1 files changed, 370 insertions, 0 deletions

diff --git a/src/fids/main.c b/src/fids/main.c
new file mode 100644
index 000000000..b53a9828e
--- /dev/null
+++ b/src/fids/main.c
@@ -0,0 +1,370 @@
+/*
+ * 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"
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <dirent.h>
+#include <glob.h>
+
+#define MAXBUF 4096
+
+static int dir_level = 1;
+static int include_level = 0;
+int arg_init = 0;
+int arg_check = 0;
+char *arg_homedir = NULL;
+char *arg_dbfile = NULL;
+
+int f_scanned = 0;
+int f_modified = 0;
+int f_new = 0;
+int f_removed = 0;
+int f_permissions = 0;
+
+
+
+static inline int is_dir(const char *fname) {
+        assert(fname);
+
+        struct stat s;
+        int rv = stat(fname, &s);
+        if (S_ISDIR(s.st_mode))
+                return 1;
+        return 0;
+}
+
+static inline int is_link(const char *fname) {
+        assert(fname);
+
+        char c;
+        ssize_t rv = readlink(fname, &c, 1);
+        return (rv != -1);
+}
+
+// mode is an array of 10 chars or more
+static inline void file_mode(const char *fname, char *mode) {
+        assert(fname);
+        assert(mode);
+
+        struct stat s;
+        if (stat(fname, &s)) {
+                *mode = '\0';
+                return;
+        }
+
+        sprintf(mode, (s.st_mode & S_IRUSR) ? "r" : "-");
+        sprintf(mode + 1, (s.st_mode & S_IWUSR) ? "w" : "-");
+        sprintf(mode + 2, (s.st_mode & S_IXUSR) ? "x" : "-");
+        sprintf(mode + 3, (s.st_mode & S_IRGRP) ? "r" : "-");
+        sprintf(mode + 4, (s.st_mode & S_IWGRP) ? "w" : "-");
+        sprintf(mode + 5, (s.st_mode & S_IXGRP) ? "x" : "-");
+        sprintf(mode + 6, (s.st_mode & S_IROTH) ? "r" : "-");
+        sprintf(mode + 7, (s.st_mode & S_IWOTH) ? "w" : "-");
+        sprintf(mode + 8, (s.st_mode & S_IXOTH) ? "x" : "-");
+}
+
+
+static void file_checksum(const char *fname) {
+        assert(fname);
+
+        int fd = open(fname, O_RDONLY);
+        if (fd == -1)
+                return;
+
+        off_t size = lseek(fd, 0, SEEK_END);
+        if (size < 0) {
+                close(fd);
+                return;
+        }
+
+        char *content = "empty";
+        int mmapped = 0;
+        if (size == 0) {
+                // empty files don't mmap - use "empty" string as the file content
+                size = 6; // strlen("empty") + 1
+        }
+        else {
+                content = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
+                close(fd);
+                mmapped = 1;
+        }
+
+        unsigned char checksum[KEY_SIZE / 8];
+        blake2b(checksum, sizeof(checksum), content, size);
+        if (mmapped)
+                munmap(content, size);
+
+        // calculate blake2 checksum
+        char str_checksum[(KEY_SIZE / 8) * 2 + 1];
+        int i;
+        char *ptr = str_checksum;
+        for (i = 0; i < sizeof(checksum); i++, ptr += 2)
+                sprintf(ptr, "%02x", (unsigned char ) checksum[i]);
+
+        // build permissions string
+        char mode[10];
+        file_mode(fname, mode);
+
+        if (arg_init)
+                printf("%s\t%s\t%s\n", mode, str_checksum, fname);
+        else if (arg_check)
+                db_check(fname, str_checksum, mode);
+        else
+                assert(0);
+
+        f_scanned++;
+        if (f_scanned % 500 == 0)
+                fprintf(stderr, "%d ", f_scanned);
+        fflush(0);
+}
+
+void list_directory(const char *fname) {
+        assert(fname);
+        if (dir_level > MAX_DIR_LEVEL) {
+                fprintf(stderr, "Warning fids: maximum depth level exceeded for %s\n", fname);
+                return;
+        }
+
+        if (db_exclude_check(fname))
+                return;
+
+        if (is_link(fname))
+                return;
+
+        if (!is_dir(fname)) {
+                file_checksum(fname);
+                return;
+        }
+
+        DIR *dir;
+        struct dirent *entry;
+
+        if (!(dir = opendir(fname)))
+                return;
+
+        dir_level++;
+        while ((entry = readdir(dir)) != NULL) {
+                if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0)
+                        continue;
+                char *path;
+                if (asprintf(&path, "%s/%s", fname, entry->d_name) == -1)
+                        errExit("asprintf");
+                list_directory(path);
+                free(path);
+        }
+        closedir(dir);
+        dir_level--;
+}
+
+void globbing(const char *fname) {
+        assert(fname);
+
+        // filter top directory
+        if (strcmp(fname, "/") == 0)
+                return;
+
+        glob_t globbuf;
+        int globerr = glob(fname, GLOB_NOCHECK | GLOB_NOSORT | GLOB_PERIOD, NULL, &globbuf);
+        if (globerr) {
+                fprintf(stderr, "Error fids: failed to glob pattern %s\n", fname);
+                exit(1);
+        }
+
+        int i;
+        for (i = 0; i < globbuf.gl_pathc; i++) {
+                char *path = globbuf.gl_pathv[i];
+                assert(path);
+
+                list_directory(path);
+        }
+
+        globfree(&globbuf);
+}
+
+static void process_config(const char *fname) {
+        assert(fname);
+
+        if (++include_level >= MAX_INCLUDE_LEVEL) {
+                fprintf(stderr, "Error ids: maximum include level for config files exceeded\n");
+                exit(1);
+        }
+
+        // make sure the file is owned by root
+        struct stat s;
+        if (stat(fname, &s)) {
+                if (include_level == 1) {
