symlink invocation

3 files changed, 98 insertions, 0 deletions

diff --git a/src/firejail/firejail.h b/src/firejail/firejail.h
index 1de38c43a..ba8a9dc48 100644
--- a/src/firejail/firejail.h
+++ b/src/firejail/firejail.h
@@ -500,5 +500,8 @@ void fs_logger_change_owner(void);
 void fs_logger_print_log_name(const char *name);
 void fs_logger_print_log(pid_t pid);
 
+// run_symlink.c
+void run_symlink(int argc, char **argv);
+
 #endif
 
diff --git a/src/firejail/main.c b/src/firejail/main.c
index 58d735010..43d2f0fa2 100644
--- a/src/firejail/main.c
+++ b/src/firejail/main.c
@@ -459,6 +459,10 @@ int main(int argc, char **argv) {
         int highest_errno = errno_highest_nr();
 #endif
 
+        // check argv[0] symlink wrapper
+        run_symlink(argc, argv);
+
+
         // check if we already have a sandbox running
         int rv = check_kernel_procs();
         if (rv == 0) {
diff --git a/src/firejail/run_symlink.c b/src/firejail/run_symlink.c
new file mode 100644
index 000000000..5f8d131ae
--- /dev/null
+++ b/src/firejail/run_symlink.c
@@ -0,0 +1,91 @@
+/*
+ * Copyright (C) 2014-2016 Firejail Authors
+ *
+ * This file is part of firejail project
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#include "firejail.h"
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+void run_symlink(int argc, char **argv) {
+        char *program = strrchr(argv[0], '/');
+        if (program)
+                program += 1;
+        else
+                program = argv[0];
+        if (strcmp(program, "firejail") == 0)
+                return;
+
+        // find the real program
+        // probably the first entry returend by "which -a" is a symlink - use the second entry!
+        char *p = getenv("PATH");
+        if (!p) {
+                fprintf(stderr, "Error: PATH environment variable not set\n");
+                exit(1);
+        }
+        
+        char *path = strdup(p);
+        if (!path)
+                errExit("strdup");
+        
+        // look in path for our program
+        char *tok = strtok(path, ":");
+        int found = 0;
+        while (tok) {
+                char *name;
+                if (asprintf(&name, "%s/%s", tok, program) == -1)
+                        errExit("asprintf");
+
+                struct stat s;
+                if (stat(name, &s) == 0) {
+                        if (!is_link(name)) {
+                                program = strdup(name);
+                                found = 1;
+                                break;
+                        }
+                }
+                
+                free(name);
+                tok = strtok(NULL, ":");
+        }       
+        if (!found) {
+                fprintf(stderr, "Error: cannot find the program in the path\n");
+                exit(1);
+        }
+                
+
+        // start the argv[0] program in a new sandbox
+        char *firejail;
+        if (asprintf(&firejail, "%s/bin/firejail", PREFIX) == -1)
+                errExit("asprintf");
+
+        printf("Redirecting symlink to %s\n", firejail, program);
+
+        // run command
+        char *a[3 + argc];
+        a[0] = firejail;
+        a[1] = program;
+        int i;
+        for (i = 0; i < (argc - 1); i++)
+                a[i + 2] = argv[i + 1];
+        a[i + 2] = NULL;
+        execvp(a[0], a); 
+
+        perror("execvp");
+        exit(1);
+}