From nobody Mon Sep 28 17:48:33 2026 Received: from mail-pj1-f72.google.com (mail-pj1-f72.google.com [209.85.216.72]) (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 EDC852DECC2 for ; Wed, 19 Aug 2026 10:27:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.72 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787135235; cv=none; b=PPHnjbaSCTtFKiRWxrnNpbHlsjjOxzlu2Zaw6WHOM6/vlNMi1D9nNZy9mNmiTftGXXoJPtofE6Fm/aKVG3kVp0lgQUF3U/bdZriwqQ4yPcGAef+B7u7puwC96FL3NJvwzO8EY/6mdej9yyLGCL+ZUBTh3IRURnM/dTuYaa63j5Q= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787135235; c=relaxed/simple; bh=Mk813TFCqqlmMVYF58q8Ra7/eYmWpuXZ8bzgguh1pHY=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=GZjXVYwO2gR82WFaHf7jYRz3vM1TK7oYepGcnObreG4aLjeaLf3lEa/eyvJPrww/mp9B779marfLD9qSTC50vtcQmMYrVb6DbEpXPmhpEY01B5MCaJ8+wPB1E9GhtXrNFCX09ng0yGgZL4Z3xBgq1dgmQhG+mTiC22CbOgda9aE= 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=YEyBm0eq; arc=none smtp.client-ip=209.85.216.72 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="YEyBm0eq" Received: by mail-pj1-f72.google.com with SMTP id 98e67ed59e1d1-38e11baa66eso1357940a91.2 for ; Wed, 19 Aug 2026 03:27:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1787135233; x=1787740033; 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=RsoC28vCQHKdnNG2zgOJgL5SSi8lYenXYvOZo5k+sWA=; b=YEyBm0eqeq0ujLc/q9HnmeHFTX/4B8yTcMeEsh9oppaWse8XTsjmqnrnkE10TtR8uZ exLpXZ7SbyVC0bNcdlE/lqhGE9PBSrNSxFlns//uh4x+I2CRW39YEaaUdF7JihSbVA/Y LMejCJYkoABo+W3V49BwlnylTZlnh6fwVT07lUMwSa2u9dMGYFbrT+mrE3l8t1pkenwq yC/48zdn+jN0K9hgzZXf+KYjVfzEG44E3t/ihKS2gkRNlty0cXN4vgvbeLmZ6Esb9hTj vIpmXRbdDk2gXl/Ly8R2qHHL8eA7CmcQ/KPjCTYHuIgAzZuWexG4qTr6Wp/ZBM4jW4/T 0ULA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1787135233; x=1787740033; 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=RsoC28vCQHKdnNG2zgOJgL5SSi8lYenXYvOZo5k+sWA=; b=p8031uF/OWJ63jUcgeHI2Mva2M2TaQwYJMMQKl2A+tvgCLMPtbWgSpcGFHkPQvCxrG dR0O6bg7vMQuMN0hG44ij4a98gR1+1kykZyup5gJs+DytFMO+tAy6G9oKAIHMtIcbC5C nQQdJbmUirtxbJfHd2E3ET6nHsvPuLmSHEkaDpTBAnDmei0Q8F9rz9E1XRjLgdp33yjE r2bbyjEUiC4466rj3Xbm5pMG/f4HOFlIL2pPw9SaULse/xOpW+p10umNgJ/3KUZ0cFVN jTaVi6Z67rGjGEX9JhMLxuOyBbl59bwpniSRw/tFxji9b4oWZiE3YvRiUuZ6I62b219q NfeA== X-Forwarded-Encrypted: i=1; AHgh+RoytoRfnnN4WM9vlKPwmi9gz7Uotx0rB4UnbqD1lgORBfpG3zyUnlnYH/S/vtKGwFnNyLA9VozvFmDnGAQ=@vger.kernel.org X-Gm-Message-State: AOJu0Yyp+B+s+YmNCpcjBCs23B7ujIGZQwH9Oz0I9fyCQrNUTpnXZxE5 BvhIz4AliX7yrlVt+j9eDmaDDTA2xX3nQsWWQ0aKVI3Hvf/0AtDVkvfjziEBMAv/4xS1gxFsEHN 5rieOoDlqTV6EbGGKpFJk+44Xi1TwT2S3cg== X-Received: from pgla22.prod.google.com ([2002:a63:b56:0:b0:c99:5634:7551]) (user=sonalipradhan job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a20:3ca1:b0:3c3:66c5:68d6 with SMTP id adf61e73a8af0-3cd00f77410mr6894163637.9.1787135233076; Wed, 19 Aug 2026 03:27:13 -0700 (PDT) Date: Wed, 19 Aug 2026 10:27:09 +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 2.55.0.737.g08866a6d13-goog Message-ID: <20260819102709.212646-1-sonalipradhan@google.com> Subject: [PATCH] usb: gadget: f_midi: fix UAF race during IN request handling From: Sonali Pradhan To: Greg Kroah-Hartman Cc: Kees Cook , Victor Krawiec , Fan Wu , Christophe JAILLET , "Felipe F. Tonello" , Felipe Balbi , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Sonali Pradhan Content-Transfer-Encoding: quoted-printable 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 --- drivers/usb/gadget/function/f_midi.c | 22 +++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-) diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/func= tion/f_midi.c index fba8cf787d6c..ee64147b12f1 100644 --- a/drivers/usb/gadget/function/f_midi.c +++ b/drivers/usb/gadget/function/f_midi.c @@ -280,9 +280,20 @@ 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 =3D=3D 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 =3D 0; + spin_unlock_irqrestore(&midi->transmit_lock, flags); + queue_work(system_highpri_wq, &midi->work); return; } @@ -420,6 +431,7 @@ static void f_midi_disable(struct usb_function *f) struct f_midi *midi =3D func_to_midi(f); struct usb_composite_dev *cdev =3D f->config->cdev; struct usb_request *req =3D NULL; + unsigned long flags; =20 DBG(cdev, "disable\n"); =20 @@ -431,8 +437,10 @@ static void f_midi_disable(struct usb_function *f) usb_ep_disable(midi->out_ep); =20 /* 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); =20 f_midi_drop_out_substreams(midi); } @@ -678,10 +686,11 @@ static void f_midi_transmit(struct f_midi *midi) unsigned long flags; =20 /* 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; + } =20 do { ret =3D f_midi_do_transmit(midi, ep); --