1 files changed, 159 insertions, 0 deletions

diff --git a/src/fids/db.c b/src/fids/db.c
new file mode 100644
index 000000000..e0021bc48
--- /dev/null
+++ b/src/fids/db.c
@@ -0,0 +1,159 @@
+/*
+ * Copyright (C) 2014-2021 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"fids.h"
+
+typedef struct db_t {
+        struct db_t *next;
+        char *fname;
+        char *checksum;
+        char *mode;
+        int checked;
+} DB;
+
+#define MAXBUF 4096
+static DB *database[HASH_MAX] = {NULL};
+
+// djb2 hash function by Dan Bernstein
+static unsigned hash(const char *str) {
+        const unsigned char *s = (unsigned char *) str;
+        unsigned long hash = 5381;
+        int c;
+
+        while (c = *s++)
+                hash = ((hash << 5) + hash) + c; /* hash * 33 + c */
+
+        return hash & (HASH_MAX - 1);
+}
+
+#if 0
+// for testing the hash table
+static void db_print(void) {
+        int i;
+        for (i = 0; i < HASH_MAX; i++) {
+                int cnt = 0;
+                DB *ptr = database[i];
+                while (ptr) {
+                        cnt++;
+                        ptr = ptr->next;
+                }
+                printf("%d ", cnt);
+                fflush(0);
+        }
+        printf("\n");
+}
+#endif
+
+static void db_add(const char *fname, const char *checksum, const char *mode) {
+        DB *ptr = malloc(sizeof(DB));
+        if (!ptr)
+                errExit("malloc");
+        ptr->fname = strdup(fname);
+        ptr->checksum = strdup(checksum);
+        ptr->mode = strdup(mode);
+        ptr->checked = 0;
+        if (!ptr->fname || !ptr->checksum || !ptr->mode)
+                errExit("strdup");
+
+        unsigned h = hash(fname);
+        ptr->next = database[h];
+        database[h] = ptr;
+}
+
+void db_check(const char *fname, const char *checksum, const char *mode) {
+        assert(fname);
+        assert(checksum);
+        assert(mode);
+
+        unsigned h =hash(fname);
+        DB *ptr = database[h];
+        while (ptr) {
+                if (strcmp(fname, ptr->fname) == 0) {
+                        ptr->checked = 1;
+                        break;
+                }
+                ptr = ptr->next;
+        }
+
+        if (ptr ) {
+                if (strcmp(checksum, ptr->checksum)) {
+                        f_modified++;
+                        fprintf(stderr, "\nWarning: modified %s\n", fname);
+                }
+                if (strcmp(mode, ptr->mode)) {
+                        f_permissions++;
+                        fprintf(stderr, "\nWarning: permissions %s: old %s, new %s\n",
+                                fname, ptr->mode, mode);
+                }
+        }
+        else {
+                f_new++;
+                fprintf(stderr, "\nWarning: new file %s\n", fname);
+        }
+}
+
+void db_missing(void) {
+        int i;
+        for (i = 0; i < HASH_MAX; i++) {
+                DB *ptr = database[i];
+                while (ptr) {
+                        if (!ptr->checked) {
+                                f_removed++;
+                                fprintf(stderr, "Warning: removed %s\n", ptr->fname);
+                        }
+                        ptr = ptr->next;
+                }
+        }
+}
+
+// return 0 if ok, 1 if error
+int db_init(void) {
+        char buf[MAXBUF];
+        while(fgets(buf, MAXBUF, stdin)) {
+                // split - tab separated
+
+                char *mode = buf;
+                char *ptr = strchr(buf, '\t');
+                if (!ptr)
+                        goto errexit;
+                *ptr = '\0';
+
+                char *checksum = ptr + 1;
+                ptr = strchr(checksum, '\t');
+                if (!ptr)
+                        goto errexit;
+                *ptr = '\0';
+
+                char *fname = ptr + 1;
+                ptr = strchr(fname, '\n');
+                if (!ptr)
+                        goto errexit;
+                *ptr = '\0';
+
+                db_add(fname, checksum, mode);
+        }
+//      db_print();
+
+        return 0;
+
+errexit:
+        fprintf(stderr, "Error fids: database corrupted\n");
+        exit(1);
+}
+