From: Dan Carpenter <dan.carpenter@linaro.org>
To: Simon Horman <horms@kernel.org>
Cc: Marcel Holtmann <marcel@holtmann.org>,
Johan Hedberg <johan.hedberg@gmail.com>,
Luiz Augusto von Dentz <luiz.dentz@gmail.com>,
linux-bluetooth@vger.kernel.org
Subject: Re: [PATCH] Bluetooth: L2CAP: don't check for out-of-bounds value
Date: Fri, 26 May 2023 17:34:30 +0300 [thread overview]
Message-ID: <fdab8adc-0f61-4664-a2f9-6f532b0c85be@kili.mountain> (raw)
In-Reply-To: <20230526-l2cap-16bit-v1-1-2cfb83dd28ee@kernel.org>
On Fri, May 26, 2023 at 04:16:54PM +0200, Simon Horman wrote:
> @@ -4161,8 +4161,12 @@ static struct l2cap_chan *l2cap_connect(struct l2cap_conn *conn,
>
> result = L2CAP_CR_NO_MEM;
>
> - /* Check for valid dynamic CID range (as per Erratum 3253) */
> - if (scid < L2CAP_CID_DYN_START || scid > L2CAP_CID_DYN_END) {
> + /* Check for valid dynamic CID range (as per Erratum 3253).
> + * As scid is an unsigned 16bit variable it's maximum
> + * value is L2CAP_CID_DYN_END (0xffff): there is no need to check
> + * if scid exceeds that value here.
> + */
> + if (scid < L2CAP_CID_DYN_START) {
This is a false positive. To me the warning looks reasonable. But one
way we could silence it would be to keep a list of macros where the
check is impossible but we still want to have it.
I could create something where we do:
echo "L2CAP_CID_DYN_END" >> smatch_data/kernel.allowed_impossible_limits
I'd do the same for unsigned comparisons with zero like:
if (dpmcp_dev->obj_desc.ver_major < DPMCP_MIN_VER_MAJOR ||
(dpmcp_dev->obj_desc.ver_major == DPMCP_MIN_VER_MAJOR &&
dpmcp_dev->obj_desc.ver_minor < DPMCP_MIN_VER_MINOR)) {
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
dev_err(&dpmcp_dev->dev,
"ERROR: Version %d.%d of DPMCP not supported.\n",
echo "DPMCP_MIN_VER_MINOR" >> smatch_data/kernel.allowed_impossible_limits
I can do that on Monday if you want. Other static checkers might
complain still though.
regards,
dan carpenter
next prev parent reply other threads:[~2023-05-26 14:36 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-26 14:16 [PATCH] Bluetooth: L2CAP: don't check for out-of-bounds value Simon Horman
2023-05-26 14:34 ` Dan Carpenter [this message]
2023-05-26 15:19 ` Simon Horman
2023-05-30 6:33 ` Dan Carpenter
2023-05-26 14:57 ` bluez.test.bot
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