scsi: lpfc: Fix a possible null pointer dereference

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,
use scnprintf to notify the user and return len.

Fixes: 479b0917e447 ("scsi: lpfc: Create a sysfs entry called lpfc_xcvr_data for transceiver info")
Signed-off-by: Huai-Yuan Liu <qq810974084@gmail.com>
Link: https://lore.kernel.org/r/20240621082545.449170-1-qq810974084@gmail.com
Reviewed-by: Justin Tee <justin.tee@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/lpfc/lpfc_attr.c b/drivers/scsi/lpfc/lpfc_attr.c
index a46c73e8d7c409d9edaa9a82838244b9390b811f..0a9d6978cb0c3427e83367c5e4935566a6524718 100644 (file)
--- a/drivers/scsi/lpfc/lpfc_attr.c
+++ b/drivers/scsi/lpfc/lpfc_attr.c
@@ -1907,6 +1907,11 @@ 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,
+                               "SPF info NA: alloc failure\n");
+               return len;
+       }
 
        rc = lpfc_get_sfp_info_wait(phba, rdp_context);
        if (rc) {