Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:18 as permitted sender) client-ip=2620:137:e000::1:18;
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Takashi Iwai <tiwai@suse.de>
Subject: [PATCH 5.4 26/68] ALSA: wavefront: Proper check of get_user() error
Date:   Mon, 23 May 2022 19:04:53 +0200
Message-Id: <20220523165806.949229632@linuxfoundation.org>
In-Reply-To: <20220523165802.500642349@linuxfoundation.org>
References: <20220523165802.500642349@linuxfoundation.org>
User-Agent: quilt/0.66
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Takashi Iwai <tiwai@suse.de>

commit a34ae6c0660d3b96b0055f68ef74dc9478852245 upstream.

The antient ISA wavefront driver reads its sample patch data (uploaded
over an ioctl) via __get_user() with no good reason; likely just for
some performance optimizations in the past.  Let's change this to the
standard get_user() and the error check for handling the fault case
properly.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220510103626.16635-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 sound/isa/wavefront/wavefront_synth.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/sound/isa/wavefront/wavefront_synth.c
+++ b/sound/isa/wavefront/wavefront_synth.c
@@ -1088,7 +1088,8 @@ wavefront_send_sample (snd_wavefront_t *
 
 			if (dataptr < data_end) {
 		
-				__get_user (sample_short, dataptr);
+				if (get_user(sample_short, dataptr))
+					return -EFAULT;
 				dataptr += skip;
 		
 				if (data_is_unsigned) { /* GUS ? */