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SubjectRe: [CHECKER] 4 security holes in 2.4.4-ac8
On Tue, May 29, 2001 at 03:00:56PM -0700, Dawson Engler wrote:
> -----------------------------------------------------------------------------
> [BUG] ./drivers/usb/bluetooth.c: dereference of 'buf' at the beginning of
> the switch, and then does a copyin.

This is a real bug, thanks.
The attached patch, against the latest -ac tree should fix it.

greg k-h
diff -Nru a/drivers/usb/bluetooth.c b/drivers/usb/bluetooth.c
--- a/drivers/usb/bluetooth.c Wed May 30 11:10:08 2001
+++ b/drivers/usb/bluetooth.c Wed May 30 11:10:08 2001
@@ -1,11 +1,20 @@
/*
- * bluetooth.c Version 0.9
+ * bluetooth.c Version 0.10
*
* Copyright (c) 2000, 2001 Greg Kroah-Hartman <greg@kroah.com>
* Copyright (c) 2000 Mark Douglas Corner <mcorner@umich.edu>
*
* USB Bluetooth driver, based on the Bluetooth Spec version 1.0B
*
+ * (2001/05/28) Version 0.10 gkh
+ * - Fixed problem with using data from userspace in the bluetooth_write
+ * function as found by the CHECKER project.
+ * - Added a buffer to the write_urb_pool which reduces the number of
+ * buffers being created and destroyed for ever write. Also cleans
+ * up the logic a bit.
+ * - Added a buffer to the control_urb_pool which fixes a memory leak
+ * when the device is removed from the system.
+ *
* (2001/05/28) Version 0.9 gkh
* Fixed problem with bluetooth==NULL for bluetooth_read_bulk_callback
* which was found by both the CHECKER project and Mikko Rahkonen.
@@ -101,7 +110,7 @@
/*
* Version Information
*/
-#define DRIVER_VERSION "v0.9"
+#define DRIVER_VERSION "v0.10"
#define DRIVER_AUTHOR "Greg Kroah-Hartman, Mark Douglas Corner"
#define DRIVER_DESC "USB Bluetooth driver"

@@ -264,7 +273,7 @@
}


-static int bluetooth_ctrl_msg (struct usb_bluetooth *bluetooth, int request, int value, void *buf, int len)
+static int bluetooth_ctrl_msg (struct usb_bluetooth *bluetooth, int request, int value, const unsigned char *buf, int len)
{
struct urb *urb = NULL;
devrequest *dr = NULL;
@@ -286,11 +295,23 @@
return -ENOMEM;
}

- /* free up the last buffer that this urb used */
- if (urb->transfer_buffer != NULL) {
- kfree(urb->transfer_buffer);
- urb->transfer_buffer = NULL;
+ /* keep increasing the urb transfer buffer to fit the size of the message */
+ if (urb->transfer_buffer == NULL) {
+ urb->transfer_buffer = kmalloc (len, GFP_KERNEL);
+ if (urb->transfer_buffer == NULL) {
+ err (__FUNCTION__" - out of memory");
+ return -ENOMEM;
+ }
+ }
+ if (urb->transfer_buffer_length < len) {
+ kfree (urb->transfer_buffer);
+ urb->transfer_buffer = kmalloc (len, GFP_KERNEL);
+ if (urb->transfer_buffer == NULL) {
+ err (__FUNCTION__" - out of memory");
+ return -ENOMEM;
+ }
}
+ memcpy (urb->transfer_buffer, buf, len);

dr->requesttype = BLUETOOTH_CONTROL_REQUEST_TYPE;
dr->request = request;
@@ -299,14 +320,14 @@
dr->length = cpu_to_le16p(&len);

FILL_CONTROL_URB (urb, bluetooth->dev, usb_sndctrlpipe(bluetooth->dev, 0),
- (unsigned char*)dr, buf, len, bluetooth_ctrl_callback, bluetooth);
+ (unsigned char*)dr, urb->transfer_buffer, len, bluetooth_ctrl_callback, bluetooth);

/* send it down the pipe */
status = usb_submit_urb(urb);
if (status)
dbg(__FUNCTION__ " - usb_submit_urb(control) failed with status = %d", status);

- return 0;
+ return status;
}


@@ -405,12 +426,13 @@
{
struct usb_bluetooth *bluetooth = get_usb_bluetooth ((struct usb_bluetooth *)tty->driver_data, __FUNCTION__);
struct urb *urb = NULL;
- unsigned char *new_buffer;
+ unsigned char *temp_buffer = NULL;
+ const unsigned char *current_buffer;
const unsigned char *current_position;
- int status;
int bytes_sent;
int buffer_size;
int i;
+ int retval = 0;

if (!bluetooth) {
return -ENODEV;
@@ -440,38 +462,39 @@
printk ("\n");
#endif

- switch (*buf) {
+ if (from_user) {
+ temp_buffer = kmalloc (count, GFP_KERNEL);
+ if (temp_buffer == NULL) {
+ err (__FUNCTION__ "- out of memory.");
+ retval = -ENOMEM;
+ goto exit;
+ }
+ copy_from_user (temp_buffer, buf, count);
+ current_buffer = temp_buffer;
+ } else {
+ current_buffer = buf;
+ }
+
+ switch (*current_buffer) {
/* First byte indicates the type of packet */
case CMD_PKT:
/* dbg(__FUNCTION__ "- Send cmd_pkt len:%d", count);*/

if (in_interrupt()){
printk("cmd_pkt from interrupt!\n");
- return count;
- }
-
- new_buffer = kmalloc (count-1, GFP_KERNEL);
-
- if (!new_buffer) {
- err (__FUNCTION__ "- out of memory.");
- return -ENOMEM;
+ retval = count;
+ goto exit;
}

