dbus: add some more safety checks before accepting data from bus clients

[elogind.git] / src / shared / util.c

diff --git a/src/shared/util.c b/src/shared/util.c
index 97f766c33c5b043559472d3b6817d442626c4bc1..64d6e62a5323b573d87c3f32f2ee76618212be59 100644 (file)
--- a/src/shared/util.c
+++ b/src/shared/util.c
@@ -56,6 +56,7 @@
 #include <sys/mman.h>
 #include <sys/vfs.h>
 #include <linux/magic.h>
+#include <limits.h>
 
 #include "macro.h"
 #include "util.h"
@@ -71,6 +72,8 @@
 int saved_argc = 0;
 char **saved_argv = NULL;
 
+static int parsed_columns = 0;
+
 size_t page_size(void) {
         static __thread size_t pgsz = 0;
         long r;
@@ -1686,7 +1689,8 @@ char *xescape(const char *s, const char *bad) {
          * chars, in \xFF style escaping. May be reversed with
          * cunescape. */
 
-        if (!(r = new(char, strlen(s)*4+1)))
+        r = new(char, strlen(s) * 4 + 1);
+        if (!r)
                 return NULL;
 
         for (f = s, t = r; *f; f++) {
@@ -3740,7 +3744,7 @@ int fd_columns(int fd) {
 }
 
 static unsigned columns_cached(bool cached) {
-        static __thread int parsed_columns = 0, env_columns = -1;
+        static __thread int env_columns = -1;
         const char *e;
 
         if (_likely_(parsed_columns > 0 && cached))
@@ -3776,6 +3780,11 @@ unsigned columns_uncached(void) {
         return columns_cached(false);
 }
 
+/* intended to be used as a SIGWINCH sighandler */
+void columns_cache_reset(int signum) {
+        parsed_columns = 0;
+}
+
 int fd_lines(int fd) {
         struct winsize ws;
         zero(ws);
@@ -5843,3 +5852,39 @@ void closedirp(DIR **d) {
 void umaskp(mode_t *u) {
         umask(*u);
 }
+
+bool filename_is_safe(const char *p) {
+
+        if (isempty(p))
+                return false;
+
+        if (strchr(p, '/'))
+                return false;
+
+        if (streq(p, "."))
+                return false;
+
+        if (streq(p, ".."))
+                return false;
+
+        if (strlen(p) > FILENAME_MAX)
+                return false;
+
+        return true;
+}
+
+bool string_is_safe(const char *p) {
+        const char *t;
+
+        assert(p);
+
+        for (t = p; *t; t++) {
+                if (*p < ' ')
+                        return false;
+
+                if (strchr("\\\"\'", *p))
+                        return false;
+        }
+
+        return true;
+}