Updated header function description for interactive_access

Creating files grants permanent permissions to them now. This makes
sense because if a program creates a new file, then it clearly can't
steal any data. This is particularly useful for programs which open an
obscene amount of auxilary files (e.g. neovim with a huge amount of
plugins).

.gitignore

@@ -2,4 +2,5 @@ build/*
 .clang-tidy
 .cache
 test/protected/*
+test/.pt.db
 compile_commands.json

Makefile

@@ -12,7 +12,7 @@ CXX := g++
 
 # dependencies
 
-PACKAGE_NAMES := fuse3
+PACKAGE_NAMES := fuse3 sqlite3
 
 ifeq ($(TEST), 1)
 	#	PACKAGE_NAMES += check # TODO: use check?
@@ -56,7 +56,7 @@ default: $(TARGETS)
 
 .PHONY: clean
 
-$(BUILD_DIR)/icfs: $(BUILD_DIR)/main.o $(BUILD_DIR)/fuse_operations.o $(BUILD_DIR)/sourcefs.o $(BUILD_DIR)/ui-socket.o $(BUILD_DIR)/temp_permissions_table.o
+$(BUILD_DIR)/icfs: $(BUILD_DIR)/main.o $(BUILD_DIR)/fuse_operations.o $(BUILD_DIR)/sourcefs.o $(BUILD_DIR)/ui-socket.o $(BUILD_DIR)/temp_permissions_table.o $(BUILD_DIR)/perm_permissions_table.o
 	$(CC) $(CFLAGS) $^ $(LDFLAGS) -o $(BUILD_DIR)/icfs
 
 icfs_test: $(BUILD_DIR)/icfs
@@ -80,5 +80,9 @@ $(BUILD_DIR)/ui-socket.o: $(SOURCES_DIR)/ui-socket.c $(SOURCES_DIR)/ui-socket.h
 $(BUILD_DIR)/temp_permissions_table.o: $(SOURCES_DIR)/temp_permissions_table.c $(SOURCES_DIR)/temp_permissions_table.h
 	$(CC) $(CFLAGS) -c $< $(LDFLAGS) -o $@
 
+$(BUILD_DIR)/perm_permissions_table.o: $(SOURCES_DIR)/perm_permissions_table.c $(SOURCES_DIR)/perm_permissions_table.h
+	$(CC) $(CFLAGS) -c $< $(LDFLAGS) -o $@
+
+
 clean:
 	rm $(BUILD_DIR)/*.o $(BUILD_DIR)/icfs*

src/fuse_operations.c

@@ -116,12 +116,11 @@ static int xmp_access(const char *path, int mask) {
     struct fuse_context *fc = fuse_get_context();
 
     pi.PID = fc->pid;
-    pi.UID = fc->uid;
     pi.name = get_process_name_by_pid(pi.PID);
 
     // fprintf(stderr, "%s, %d\n", path, ask_access(path, pi));
 
-    if (!interactive_access(real_filename(path), pi)) {
+    if (!interactive_access(real_filename(path), pi, 0)) {
       free(pi.name);
       return -EACCES;
     }
@@ -281,12 +280,11 @@ static int xmp_unlink(const char *path) {
 
   // ask the user for the permission for deleting the file
   pi.PID = fc->pid;
-  pi.UID = fc->uid;
   pi.name = get_process_name_by_pid(pi.PID);
 
   // fprintf(stderr, "%s, %d\n", path, ask_access(path, pi));
 
-  if (!interactive_access(real_filename(path), pi)) {
+  if (!interactive_access(real_filename(path), pi, 0)) {
     free(pi.name);
     return -EACCES;
   }
@@ -330,12 +328,11 @@ static int xmp_rename(const char *from, const char *to, unsigned int flags) {
   struct fuse_context *fc = fuse_get_context();
 
   pi.PID = fc->pid;
-  pi.UID = fc->uid;
   pi.name = get_process_name_by_pid(pi.PID);
 
   // fprintf(stderr, "%s, %d\n", path, ask_access(path, pi));
 
