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Message-ID: <8fbcb2e2d05bc394fd4e15d44cc78b531f69ee8f.1729230718.git.mchehab+huawei@kernel.org>
Date: Fri, 18 Oct 2024 07:53:15 +0200
From: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
To:
Cc: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>,
Hans Verkuil <hverkuil@...all.nl>,
Mauro Carvalho Chehab <mchehab+huawei@...nel.org>,
linux-kernel@...r.kernel.org,
linux-media@...r.kernel.org,
stable@...r.kernel.org
Subject: [PATCH v2 13/13] media: pulse8-cec: fix data timestamp at pulse8_setup()
As pointed by Coverity, there is a hidden overflow condition there.
As date is signed and u8 is unsigned, doing:
date = (data[0] << 24)
With a value bigger than 07f will make all upper bits of date
0xffffffff. This can be demonstrated with this small code:
<code>
typedef int64_t time64_t;
typedef uint8_t u8;
int main(void)
{
u8 data[] = { 0xde ,0xad , 0xbe, 0xef };
time64_t date;
date = (data[0] << 24) | (data[1] << 16) | (data[2] << 8) | data[3];
printf("Invalid data = 0x%08lx\n", date);
date = ((unsigned)data[0] << 24) | (data[1] << 16) | (data[2] << 8) | data[3];
printf("Expected data = 0x%08lx\n", date);
return 0;
}
</code>
Fix it by converting the upper bit calculation to unsigned.
Fixes: cea28e7a55e7 ("media: pulse8-cec: reorganize function order")
Cc: stable@...r.kernel.org
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
---
drivers/media/cec/usb/pulse8/pulse8-cec.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/media/cec/usb/pulse8/pulse8-cec.c b/drivers/media/cec/usb/pulse8/pulse8-cec.c
index ba67587bd43e..171366fe3544 100644
--- a/drivers/media/cec/usb/pulse8/pulse8-cec.c
+++ b/drivers/media/cec/usb/pulse8/pulse8-cec.c
@@ -685,7 +685,7 @@ static int pulse8_setup(struct pulse8 *pulse8, struct serio *serio,
err = pulse8_send_and_wait(pulse8, cmd, 1, cmd[0], 4);
if (err)
return err;
- date = (data[0] << 24) | (data[1] << 16) | (data[2] << 8) | data[3];
+ date = ((unsigned)data[0] << 24) | (data[1] << 16) | (data[2] << 8) | data[3];
dev_info(pulse8->dev, "Firmware build date %ptT\n", &date);
dev_dbg(pulse8->dev, "Persistent config:\n");
--
2.47.0
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