[PATCH] scsi: lpfc: Fix a possible null pointer dereference

[PATCH] scsi: lpfc: Fix a possible null pointer dereference

[Huai-Yuan Liu]

In function lpfc_xcvr_data_show, the memory allocation with kmalloc might
fail, thereby making rdp_context a null pointer. In the following context 
and functions that use this pointer, there are dereferencing operations,
leading to null pointer dereference.

To fix this issue, a null pointer check should be added. If it is null, 
write error message and jump to 'out_free_rdp'.

Fixes: 479b0917e447 ("scsi: lpfc: Create a sysfs entry called lpfc_xcvr_data for transceiver info")
Signed-off-by: Huai-Yuan Liu <qq810974084@gmail.com>
---
 drivers/scsi/lpfc/lpfc_attr.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/scsi/lpfc/lpfc_attr.c b/drivers/scsi/lpfc/lpfc_attr.c
index b1c9107d3408..b11e5114b7f2 100644
--- a/drivers/scsi/lpfc/lpfc_attr.c
+++ b/drivers/scsi/lpfc/lpfc_attr.c
@@ -1904,6 +1904,11 @@ lpfc_xcvr_data_show(struct device *dev, struct device_attribute *attr,
 
 	/* Get transceiver information */
 	rdp_context = kmalloc(sizeof(*rdp_context), GFP_KERNEL);
+	if (!rdp_context) {
+		len = scnprintf(buf, PAGE_SIZE - len,
+				"ERROR: Not enough memory\n");
+		goto out_free_rdp;
+	}
 
 	rc = lpfc_get_sfp_info_wait(phba, rdp_context);
 	if (rc) {
-- 
2.34.1

Re: [PATCH] scsi: lpfc: Fix a possible null pointer dereference

[刘怀远]

Hi,

I'm a newbie in the Linux community. Due to my oversight, the patch I
submitted has an extra blank line, causing two consecutive emails to
lack a subject. However, these emails are identical in content to the
one with a subject. Please review the email with a subject. Apologies
for any confusion caused.

Thanks,
Liu.

Re: [PATCH] scsi: lpfc: Fix a possible null pointer dereference

[Bart Van Assche]

On 4/2/24 6:40 PM, Huai-Yuan Liu wrote:
> In function lpfc_xcvr_data_show, the memory allocation with kmalloc might
> fail, thereby making rdp_context a null pointer. In the following context
> and functions that use this pointer, there are dereferencing operations,
> leading to null pointer dereference.
> 
> To fix this issue, a null pointer check should be added. If it is null,
> write error message and jump to 'out_free_rdp'.
> 
> Fixes: 479b0917e447 ("scsi: lpfc: Create a sysfs entry called lpfc_xcvr_data for transceiver info")
> Signed-off-by: Huai-Yuan Liu <qq810974084@gmail.com>
> ---
>   drivers/scsi/lpfc/lpfc_attr.c | 5 +++++
>   1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/scsi/lpfc/lpfc_attr.c b/drivers/scsi/lpfc/lpfc_attr.c
> index b1c9107d3408..b11e5114b7f2 100644
> --- a/drivers/scsi/lpfc/lpfc_attr.c
> +++ b/drivers/scsi/lpfc/lpfc_attr.c
> @@ -1904,6 +1904,11 @@ lpfc_xcvr_data_show(struct device *dev, struct device_attribute *attr,
>   
>   	/* Get transceiver information */
>   	rdp_context = kmalloc(sizeof(*rdp_context), GFP_KERNEL);
> +	if (!rdp_context) {
> +		len = scnprintf(buf, PAGE_SIZE - len,
> +				"ERROR: Not enough memory\n");
> +		goto out_free_rdp;
> +	}
>   

Has this patch been verified with checkpatch? Checkpatch should have
reported the following for the above patch:

   Possible unnecessary 'out of memory' message

Thanks,

Bart.

Re: [PATCH] scsi: lpfc: Fix a possible null pointer dereference

[刘怀远]

Hi.

The patch passed the checkpatch validation without reporting the
related information. I have sent the patch V2 email, thank you for
your suggestions.

Thanks,

Liu.