From: Greg Kroah-Hartman
stable inclusion
form stable-v5.10.85
commit 7193ad3e50e596ac2192531c58ba83b9e6d2444b
issue: #I4RVJ4
CVE: CVE-2021-39685
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
Signed-off-by: Yu Changchun
--------------------------------
Sometimes USB hosts can ask for buffers that are too large from endpoint
0, which should not be allowed. If this happens for OUT requests, stall
the endpoint, but for IN requests, trim the request size to the endpoint
buffer size.
Co-developed-by: Szymon Heidrich
Signed-off-by: Greg Kroah-Hartman
Signed-off-by: Chen Jun
Signed-off-by: Zheng Zengkai
Signed-off-by: Yu Changchun
---
drivers/usb/gadget/composite.c | 12 ++++++++++++
drivers/usb/gadget/legacy/dbgp.c | 13 +++++++++++++
drivers/usb/gadget/legacy/inode.c | 16 +++++++++++++++-
3 files changed, 40 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index a8704e6498ab..426132988512 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -1648,6 +1648,18 @@ composite_setup(struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
struct usb_function *f = NULL;
u8 endp;
+ if (w_length > USB_COMP_EP0_BUFSIZ) {
+ if (ctrl->bRequestType == USB_DIR_OUT) {
+ goto done;
+ } else {
+ /* Cast away the const, we are going to overwrite on purpose. */
+ __le16 *temp = (__le16 *)&ctrl->wLength;
+
+ *temp = cpu_to_le16(USB_COMP_EP0_BUFSIZ);
+ w_length = USB_COMP_EP0_BUFSIZ;
+ }
+ }
+
/* partial re-init of the response message; the function or the
* gadget might need to intercept e.g. a control-OUT completion
* when we delegate to it.
diff --git a/drivers/usb/gadget/legacy/dbgp.c b/drivers/usb/gadget/legacy/dbgp.c
index e1d566c9918a..e567afcb2794 100644
--- a/drivers/usb/gadget/legacy/dbgp.c
+++ b/drivers/usb/gadget/legacy/dbgp.c
@@ -345,6 +345,19 @@ static int dbgp_setup(struct usb_gadget *gadget,
void *data = NULL;
u16 len = 0;
+ if (length > DBGP_REQ_LEN) {
+ if (ctrl->bRequestType == USB_DIR_OUT) {
+ return err;
+ } else {
+ /* Cast away the const, we are going to overwrite on purpose. */
+ __le16 *temp = (__le16 *)&ctrl->wLength;
+
+ *temp = cpu_to_le16(DBGP_REQ_LEN);
+ length = DBGP_REQ_LEN;
+ }
+ }
+
+
if (request == USB_REQ_GET_DESCRIPTOR) {
switch (value>>8) {
case USB_DT_DEVICE:
diff --git a/drivers/usb/gadget/legacy/inode.c b/drivers/usb/gadget/legacy/inode.c
index 71e7d10dd76b..04b9c4f5f129 100644
--- a/drivers/usb/gadget/legacy/inode.c
+++ b/drivers/usb/gadget/legacy/inode.c
@@ -110,6 +110,8 @@ enum ep0_state {
/* enough for the whole queue: most events invalidate others */
#define N_EVENT 5
+#define RBUF_SIZE 256
+
struct dev_data {
spinlock_t lock;
refcount_t count;
@@ -144,7 +146,7 @@ struct dev_data {
struct dentry *dentry;
/* except this scratch i/o buffer for ep0 */
- u8 rbuf [256];
+ u8 rbuf[RBUF_SIZE];
};
static inline void get_dev (struct dev_data *data)
@@ -1333,6 +1335,18 @@ gadgetfs_setup (struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
u16 w_value = le16_to_cpu(ctrl->wValue);
u16 w_length = le16_to_cpu(ctrl->wLength);
+ if (w_length > RBUF_SIZE) {
+ if (ctrl->bRequestType == USB_DIR_OUT) {
+ return value;
+ } else {
+ /* Cast away the const, we are going to overwrite on purpose. */
+ __le16 *temp = (__le16 *)&ctrl->wLength;
+
+ *temp = cpu_to_le16(RBUF_SIZE);
+ w_length = RBUF_SIZE;
+ }
+ }
+
spin_lock (&dev->lock);
dev->setup_abort = 0;
if (dev->state == STATE_DEV_UNCONNECTED) {
--
2.25.1