- if (from_user)
- copy_from_user (new_buffer, buf+1, count-1);
- else
- memcpy (new_buffer, buf+1, count-1);
-
- if (bluetooth_ctrl_msg (bluetooth, 0x00, 0x00, new_buffer, count-1) != 0) {
- kfree (new_buffer);
- return 0;
+ retval = bluetooth_ctrl_msg (bluetooth, 0x00, 0x00, &current_buffer[1], count-1);
+ if (retval) {
+ goto exit;
}
-
- /* need to free new_buffer somehow... FIXME */
- return count;
+ retval = count;
+ break;

case ACL_PKT:
- current_position = buf;
+ current_position = current_buffer;
++current_position;
--count;
bytes_sent = 0;
@@ -488,37 +511,25 @@
}
if (urb == NULL) {
dbg (__FUNCTION__ " - no free urbs");
- return bytes_sent;
+ retval = bytes_sent;
+ goto exit;
}

- /* free up the last buffer that this urb used */
- if (urb->transfer_buffer != NULL) {
- kfree(urb->transfer_buffer);
- urb->transfer_buffer = NULL;
- }

buffer_size = MIN (count, bluetooth->bulk_out_buffer_size);
-
- new_buffer = kmalloc (buffer_size, GFP_KERNEL);
- if (new_buffer == NULL) {
- err(__FUNCTION__" no more kernel memory...");
- return bytes_sent;
- }
-
- if (from_user)
- copy_from_user(new_buffer, current_position, buffer_size);
- else
- memcpy (new_buffer, current_position, buffer_size);
+ memcpy (urb->transfer_buffer, current_position, buffer_size);

/* build up our urb */
FILL_BULK_URB (urb, bluetooth->dev, usb_sndbulkpipe(bluetooth->dev, bluetooth->bulk_out_endpointAddress),
- new_buffer, buffer_size, bluetooth_write_bulk_callback, bluetooth);
+ urb->transfer_buffer, buffer_size, bluetooth_write_bulk_callback, bluetooth);
urb->transfer_flags |= USB_QUEUE_BULK;

/* send it down the pipe */
- status = usb_submit_urb(urb);
- if (status)
- dbg(__FUNCTION__ " - usb_submit_urb(write bulk) failed with status = %d", status);
+ retval = usb_submit_urb(urb);
+ if (retval) {
+ dbg(__FUNCTION__ " - usb_submit_urb(write bulk) failed with error = %d", retval);
+ goto exit;
+ }
#ifdef BTBUGGYHARDWARE
/* A workaround for the stalled data bug */
/* May or may not be needed...*/
@@ -531,13 +542,20 @@
count -= buffer_size;
}

- return bytes_sent + 1;
+ retval = bytes_sent + 1;
+ break;

default :
dbg(__FUNCTION__" - unsupported (at this time) write type");
+ retval = -EINVAL;
+ break;
}

- return 0;
+exit:
+ if (temp_buffer != NULL)
+ kfree (temp_buffer);
+
+ return retval;
}


@@ -1121,7 +1139,11 @@
err("No free urbs available");
goto probe_error;
}
- urb->transfer_buffer = NULL;
+ urb->transfer_buffer = kmalloc (bluetooth->bulk_out_buffer_size, GFP_KERNEL);
+ if (urb->transfer_buffer == NULL) {
+ err("out of memory");
+ goto probe_error;
+ }
bluetooth->write_urb_pool[i] = urb;
}

@@ -1163,11 +1185,17 @@
if (bluetooth->interrupt_in_buffer)
kfree (bluetooth->interrupt_in_buffer);
for (i = 0; i < NUM_BULK_URBS; ++i)
- if (bluetooth->write_urb_pool[i])
+ if (bluetooth->write_urb_pool[i]) {
+ if (bluetooth->write_urb_pool[i]->transfer_buffer)
+ kfree (bluetooth->write_urb_pool[i]->transfer_buffer);
usb_free_urb (bluetooth->write_urb_pool[i]);
+ }
for (i = 0; i < NUM_CONTROL_URBS; ++i)
- if (bluetooth->control_urb_pool[i])
+ if (bluetooth->control_urb_pool[i]) {
+ if (bluetooth->control_urb_pool[i]->transfer_buffer)
+ kfree (bluetooth->control_urb_pool[i]->transfer_buffer);
usb_free_urb (bluetooth->control_urb_pool[i]);
+ }

bluetooth_table[minor] = NULL;
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