OpenSSH tmp cleanup
Markus Friedl
Markus.Friedl at informatik.uni-erlangen.de
Wed Jun 6 00:54:04 EST 2001
On Tue, Jun 05, 2001 at 09:21:46AM +0300, Jarno Huuskonen wrote:
> I noticed that Markus has fixed the temporary file cleanup problems in
> OpenSSH cvs. What files need patching for this ? I only noticed
> changes in: session.c, channels.h and channels.c.
yes.
i tried to port this back to 2.9, but i don't have time for
testing etc.
simple fix is
s/cookies/x11_forwarding_with_openssh_is_fun/
in session.c
correct fix looks like:
Index: channels.c
===================================================================
RCS file: /home/markus/cvs/ssh/channels.c,v
retrieving revision 1.109
diff -u -r1.109 channels.c
--- channels.c 2001/04/17 12:55:03 1.109
+++ channels.c 2001/06/05 14:38:42
@@ -2524,10 +2524,17 @@
/* removes the agent forwarding socket */
void
-cleanup_socket(void)
+auth_sock_cleanup_proc(void *_pw)
{
- unlink(channel_forwarded_auth_socket_name);
- rmdir(channel_forwarded_auth_socket_dir);
+ struct passwd *pw = _pw;
+
+ if (channel_forwarded_auth_socket_name) {
+ temporarily_use_uid(pw);
+ unlink(channel_forwarded_auth_socket_name);
+ rmdir(channel_forwarded_auth_socket_dir);
+ channel_forwarded_auth_socket_name = NULL;
+ restore_uid();
+ }
}
/*
@@ -2566,11 +2573,9 @@
snprintf(channel_forwarded_auth_socket_name, MAX_SOCKET_NAME, "%s/agent.%d",
channel_forwarded_auth_socket_dir, (int) getpid());
- if (atexit(cleanup_socket) < 0) {
- int saved = errno;
- cleanup_socket();
- packet_disconnect("socket: %.100s", strerror(saved));
- }
+ /* delete agent socket on fatal() */
+ fatal_add_cleanup(auth_sock_cleanup_proc, pw);
+
/* Create the socket. */
sock = socket(AF_UNIX, SOCK_STREAM, 0);
if (sock < 0)
Index: channels.h
===================================================================
RCS file: /home/markus/cvs/ssh/channels.h,v
retrieving revision 1.31
diff -u -r1.31 channels.h
--- channels.h 2001/04/13 22:46:53 1.31
+++ channels.h 2001/06/05 14:37:23
@@ -293,6 +293,8 @@
*/
char *auth_get_socket_name(void);
+void auth_sock_cleanup_proc(void *_pw);
+
/*
* This is called to process SSH_CMSG_AGENT_REQUEST_FORWARDING on the server.
* This starts forwarding authentication requests.
Index: session.c
===================================================================
RCS file: /home/markus/cvs/ssh/session.c,v
retrieving revision 1.74
diff -u -r1.74 session.c
--- session.c 2001/04/17 19:34:25 1.74
+++ session.c 2001/06/05 14:39:54
@@ -89,12 +89,15 @@
void session_set_fds(Session *s, int fdin, int fdout, int fderr);
void session_pty_cleanup(Session *s);
void session_proctitle(Session *s);
+int session_setup_x11fwd(Session *s);
+void session_close(Session *s);
void do_exec_pty(Session *s, const char *command);
void do_exec_no_pty(Session *s, const char *command);
void do_login(Session *s, const char *command);
void do_child(Session *s, const char *command);
void do_motd(void);
int check_quietlogin(Session *s, const char *command);
+void xauthfile_cleanup_proc(void *pw);
void do_authenticated1(Authctxt *authctxt);
void do_authenticated2(Authctxt *authctxt);
@@ -154,18 +157,26 @@
do_authenticated2(authctxt);
else
do_authenticated1(authctxt);
+
+ /* remote user's local Xauthority file and agent socket */
+ if (xauthfile)
+ xauthfile_cleanup_proc(authctxt->pw);
+ if (auth_get_socket_name())
+ auth_sock_cleanup_proc(authctxt->pw);
}
/*
* Remove local Xauthority file.
