1 files changed, 29 insertions, 132 deletions

diff --git a/svr-chansession.c b/svr-chansession.c
index 7cedb8e..060a235 100644
--- a/svr-chansession.c
+++ b/svr-chansession.c
@@ -47,7 +47,7 @@ static int sessionsignal(struct ChanSess *chansess);
 static int noptycommand(struct Channel *channel, struct ChanSess *chansess);
 static int ptycommand(struct Channel *channel, struct ChanSess *chansess);
 static int sessionwinchange(struct ChanSess *chansess);
-static void execchild(struct ChanSess *chansess);
+static void execchild(void *user_data_chansess);
 static void addchildpid(struct ChanSess *chansess, pid_t pid);
 static void sesssigchild_handler(int val);
 static void closechansess(struct Channel *channel);
@@ -633,100 +633,37 @@ static int sessioncommand(struct Channel *channel, struct ChanSess *chansess,
  * pty.
  * Returns DROPBEAR_SUCCESS or DROPBEAR_FAILURE */
 static int noptycommand(struct Channel *channel, struct ChanSess *chansess) {
-
-	int infds[2];
-	int outfds[2];
-	int errfds[2];
-	pid_t pid;
-	unsigned int i;
+	int ret;
 
 	TRACE(("enter noptycommand"))
+	ret = spawn_command(execchild, chansess, 
+			&channel->writefd, &channel->readfd, &channel->errfd,
+			&chansess->pid);
 
-	/* redirect stdin/stdout/stderr */
-	if (pipe(infds) != 0)
-		return DROPBEAR_FAILURE;
-	if (pipe(outfds) != 0)
-		return DROPBEAR_FAILURE;
-	if (pipe(errfds) != 0)
-		return DROPBEAR_FAILURE;
-
-#ifdef __uClinux__
-	pid = vfork();
-#else
-	pid = fork();
-#endif
-
-	if (pid < 0)
-		return DROPBEAR_FAILURE;
-
-	if (!pid) {
-		/* child */
-
-		TRACE(("back to normal sigchld"))
-		/* Revert to normal sigchld handling */
-		if (signal(SIGCHLD, SIG_DFL) == SIG_ERR) {
-			dropbear_exit("signal() error");
-		}
-
-		/* redirect stdin/stdout */
-#define FDIN 0
-#define FDOUT 1
-		if ((dup2(infds[FDIN], STDIN_FILENO) < 0) ||
-			(dup2(outfds[FDOUT], STDOUT_FILENO) < 0) ||
-			(dup2(errfds[FDOUT], STDERR_FILENO) < 0)) {
-			TRACE(("leave noptycommand: error redirecting FDs"))
-			return DROPBEAR_FAILURE;
-		}
-
-		close(infds[FDOUT]);
-		close(infds[FDIN]);
-		close(outfds[FDIN]);
-		close(outfds[FDOUT]);
-		close(errfds[FDIN]);
-		close(errfds[FDOUT]);
-
-		execchild(chansess);
-		/* not reached */
+	if (ret == DROPBEAR_FAILURE) {
+		return ret;
+	}
 
-	} else {
-		/* parent */
-		TRACE(("continue noptycommand: parent"))
-		chansess->pid = pid;
-		TRACE(("child pid is %d", pid))
+	ses.maxfd = MAX(ses.maxfd, channel->writefd);
+	ses.maxfd = MAX(ses.maxfd, channel->readfd);
+	ses.maxfd = MAX(ses.maxfd, channel->errfd);
 
-		addchildpid(chansess, pid);
+	addchildpid(chansess, chansess->pid);
 
