From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f197.google.com (mail-pg1-f197.google.com [209.85.215.197]) (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 A74A7556FFA for ; Mon, 19 Oct 2026 13:57:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.197 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792418228; cv=none; b=g5TlLYy5C2Xcpl0NR/HPChSwUuovm+9oA4sNre79wKp3tMCIqci5FPJQ9GG6CuJsu9m9gjMPVApGnk9d4F27ERPLRGPAromj3FBYGUgrM0PlBWTQGv1O1Eij6HZAFONfM7uAy+7XEd51tkY/9nWEUlGry5X7UxHvYUdI+f53i5o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792418228; c=relaxed/simple; bh=94NKhQ0BK8ivfdo45xkT5X7BxKzocBpCjfSwp9vfESc=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=nG5/jpsWv0GcA1Oz4c4B83Vtz8qGmOMgXkDpiFkhu+ZqjiuNTdPs8X6c9wCJeRzc/XMGIq/wiOeCojg48ORPqaoXfbW9LN8c4WAbnfEctRjpMUT9Wnoj5uAH5FlwnaL5hqG17OIjtnwJqFtqRWKJSnx0IA2uB8KiPP2KixdsrcM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--sonalipradhan.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=RKogFDz4; arc=none smtp.client-ip=209.85.215.197 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--sonalipradhan.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="RKogFDz4" Received: by mail-pg1-f197.google.com with SMTP id 41be03b00d2f7-cc4ac5feaa4so1220350a12.1 for ; Mon, 19 Oct 2026 06:57:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1792418226; x=1793023026; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:mime-version:date:from :to:cc:subject:date:message-id:reply-to:content-type; bh=YIFf3SdOPdRgXsOGaFFzUQihN4zspixzOF8xtHPh48c=; b=RKogFDz4bhfktU8zwKFbXlABqyRUo7Hd4Lbav27SA/XmjlXU2rISbFFJBpXwmoSbGZ GXqI1VE17yEfbbcHRH+q+qJLKS9rGyv+AhqSodh6zf1TdJIs0IaQxmcCYBSzykBxDy5m 9/708k5z9RQXvmftdekzXfIWPagR7zXKqbe7nAoWZTl8nEjUGbI9AzILVUL5vGHi0s8o LD1QUavnZAIrZfTlSJynkn5NUeplArLjju6KEJ4v5K/HCsuYyEAbDcMUL19EcFi1HxVn 3KfKGk6IyBKcLSEOyzpeTLeDY0vUOX1Vjyx65rynKfEcxAKigLo4B7MO2vanDi8sfaa/ voxA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1792418226; x=1793023026; h=content-type:cc:to:from:subject:message-id:mime-version:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=YIFf3SdOPdRgXsOGaFFzUQihN4zspixzOF8xtHPh48c=; b=AyFVz2iAurmIW+boVbMkjArDiZ8UgopfapUiKYhFzlhsOwVI4dRuLeZVlQuWvrFYUu Y0a/dsa9hOAtbv0am5+bmWOKKvQlk5GBHSYB5EaOwdW+Hzvm1aPaLxS7NNQ3rQl+Q0A0 FOmp/CQsF446PFuNFjAY+qAJKVAoNIQmEba3nXgdzfwQQCFd3u4v0SOfctvmzGlRGrZx PYvkVMGi5AAvrEvZO6Xm9OPxrIAPsA1u+bafWYJXe2VaJtBxUbhlbGbSOtbcVm7FPG+y EgQwZ6KnnvVpiDvoxR0EMsbjNmkNKyl9v6cLcXoZ2715Nuspf9p4WEgyoEjvP8pdV8qy O1Hw== X-Forwarded-Encrypted: i=1; AKwUvBzwbdbltjXo9QWYe/WsV5C51iQd5uIKSAG1bDVaEBcnOUGLrGKMmNQR5xUbxnKgRMROdUVWRMMRWZNVG5I=@vger.kernel.org X-Gm-Message-State: AFq9FYL6Jqjm9C/xyKZlkJTTaNtBbOTvCXh/yTnq3a0OKVc8eOiLMgMn coionv4fJX+hHTMRIhfo38fJqlxTq6DuJKaooRrM/dd0miIoGxKzFvi87/L/J+Fk6XQ7+ue0Aao haady84Ti96t2tpkeNBUBw024ycnhXakF4Q== X-Received: from pgac23.prod.google.com ([2002:a05:6a02:2957:b0:cc7:9d5b:c2ac]) (user=sonalipradhan job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a21:730c:b0:3e1:b678:3d7b with SMTP id adf61e73a8af0-3e225f91672mr6316738637.19.1792418225152; Mon, 19 Oct 2026 06:57:05 -0700 (PDT) Date: Mon, 19 