+                        fprintf(stderr, "Error ids: config file not found\n");
+                        exit(1);
+                }
+                return;
+        }
+        if (s.st_uid || s.st_gid) {
+                fprintf(stderr, "Error ids: config file not owned by root\n");
+                exit(1);
+        }
+
+        fprintf(stderr, "Loading %s config file\n", fname);
+        FILE *fp = fopen(fname, "r");
+        if (!fp) {
+                fprintf(stderr, "Error fids: cannot open config file %s\n", fname);
+                exit(1);
+        }
+
+        char buf[MAXBUF];
+        int line = 0;
+        while (fgets(buf, MAXBUF, fp)) {
+                line++;
+
+                // trim \n
+                char *ptr = strchr(buf, '\n');
+                if (ptr)
+                        *ptr = '\0';
+
+                // comments
+                ptr = strchr(buf, '#');
+                if (ptr)
+                        *ptr = '\0';
+
+                // empty space
+                ptr = buf;
+                while (*ptr == ' ' || *ptr == '\t')
+                        ptr++;
+                char *start = ptr;
+
+                // empty line
+                if (*start == '\0')
+                        continue;
+
+                // trailing spaces
+                ptr = start + strlen(start);
+                ptr--;
+                while (*ptr == ' ' || *ptr == '\t')
+                        *ptr-- = '\0';
+
+                // replace ${HOME}
+                if (strncmp(start, "include", 7) == 0) {
+                        ptr = start + 7;
+                        if ((*ptr != ' ' && *ptr != '\t') || *ptr == '\0') {
+                                fprintf(stderr, "Error fids: invalid line %d in %s\n", line, fname);
+                                exit(1);
+                        }
+                        while (*ptr == ' ' || *ptr == '\t')
+                                ptr++;
+
+                        if (*ptr == '/')
+                                process_config(ptr);
+                        else {
+                                // assume the file is in /etc/firejail
+                                char *tmp;
+                                if (asprintf(&tmp, "/etc/firejail/%s", ptr) == -1)
+                                        errExit("asprintf");
+                                process_config(tmp);
+                                free(tmp);
+                        }
+                }
+                else if (*start == '!') {
+                        // exclude file or dir
+                        start++;
+                        if (strncmp(start, "${HOME}", 7))
+                                db_exclude_add(start);
+                        else {
+                                char *fname;
+                                if (asprintf(&fname, "%s%s", arg_homedir, start + 7) == -1)
+                                        errExit("asprintf");
+                                db_exclude_add(fname);
+                                free(fname);
+                        }
+                }
+                else if (strncmp(start, "${HOME}", 7))
+                        globbing(start);
+                else {
+                        char *fname;
+                        if (asprintf(&fname, "%s%s", arg_homedir, start + 7) == -1)
+                                errExit("asprintf");
+                        globbing(fname);
+                        free(fname);
+                }
+        }
+
+        fclose(fp);
+        include_level--;
+}
+
+
+
+void usage(void) {
+        printf("Usage: fids [--help|-h|-?] --init|--check homedir\n");
+}
+
+int main(int argc, char **argv) {
+        int i;
+        for (i = 1; i < argc; i++) {
+                if (strcmp(argv[i], "-h") == 0 ||
+                    strcmp(argv[i], "-?") == 0 ||
+                    strcmp(argv[i], "--help") == 0) {
+                        usage();
+                        return 0;
+                }
+                else if (strcmp(argv[i], "--init") == 0)
+                        arg_init = 1;
+                else if (strcmp(argv[i], "--check") == 0)
+                        arg_check = 1;
+                else if (strncmp(argv[i], "--", 2) == 0) {
+                        fprintf(stderr, "Error fids: invalid argument %s\n", argv[i]);
+                        exit(1);
+                }
+        }
+
+        if (argc != 3) {
+                fprintf(stderr, "Error fids: invalid number of arguments\n");
+                exit(1);
+        }
+        arg_homedir = argv[2];
+
+        int op = arg_check + arg_init;
+        if (op == 0 || op == 2) {
+                fprintf(stderr, "Error fids: use either --init or --check\n");
+                exit(1);
+        }
+
+        if (arg_init) {
+                process_config(SYSCONFDIR"/ids.config");
+                fprintf(stderr, "\n%d files scanned\n", f_scanned);
+                fprintf(stderr, "IDS database initialized\n");
+        }
+        else if (arg_check) {
+                if (db_init()) {
+                        fprintf(stderr, "Error: IDS database not initialized, please run \"firejail --ids-init\"\n");
+                        exit(1);
+                }
+
+                process_config(SYSCONFDIR"/ids.config");
+                fprintf(stderr, "\n%d files scanned: modified %d, permissions %d, new %d, removed %d\n",
+                        f_scanned, f_modified, f_permissions, f_new, f_removed);
+                db_missing();
+        }
+        else
+                assert(0);
+
+        return 0;
+}