Received-SPF: pass (google.com: domain of linux-kernel+bounces-125763-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45d1:ec00::1 as permitted sender) client-ip=2604:1380:45d1:ec00::1;
From: Erick Archer <erick.archer@outlook.com>
To: Vinod Koul <vkoul@kernel.org>,
	Kees Cook <keescook@chromium.org>,
	"Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc: Erick Archer <erick.archer@outlook.com>,
	dmaengine@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	linux-hardening@vger.kernel.org
Subject: [PATCH v2] dmaengine: pl08x: Use kcalloc() instead of kzalloc()
Date: Sat, 30 Mar 2024 16:23:23 +0100
Message-ID:
 <AS8PR02MB72373D9261B3B166048A8E218B392@AS8PR02MB7237.eurprd02.prod.outlook.com>
Content-Transfer-Encoding: 8bit
Content-Type: text/plain
Precedence: bulk
MIME-Version: 1.0
X-MS-Exchange-MessageSentRepresentingType: 1
X-MS-PublicTrafficType: Email
X-MS-TrafficTypeDiagnostic: AS8PR02MB7237:EE_|AS2PR02MB9882:EE_
X-MS-Office365-Filtering-Correlation-Id: 9acbc5fe-8466-48f9-1e8e-08dc50cd6b02
X-Microsoft-Antispam: BCL:0;
X-Microsoft-Antispam-Message-Info:
	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
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0:
	=?us-ascii?Q?0HGE0KKMrerG8fW8ZVNVKakfgO/am0xbrrLhef+1jcscfzfb/L4P5xDDpLOI?=
 =?us-ascii?Q?D/Rhie2g0TkNtnC1daXV+LIM60rl0eGgwYzqAdxMsMYMPHAlSy1egDTVnrQe?=
 =?us-ascii?Q?VzED/E0GRovOGUCPNNzFE0LcnNRvRPK2C8PWp1Kawd2S4yyByEUF6ypidUl6?=
 =?us-ascii?Q?/QkeWKqe+TPamM9l3k2OlKb3tUWsVHiN1jfGFmkLKrpupDZH6JT5GQsWxacc?=
 =?us-ascii?Q?KT/oBMjtsVdpSY3Bk54gnBoI/MNzCcUgze1fxqzXvyVX1yfLaNiCOg+0yzWU?=
 =?us-ascii?Q?8fk2JAtwmKq637U16jkpogmYLI40X54FvYnQfO52vcAaRym2+LrAWAhQ1I6A?=
 =?us-ascii?Q?wV6Ku32nwp0Qig8+10ODiX+nyNQDa7TDw/7Kd01Zkg8uQiQvwxD9eI7ULh9H?=
 =?us-ascii?Q?O8OzO5KCrVwv6NbOZuWjV7UG3iWeeVH6ES4DMOvXE07tCFfP6xRN4oHSeYx9?=
 =?us-ascii?Q?j4WDurJLaJmEyORW2fsEeggwwuWPVKl58zsjBaChZjZRtxAhl3PcD7heUocL?=
 =?us-ascii?Q?rsGdaHBCZGDIYp91lPDUFZJ4D8okK0EG6/T10TASdU33//vaxjTupDLUdMVd?=
 =?us-ascii?Q?g7UjRs0RzqCs6rpTFIZFzX0dWZ8CGhbG8Okypo1YCwSBxJ7ZPpxi1b/CBI9I?=
 =?us-ascii?Q?lr2k7rNjs5O5GsQKS01Pun6s5yv+81ElDxZzJdi9xWLBPD2XstYJO0z2oVGe?=
 =?us-ascii?Q?yjH7MQAWBOsS6SlgoLWAa2X13/9ZKT1+Vl4m4i0oAsWurZb4qBwwSECY4oV8?=
 =?us-ascii?Q?EHahFCktkDftrGsLJ75UExvEw/Uln4zn4zYzE95XRMMSt+GZF9AcsQq5IB0u?=
 =?us-ascii?Q?KZNvmp9bVTtcT79fr2CZiEPk9jLPVfL6Fg0V6Ap0NaQGYhRojKUJfDr58Xf+?=
 =?us-ascii?Q?VGLsFa8l3VlloFPtm+XWosL5+CDvM4Vf0YcRKgqyKvPvyikkWTAqR+JEue3p?=
 =?us-ascii?Q?FepXxVFT0v8BvEce4cTBr+/t7OBb86L/5MsyvUqA74ui1Pf7NIyhCBFrb2az?=
 =?us-ascii?Q?+ggnqbtw8gqC2VzYvmropJ22awpdc2NVMI37AheHRaHhJs+I8EEyoc5wXL4q?=
 =?us-ascii?Q?uP9V9NgljEJt8SqOnmVOrWS+YOxzmzY5MSCbJwq6k2ems6iDj5NpN2BA7qan?=
 =?us-ascii?Q?xr9QuMMrowpoFNmfdjQbNosgE3A5sGrlHnoFbIqcnH/A43iSytp31rv5kr8B?=
 =?us-ascii?Q?i0t4P1Eb7LQfdhGfTVLjxSNDLwULUFSeIHXhUA0e60hXgq4VKFLe/+oSQwhE?=
 =?us-ascii?Q?lLBpDEdDlr0ZPRzYHb8t?=
X-OriginatorOrg: outlook.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 9acbc5fe-8466-48f9-1e8e-08dc50cd6b02
X-MS-Exchange-CrossTenant-AuthSource: AS8PR02MB7237.eurprd02.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 30 Mar 2024 15:23:57.5121
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 84df9e7f-e9f6-40af-b435-aaaaaaaaaaaa
X-MS-Exchange-CrossTenant-RMS-PersistedConsumerOrg:
	00000000-0000-0000-0000-000000000000
X-MS-Exchange-Transport-CrossTenantHeadersStamped: AS2PR02MB9882

