth: Got callback for unknown connection!?");
return;
}
proc = Conn_GetProcStat(conn);
client = Conn_GetClient(conn);
/* Read result from pipe */
len = Proc_Read(proc, &result, sizeof(result));
if (len == 0)
return;
/* Make sure authenticator sub-process is dead now ... */
Proc_Kill(proc);
if (len != sizeof(result)) {
Log(LOG_CRIT, "Auth: Got malformed result!");
Reject_Client(client);
return;
}
if (result == true)
(void)Hello_User_PostAuth(client);
else
Reject_Client(client);
}
#endif
static void
Reject_Client(CLIENT *Client)
{
Log(LOG_ERR,
"User \"%s\" rejected (connection %d): Access denied!",
Client_Mask(Client), Client_Conn(Client));
Conn_Close(Client_Conn(Client), NULL,
"Access denied! Bad password?", true);
}
static bool
Hello_User_PostAuth(CLIENT *Client)
{
Introduce_Client(NULL, Client, CLIENT_USER);
if (!IRC_WriteStrClient
@ -805,7 +901,7 @@ Hello_User(CLIENT * Client)
IRC_SetPenalty(Client, 1);
return CONNECTED;
} /* Hello_User */
}
static void