Winbind client-side cleanups.

The global winbind file descriptor can cause havoc in some situations -
particulary when it becomes 0, 1 or 2.  This patch (based on some very nice
work by Hannes Schmidt <mail@schmidt-net.via.t-online.de>) starts to recitfy
the problem by ensuring that the close-on-exec flag is set, and that we move
above 3 in the file descriptor table.

I've also decided that the PAM module can close it's pipe handle on every
request - this isn't performance-critical code.

The next step is to do the same for nss_winbind.  (But things like getent()
might get in our way there).

This also cleans up some function prototypes, puts them in just one place.

Andrew Bartlett
(This used to be commit 442eb39657b98f67cd229ed3110b63aae8bf4e3c)

6 files changed, 94 insertions, 37 deletions

diff --git a/source3/nsswitch/pam_winbind.c b/source3/nsswitch/pam_winbind.c
index 29ceca4e79..f95caefb4c 100644
--- a/source3/nsswitch/pam_winbind.c
+++ b/source3/nsswitch/pam_winbind.c
@@ -11,11 +11,6 @@
 
 #include "pam_winbind.h"
 
-/* prototypes from common.c */
-void init_request(struct winbindd_request *req,int rq_type);
-int write_sock(void *buffer, int count);
-int read_reply(struct winbindd_response *response);
-
 /* data tokens */
 
 #define MAX_PASSWD_TRIES	3
@@ -99,24 +94,30 @@ static int _make_remark(pam_handle_t * pamh, int type, const char *text)
 	return retval;
 }
 
-static int winbind_request(enum winbindd_cmd req_type,
-                           struct winbindd_request *request,
-                           struct winbindd_response *response)
+static int pam_winbind_request(enum winbindd_cmd req_type,
+			       struct winbindd_request *request,
+			       struct winbindd_response *response)
 {
+
 	/* Fill in request and send down pipe */
 	init_request(request, req_type);
 	
 	if (write_sock(request, sizeof(*request)) == -1) {
 		_pam_log(LOG_ERR, "write to socket failed!");
+		close_sock();
 		return PAM_SERVICE_ERR;
 	}
 	
 	/* Wait for reply */
 	if (read_reply(response) == -1) {
 		_pam_log(LOG_ERR, "read from socket failed!");
+		close_sock();
 		return PAM_SERVICE_ERR;
 	}
 
+	/* We are done with the socket - close it and avoid mischeif */
+	close_sock();
+
 	/* Copy reply data from socket */
 	if (response->result != WINBINDD_OK) {
 		if (response->data.auth.pam_error != PAM_SUCCESS) {
@@ -148,7 +149,7 @@ static int winbind_auth_request(const char *user, const char *pass, int ctrl)
 	strncpy(request.data.auth.pass, pass, 
                 sizeof(request.data.auth.pass)-1);
 	
-        retval = winbind_request(WINBINDD_PAM_AUTH, &request, &response);
+        retval = pam_winbind_request(WINBINDD_PAM_AUTH, &request, &response);
 
 	switch (retval) {
 	case PAM_AUTH_ERR:
@@ -217,7 +218,7 @@ static int winbind_chauthtok_request(const char *user, const char *oldpass,
             request.data.chauthtok.newpass[0] = '\0';
         }
 	
-        return winbind_request(WINBINDD_PAM_CHAUTHTOK, &request, &response);
+        return pam_winbind_request(WINBINDD_PAM_CHAUTHTOK, &request, &response);
 }
 
 /*
diff --git a/source3/nsswitch/pam_winbind.h b/source3/nsswitch/pam_winbind.h
index 9897249e16..fae635d806 100644
--- a/source3/nsswitch/pam_winbind.h
+++ b/source3/nsswitch/pam_winbind.h
@@ -90,5 +90,4 @@ do {                             \
 #define on(x, y) (x & y)
 #define off(x, y) (!(x & y))
 
-#include "winbind_nss_config.h"
-#include "winbindd_nss.h"
+#include "winbind_client.h"
diff --git a/source3/nsswitch/wb_common.c b/source3/nsswitch/wb_common.c
index 9bc9faafb5..0d1be4d5d1 100644
--- a/source3/nsswitch/wb_common.c
+++ b/source3/nsswitch/wb_common.c
@@ -5,6 +5,8 @@
 
    Copyright (C) Tim Potter 2000
    Copyright (C) Andrew Tridgell 2000
+   Copyright (C) Andrew Bartlett 2002
+   
    
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
@@ -75,7 +77,7 @@ void init_response(struct winbindd_response *response)
 
 /* Close established socket */
 
-static void close_sock(void)
+void close_sock(void)
 {
 	if (winbindd_fd != -1) {
 		close(winbindd_fd);
@@ -83,6 +85,64 @@ static void close_sock(void)
 	}
 }
 