-  if (!interactive_access(real_filename(from), pi)) {
+  if (!interactive_access(real_filename(from), pi, 0)) {
     free(pi.name);
     return -EACCES;
   }
@@ -343,7 +340,7 @@ static int xmp_rename(const char *from, const char *to, unsigned int flags) {
   // the "to" file may exist and the process needs to get persmission to modify
   // it
   if (source_access(to, F_OK) == 0 &&
-      !interactive_access(real_filename(to), pi)) {
+      !interactive_access(real_filename(to), pi, 0)) {
     free(pi.name);
     return -EACCES;
   }
@@ -363,11 +360,10 @@ static int xmp_link(const char *from, const char *to) {
   struct fuse_context *fc = fuse_get_context();
 
   pi.PID = fc->pid;
-  pi.UID = fc->uid;
   pi.name = get_process_name_by_pid(pi.PID);
 
   // fprintf(stderr, "%s, %d\n", path, ask_access(path, pi));
-  if (!interactive_access(real_filename(from), pi)) {
+  if (!interactive_access(real_filename(from), pi, 0)) {
     free(pi.name);
     return -EACCES;
   }
@@ -389,11 +385,10 @@ static int xmp_chmod(const char *path, mode_t mode, struct fuse_file_info *fi) {
   struct fuse_context *fc = fuse_get_context();
 
   pi.PID = fc->pid;
-  pi.UID = fc->uid;
   pi.name = get_process_name_by_pid(pi.PID);
 
   // fprintf(stderr, "%s, %d\n", path, ask_access(path, pi));
-  if (!interactive_access(real_filename(path), pi)) {
+  if (!interactive_access(real_filename(path), pi, 0)) {
     free(pi.name);
     return -EACCES;
   }
@@ -421,11 +416,10 @@ static int xmp_chown(const char *path, uid_t uid, gid_t gid,
   struct fuse_context *fc = fuse_get_context();
 
   pi.PID = fc->pid;
-  pi.UID = fc->uid;
   pi.name = get_process_name_by_pid(pi.PID);
 
   // fprintf(stderr, "%s, %d\n", path, ask_access(path, pi));
-  if (!interactive_access(real_filename(path), pi)) {
+  if (!interactive_access(real_filename(path), pi, 0)) {
     free(pi.name);
     return -EACCES;
   }
@@ -476,17 +470,16 @@ static int xmp_utimens(const char *path, const struct timespec ts[2],
 
 static int xmp_create(const char *path, mode_t mode,
                       struct fuse_file_info *fi) {
-  int fd;
+  int fd = -1;
   struct process_info pi;
   struct fuse_context *fc = fuse_get_context();
 
   pi.PID = fc->pid;
-  pi.UID = fc->uid;
   pi.name = get_process_name_by_pid(pi.PID);
 
   // fprintf(stderr, "%s, %d\n", path, ask_access(path, pi));
 
-  if (!interactive_access(real_filename(path), pi)) {
+  if (!interactive_access(real_filename(path), pi, GRANT_PERM)) {
     free(pi.name);
     return -EACCES;
   }
@@ -507,11 +500,10 @@ static int xmp_open(const char *path, struct fuse_file_info *fi) {
   struct fuse_context *fc = fuse_get_context();
 
   pi.PID = fc->pid;
-  pi.UID = fc->uid;
   pi.name = get_process_name_by_pid(pi.PID);
 
   // fprintf(stderr, "%s, %d\n", path, ask_access(path, pi));
-  if (!interactive_access(real_filename(path), pi)) {
+  if (!interactive_access(real_filename(path), pi, 0)) {
     free(pi.name);
     return -EACCES;
   }

src/main.c

@@ -38,7 +38,7 @@ int main(int argc, char *argv[]) {
 
   ret = init_ui_socket();
   if (ret != 0) {
-    perror("init_ui_socket");
+    fprintf(stderr, "Could not initalize ui-socket.\n");
     exit(EXIT_FAILURE);
   }
 

