[PATCH v4] soc: aspeed: Add NULL check in aspeed_lpc_enable_snoop()

[PATCH v4] soc: aspeed: Add NULL check in aspeed_lpc_enable_snoop()

[Henry Martin]

devm_kasprintf() returns NULL when memory allocation fails. Currently,
aspeed_lpc_enable_snoop() does not check for this case, which results in a
NULL pointer dereference.

Add NULL check after devm_kasprintf() to prevent this issue.

Fixes: 3772e5da4454 ("soc: aspeed: Aspeed LPC snoop output using misc chardev")
Signed-off-by: Henry Martin <bsdhenrymartin@gmail.com>
---
V3 -> V4: 
- Add proper cleanup when devm_kasprintf() fails
- Ensure kfifo and miscdevice get released on error
V2 -> V3: 
- Simplify the array access and correct commit message.
V1 -> V2: 
- Remove blank line between tags.

 drivers/soc/aspeed/aspeed-lpc-snoop.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/soc/aspeed/aspeed-lpc-snoop.c b/drivers/soc/aspeed/aspeed-lpc-snoop.c
index 9ab5ba9cf1d6..3e3f178b1226 100644
--- a/drivers/soc/aspeed/aspeed-lpc-snoop.c
+++ b/drivers/soc/aspeed/aspeed-lpc-snoop.c
@@ -200,11 +200,15 @@ static int aspeed_lpc_enable_snoop(struct aspeed_lpc_snoop *lpc_snoop,
 	lpc_snoop->chan[channel].miscdev.minor = MISC_DYNAMIC_MINOR;
 	lpc_snoop->chan[channel].miscdev.name =
 		devm_kasprintf(dev, GFP_KERNEL, "%s%d", DEVICE_NAME, channel);
+	if (!lpc_snoop->chan[channel].miscdev.name) {
+		rc = -ENOMEM;
+		goto err_free_fifo;
+	}
 	lpc_snoop->chan[channel].miscdev.fops = &snoop_fops;
 	lpc_snoop->chan[channel].miscdev.parent = dev;
 	rc = misc_register(&lpc_snoop->chan[channel].miscdev);
 	if (rc)
-		return rc;
+		goto err_free_fifo;
 
 	/* Enable LPC snoop channel at requested port */
 	switch (channel) {
@@ -221,7 +225,8 @@ static int aspeed_lpc_enable_snoop(struct aspeed_lpc_snoop *lpc_snoop,
 		hicrb_en = HICRB_ENSNP1D;
 		break;
 	default:
-		return -EINVAL;
+		rc = -EINVAL;
+		goto err_misc_deregister;
 	}
 
 	regmap_update_bits(lpc_snoop->regmap, HICR5, hicr5_en, hicr5_en);
@@ -231,6 +236,12 @@ static int aspeed_lpc_enable_snoop(struct aspeed_lpc_snoop *lpc_snoop,
 		regmap_update_bits(lpc_snoop->regmap, HICRB,
 				hicrb_en, hicrb_en);
 
+	return 0;
+
+err_misc_deregister:
+	misc_deregister(&lpc_snoop->chan[channel].miscdev);
+err_free_fifo:
+	kfifo_free(&lpc_snoop->chan[channel].fifo);
 	return rc;
 }
 
-- 
2.34.1

Re: [PATCH v4] soc: aspeed: Add NULL check in aspeed_lpc_enable_snoop()

[Andrew Jeffery]

On Tue, 01 Apr 2025 15:46:47 +0800, Henry Martin wrote:
> devm_kasprintf() returns NULL when memory allocation fails. Currently,
> aspeed_lpc_enable_snoop() does not check for this case, which results in a
> NULL pointer dereference.
> 
> Add NULL check after devm_kasprintf() to prevent this issue.
> 
> 
> [...]

Thanks, I've applied this to be picked up through the BMC tree.

--
Andrew Jeffery <andrew@codeconstruct.com.au>