This is an effort to get rid of all multiplications from allocation
functions in order to prevent integer overflows [1].

Here the multiplication is obviously safe because the "channels"
member can only be 8 or 2. This value is set when the "vendor_data"
structs are initialized.

static struct vendor_data vendor_pl080 = {
	[...]
	.channels = 8,
	[...]
};

static struct vendor_data vendor_nomadik = {
	[...]
	.channels = 8,
	[...]
};

static struct vendor_data vendor_pl080s = {
	[...]
	.channels = 8,
	[...]
};

static struct vendor_data vendor_pl081 = {
	[...]
	.channels = 2,
	[...]
};

However, using kcalloc() is more appropriate [1] and improves
readability. This patch has no effect on runtime behavior.

Link: https://github.com/KSPP/linux/issues/162 [1]
Link: https://www.kernel.org/doc/html/next/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [1]
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Erick Archer <erick.archer@outlook.com>
---
Changes in v2:
- Add the "Reviewed-by:" tag.
- Rebase against linux-next.

Previous versions:
v1 -> https://lore.kernel.org/linux-hardening/20240128115236.4791-1-erick.archer@gmx.com/

Hi everyone,

This patch seems to be lost. Gustavo reviewed it on January 30, 2024
but the patch has not been applied since.

Thanks,
Erick
---
 drivers/dma/amba-pl08x.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/amba-pl08x.c b/drivers/dma/amba-pl08x.c
index fbf048f432bf..73a5cfb4da8a 100644
--- a/drivers/dma/amba-pl08x.c
+++ b/drivers/dma/amba-pl08x.c
@@ -2855,8 +2855,8 @@ static int pl08x_probe(struct amba_device *adev, const struct amba_id *id)
 	}
 
 	/* Initialize physical channels */
-	pl08x->phy_chans = kzalloc((vd->channels * sizeof(*pl08x->phy_chans)),
-			GFP_KERNEL);
+	pl08x->phy_chans = kcalloc(vd->channels, sizeof(*pl08x->phy_chans),
+				   GFP_KERNEL);
 	if (!pl08x->phy_chans) {
 		ret = -ENOMEM;
 		goto out_no_phychans;
-- 
2.25.1