*/
void
-xauthfile_cleanup_proc(void *ignore)
+xauthfile_cleanup_proc(void *_pw)
{
- debug("xauthfile_cleanup_proc called");
+ struct passwd *pw = _pw;
+ char *p;
+ debug("xauthfile_cleanup_proc called");
if (xauthfile != NULL) {
- char *p;
+ temporarily_use_uid(pw);
unlink(xauthfile);
p = strrchr(xauthfile, '/');
if (p != NULL) {
@@ -174,6 +185,7 @@
}
xfree(xauthfile);
xauthfile = NULL;
+ restore_uid();
}
}
@@ -209,7 +221,7 @@
{
Session *s;
char *command;
- int success, type, fd, n_bytes, plen, screen_flag, have_pty = 0;
+ int success, type, n_bytes, plen, screen_flag, have_pty = 0;
int compression_level = 0, enable_compression_after_reply = 0;
u_int proto_len, data_len, dlen;
@@ -290,22 +302,6 @@
break;
case SSH_CMSG_X11_REQUEST_FORWARDING:
- if (!options.x11_forwarding) {
- packet_send_debug("X11 forwarding disabled in server configuration file.");
- break;
- }
- if (!options.xauth_location) {
- packet_send_debug("No xauth program; cannot forward with spoofing.");
- break;
- }
- if (no_x11_forwarding_flag) {
- packet_send_debug("X11 forwarding not permitted for this authentication.");
- break;
- }
- debug("Received request for X11 forwarding with auth spoofing.");
- if (s->display != NULL)
- packet_disconnect("Protocol error: X11 display already set.");
-
s->auth_proto = packet_get_string(&proto_len);
s->auth_data = packet_get_string(&data_len);
@@ -325,31 +321,11 @@
4 + proto_len + 4 + data_len, type);
s->screen = 0;
}
- s->display = x11_create_display_inet(s->screen, options.x11_display_offset);
-
- if (s->display == NULL)
- break;
-
- /* Setup to always have a local .Xauthority. */
- xauthfile = xmalloc(MAXPATHLEN);
- strlcpy(xauthfile, "/tmp/ssh-XXXXXXXX", MAXPATHLEN);
- temporarily_use_uid(s->pw);
- if (mkdtemp(xauthfile) == NULL) {
- restore_uid();
- error("private X11 dir: mkdtemp %s failed: %s",
- xauthfile, strerror(errno));
- xfree(xauthfile);
- xauthfile = NULL;
- /* XXXX remove listening channels */
- break;
+ success = session_setup_x11fwd(s);
+ if (!success) {
+ xfree(s->auth_proto);
+ xfree(s->auth_data);
}
- strlcat(xauthfile, "/cookies", MAXPATHLEN);
- fd = open(xauthfile, O_RDWR|O_CREAT|O_EXCL, 0600);
- if (fd >= 0)
- close(fd);
- restore_uid();
- fatal_add_cleanup(xauthfile_cleanup_proc, NULL);
- success = 1;
break;
case SSH_CMSG_AGENT_REQUEST_FORWARDING:
@@ -402,9 +378,7 @@
if (command != NULL)
xfree(command);
- /* Cleanup user's local Xauthority file. */
- if (xauthfile)
- xauthfile_cleanup_proc(NULL);
+ session_close(s);
return;
default:
@@ -1372,23 +1346,7 @@
int
session_x11_req(Session *s)
{
- int fd;
- if (no_x11_forwarding_flag) {
- debug("X11 forwarding disabled in user configuration file.");
- return 0;
- }
- if (!options.x11_forwarding) {
- debug("X11 forwarding disabled in server configuration file.");
- return 0;
- }
- if (xauthfile != NULL) {
- debug("X11 fwd already started.");
- return 0;
- }
-