-		if (svr_ses.lastexit.exitpid != -1) {
-			TRACE(("parent side: lastexitpid is %d", svr_ses.lastexit.exitpid))
-			/* The child probably exited and the signal handler triggered
-			 * possibly before we got around to adding the childpid. So we fill
-			 * out its data manually */
-			for (i = 0; i < svr_ses.childpidsize; i++) {
-				if (svr_ses.childpids[i].pid == svr_ses.lastexit.exitpid) {
-					TRACE(("found match for lastexitpid"))
-					svr_ses.childpids[i].chansess->exit = svr_ses.lastexit;
-					svr_ses.lastexit.exitpid = -1;
-				}
+	if (svr_ses.lastexit.exitpid != -1) {
+		TRACE(("parent side: lastexitpid is %d", svr_ses.lastexit.exitpid))
+		/* The child probably exited and the signal handler triggered
+		 * possibly before we got around to adding the childpid. So we fill
+		 * out its data manually */
+		int i;
+		for (i = 0; i < svr_ses.childpidsize; i++) {
+			if (svr_ses.childpids[i].pid == svr_ses.lastexit.exitpid) {
+				TRACE(("found match for lastexitpid"))
+				svr_ses.childpids[i].chansess->exit = svr_ses.lastexit;
+				svr_ses.lastexit.exitpid = -1;
 			}
 		}
-
-		close(infds[FDIN]);
-		close(outfds[FDOUT]);
-		close(errfds[FDOUT]);
-		channel->writefd = infds[FDOUT];
-		channel->readfd = outfds[FDIN];
-		channel->errfd = errfds[FDIN];
-		ses.maxfd = MAX(ses.maxfd, channel->writefd);
-		ses.maxfd = MAX(ses.maxfd, channel->readfd);
-		ses.maxfd = MAX(ses.maxfd, channel->errfd);
-
-		setnonblocking(channel->readfd);
-		setnonblocking(channel->writefd);
-		setnonblocking(channel->errfd);
-
 	}
-#undef FDIN
-#undef FDOUT
 
 	TRACE(("leave noptycommand"))
 	return DROPBEAR_SUCCESS;
@@ -871,12 +808,9 @@ static void addchildpid(struct ChanSess *chansess, pid_t pid) {
 
 /* Clean up, drop to user privileges, set up the environment and execute
  * the command/shell. This function does not return. */
-static void execchild(struct ChanSess *chansess) {
-
-	char *argv[4];
-	char * usershell = NULL;
-	char * baseshell = NULL;
-	unsigned int i;
+static void execchild(void *user_data) {
+	struct ChanSess *chansess = user_data;
+	char *usershell = NULL;
 
     /* with uClinux we'll have vfork()ed, so don't want to overwrite the
      * hostkey. can't think of a workaround to clear it */
@@ -889,12 +823,6 @@ static void execchild(struct ChanSess *chansess) {
 	reseedrandom();
 #endif
 
-	/* close file descriptors except stdin/stdout/stderr
-	 * Need to be sure FDs are closed here to avoid reading files as root */
-	for (i = 3; i <= (unsigned int)ses.maxfd; i++) {
-		m_close(i);
-	}
-
 	/* clear environment */
 	/* if we're debugging using valgrind etc, we need to keep the LD_PRELOAD
 	 * etc. This is hazardous, so should only be used for debugging. */
@@ -933,18 +861,11 @@ static void execchild(struct ChanSess *chansess) {
 		}
 	}
 
-	/* an empty shell should be interpreted as "/bin/sh" */
-	if (ses.authstate.pw_shell[0] == '\0') {
-		usershell = "/bin/sh";
-	} else {
-		usershell = ses.authstate.pw_shell;
-	}
-
 	/* set env vars */
 	addnewvar("USER", ses.authstate.pw_name);
 	addnewvar("LOGNAME", ses.authstate.pw_name);
 	addnewvar("HOME", ses.authstate.pw_dir);
-	addnewvar("SHELL", usershell);
+	addnewvar("SHELL", get_user_shell());
 	if (chansess->term != NULL) {
 		addnewvar("TERM", chansess->term);
 	}
@@ -963,32 +884,8 @@ static void execchild(struct ChanSess *chansess) {
 	agentset(chansess);
 #endif
 
-	/* Re-enable SIGPIPE for the executed process */
-	if (signal(SIGPIPE, SIG_DFL) == SIG_ERR) {
-		dropbear_exit("signal() error");
-	}
-
-	baseshell = basename(usershell);
-
-	if (chansess->cmd != NULL) {
-		argv[0] = baseshell;
-	} else {
-		/* a login shell should be "-bash" for "/bin/bash" etc */
-		int len = strlen(baseshell) + 2; /* 2 for "-" */
-		argv[0] = (char*)m_malloc(len);
-		snprintf(argv[0], len, "-%s", baseshell);
-	}
-
-	if (chansess->cmd != NULL) {
-		argv[1] = "-c";
-		argv[2] = chansess->cmd;
-		argv[3] = NULL;
-	} else {
-		/* construct a shell of the form "-bash" etc */
-		argv[1] = NULL;
-	}
-
-	execv(usershell, argv);
+	usershell = m_strdup(get_user_shell());
+	run_shell_command(chansess->cmd, ses.maxfd, usershell);
 
 	/* only reached on error */
 	dropbear_exit("child failed");