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From: Kees Cook <keescook@chromium.org>
To: Gen Zhang <blackgod016574@gmail.com>,
	Greg KH <gregkh@linuxfoundation.org>
Cc: jslaby@suse.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] consolemap: Fix a memory leaking bug in drivers/tty/vt/consolemap.c
Date: Thu, 23 May 2019 09:54:18 -0700	[thread overview]
Message-ID: <201905230952.B47ADA17A@keescook> (raw)
In-Reply-To: <20190523003452.GB14060@zhanggen-UX430UQ>

On Thu, May 23, 2019 at 08:34:52AM +0800, Gen Zhang wrote:
> 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@gmail.com>

As far as I can see this is correct, as it's just restoring the prior
state before the p1 allocation.

Reviewed-by: Kees Cook <keescook@chromium.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) */
>  	}
>  
> ---

-- 
Kees Cook

  reply	other threads:[~2019-05-23 16:54 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-21  9:29 [PATCH] consolemap: Fix a memory leaking bug in drivers/tty/vt/consolemap.c Gen Zhang
2019-05-21 20:44 ` Kees Cook
2019-05-22  1:50   ` Gen Zhang
2019-05-22 20:54     ` Kees Cook
2019-05-23  0:29       ` Gen Zhang
2019-05-23  0:34       ` [PATCH v2] " Gen Zhang
2019-05-23 16:54         ` Kees Cook [this message]
2019-05-24  2:14           ` Gen Zhang
2019-05-24  2:19           ` [PATCH v2] consolemap: Fix a memory leaking bug in con_insert_unipair() Gen Zhang
2019-05-24  8:02             ` Greg KH
2019-05-24  9:37           ` [PATCH v2] consolemap: Fix a memory leaking bug in drivers/tty/vt/consolemap.c Jon Hunter
2019-05-25  6:04             ` Kees Cook

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