[PATCH v2] usb: gadget: functioni: Fix a oob problem in rndis

[jackysliu]

From: Siyang Liu <1972843537@xxxxxx>

An out-of-bounds memory access vulnerability exists in the RNDIS
(Remote Network Driver Interface Specification) implementation.
The vulnerability stems from insufficient boundary validation when
processing SET requests with user-controlled InformationBufferOffset
and InformationBufferLength parameters.

Fix on commit id:
commit 5f60d5f6bbc1 ("move asm/unaligned.h to linux/unaligned.h")

The vulnerability can be fixed by adding addtional boundary checks

Signed-off-by: Siyang Liu <1972843537@xxxxxx>
---
 drivers/usb/gadget/function/rndis.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/gadget/function/rndis.c b/drivers/usb/gadget/function/rndis.c
index afd75d72412c..cc522fb4c06c 100644
--- a/drivers/usb/gadget/function/rndis.c
+++ b/drivers/usb/gadget/function/rndis.c
@@ -641,7 +641,8 @@ static int rndis_set_response(struct rndis_params *params,
 	BufOffset = le32_to_cpu(buf->InformationBufferOffset);
 	if ((BufLength > RNDIS_MAX_TOTAL_SIZE) ||
 	    (BufOffset > RNDIS_MAX_TOTAL_SIZE) ||
-	    (BufOffset + 8 >= RNDIS_MAX_TOTAL_SIZE))
+	    (BufOffset + 8 >= RNDIS_MAX_TOTAL_SIZE) ||
+		(BufOffset + BufLength+8 > RNDIS_MAX_TOTAL_SIZE))
 		    return -EINVAL;
 
 	r = rndis_add_response(params, sizeof(rndis_set_cmplt_type));
-- 
2.43.5