- More reformatting merged from OpenBSD CVS
- Merged OpenBSD CVS changes:
- [channels.c]
report from mrwizard@psu.edu via djm@ibs.com.au
- [channels.c]
set SO_REUSEADDR and SO_LINGER for forwarded ports.
chip@valinux.com via damien@ibs.com.au
- [nchan.c]
it's not an error() if shutdown_write failes in nchan.
- [readconf.c]
remove dead #ifdef-0-code
- [readconf.c servconf.c]
strcasecmp instead of tolower
- [scp.c]
progress meter overflow fix from damien@ibs.com.au
- [ssh-add.1 ssh-add.c]
SSH_ASKPASS support
- [ssh.1 ssh.c]
postpone fork_after_authentication until command execution,
request/patch from jahakala@cc.jyu.fi via damien@ibs.com.au
plus: use daemon() for backgrounding
diff --git a/ssh.c b/ssh.c
index 8d73e61..21147f7 100644
--- a/ssh.c
+++ b/ssh.c
@@ -11,7 +11,7 @@
*/
#include "includes.h"
-RCSID("$Id: ssh.c,v 1.11 1999/11/24 13:26:23 damien Exp $");
+RCSID("$Id: ssh.c,v 1.12 1999/11/25 00:54:59 damien Exp $");
#include "xmalloc.h"
#include "ssh.h"
@@ -30,35 +30,43 @@
/* Flag indicating whether debug mode is on. This can be set on the command line. */
int debug_flag = 0;
-/* Flag indicating whether to allocate a pseudo tty. This can be set on the command
- line, and is automatically set if no command is given on the command line. */
int tty_flag = 0;
-/* Flag indicating that nothing should be read from stdin. This can be set
- on the command line. */
+/*
+ * Flag indicating that nothing should be read from stdin. This can be set
+ * on the command line.
+ */
int stdin_null_flag = 0;
-/* Flag indicating that ssh should fork after authentication. This is useful
- so that the pasphrase can be entered manually, and then ssh goes to the
- background. */
+/*
+ * Flag indicating that ssh should fork after authentication. This is useful
+ * so that the pasphrase can be entered manually, and then ssh goes to the
+ * background.
+ */
int fork_after_authentication_flag = 0;
-/* General data structure for command line options and options configurable
- in configuration files. See readconf.h. */
+/*
+ * General data structure for command line options and options configurable
+ * in configuration files. See readconf.h.
+ */
Options options;
-/* Name of the host we are connecting to. This is the name given on the
- command line, or the HostName specified for the user-supplied name
- in a configuration file. */
+/*
+ * Name of the host we are connecting to. This is the name given on the
+ * command line, or the HostName specified for the user-supplied name in a
+ * configuration file.
+ */
char *host;
/* socket address the host resolves to */
struct sockaddr_in hostaddr;
-/* Flag to indicate that we have received a window change signal which has
- not yet been processed. This will cause a message indicating the new
- window size to be sent to the server a little later. This is volatile
- because this is updated in a signal handler. */
+/*
+ * Flag to indicate that we have received a window change signal which has
+ * not yet been processed. This will cause a message indicating the new
+ * window size to be sent to the server a little later. This is volatile
+ * because this is updated in a signal handler.
+ */
volatile int received_window_change_signal = 0;
/* Value of argv[0] (set in the main program). */
@@ -165,8 +173,10 @@
uid_t original_effective_uid;
int plen;
- /* Save the original real uid. It will be needed later
- (uid-swapping may clobber the real uid). */
+ /*
+ * Save the original real uid. It will be needed later (uid-swapping
+ * may clobber the real uid).
+ */
original_real_uid = getuid();
original_effective_uid = geteuid();
@@ -177,18 +187,21 @@
if (setrlimit(RLIMIT_CORE, &rlim) < 0)
fatal("setrlimit failed: %.100s", strerror(errno));
}
- /* Use uid-swapping to give up root privileges for the duration of
- option processing. We will re-instantiate the rights when we
- are ready to create the privileged port, and will permanently
- drop them when the port has been created (actually, when the
- connection has been made, as we may need to create the port
- several times). */
+ /*
+ * Use uid-swapping to give up root privileges for the duration of
+ * option processing. We will re-instantiate the rights when we are
+ * ready to create the privileged port, and will permanently drop
+ * them when the port has been created (actually, when the connection
+ * has been made, as we may need to create the port several times).
+ */
temporarily_use_uid(original_real_uid);
- /* Set our umask to something reasonable, as some files are
- created with the default umask. This will make them
- world-readable but writable only by the owner, which is ok for
- all files for which we don't set the modes explicitly. */
+ /*
+ * Set our umask to something reasonable, as some files are created
+ * with the default umask. This will make them world-readable but
+ * writable only by the owner, which is ok for all files for which we
+ * don't set the modes explicitly.
+ */
umask(022);
/* Save our own name. */
@@ -387,10 +400,11 @@
/* Initialize the command to execute on remote host. */
buffer_init(&command);
- /* Save the command to execute on the remote host in a buffer.
- There is no limit on the length of the command, except by the
- maximum packet size. Also sets the tty flag if there is no
- command. */
+ /*
+ * Save the command to execute on the remote host in a buffer. There
+ * is no limit on the length of the command, except by the maximum
+ * packet size. Also sets the tty flag if there is no command.
