Clean up string encoding handling

We should handle this in the low-level protocol code as much as possible
to avoid mistakes. This way the rest of the code can assume that strings
are always UTF-8 with \n line endings.

3 files changed, 16 insertions, 0 deletions

diff --git a/unix/xserver/hw/vnc/RFBGlue.cc b/unix/xserver/hw/vnc/RFBGlue.cc
index 2fbc27ee..25431b65 100644
--- a/unix/xserver/hw/vnc/RFBGlue.cc
+++ b/unix/xserver/hw/vnc/RFBGlue.cc
@@ -248,3 +248,12 @@ char* vncUTF8ToLatin1(const char* src, size_t bytes)
     return NULL;
   }
 }
+
+int vncIsValidUTF8(const char* str, size_t bytes)
+{
+  try {
+    return isValidUTF8(str, bytes);
+  } catch (...) {
+    return 0;
+  }
+}
diff --git a/unix/xserver/hw/vnc/RFBGlue.h b/unix/xserver/hw/vnc/RFBGlue.h
index d2b2e8aa..30c13bd2 100644
--- a/unix/xserver/hw/vnc/RFBGlue.h
+++ b/unix/xserver/hw/vnc/RFBGlue.h
@@ -53,6 +53,8 @@ char* vncConvertLF(const char* src, size_t bytes);
 char* vncLatin1ToUTF8(const char* src, size_t bytes);
 char* vncUTF8ToLatin1(const char* src, size_t bytes);
 
+int vncIsValidUTF8(const char* str, size_t bytes);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/unix/xserver/hw/vnc/vncSelection.c b/unix/xserver/hw/vnc/vncSelection.c
index 1ed35149..f7f3c51d 100644
--- a/unix/xserver/hw/vnc/vncSelection.c
+++ b/unix/xserver/hw/vnc/vncSelection.c
@@ -611,6 +611,11 @@ static void vncHandleSelection(Atom selection, Atom target,
     if (prop->type != xaUTF8_STRING)
       return;
 
+    if (!vncIsValidUTF8(prop->data, prop->size)) {
+      LOG_ERROR("Invalid UTF-8 sequence in clipboard");
+      return;
+    }
+
     filtered = vncConvertLF(prop->data, prop->size);
     if (filtered == NULL)
       return;