Oct 2026 13:57:01 +0000 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.56.0.176.g3575e65682-goog Message-ID: <20261019135701.2767078-1-sonalipradhan@google.com> Subject: [PATCH RESEND] usb: gadget: f_midi: fix UAF race during IN request handling From: Sonali Pradhan To: Greg Kroah-Hartman , Neill Kapron Cc: Takashi Iwai , Christophe JAILLET , Fan Wu , Victor Krawiec , Felipe Balbi , "Felipe F. Tonello" , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Sonali Pradhan Content-Type: text/plain; charset="UTF-8" f_midi_disable() frees pre-allocated IN requests from in_req_fifo without holding midi->transmit_lock. Concurrent f_midi_transmit() or f_midi_complete() calls can then access these request buffers after they are freed, leading to a use-after-free. Fix this by acquiring midi->transmit_lock in f_midi_disable() while releasing IN requests, and checking ep->enabled under midi->transmit_lock in f_midi_transmit() and f_midi_complete() before modifying requests. Fixes: e1e3d7ec5da3 ("usb: gadget: f_midi: pre-allocate IN requests") Cc: stable@vger.kernel.org Signed-off-by: Sonali Pradhan --- Resending and rebasing on latest linux-next as I haven't received feedback on my initial submission: https://lore.kernel.org/all/20260819102709.212646-1-sonalipradhan@google.com/ drivers/usb/gadget/function/f_midi.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c index 63fb6ee70a3d..c26d04eb9209 100644 --- a/drivers/usb/gadget/function/f_midi.c +++ b/drivers/usb/gadget/function/f_midi.c @@ -280,9 +280,18 @@ f_midi_complete(struct usb_ep *ep, struct usb_request *req) /* We received stuff. req is queued again, below */ f_midi_handle_out_data(ep, req); } else if (ep == midi->in_ep) { + unsigned long flags; + /* Our transmit completed. See if there's more to go. * f_midi_transmit eats req, don't queue it again. */ + spin_lock_irqsave(&midi->transmit_lock, flags); + if (!ep->enabled) { + spin_unlock_irqrestore(&midi->transmit_lock, flags); + return; + } req->length = 0; + spin_unlock_irqrestore(&midi->transmit_lock, flags); + queue_work(system_highpri_wq, &midi->work); return; } @@ -420,6 +429,7 @@ static void f_midi_disable(struct usb_function *f) struct f_midi *midi = func_to_midi(f); struct usb_composite_dev *cdev = f->config->cdev; struct usb_request *req = NULL; + unsigned long flags; DBG(cdev, "disable\n"); @@ -431,8 +441,10 @@ static void f_midi_disable(struct usb_function *f) usb_ep_disable(midi->out_ep); /* release IN requests */ + spin_lock_irqsave(&midi->transmit_lock, flags); while (kfifo_get(&midi->in_req_fifo, &req)) free_ep_req(midi->in_ep, req); + spin_unlock_irqrestore(&midi->transmit_lock, flags); f_midi_drop_out_substreams(midi); } @@ -678,10 +690,11 @@ static void f_midi_transmit(struct f_midi *midi) unsigned long flags; /* We only care about USB requests if IN endpoint is enabled */ - if (!ep || !ep->enabled) - goto drop_out; - spin_lock_irqsave(&midi->transmit_lock, flags); + if (!ep || !ep->enabled) { + spin_unlock_irqrestore(&midi->transmit_lock, flags); + goto drop_out; + } do { ret = f_midi_do_transmit(midi, ep); -- 2.56.0.176.g3575e65682-goog