+ */
if (optind == ac) {
/* No command specified - execute shell on a tty. */
tty_flag = 1;
@@ -474,11 +488,15 @@
options.rhosts_authentication = 0;
options.rhosts_rsa_authentication = 0;
}
- /* If using rsh has been selected, exec it now (without trying
- anything else). Note that we must release privileges first. */
+ /*
+ * If using rsh has been selected, exec it now (without trying
+ * anything else). Note that we must release privileges first.
+ */
if (options.use_rsh) {
- /* Restore our superuser privileges. This must be done
- before permanently setting the uid. */
+ /*
+ * Restore our superuser privileges. This must be done
+ * before permanently setting the uid.
+ */
restore_uid();
/* Switch to the original uid permanently. */
@@ -491,8 +509,10 @@
/* Restore our superuser privileges. */
restore_uid();
- /* Open a connection to the remote host. This needs root
- privileges if rhosts_{rsa_}authentication is enabled. */
+ /*
+ * Open a connection to the remote host. This needs root privileges
+ * if rhosts_{rsa_}authentication is enabled.
+ */
ok = ssh_connect(host, &hostaddr, options.port,
options.connection_attempts,
@@ -501,31 +521,38 @@
original_real_uid,
options.proxy_command);
- /* If we successfully made the connection, load the host private
- key in case we will need it later for combined rsa-rhosts
- authentication. This must be done before releasing extra
- privileges, because the file is only readable by root. */
+ /*
+ * If we successfully made the connection, load the host private key
+ * in case we will need it later for combined rsa-rhosts
+ * authentication. This must be done before releasing extra
+ * privileges, because the file is only readable by root.
+ */
if (ok) {
host_private_key = RSA_new();
if (load_private_key(HOST_KEY_FILE, "", host_private_key, NULL))
host_private_key_loaded = 1;
}
- /* Get rid of any extra privileges that we may have. We will no
- longer need them. Also, extra privileges could make it very
- hard to read identity files and other non-world-readable files
- from the user's home directory if it happens to be on a NFS
- volume where root is mapped to nobody. */
+ /*
+ * Get rid of any extra privileges that we may have. We will no
+ * longer need them. Also, extra privileges could make it very hard
+ * to read identity files and other non-world-readable files from the
+ * user's home directory if it happens to be on a NFS volume where
+ * root is mapped to nobody.
+ */
- /* Note that some legacy systems need to postpone the following
- call to permanently_set_uid() until the private hostkey is
- destroyed with RSA_free(). Otherwise the calling user could
- ptrace() the process, read the private hostkey and impersonate
- the host. OpenBSD does not allow ptracing of setuid processes. */
-
+ /*
+ * Note that some legacy systems need to postpone the following call
+ * to permanently_set_uid() until the private hostkey is destroyed
+ * with RSA_free(). Otherwise the calling user could ptrace() the
+ * process, read the private hostkey and impersonate the host.
+ * OpenBSD does not allow ptracing of setuid processes.
+ */
permanently_set_uid(original_real_uid);
- /* Now that we are back to our own permissions, create ~/.ssh
- directory if it doesn\'t already exist. */
+ /*
+ * Now that we are back to our own permissions, create ~/.ssh
+ * directory if it doesn\'t already exist.
+ */
snprintf(buf, sizeof buf, "%.100s/%.100s", pw->pw_dir, SSH_USER_DIR);
if (stat(buf, &st) < 0)
if (mkdir(buf, 0755) < 0)
@@ -569,15 +596,6 @@
/* Close connection cleanly after attack. */
cipher_attack_detected = packet_disconnect;
- /* If requested, fork and let ssh continue in the background. */
- if (fork_after_authentication_flag) {
- int ret = fork();
- if (ret == -1)
- fatal("fork failed: %.100s", strerror(errno));
- if (ret != 0)
- exit(0);
- setsid();
- }
/* Enable compression if requested. */
if (options.compression) {
debug("Requesting compression at level %d.", options.compression_level);
@@ -653,12 +671,14 @@
if (f)
pclose(f);
#endif /* XAUTH_PATH */
- /* If we didn't get authentication data, just make up some
- data. The forwarding code will check the validity of
- the response anyway, and substitute this data. The X11
- server, however, will ignore this fake data and use
- whatever authentication mechanisms it was using
- otherwise for the local connection. */
+ /*
+ * If we didn't get authentication data, just make up some
+ * data. The forwarding code will check the validity of the
+ * response anyway, and substitute this data. The X11
+ * server, however, will ignore this fake data and use
+ * whatever authentication mechanisms it was using otherwise
+ * for the local connection.
+ */
if (!got_data) {
u_int32_t rand = 0;
@@ -670,8 +690,10 @@
rand >>= 8;
}
}
- /* Got local authentication reasonable information.
- Request forwarding with authentication spoofing. */
+ /*
+ * Got local authentication reasonable information. Request
+ * forwarding with authentication spoofing.
+ */
debug("Requesting X11 forwarding with authentication spoofing.");
x11_request_forwarding_with_spoofing(proto, data);
@@ -728,8 +750,15 @@
options.remote_forwards[i].host_port);
}
- /* If a command was specified on the command line, execute the
- command now. Otherwise request the server to start a shell. */
+ /* If requested, let ssh continue in the background. */
+ if (fork_after_authentication_flag)
+ if (daemon(1, 1) < 0)
+ fatal("daemon() failed: %.200s", strerror(errno));
+
+ /*
+ * If a command was specified on the command line, execute the
+ * command now. Otherwise request the server to start a shell.
+ */
if (buffer_len(&command) > 0) {
int len = buffer_len(&command);
if (len > 900)