powerpc/powernv: Add a null pointer check to scom_debug_init_one()

JIRA: https://issues.redhat.com/browse/RHEL-37052
CVE: CVE-2023-52690

commit 9a260f2
Author: Kunwu Chan <chentao@kylinos.cn>
Date:   Fri Dec 8 16:59:37 2023 +0800

    powerpc/powernv: Add a null pointer check to scom_debug_init_one()

    kasprintf() returns a pointer to dynamically allocated memory
    which can be NULL upon failure.
    Add a null pointer check, and release 'ent' to avoid memory leaks.

    Fixes: bfd2f0d ("powerpc/powernv: Get rid of old scom_controller abstraction")
    Signed-off-by: Kunwu Chan <chentao@kylinos.cn>
    Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
    Link: https://msgid.link/20231208085937.107210-1-chentao@kylinos.cn

Signed-off-by: Mamatha Inamdar <minamdar@redhat.com>

Author: Mamatha Inamdar

arch/powerpc/platforms/powernv/opal-xscom.c

@@ -165,6 +165,11 @@ static int scom_debug_init_one(struct dentry *root, struct device_node *dn,
 	ent->chip = chip;
 	snprintf(ent->name, 16, "%08x", chip);
 	ent->path.data = (void *)kasprintf(GFP_KERNEL, "%pOF", dn);
+	if (!ent->path.data) {
+		kfree(ent);
+		return -ENOMEM;
+	}
+
 	ent->path.size = strlen((char *)ent->path.data);
 
 	dir = debugfs_create_dir(ent->name, root);