Create ast_safe_system which closes off file descriptors before spawning system() and so on.

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@2514 65c4cc65-6c06-0410-ace0-fbb531ad65f3

apps/app_voicemail.c

@@ -825,7 +825,7 @@ static int sendmail(char *srcemail, struct ast_vm_user *vmu, int msgnum, char *m
 		}
 		fclose(p);
 		snprintf(tmp2, sizeof(tmp2), "( %s < %s ; rm -f %s ) &", mailcmd, tmp, tmp);
-		system(tmp2);
+		ast_safe_system(tmp2);
 		ast_log(LOG_DEBUG, "Sent mail to %s with command '%s'\n", who, mailcmd);
 	} else {
 		ast_log(LOG_WARNING, "Unable to launch '%s'\n", mailcmd);
@@ -836,16 +836,27 @@ static int sendmail(char *srcemail, struct ast_vm_user *vmu, int msgnum, char *m
 
 static int sendpage(char *srcemail, char *pager, int msgnum, char *mailbox, char *callerid, long duration, struct ast_vm_user *vmu)
 {
-	FILE *p;
+	FILE *p=NULL;
+	int pfd;
 	char date[256];
 	char host[256];
 	char who[256];
 	char dur[256];
+	char tmp[80] = "/tmp/astmail-XXXXXX";
+	char tmp2[256];
 	time_t t;
 	struct tm tm;
 	struct vm_zone *the_zone = NULL;
 	p = popen(mailcmd, "w");
 
+	if (pfd > -1) {
+		p = fdopen(pfd, "w");
+		if (!p) {
+			close(pfd);
+			pfd = -1;
+		}
+	}
+
 	if (p) {
 		gethostname(host, sizeof(host));
 		if (strchr(srcemail, '@'))
@@ -883,7 +894,9 @@ static int sendpage(char *srcemail, char *pager, int msgnum, char *mailbox, char
 		strftime(date, sizeof(date), "%A, %B %d, %Y at %r", &tm);
 		fprintf(p, "New %s long msg in box %s\n"
 		           "from %s, on %s", dur, mailbox, (callerid ? callerid : "unknown"), date);
-		pclose(p);
+		fclose(p);
+		snprintf(tmp2, sizeof(tmp2), "( %s < %s ; rm -f %s ) &", mailcmd, tmp, tmp);
+		ast_safe_system(tmp2);
 		ast_log(LOG_DEBUG, "Sent mail to %s with command '%s'\n", who, mailcmd);
 	} else {
 		ast_log(LOG_WARNING, "Unable to launch '%s'\n", mailcmd);
@@ -2296,7 +2309,7 @@ static int forward_message(struct ast_channel *chan, char *context, char *dir, i
 		snprintf(todir, sizeof(todir), "%s/voicemail/%s/%s/INBOX",  (char *)ast_config_AST_SPOOL_DIR, vmtmp->context, vmtmp->mailbox);
 		snprintf(sys, sizeof(sys), "mkdir -p %s\n", todir);
 		ast_log(LOG_DEBUG, sys);
-		system(sys);
+		ast_safe_system(sys);
 
 		todircount = count_messages(todir);
 		strncpy(tmp, fmt, sizeof(tmp) - 1);
@@ -2307,11 +2320,11 @@ static int forward_message(struct ast_channel *chan, char *context, char *dir, i
 				s = "WAV";
 			snprintf(sys, sizeof(sys), "cp %s/msg%04d.%s %s/msg%04d.%s\n", dir, curmsg, s, todir, todircount, s);
 			ast_log(LOG_DEBUG, sys);
-			system(sys);
+			ast_safe_system(sys);
 		}
 		snprintf(sys, sizeof(sys), "cp %s/msg%04d.txt %s/msg%04d.txt\n", dir, curmsg, todir, todircount);
 		ast_log(LOG_DEBUG, sys);
-		system(sys);
+		ast_safe_system(sys);
 		snprintf(fn, sizeof(fn), "%s/msg%04d", todir,todircount);
 
 		/* load the information on the source message so we can send an e-mail like a new message */

asterisk.c

@@ -28,6 +28,7 @@
 #include <asterisk/pbx.h>
 #include <asterisk/enum.h>
 #include <asterisk/rtp.h>
+#include <asterisk/app.h>
 #include <sys/resource.h>
 #include <fcntl.h>
 #include <stdio.h>
@@ -153,6 +154,42 @@ static int fdprint(int fd, const char *s)
 	return write(fd, s, strlen(s) + 1);
 }
 
+int ast_safe_system(const char *s)
+{
+	/* XXX This function needs some optimization work XXX */
+	pid_t pid;
+	int x;
+	int res;
+	struct rusage rusage;
+	int status;
+	pid = fork();
+	if (pid == 0) {
+		/* Close file descriptors and launch system command */
+		for (x=STDERR_FILENO + 1; x<4096;x++) {
+			close(x);
+		}
+		res = system(s);
+		exit(res);
+	} else if (pid > 0) {
+		for(;;) {
+			res = wait4(pid, &status, 0, &rusage);
+			if (res > -1) {
+				if (WIFEXITED(status))
+					res = WEXITSTATUS(status);
+				else
+					res = -1;
+			} else {
+				if (errno != EINTR) 
+					break;
+			}
+		}
+	} else {
+		ast_log(LOG_WARNING, "Fork failed: %s\n", strerror(errno));
+		res = -1;
+	}
+	return res;
+}
+
 /*
  * write the string to all attached console clients
  */
@@ -607,9 +644,9 @@ static void consolehandler(char *s)
 		/* The real handler for bang */
 		if (s[0] == '!') {
 			if (s[1])
-				system(s+1);
+				ast_safe_system(s+1);
 			else
-				system(getenv("SHELL") ? getenv("SHELL") : "/bin/sh");
+				ast_safe_system(getenv("SHELL") ? getenv("SHELL") : "/bin/sh");
 		} else 
 		ast_cli_command(STDOUT_FILENO, s);
 	} else
@@ -627,9 +664,9 @@ static int remoteconsolehandler(char *s)
 		/* The real handler for bang */
 		if (s[0] == '!') {
 			if (s[1])
-				system(s+1);
+				ast_safe_system(s+1);
 			else
-				system(getenv("SHELL") ? getenv("SHELL") : "/bin/sh");
+				ast_safe_system(getenv("SHELL") ? getenv("SHELL") : "/bin/sh");
 			ret = 1;
 		}
 		if ((strncasecmp(s, "quit", 4) == 0 || strncasecmp(s, "exit", 4) == 0) &&

include/asterisk/app.h

@@ -45,6 +45,9 @@ extern int ast_app_has_voicemail(const char *mailbox);
 //! Determine number of new/old messages in a mailbox
 extern int ast_app_messagecount(const char *mailbox, int *newmsgs, int *oldmsgs);
 
+//! Safely spawn an external program while closingn file descriptors
+extern int ast_safe_system(const char *s);
+
 #if defined(__cplusplus) || defined(c_plusplus)
 }
 #endif