* [Qemu-devel] [PULL 1/2] usb-mtp: fix utf16_to_str
2018-12-03 19:50 [Qemu-devel] [PULL 0/2] Fixes 31 20181203 patches Gerd Hoffmann
@ 2018-12-03 19:50 ` Gerd Hoffmann
2018-12-03 20:00 ` Eric Blake
2018-12-03 19:50 ` [Qemu-devel] [PULL 2/2] usb-mtp: outlaw slashes in filenames Gerd Hoffmann
2018-12-04 9:36 ` [Qemu-devel] [PULL 0/2] Fixes 31 20181203 patches Peter Maydell
2 siblings, 1 reply; 5+ messages in thread
From: Gerd Hoffmann @ 2018-12-03 19:50 UTC (permalink / raw)
To: qemu-devel; +Cc: Gerd Hoffmann
Make utf16_to_str return an allocated string. Remove the assumtion that
the number of string bytes equals the number of utf16 chars (which is
only true for ascii chars). Instead call wcstombs twice, once to figure
the storage size and once for the actual conversion (as suggested by the
wcstombs manpage).
FIXME: surrogate pairs are not working correctly. Pre-existing bug,
fixing that is left for another day.
Reported-by: Michael Hanselmann <public@hansmi.ch>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-id: 20181203101045.27976-2-kraxel@redhat.com
---
hw/usb/dev-mtp.c | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)
diff --git a/hw/usb/dev-mtp.c b/hw/usb/dev-mtp.c
index 00a3691bae..0f6a9702ef 100644
--- a/hw/usb/dev-mtp.c
+++ b/hw/usb/dev-mtp.c
@@ -1593,17 +1593,23 @@ static void usb_mtp_cancel_packet(USBDevice *dev, USBPacket *p)
fprintf(stderr, "%s\n", __func__);
}
-static void utf16_to_str(uint8_t len, uint16_t *arr, char *name)
+static char *utf16_to_str(uint8_t len, uint16_t *arr)
{
- int count;
- wchar_t *wstr = g_new0(wchar_t, len);
+ wchar_t *wstr = g_new0(wchar_t, len + 1);
+ int count, dlen;
+ char *dest;
for (count = 0; count < len; count++) {
+ /* FIXME: not working for surrogate pairs */
wstr[count] = (wchar_t)arr[count];
}
+ wstr[count] = 0;
- wcstombs(name, wstr, len);
+ dlen = wcstombs(NULL, wstr, 0) + 1;
+ dest = g_malloc(dlen);
+ wcstombs(dest, wstr, dlen);
g_free(wstr);
+ return dest;
}
/* Wrapper around write, returns 0 on failure */
@@ -1703,7 +1709,7 @@ static void usb_mtp_write_metadata(MTPState *s)
{
MTPData *d = s->data_out;
ObjectInfo *dataset = (ObjectInfo *)d->data;
- char *filename = g_new0(char, dataset->length);
+ char *filename;
MTPObject *o;
MTPObject *p = usb_mtp_object_lookup(s, s->dataset.parent_handle);
uint32_t next_handle = s->next_handle;
@@ -1711,7 +1717,7 @@ static void usb_mtp_write_metadata(MTPState *s)
assert(!s->write_pending);
assert(p != NULL);
- utf16_to_str(dataset->length, dataset->filename, filename);
+ filename = utf16_to_str(dataset->length, dataset->filename);
o = usb_mtp_object_lookup_name(p, filename, dataset->length);
if (o != NULL) {
--
2.9.3
^ permalink raw reply related [flat|nested] 5+ messages in thread* [Qemu-devel] [PULL 2/2] usb-mtp: outlaw slashes in filenames
2018-12-03 19:50 [Qemu-devel] [PULL 0/2] Fixes 31 20181203 patches Gerd Hoffmann
2018-12-03 19:50 ` [Qemu-devel] [PULL 1/2] usb-mtp: fix utf16_to_str Gerd Hoffmann
@ 2018-12-03 19:50 ` Gerd Hoffmann
2018-12-04 9:36 ` [Qemu-devel] [PULL 0/2] Fixes 31 20181203 patches Peter Maydell
2 siblings, 0 replies; 5+ messages in thread
From: Gerd Hoffmann @ 2018-12-03 19:50 UTC (permalink / raw)
To: qemu-devel; +Cc: Gerd Hoffmann
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 <public@hansmi.ch>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20181203101045.27976-3-kraxel@redhat.com
---
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 0f6a9702ef..100b7171f4 100644
--- a/hw/usb/dev-mtp.c
+++ b/hw/usb/dev-mtp.c
@@ -1719,6 +1719,12 @@ static void usb_mtp_write_metadata(MTPState *s)
filename = utf16_to_str(dataset->length, dataset->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;
--
2.9.3
^ permalink raw reply related [flat|nested] 5+ messages in thread