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From: Peter Chen <peter.chen@nxp.com>
To: pawell@cadence.com, rogerq@ti.com
Cc: balbi@kernel.org, linux-usb@vger.kernel.org, linux-imx@nxp.com,
	gregkh@linuxfoundation.org, jun.li@nxp.com,
	Peter Chen <peter.chen@nxp.com>,
	stable@vger.kernel.org
Subject: [PATCH 1/3] usb: cdns3: gadget: suspicious implicit sign extension
Date: Fri, 16 Oct 2020 18:16:57 +0800
Message-ID: <20201016101659.29482-2-peter.chen@nxp.com> (raw)
In-Reply-To: <20201016101659.29482-1-peter.chen@nxp.com>

For code:
trb->length = cpu_to_le32(TRB_BURST_LEN(priv_ep->trb_burst_size)
	       	| TRB_LEN(length));

TRB_BURST_LEN(priv_ep->trb_burst_size) may be overflow for int 32 if
priv_ep->trb_burst_size is equal or larger than 0x80;

Below is the Coverity warning:
sign_extension: Suspicious implicit sign extension: priv_ep->trb_burst_size
with type u8 (8 bits, unsigned) is promoted in priv_ep->trb_burst_size << 24
to type int (32 bits, signed), then sign-extended to type unsigned long
(64 bits, unsigned). If priv_ep->trb_burst_size << 24 is greater than 0x7FFFFFFF,
the upper bits of the result will all be 1.

Cc: <stable@vger.kernel.org> #v5.8+
Fixes: 7733f6c32e36 ("usb: cdns3: Add Cadence USB3 DRD Driver")
Signed-off-by: Peter Chen <peter.chen@nxp.com>
---
 drivers/usb/cdns3/gadget.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/cdns3/gadget.h b/drivers/usb/cdns3/gadget.h
index 1ccecd237530..020936cb9897 100644
--- a/drivers/usb/cdns3/gadget.h
+++ b/drivers/usb/cdns3/gadget.h
@@ -1072,7 +1072,7 @@ struct cdns3_trb {
 #define TRB_TDL_SS_SIZE_GET(p)	(((p) & GENMASK(23, 17)) >> 17)
 
 /* transfer_len bitmasks - bits 31:24 */
-#define TRB_BURST_LEN(p)	(((p) << 24) & GENMASK(31, 24))
+#define TRB_BURST_LEN(p)	(unsigned int)(((p) << 24) & GENMASK(31, 24))
 #define TRB_BURST_LEN_GET(p)	(((p) & GENMASK(31, 24)) >> 24)
 
 /* Data buffer pointer bitmasks*/
-- 
2.17.1


  reply index

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-16 10:16 [PATCH 0/3] usb: cdns3: three bug fixes for v5.10 Peter Chen
2020-10-16 10:16 ` Peter Chen [this message]
2020-10-27  9:03   ` [PATCH 1/3] usb: cdns3: gadget: suspicious implicit sign extension Felipe Balbi
2020-10-27  9:48     ` Peter Chen
2020-10-27 10:08       ` David Laight
2020-10-27 14:21       ` Alan Stern
2020-10-28  6:41         ` Peter Chen
2020-10-27  9:03   ` Felipe Balbi
2020-10-16 10:16 ` [PATCH 2/3] usb: cdns3: gadget: own the lock wrongly at the suspend routine Peter Chen
2020-10-27  9:08   ` Felipe Balbi
2020-10-27  9:08   ` Felipe Balbi
2020-10-16 10:16 ` [PATCH 3/3] usb: cdns3: Fix on-chip memory overflow issue Peter Chen
2020-10-27  9:11   ` Felipe Balbi

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