1 files changed, 122 insertions, 0 deletions

diff --git a/src/fseccomp/seccomp_print.c b/src/fseccomp/seccomp_print.c
new file mode 100644
index 000000000..e22c682dc
--- /dev/null
+++ b/src/fseccomp/seccomp_print.c
@@ -0,0 +1,122 @@
+/*
+ * 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 "fseccomp.h"
+#include "../include/seccomp.h"
+#include <sys/syscall.h>
+
+static struct sock_filter *filter = NULL;
+static int filter_cnt = 0;
+
+static void load_seccomp(const char *fname) {
+        assert(fname);
+        
+        // open filter file
+        int fd = open(fname, O_RDONLY);
+        if (fd == -1)
+                goto errexit;
+
+        // calculate the number of entries
+        int size = lseek(fd, 0, SEEK_END);
+        if (size == -1)
+                goto errexit;
+        if (lseek(fd, 0 , SEEK_SET) == -1)
+                goto errexit;
+        unsigned short entries = (unsigned short) size / (unsigned short) sizeof(struct sock_filter);
+        filter_cnt = entries;
+        
+        // read filter
+        filter = malloc(size);
+        if (filter == NULL)
+                goto errexit;
+        memset(filter, 0, size);
+        int rd = 0;
+        while (rd < size) {
+                int rv = read(fd, (unsigned char *) filter + rd, size - rd);
+                if (rv == -1)
+                        goto errexit;
+                rd += rv;
+        }
+        
+        // close file
+        close(fd);
+        return;
+
+errexit:
+        fprintf(stderr, "Error fseccomp: cannot read %s\n", fname);
+        exit(1);
+}
+
+// debug filter
+void filter_print(const char *fname) {
+        assert(fname);
+        load_seccomp(fname);
+        
+        // start filter
+        struct sock_filter start[] = {
+                VALIDATE_ARCHITECTURE,
+                EXAMINE_SYSCALL
+        };
+
+        // print sizes
+        printf("SECCOMP Filter:\n");
+
+        // test the start of the filter
+        if (memcmp(&start[0], filter, sizeof(start)) == 0) {
+                printf("  VALIDATE_ARCHITECTURE\n");
+                printf("  EXAMINE_SYSCAL\n");
+        }
+        else {
+                printf("Invalid seccomp filter %s\n", fname);
+                return;
+        }
+        
+        // loop trough blacklists
+        int i = 4;
+        while (i < filter_cnt) {
+                // minimal parsing!
+                unsigned char *ptr = (unsigned char *) &filter[i];
+                int *nr = (int *) (ptr + 4);
+                if (*ptr        == 0x15 && *(ptr +14) == 0xff && *(ptr + 15) == 0x7f ) {
+                        printf("  WHITELIST %d %s\n", *nr, syscall_find_nr(*nr));
+                        i += 2;
+                }
+                else if (*ptr   == 0x15 && *(ptr +14) == 0 && *(ptr + 15) == 0) {
+                        printf("  BLACKLIST %d %s\n", *nr, syscall_find_nr(*nr));
+                        i += 2;
+                }
+                else if (*ptr   == 0x15 && *(ptr +14) == 0x5 && *(ptr + 15) == 0) {
+                        int err = *(ptr + 13) << 8 | *(ptr + 12);
+                        printf("  ERRNO %d %s %d %s\n", *nr, syscall_find_nr(*nr), err, errno_find_nr(err));
+                        i += 2;
+                }
+                else if (*ptr == 0x06 && *(ptr +6) == 0 && *(ptr + 7) == 0 ) {
+                        printf("  KILL_PROCESS\n");
+                        i++;
+                }
+                else if (*ptr == 0x06 && *(ptr +6) == 0xff && *(ptr + 7) == 0x7f ) {
+                        printf("  RETURN_ALLOW\n");
+                        i++;
+                }
+                else {
+                        printf("  UNKNOWN ENTRY!!!\n");
+                        i++;
+                }
+        }
+}