[Qemu-devel] [PATCH 96/97] usb-mtp: outlaw slashes in filenames

[Michael Roth]

From: Gerd Hoffmann <address@hidden>

Slash is unix directory separator, so they are not allowed in filenames.
Note this also stops the classic escape via "../".

Fixes: CVE-2018-16867
Reported-by: Michael Hanselmann <address@hidden>
Signed-off-by: Gerd Hoffmann <address@hidden>
Reviewed-by: Philippe Mathieu-Daudé <address@hidden>
Message-id: address@hidden
(cherry picked from commit c52d46e041b42bb1ee6f692e00a0abe37a9659f6)
Signed-off-by: Michael Roth <address@hidden>
---
 hw/usb/dev-mtp.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/hw/usb/dev-mtp.c b/hw/usb/dev-mtp.c
index 1ded7ac9a3..899c8a36ab 100644
--- a/hw/usb/dev-mtp.c
+++ b/hw/usb/dev-mtp.c
@@ -1667,6 +1667,12 @@ static void usb_mtp_write_metadata(MTPState *s)
 
     utf16_to_str(dataset->length, dataset->filename, filename);
 
+    if (strchr(filename, '/')) {
+        usb_mtp_queue_result(s, RES_PARAMETER_NOT_SUPPORTED, d->trans,
+                             0, 0, 0, 0);
+        return;
+    }
+
     o = usb_mtp_object_lookup_name(p, filename, dataset->length);
     if (o != NULL) {
         next_handle = o->handle;
-- 
2.17.1