src/perm_permissions_table.c

@@ -0,0 +1,192 @@
+#include "perm_permissions_table.h"
+#include "process_info.h"
+#include <sqlite3.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+sqlite3 *perm_database = NULL;
+const char *const table_name = "permissions";
+// one row corresponds to a permission to access one file for one executable
+const int column_count = 2;
+const char *const schema[] = {"executable", "filename"};
+const char *const types[] = {"TEXT", "TEXT"};
+
+static int check_table_col_schema(void *notused, int argc, char **argv,
+                                  char **colname) {
+  (void)notused;
+  (void)colname;
+  if (argc < 3) {
+    fprintf(stderr, "Unexpected amount of arguments given to the callback.\n");
+    return 1;
+  }
+  int i = atoi(argv[0]);
+  if (i >= column_count) {
+    fprintf(stderr, "Table contains more columns than expected.\n");
+    return 1;
+  }
+  if (strcmp(schema[i], argv[1]) == 0 && strcmp(types[i], argv[2]) == 0) {
+    return 0;
+  }
+  fprintf(stderr, "Column %d does not conform to the schema.\n", i);
+  return 1;
+}
+
+static int set_flag(void *flag, int argc, char **argv, char **colname) {
+  (void)argc;
+  (void)argv;
+  (void)colname;
+  *(int *)flag = 1;
+  return 0;
+}
+
+int create_database_schema() {
+  fprintf(stderr, "Creating table 'permissions'.\n");
+  const char *create_query = "CREATE TABLE permissions(executable TEXT NOT "
+                             "NULL, filename TEXT NOT NULL);";
+  char *err = NULL;
+  int ret = sqlite3_exec(perm_database, create_query, NULL, NULL, &err);
+
+  if (ret != SQLITE_OK) {
+    fprintf(stderr, "sqlite3 error: %s\n", err);
+    sqlite3_free(err);
+    return 1;
+  }
+
+  fprintf(stderr, "Database created successfully\n");
+  return 0;
+}
+
+/**
+ * Ensures that the database schema is correct.
+ *
+ * @return: 0 if the schema is correct, 1 if the schema could not be corrected.
+ */
+int ensure_database_schema() {
+  // Check for the table.
+  int result = sqlite3_table_column_metadata(
+      perm_database, NULL, table_name, NULL, NULL, NULL, NULL, NULL, NULL);
+  if (result == SQLITE_ERROR) {
+    fprintf(stderr, "Table '%s' does not exist.\n", table_name);
+    if (create_database_schema()) {
+      fprintf(stderr, "Table could not be created.\n");
+      return 1;
+    }
+    return 0;
+  } else if (result != SQLITE_OK) {
+    fprintf(stderr, "Database metadata could not be retrieved.\n");
+    return 1;
+  }
+
+  const char *pragma = "PRAGMA table_info(permissions);";
+  char *err = NULL;
+  int ret =
+      sqlite3_exec(perm_database, pragma, check_table_col_schema, NULL, &err);
+
+  if (ret != SQLITE_OK) {
+    fprintf(stderr, "sqlite3 error: %s\n", err);
+    sqlite3_free(err);
+    return 1;
+  }
+
+  fprintf(stderr, "Schema is correct.\n");
+  return 0;
+}
+
+/**
+ * Initializes the permanent permissions table.
+ *
+ * @param db_filename: The filename of the permissions sqlite3 database
+ * @return: 0 on success, -1 on failure
+ */
+int init_perm_permissions_table(const char *db_filename) {
+  if (sqlite3_open(db_filename, &perm_database)) {
+    perror("Can't open permanent permissions database:");
+    return -1;
+  }
+  if (ensure_database_schema()) {
+    fprintf(stderr, "Database schema is not correct.\n");
+    return -1;
+  }
+  return 0;
+}
+
+/**
+ * Destroys the permanent permissions table.
+ */
+void destroy_perm_permissions_table() { sqlite3_close(perm_database); }
+
+/**
+ * Checks if the process has a permanent access to the file.
+ *
+ * @param filename: The file that the process is trying to access
+ * @pram pi: The process information
+ * @return: 0 if access is denied, 1 if access is allowed
+ */
+int check_perm_access(const char *filename, struct process_info pi) {
+  size_t query_len =
+      56 + strlen(table_name) + strlen(filename) + strlen(pi.name);
+  const char *query = malloc(query_len);
+  size_t should_be_written = snprintf(
+      query, query_len,
+      "SELECT * FROM %s WHERE executable = \'%s\' AND filename = \'%s\';",
+      table_name, pi.name, filename);
+  // -1 for the \0
+  if (should_be_written != query_len - 1) {
+    fprintf(stderr,
+            "Unexpected query size while permanent access rule check: "
+            "Expected %lu, but snprintf returned %lu. The query: %s\n",
+            query_len, should_be_written, query);
+    return 0;
+  }
+
+  char *sqlite_error = NULL;
+  int flag = 0;
+  int ret = sqlite3_exec(perm_database, query, set_flag, &flag, &sqlite_error);
+  if (ret != SQLITE_OK) {
+    fprintf(stderr, "SQLite returned an error: %s\n", sqlite_error);
+    sqlite3_free(sqlite_error);
+    free(query);
+    return 0;
+  }
+
+  free(query);
+  return flag;
+}
+
+/**
+ * Gives permanent access to the process to the file.
+ *
+ * @param filename: The file that the process is trying to access
+ * @param pi: The process information
+ * @return: 0 on success, 1 on failure
+ */
+int give_perm_access(const char *filename, struct process_info pi) {
+  size_t query_len =
+      30 + strlen(table_name) + strlen(filename) + strlen(pi.name);
+  const char *query = malloc(query_len);
+  size_t should_be_written =
+      snprintf(query, query_len, "INSERT INTO %s VALUES (\'%s\', \'%s\');",
+               table_name, pi.name, filename);
+  // -1 for the \0
+  if (should_be_written != query_len - 1) {
+    fprintf(stderr,
+            "Unexpected query size while permanent access rule insertion: "
+            "Expected %lu, but snprintf returned %lu\n",
+            query_len, should_be_written);
+    return 1;
+  }
+
+  char *sqlite_error = NULL;
+  int ret = sqlite3_exec(perm_database, query, NULL, NULL, &sqlite_error);
+  if (ret != SQLITE_OK) {
+    fprintf(stderr, "SQLite returned an error: %s\n", sqlite_error);
+    sqlite3_free(sqlite_error);
+    free(query);
+    return 1;
+  }
+
+  free(query);
+  return 0;
+}

