From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f71.google.com (mail-oo1-f71.google.com [209.85.161.71]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 31EC73C1F for ; Mon, 31 Aug 2026 00:10:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.71 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788135023; cv=none; b=EwbYHS65//wWi0TjJScIe0+of3JjyEYPX1L0/8qiXw8SdkKGUXoBGbNuP5XBTaen1ivOhHN1PIXcf5G+qKjh/2/D2v660wm+laM9U8aKvGiIO/e02WjPhL4KtwY7ErF5LtofSBSbJeOZw4/V8GE4wV66oC7V2TqkXT9XR0Nfueg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788135023; c=relaxed/simple; bh=5kPYoH2H2zgChuEacH1BWXP1LfpDwSvK8bJDuSpqjwY=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To: Content-Type; b=T8m+ZE0Za+K6tCGtWsLyv2+GLRGIumeu4QeKJSNTpNwEHP7Y/KRLl6RGjgxhe+8T/idB+NRiNaC7buEUA2jj5mvJtVaRdjM9+z+eXDyKGr8hqBfV9M4GQzfhVKD5CBCnFZ6GTMNGDAXvrFm5Xs+4nXXu4dk2Gh5thfsLs2F0myo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.161.71 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-oo1-f71.google.com with SMTP id 006d021491bc7-6b12abf0e49so1432829eaf.0 for ; Sun, 30 Aug 2026 17:10:21 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1788135021; x=1788739821; h=content-type:to:from:subject:message-id:in-reply-to:date :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to:content-type; bh=SNpCZbxiRt+RAAxmUaTs+FBpK4/fvtQs6Gqoox7oH2o=; b=qNyT+mGABU2b7AYPIwPPh2A8dnbFGh5MOXoGobBEIM/0JOplnYTEecLhl+FmDDMY3h Mhqp4LAe4thMfwylGBy8/rapx8pJq+iULR/n4BlKN32H48RRpwNThxhGRuLZBcXQxY78 +IM2zIq+Dz77XxEDn3hRnXxXS9L5hEx1ov5tLQBvgHSZanJDGxh0F18+V0U2AkrWqHR3 6Y3j/OGgpSF5Z29lrGlbcEp6tq+ZhrkRGfSmW96sEeWvRsrG9qyOAttf243nCVT8I98d 0VozwpbLJwcCb5BocIGl7XQs9/bvEXDnLAxFQHbio9jl5FGjDf/uqJxxshe6RPZ6O4Z0 pfUQ== X-Gm-Message-State: AFuF++nK+5kvFepYnORkrNo9w93I1g3t4dHXuSBNjn6Ymh/Br1HS2x0l ZjzVN4Fz864v4lpt0z0WGTpRV/9FF9guBdeFEfVd8POzJJhSUN4RUS977oh4xBSCYfy5tRSd9nH 9WI5M0J42r3Q63/sifGSgpZ4GRpZ0agEw+rlmL5Qi21Nk/TMTsGSv2xJgdLY= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:f0c:b0:6b1:7798:a80e with SMTP id 006d021491bc7-6b36b51e32dmr168015eaf.6.1788135021065; Sun, 30 Aug 2026 17:10:21 -0700 (PDT) Date: Sun, 30 Aug 2026 17:10:21 -0700 In-Reply-To: <6a944641.4d659fcc.734b4.003c.GAE@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a94c66d.4d659fcc.734b4.003f.GAE@google.com> Subject: Forwarded: [PATCH] USB: serial: keyspan: fix use-after-free in keyspan_close From: syzbot To: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" For archival purposes, forwarding an incoming command email to linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com. *** Subject: [PATCH] USB: serial: keyspan: fix use-after-free in keyspan_close Author: kartikey406@gmail.com #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master keyspan_port_remove() frees the port's private data (p_priv) while keyspan_close() may still be running concurrently on another task, e.g. triggered by an explicit TIOCVHANGUP ioctl on an already-open tty racing with device disconnect. This results in keyspan_close() dereferencing freed memory. Fix this by adding a mutex to keyspan_serial_private that serializes keyspan_close() against keyspan_port_remove(): the latter clears the port's private data pointer under the lock before freeing it, and the former re-fetches and checks that pointer under the same lock before use. Reported-by: syzbot+5fabc1ae99ff40690d84@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=5fabc1ae99ff40690d84 Signed-off-by: Deepanshu Kartikey --- drivers/usb/serial/keyspan.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/drivers/usb/serial/keyspan.c b/drivers/usb/serial/keyspan.c index 4d3746c7a94e..623f15b51a6a 100644 --- a/drivers/usb/serial/keyspan.c +++ b/drivers/usb/serial/keyspan.c @@ -541,6 +541,7 @@ struct keyspan_serial_private { struct urb *glocont_urb; char *glocont_buf; char *ctrl_buf; /* for EP0 control message */ + struct mutex lock; /* protects p_priv vs port_remove races */ }; struct keyspan_port_private { @@ -1581,8 +1582,15 @@ static void keyspan_close(struct usb_serial_port *port) { int i; struct keyspan_port_private *p_priv; + struct keyspan_serial_private *s_priv = usb_get_serial_data(port->serial); + mutex_lock(&s_priv->lock); p_priv = usb_get_serial_port_data(port); + if (!p_priv) { + /* port_remove() already ran and freed this */ + mutex_unlock(&s_priv->lock); + return ; + } p_priv->rts_state = 0; p_priv->dtr_state = 0; @@ -1599,6 +1607,7 @@ static void keyspan_close(struct usb_serial_port *port) usb_kill_urb(p_priv->in_urbs[i]); usb_kill_urb(p_priv->out_urbs[i]); } + mutex_unlock(&s_priv->lock); } /* download the firmware to a pre-renumeration device */ @@ -2794,7 +2803,7 @@ static int keyspan_startup(struct usb_serial *serial) s_priv = kzalloc_obj(struct keyspan_serial_private); if (!s_priv) return -ENOMEM; - + mutex_init(&s_priv->lock); s_priv->instat_buf = kzalloc(INSTAT_BUFLEN, GFP_KERNEL); if (!s_priv->instat_buf) goto err_instat_buf; @@ -2971,10 +2980,14 @@ static int keyspan_port_probe(struct usb_serial_port *port) static void keyspan_port_remove(struct usb_serial_port *port) { + struct keyspan_serial_private *s_priv = usb_get_serial_data(port->serial); struct keyspan_port_private *p_priv; int i; + mutex_lock(&s_priv->lock); p_priv = usb_get_serial_port_data(port); + usb_set_serial_port_data(port, NULL); + mutex_unlock(&s_priv->lock); usb_kill_urb(p_priv->inack_urb); usb_kill_urb(p_priv->outcont_urb); -- 2.43.0