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From: Andrej Shadura <andrew.shadura@collabora.co.uk>
To: "Jiří Kosina" <jikos@kernel.org>
Cc: linux-input@vger.kernel.org, linux-usb@vger.kernel.org,
	stable@vger.kernel.org, kernel@collabora.com
Subject: [PATCH v2 1/2] HID: u2fzero: explicitly check for errors
Date: Mon, 18 Oct 2021 14:21:43 +0200	[thread overview]
Message-ID: <20211018122144.25131-1-andrew.shadura@collabora.co.uk> (raw)

The previous commit fixed handling of incomplete packets but broke error
handling: offsetof returns an unsigned value (size_t), but when compared
against the signed return value, the return value is interpreted as if
it were unsigned, so negative return values are never less than the
offset.

Fixes: 22d65765f211 ("HID: u2fzero: ignore incomplete packets without data")
Fixes: 42337b9d4d95 ("HID: add driver for U2F Zero built-in LED and RNG")
Signed-off-by: Andrej Shadura <andrew.shadura@collabora.co.uk>
---
 drivers/hid/hid-u2fzero.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hid/hid-u2fzero.c b/drivers/hid/hid-u2fzero.c
index d70cd3d7f583..5145d758bea0 100644
--- a/drivers/hid/hid-u2fzero.c
+++ b/drivers/hid/hid-u2fzero.c
@@ -200,7 +200,7 @@ static int u2fzero_rng_read(struct hwrng *rng, void *data,
 	ret = u2fzero_recv(dev, &req, &resp);
 
 	/* ignore errors or packets without data */
-	if (ret < offsetof(struct u2f_hid_msg, init.data))
+	if (ret < 0 || ret < offsetof(struct u2f_hid_msg, init.data))
 		return 0;
 
 	/* only take the minimum amount of data it is safe to take */
-- 
2.33.0


             reply	other threads:[~2021-10-18 12:38 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-18 12:21 Andrej Shadura [this message]
2021-10-18 12:21 ` [PATCH v2 2/2] HID: u2fzero: properly handle timeouts in usb_submit_urb Andrej Shadura
2021-10-18 14:15 ` [PATCH v2 1/2] HID: u2fzero: explicitly check for errors Alan Stern
2021-10-18 14:17   ` Andrej Shadura
2021-10-18 14:38     ` Alan Stern

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