- debug("Received request for X11 forwarding with auth spoofing.");
- if (s->display != NULL)
- packet_disconnect("Protocol error: X11 display already set.");
+ int success;
s->single_connection = packet_get_char();
s->auth_proto = packet_get_string(NULL);
@@ -1396,33 +1354,12 @@
s->screen = packet_get_int();
packet_done();
- s->display = x11_create_display_inet(s->screen, options.x11_display_offset);
- if (s->display == NULL) {
+ success = session_setup_x11fwd(s);
+ if (!success) {
xfree(s->auth_proto);
xfree(s->auth_data);
- return 0;
}
- xauthfile = xmalloc(MAXPATHLEN);
- strlcpy(xauthfile, "/tmp/ssh-XXXXXXXX", MAXPATHLEN);
- temporarily_use_uid(s->pw);
- if (mkdtemp(xauthfile) == NULL) {
- restore_uid();
- error("private X11 dir: mkdtemp %s failed: %s",
- xauthfile, strerror(errno));
- xfree(xauthfile);
- xauthfile = NULL;
- xfree(s->auth_proto);
- xfree(s->auth_data);
- /* XXXX remove listening channels */
- return 0;
- }
- strlcat(xauthfile, "/cookies", MAXPATHLEN);
- fd = open(xauthfile, O_RDWR|O_CREAT|O_EXCL, 0600);
- if (fd >= 0)
- close(fd);
- restore_uid();
- fatal_add_cleanup(xauthfile_cleanup_proc, s);
- return 1;
+ return success;
}
int
@@ -1636,6 +1573,10 @@
void
session_close(Session *s)
{
+ if (s->display) {
+ xauthfile_cleanup_proc(s->pw);
+ fatal_remove_cleanup(xauthfile_cleanup_proc, s->pw);
+ }
session_pty_cleanup(s);
session_free(s);
session_proctitle(s);
@@ -1710,11 +1651,57 @@
setproctitle("%s@%s", s->pw->pw_name, session_tty_list());
}
+int
+session_setup_x11fwd(Session *s)
+{
+ int fd;
+ struct stat st;
+
+ if (no_x11_forwarding_flag) {
+ packet_send_debug("X11 forwarding disabled in user configuration file.");
+ return 0;
+ }
+ if (!options.x11_forwarding) {
+ debug("X11 forwarding disabled in server configuration file.");
+ return 0;
+ }
+ if (!options.xauth_location ||
+ (stat(options.xauth_location, &st) == -1)) {
+ packet_send_debug("No xauth program; cannot forward with spoofing.");
+ return 0;
+ }
+ if (s->display != NULL) {
+ debug("X11 display already set.");
+ return 0;
+ }
+ xauthfile = xmalloc(MAXPATHLEN);
+ strlcpy(xauthfile, "/tmp/ssh-XXXXXXXX", MAXPATHLEN);
+ temporarily_use_uid(s->pw);
+ if (mkdtemp(xauthfile) == NULL) {
+ restore_uid();
+ error("private X11 dir: mkdtemp %s failed: %s",
+ xauthfile, strerror(errno));
+ xfree(xauthfile);
+ xauthfile = NULL;
+ return 0;
+ }
+ strlcat(xauthfile, "/cookies", MAXPATHLEN);
+ fd = open(xauthfile, O_RDWR|O_CREAT|O_EXCL, 0600);
+ if (fd >= 0)
+ close(fd);
+ restore_uid();
+ s->display = x11_create_display_inet(s->screen, options.x11_display_offset);
+ if (s->display == NULL) {
+ xauthfile_cleanup_proc(s->pw);
+ return 0;
+ }
+ fatal_add_cleanup(xauthfile_cleanup_proc, s->pw);
+ return 1;
+}
+
void
do_authenticated2(Authctxt *authctxt)
{
server_loop2();
- if (xauthfile)
- xauthfile_cleanup_proc(NULL);
}
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