+/* Make sure socket handle isn't stdin, stdout or stderr */
+#define RECURSION_LIMIT 3
+
+static int make_nonstd_fd_internals(int fd, int limit /* Recursion limiter */) 
+{
+	int new_fd;
+	if (fd >= 0 && fd <= 2) {
+#ifdef F_DUPFD 
+		if ((new_fd = fcntl(fd, F_DUPFD, 3)) == -1) {
+			return -1;
+		}
+		/* Parinoia */
+		if (new_fd < 3) {
+			return -1;
+		}
+		close(fd);
+		return new_fd;
+#else
+		if (limit <= 0)
+			return -1;
+		
+		new_fd = dup(fd);
+		if (new_fd == -1) 
+			return -1;
+
+		/* use the program stack to hold our list of FDs to close */
+		new_fd = make_nonstd_fd_internals(new_fd, limit - 1);
+		close(fd);
+		return new_fd;
+#endif
+	}
+	return fd;
+}
+
+static int make_safe_fd(int fd) 
+{
+	int result, flags;
+	int new_fd = make_nonstd_fd_internals(fd, RECURSION_LIMIT);
+	if (new_fd == -1) {
+		close(fd);
+		return -1;
+	}
+	/* Socket should be closed on exec() */
+	
+#ifdef FD_CLOEXEC
+	result = flags = fcntl(new_fd, F_GETFD, 0);
+	if (flags >= 0) {
+		flags |= FD_CLOEXEC;
+		result = fcntl( new_fd, F_SETFD, flags );
+	}
+	if (result < 0) {
+		close(new_fd);
+		return -1;
+	}
+#endif
+	return new_fd;
+}
+
 /* Connect to winbindd socket */
 
 int winbind_open_pipe_sock(void)
@@ -91,6 +151,7 @@ int winbind_open_pipe_sock(void)
 	static pid_t our_pid;
 	struct stat st;
 	pstring path;
+	int fd;
 	
 	if (our_pid != getpid()) {
 		close_sock();
@@ -144,9 +205,13 @@ int winbind_open_pipe_sock(void)
 	
 	/* Connect to socket */
 	
-	if ((winbindd_fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
+	if ((fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
 		return -1;
 	}
+
+	if ((winbindd_fd = make_safe_fd( fd)) == -1) {
+		return winbindd_fd;
+	}
 	
 	if (connect(winbindd_fd, (struct sockaddr *)&sunaddr, 
 		    sizeof(sunaddr)) == -1) {
@@ -366,8 +431,8 @@ NSS_STATUS winbindd_get_response(struct winbindd_response *response)
 /* Handle simple types of requests */
 
 NSS_STATUS winbindd_request(int req_type, 
-				 struct winbindd_request *request,
-				 struct winbindd_response *response)
+			    struct winbindd_request *request,
+			    struct winbindd_response *response)
 {
 	NSS_STATUS status;
 
diff --git a/source3/nsswitch/wbinfo.c b/source3/nsswitch/wbinfo.c
index d7d70b9e52..a0fdd033d7 100644
--- a/source3/nsswitch/wbinfo.c
+++ b/source3/nsswitch/wbinfo.c
@@ -28,11 +28,7 @@
 #undef DBGC_CLASS
 #define DBGC_CLASS DBGC_WINBIND
 
-/* Prototypes from common.h */
-
-NSS_STATUS winbindd_request(int req_type, 
-			    struct winbindd_request *request,
-			    struct winbindd_response *response);
+extern int winbindd_fd;
 
 static char winbind_separator(void)
 {
@@ -608,13 +604,13 @@ static BOOL wbinfo_set_auth_user(char *username)
 static BOOL wbinfo_ping(void)
 {
         NSS_STATUS result;
-	
+
 	result = winbindd_request(WINBINDD_PING, NULL, NULL);
 
 	/* Display response */
 
-        d_printf("'ping' to winbindd %s\n", 
-               (result == NSS_STATUS_SUCCESS) ? "succeeded" : "failed");
+        d_printf("'ping' to winbindd %s on fd %d\n", 
+               (result == NSS_STATUS_SUCCESS) ? "succeeded" : "failed", winbindd_fd);
 
         return result == NSS_STATUS_SUCCESS;
 }
diff --git a/source3/nsswitch/winbind_nss.c b/source3/nsswitch/winbind_nss.c
index 594b5fbadb..0b4c0ce1d0 100644
--- a/source3/nsswitch/winbind_nss.c
+++ b/source3/nsswitch/winbind_nss.c
@@ -21,8 +21,7 @@
    Boston, MA  02111-1307, USA.   
 */
 
-#include "winbind_nss_config.h"
-#include "winbindd_nss.h"
+#include "winbind_client.h"
 
 #ifdef HAVE_NS_API_H
 #undef VOLATILE
@@ -37,17 +36,6 @@
 
 extern int winbindd_fd;
 
-void init_request(struct winbindd_request *req,int rq_type);
-NSS_STATUS winbindd_send_request(int req_type,
-				 struct winbindd_request *request);
-NSS_STATUS winbindd_get_response(struct winbindd_response *response);
-NSS_STATUS winbindd_request(int req_type, 
-				 struct winbindd_request *request,
-				 struct winbindd_response *response);
-int winbind_open_pipe_sock(void);
-int write_sock(void *buffer, int count);
-int read_reply(struct winbindd_response *response);
-void free_response(struct winbindd_response *response);
 
 #ifdef HAVE_NS_API_H
 /* IRIX version */
diff --git a/source3/nsswitch/winbind_nss_config.h b/source3/nsswitch/winbind_nss_config.h
index 00cd5c12e4..d9a9b8aaae 100644
--- a/source3/nsswitch/winbind_nss_config.h
+++ b/source3/nsswitch/winbind_nss_config.h
@@ -62,6 +62,14 @@
 #include <string.h>
 #endif
 
+#ifdef HAVE_FCNTL_H
+#include <fcntl.h>
+#else
+#ifdef HAVE_SYS_FCNTL_H
+#include <sys/fcntl.h>
+#endif
+#endif
+
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <errno.h>