diff options
| author | Jim Paris <jim@jtan.com> | 2009-08-24 14:56:12 -0400 |
|---|---|---|
| committer | Aurelien Jarno <aurelien@aurel32.net> | 2009-10-04 13:16:01 +0200 |
| commit | babd03fde68093482528010a5435c14ce9128e3f (patch) | |
| tree | 4c27acffba097d7473bc497fcda80dfe89819588 | |
| parent | 6166c0f95e8093d695835d07798557439a226f48 (diff) | |
usb-linux.c: fix buffer overflow
In usb-linux.c:usb_host_handle_control, we pass a 1024-byte buffer and
length to the kernel. However, the length was provided by the caller
of dev->handle_packet, and is not checked, so the kernel might provide
too much data and overflow our buffer.
For example, hw/usb-uhci.c could set the length to 2047.
hw/usb-ohci.c looks like it might go up to 4096 or 8192.
This causes a qemu crash, as reported here:
http://www.mail-archive.com/kvm@vger.kernel.org/msg18447.html
This patch increases the usb-linux.c buffer size to 2048 to fix the
specific device reported, and adds a check to avoid the overflow in
any case.
Signed-off-by: Jim Paris <jim@jtan.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
| -rw-r--r-- | usb-linux.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/usb-linux.c b/usb-linux.c index 043f6b6ba1..eb1c5f071b 100644 --- a/usb-linux.c +++ b/usb-linux.c @@ -115,7 +115,7 @@ struct ctrl_struct { uint16_t offset; uint8_t state; struct usb_ctrlrequest req; - uint8_t buffer[1024]; + uint8_t buffer[2048]; }; typedef struct USBHostDevice { @@ -552,6 +552,7 @@ static int usb_host_handle_control(USBHostDevice *s, USBPacket *p) struct usbdevfs_urb *urb; AsyncURB *aurb; int ret, value, index; + int buffer_len; /* * Process certain standard device requests. @@ -580,6 +581,13 @@ static int usb_host_handle_control(USBHostDevice *s, USBPacket *p) /* The rest are asynchronous */ + buffer_len = 8 + s->ctrl.len; + if (buffer_len > sizeof(s->ctrl.buffer)) { + fprintf(stderr, "husb: ctrl buffer too small (%u > %lu)\n", + buffer_len, sizeof(s->ctrl.buffer)); + return USB_RET_STALL; + } + aurb = async_alloc(); aurb->hdev = s; aurb->packet = p; @@ -596,7 +604,7 @@ static int usb_host_handle_control(USBHostDevice *s, USBPacket *p) urb->endpoint = p->devep; urb->buffer = &s->ctrl.req; - urb->buffer_length = 8 + s->ctrl.len; + urb->buffer_length = buffer_len; urb->usercontext = s; |