src/perm_permissions_table.h

@@ -0,0 +1,38 @@
+
+#ifndef PERM_PERMISSION_TABLE_H
+#define PERM_PERMISSION_TABLE_H
+
+#include "process_info.h"
+
+/**
+ * Initializes the permanent permissions table.
+ *
+ * @param db_filename: The filename of the permissions sqlite3 database
+ * @return: 0 on success, -1 on failure (e.g. ENOMEM)
+ */
+int init_perm_permissions_table(const char *db_filename);
+
+/**
+ * Destroys the permanent permissions table.
+ */
+void destroy_perm_permissions_table();
+
+/**
+ * Checks if the process has a permanent access to the file.
+ *
+ * @param filename: The file that the process is trying to access
+ * @pram pi: The process information
+ * @return: 0 if access is denied, 1 if access is allowed
+ */
+int check_perm_access(const char *filename, struct process_info pi);
+
+/**
+ * Gives permanent access to the process to the file.
+ *
+ * @param filename: The file that the process is trying to access
+ * @param pi: The process information
+ * @return: 0 on success, -1 on failure
+ */
+int give_perm_access(const char *filename, struct process_info pi);
+
+#endif // #ifdef PERM_PERMISSION_TABLE_H

src/process_info.h

@@ -6,7 +6,6 @@
 struct process_info {
   pid_t PID;
   const char *name;
-  uid_t UID;
 };
 
 #endif // PROCESS_INFO_H

src/ui-socket.c

@@ -10,7 +10,7 @@
 #include <sys/types.h>
 #include <time.h>
 #define _GNU_SOURCE
-#include "cc.h"
+#include "perm_permissions_table.h"
 #include "temp_permissions_table.h"
 #include "ui-socket.h"
 #include <errno.h>
@@ -26,7 +26,16 @@ int init_ui_socket() {
   char line[256];
   FILE *fp;
 
