linux-kernel - [PATCH v2] consolemap: Fix a memory leaking bug in con_insert

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Date:   Fri, 24 May 2019 10:19:32 +0800
From:   Gen Zhang <blackgod016574@...il.com>
To:     jslaby@...e.com
Cc:     keescook@...omium.org, khorenko@...tuozzo.com,
        linux-kernel@...r.kernel.org
Subject: [PATCH v2] consolemap: Fix a memory leaking bug in
 con_insert_unipair()

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: Gen Zhang <blackgod016574@...il.com>
Reviewed-by: Kees Cook <keescook@...omium.org>
---
diff --git a/drivers/tty/vt/consolemap.c b/drivers/tty/vt/consolemap.c
index b28aa0d..79fcc96 100644
--- a/drivers/tty/vt/consolemap.c
+++ b/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) */
 	}
 
---