consolemap: Fix a memory leaking bug in drivers/tty/vt/consolemap.c

mainline inclusion
from mainline-5.3
commit 84ecc2f6
category: bugfix
bugzilla: 13690
CVE: CVE-2019-12379

-------------------------------------------------

In function con_insert_unipair(), when allocation for p2 and p1[n]
fails, ENOMEM is returned, but previously allocated p1 is not freed,
remains as leaking memory. Thus we should free p1 as well when this
allocation fails.
Signed-off-by: NGen Zhang <blackgod016574@gmail.com>
Reviewed-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Reviewed-by: NYue Haibing <yuehaibing@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

drivers/tty/vt/consolemap.c

@@ -489,7 +489,11 @@ con_insert_unipair(struct uni_pagedir *p, u_short unicode, u_short fontpos)
 	p2 = p1[n = (unicode >> 6) & 0x1f];
 	if (!p2) {
 		p2 = p1[n] = kmalloc_array(64, sizeof(u16), GFP_KERNEL);
-		if (!p2) return -ENOMEM;
+		if (!p2) {
+			kfree(p1);
+			p->uni_pgdir[n] = NULL;
+			return -ENOMEM;
+		}
 		memset(p2, 0xff, 64*sizeof(u16)); /* No glyphs for the characters (yet) */
 	}