-  init_temp_permissions_table();
+  if (init_temp_permissions_table()) {
+    fprintf(stderr, "Could not initialize temporary permissions table.\n");
+    return 1;
+  }
+
+  if (init_perm_permissions_table(
+          "/home/fedir/Developement/uni/ICFS/test/.pt.db")) {
+    fprintf(stderr, "Could not initialize permanent permissions table.\n");
+    return 1;
+  }
 
   // Test if Zenity is installed (get version)
   fp = popen("zenity --version", "r");
@@ -41,19 +50,21 @@ int init_ui_socket() {
   return 0;
 }
 
-void destroy_ui_socket() { destroy_temp_permissions_table(); }
+void destroy_ui_socket() {
+  destroy_temp_permissions_table();
+  destroy_perm_permissions_table();
+}
 
 /**
  * Asks the user if the process should be allowed to access the file using the
  * GUI
  *
  * @param filename: The file that the process is trying to access
- * @pram pi: The process information
- * @return: 0 if access is denied, 1 if access is allowed, 2 if access is allwed
- * for the runtime of the process
+ * @param pi: The process information
+ * @return: 0 if access is denied, 1 if access is allowed, 2 if access is
+ * allowed for the runtime of the process
  */
 int ask_access(const char *filename, struct process_info pi) {
-
   FILE *fp;
   size_t command_len =
       139 + sizeof(pid_t) * 8 + strlen(pi.name) + strlen(filename);
@@ -86,6 +97,7 @@ int ask_access(const char *filename, struct process_info pi) {
   }
 
   int zenity_exit_code = WEXITSTATUS(pclose(fp));
+  fprintf(stderr, "zenity returned %d\n", zenity_exit_code);
   // zenity returns 1 on "No" >:(
   if (zenity_exit_code == 0) {
     return 1;
@@ -94,22 +106,6 @@ int ask_access(const char *filename, struct process_info pi) {
   return 0;
 }
 
-/**
- * Checks if the process has a permanent access to the file.
- *
- * @param filename: The file that the process is trying to access
- * @pram pi: The process information
- * @return: 0 if access is denied, 1 if access is allowed
- */
-int check_perm_access(const char *filename, struct process_info pi) {
-  perror("Not implemented");
-  return 0;
-}
-int give_perm_access(const char *filename, struct process_info pi) {
-  perror("Not implemented");
-  return -1;
-}
-
 /**
  * Check access according to:
  * 1. temp permission table
@@ -118,15 +114,28 @@ int give_perm_access(const char *filename, struct process_info pi) {
  *
  * @param filename: The file that the process is trying to access
  * @pram pi: The process information
+ * @param opts: options (GRANT_TEMP, GRANT_PERM)
  * @return: 0 if access is denied, 1 if access is allowed
  */
-int interactive_access(const char *filename, struct process_info pi) {
+int interactive_access(const char *filename, struct process_info pi, int opts) {
 
   if (check_temp_access(filename, pi) || check_perm_access(filename, pi)) {
     // access was already granted before
     return 1;
   }
 
+  // if noth GRANT_TEMP and GRANT_PERM are selected, then only permanent
+  // permissions are granted
+
+  if (opts & GRANT_PERM) {
+    give_perm_access(filename, pi);
+    return 1;
+  }
+  if (opts & GRANT_TEMP) {
+    give_temp_access(filename, pi);
+    return 1;
+  }
+
   int user_response = ask_access(filename, pi);
   if (user_response == 1) {
     // user said "yes"

src/ui-socket.h

@@ -36,8 +36,13 @@ void destroy_ui_socket(void);
  *
  * @param filename: The file that the process is trying to access
  * @pram pi: The process information
+ * @param opts: options (GRANT_TEMP, GRANT_PERM)
  * @return: 0 if access is denied, 1 if access is allowed
  */
-int interactive_access(const char *filename, struct process_info pi);
+int interactive_access(const char *filename, struct process_info pi, int opts);
+
+#define GRANT_TEMP 1
+#define GRANT_PERM 2
+// #define TABLE_ONLY 4 // NOTE: Add this in the future?
 
