From 15b3cd8ef46ad1b100e0d3c7e38774f330726820 Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Tue, 4 Jun 2019 19:00:39 +0100 Subject: [PATCH] Revert "consolemap: Fix a memory leaking bug in drivers/tty/vt/consolemap.c" This reverts commit 84ecc2f6eb1cb12e6d44818f94fa49b50f06e6ac. con_insert_unipair() is working with a sparse 3-dimensional array: - p->uni_pgdir[] is the top layer - p1 points to a middle layer - p2 points to a bottom layer If it needs to allocate a new middle layer, and then fails to allocate a new bottom layer, it would previously free only p2, and now it frees both p1 and p2. But since the new middle layer was already registered in the top layer, it was not leaked. However, if it looks up an *existing* middle layer and then fails to allocate a bottom layer, it now frees both p1 and p2 but does *not* free any other bottom layers under p1. So it *introduces* a memory leak. The error path also cleared the wrong index in p->uni_pgdir[], introducing a use-after-free. Signed-off-by: Ben Hutchings Fixes: 84ecc2f6eb1c ("consolemap: Fix a memory leaking bug in drivers/tty/vt/consolemap.c") Signed-off-by: Greg Kroah-Hartman --- drivers/tty/vt/consolemap.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/drivers/tty/vt/consolemap.c b/drivers/tty/vt/consolemap.c index 79fcc96cc7c0..b28aa0d289f8 100644 --- a/drivers/tty/vt/consolemap.c +++ b/drivers/tty/vt/consolemap.c @@ -489,11 +489,7 @@ 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) { - kfree(p1); - p->uni_pgdir[n] = NULL; - return -ENOMEM; - } + if (!p2) return -ENOMEM; memset(p2, 0xff, 64*sizeof(u16)); /* No glyphs for the characters (yet) */ } -- 2.45.2