lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite for Android: free password hash cracker in your pocket
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20190904175306.656801287@linuxfoundation.org>
Date:   Wed,  4 Sep 2019 19:53:42 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Takashi Iwai <tiwai@...e.de>
Subject: [PATCH 4.19 40/93] ALSA: usb-audio: Check mixer unit bitmap yet more strictly

From: Takashi Iwai <tiwai@...e.de>

commit f9f0e9ed350e15d51ad07364b4cf910de50c472a upstream.

The bmControls (for UAC1) or bmMixerControls (for UAC2/3) bitmap has a
variable size depending on both input and output pins.  Its size is to
fit with input * output bits.  The problem is that the input size
can't be determined simply from the unit descriptor itself but it
needs to parse the whole connected sources.  Although the
uac_mixer_unit_get_channels() tries to check some possible overflow of
this bitmap, it's incomplete due to the lack of the  evaluation of
input pins.

For covering possible overflows, this patch adds the bitmap overflow
check in the loop of input pins in parse_audio_mixer_unit().

Fixes: 0bfe5e434e66 ("ALSA: usb-audio: Check mixer unit descriptors more strictly")
Cc: <stable@...r.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@...e.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 sound/usb/mixer.c |   36 ++++++++++++++++++++++++++++--------
 1 file changed, 28 insertions(+), 8 deletions(-)

--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -754,7 +754,6 @@ static int uac_mixer_unit_get_channels(s
 				       struct uac_mixer_unit_descriptor *desc)
 {
 	int mu_channels;
-	void *c;
 
 	if (desc->bLength < sizeof(*desc))
 		return -EINVAL;
@@ -777,13 +776,6 @@ static int uac_mixer_unit_get_channels(s
 		break;
 	}
 
-	if (!mu_channels)
-		return 0;
-
-	c = uac_mixer_unit_bmControls(desc, state->mixer->protocol);
-	if (c - (void *)desc + (mu_channels - 1) / 8 >= desc->bLength)
-		return 0; /* no bmControls -> skip */
-
 	return mu_channels;
 }
 
@@ -2028,6 +2020,31 @@ static int parse_audio_feature_unit(stru
  * Mixer Unit
  */
 
+/* check whether the given in/out overflows bmMixerControls matrix */
+static bool mixer_bitmap_overflow(struct uac_mixer_unit_descriptor *desc,
+				  int protocol, int num_ins, int num_outs)
+{
+	u8 *hdr = (u8 *)desc;
+	u8 *c = uac_mixer_unit_bmControls(desc, protocol);
+	size_t rest; /* remaining bytes after bmMixerControls */
+
+	switch (protocol) {
+	case UAC_VERSION_1:
+	default:
+		rest = 1; /* iMixer */
+		break;
+	case UAC_VERSION_2:
+		rest = 2; /* bmControls + iMixer */
+		break;
+	case UAC_VERSION_3:
+		rest = 6; /* bmControls + wMixerDescrStr */
+		break;
+	}
+
+	/* overflow? */
+	return c + (num_ins * num_outs + 7) / 8 + rest > hdr + hdr[0];
+}
+
 /*
  * build a mixer unit control
  *
@@ -2156,6 +2173,9 @@ static int parse_audio_mixer_unit(struct
 		if (err < 0)
 			return err;
 		num_ins += iterm.channels;
+		if (mixer_bitmap_overflow(desc, state->mixer->protocol,
+					  num_ins, num_outs))
+			break;
 		for (; ich < num_ins; ich++) {
 			int och, ich_has_controls = 0;
 


Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