 #endif // !UI_SOCKET_H

test/mock/zenity

@@ -20,4 +20,4 @@ else
   fi
 fi
 
-exit -1 # TODO: call actual zenity here
+exit 255 # TODO: call actual zenity here

test/test.bash

@@ -2,6 +2,7 @@
 
 # clean what was left from previous tests
 
+rm -f ./.pt.db
 rm -rf ./protected
 mkdir protected
 touch ./protected/do-not-remove ./protected/should-be-removed ./protected/truth ./protected/perm000 ./protected/perm777 ./protected/should-be-renamed ./protected/do-not-rename
@@ -17,29 +18,32 @@ PATH="$(realpath ./mock/):$PATH"
 echo "Run $(date -u +%Y-%m-%dT%H:%M:%S) "
 valgrind -s ../build/icfs -o default_permissions ./protected &
 
-sleep 1
+sleep 5
+
+# WARN: please don't use `>` or `>>` operators. They force **this script** to open the file, **not the program you are trying to run**. This is probably not what you mean when you want to test a specific program's access.
+# WARN: avoid using touch, since it generates errors because setting times is not implemented in icfs **yet**.
 
 # create files
 
 zenity --set-fake-response no
-touch ./protected/should-not-exist 2>/dev/null &&
-  echo "[ICFS-TEST]: touch can create protected/should-not-exist despite access being denied!" ||
-  echo "[ICFS-TEST]: OK" # EACCESS
+truncate -s 0 ./protected/should-exist-anyway 2>/dev/null &&
+  echo "[ICFS-TEST]: OK" ||
+  echo "[ICFS-TEST]: truncate cannot create protected/should-exist despite access being permitted!" # OK
 
 zenity --set-fake-response yes_tmp
-touch ./protected/should-exist 2>/dev/null &&
+truncate -s 0 ./protected/should-exist 2>/dev/null &&
   echo "[ICFS-TEST]: OK" ||
-  echo "[ICFS-TEST]: touch cannot create protected/should-exist despite access being permitted!" # OK
+  echo "[ICFS-TEST]: truncate cannot create protected/should-exist despite access being permitted!" # OK
 
 # write to files
 
 zenity --set-fake-response no
-echo "Linux is a cancer that attaches itself in an intellectual property sense to everything it touches." >./protected/truth 2>/dev/null &&
+sed -e 'a\'"Linux is a cancer that attaches itself in an intellectual property sense to everything it touches." "./protected/truth" 2>/dev/null &&
   echo "[ICFS-TEST]: echo can write to protected/lie despite access being denied!" ||
   echo "[ICFS-TEST]: OK" # EACCESS
 
 zenity --set-fake-response yes_tmp
-echo "Sharing knowledge is the most fundamental act of friendship. Because it is a way you can give something without loosing something." >./protected/truth 2>/dev/null &&
+sed -e 'a\'"Sharing knowledge is the most fundamental act of friendship. Because it is a way you can give something without loosing something." "./protected/truth" 2>/dev/null &&
   echo "[ICFS-TEST]: OK" ||
   echo "[ICFS-TEST]: echo cannot write to protected/truth despite access being permitted!" # OK
 
@@ -89,6 +93,18 @@ chmod 000 ./protected/perm000 2>/dev/null &&
   echo "[ICFS-TEST]: OK" ||
   echo "[ICFS-TEST]: chmod cannot change permissions of protected/perm000 despite access being permitted!" # OK
 
+# test permanent permissions
+
+zenity --set-fake-response yes
+cat ./protected/motto >/dev/null 2>/dev/null &&
+  echo "[ICFS-TEST]: OK" ||
+  echo "[ICFS-TEST]: echo cannot read protected/motto despite access being permitted!" # OK
+
+zenity --set-fake-response no # this should be ignored
+cat ./protected/motto >/dev/null 2>/dev/null &&
+  echo "[ICFS-TEST]: OK" ||
+  echo "[ICFS-TEST]: echo cannot read protected/motto despite access being permitted!" # OK
+
 # unmount
 
 sleep 0.5