From eea4c860c3b366369eff0489d94ee4f0571d467d Mon Sep 17 00:00:00 2001
From: Robin Guo <guoweibin@inspur.com>
Date: Tue, 6 Sep 2022 10:21:19 +0800
Subject: [PATCH] usb: musb: Fix musb_gadget.c rxstate overflow bug
Git-commit: eea4c860c3b366369eff0489d94ee4f0571d467d
Patch-mainline: v6.1-rc1
References: git-fixes

The usb function device call musb_gadget_queue() adds the passed
request to musb_ep::req_list,If the (request->length > musb_ep->packet_sz)
and (is_buffer_mapped(req) return false),the rxstate() will copy all data
in fifo to request->buf which may cause request->buf out of bounds.

Fix it by add the length check :
fifocnt = min_t(unsigned, request->length - request->actual, fifocnt);

Signed-off-by: Robin Guo <guoweibin@inspur.com>
Link: https://lore.kernel.org/r/20220906102119.1b071d07a8391ff115e6d1ef@inspur.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/usb/musb/musb_gadget.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c
index daada4b66a92..6704a62a1665 100644
--- a/drivers/usb/musb/musb_gadget.c
+++ b/drivers/usb/musb/musb_gadget.c
@@ -760,6 +760,9 @@ static void rxstate(struct musb *musb, struct musb_request *req)
 			musb_writew(epio, MUSB_RXCSR, csr);
 
 buffer_aint_mapped:
+			fifo_count = min_t(unsigned int,
+					request->length - request->actual,
+					(unsigned int)fifo_count);
 			musb_read_fifo(musb_ep->hw_ep, fifo_count, (u8 *)
 					(request->buf + request->actual));
 			request->actual += fifo_count;
-- 
2.35.3