From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793213039; b=nGr+9Qj8TTF9HQtQbuFmSQATCYRAn8uNc0kcHyp0IdKQve4WkUbDuVJMsQF9Rf0UkM5k 1qF4VK4DD9/bSemf5XEGwKnnBQ4SJZZj2ep0B9vSZGwukTR3MX52ug1JHBLk7USR/cUqF UX8GPPsRMlXwfkfTo9yKezy6GyTIE6Qc/nK2gMlq6Sr5R5qTm2BYBFawnlSOTnsNvXLCD Rzjf5d823C3KowmPfCo6dCXNNRaJ/fwSqOoYv6u+KoRw24UEAopmlK7H7IgFnIWghYIDo d17ORGpEpy+UdhE6wu9iYDBuw9gImkrB0uVZyMLwxB+iDtDb0XeayCAm8TnkaL/1CWQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793213039; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=55QYiGyKQkp9MCblnVXuh7GKcxzk3fSt0cVafDZACvQ=; b=ZP22I/xfRdUebFPKGch3L/6V0l6XfFjqD5HHJuq7nIiN5JEJlrcYrjGPqoErY/XaVO/t JECovTRFNunLEyZ8XRa378hFYw6+XfSfP714zH9unNNzS2MbmlO9b0hRS8mLNd3mKAsGM Wzx5CfUYckHqxioYF64RZWLsH4KM4eS5e1KK11hQcNYCyLoFSe8RpB27t1s25W57AKeuQ B1BMLl7qpg1WFzKx7cBerQLEk9+j97sqntFgkx3dXMVQKrHgUC244Ehccus2qjlRaV0S0 +TY+WOzg4I/A8YgfC1UPU3+qls2NP4jS1pk67SJv7Rg5UyoCm1ggquQUyYwk983K8bw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b="039VS/Or"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DBF47606A31E; Wed, 28 Oct 2026 18:43:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=039VS/Or Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0DFBD1F01825; Wed, 28 Oct 2026 18:43:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793213038; bh=55QYiGyKQkp9MCblnVXuh7GKcxzk3fSt0cVafDZACvQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=039VS/OrjBuBHekwKoIlNKcq9l+rOyHGzIDBqvymv2E9ZNMeP1gj4zk3UdSX3ACKh i1dFlHhwMlVT/G7ty9iLByeDNEnhdHIs5BLnySTLC0paL5GJIrQPciUgRrqIELZWqc pxOtMKrBv44c0WVxGcO4ArjPkWRCnPeHZGRj2UuY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Gabriel Prostitis , Sasha Levin Subject: [PATCH 6.1 0365/1887] USB: gadget: ffs: fix mm lifetime handling Date: Wed, 28 Oct 2026 17:41:01 +0100 Message-ID: <20261028170507.539853704@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028170459.200466217@linuxfoundation.org> References: <20261028170459.200466217@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Gabriel Prostitis [ Upstream commit 5eb5c72c72fef76cb765ef1669b62b6a3ba1bfc8 ] io_data stores a pointer to the submitting task's mm_struct, but does not currently hold a reference to it while async requests are pending. This can result in a use-after-free if the task exits before completion handling finishes. Take a reference with mmgrab() when queuing the read request and release it with mmdrop() on request completion. Reported-by: Gabriel Prostitis Signed-off-by: Gabriel Prostitis Link: https://patch.msgid.link/20260601-mm-uaf-fix-v2-1-3c942a707bce@gmail.com Signed-off-by: Greg Kroah-Hartman Stable-dep-of: e78dcb1f7ec2 ("usb: gadget: f_fs: Fix Use-After-Free in AIO error path") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/function/f_fs.c | 27 ++++++++++++++++++++------- 1 file changed, 20 insertions(+), 7 deletions(-) --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -842,9 +842,15 @@ static void ffs_user_copy_worker(struct unsigned long flags; if (io_data->read && ret > 0) { - kthread_use_mm(io_data->mm); - ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data); - kthread_unuse_mm(io_data->mm); + if (mmget_not_zero(io_data->mm)) { + kthread_use_mm(io_data->mm); + ret = ffs_copy_to_iter(io_data->buf, ret, &io_data->data); + kthread_unuse_mm(io_data->mm); + mmput(io_data->mm); + } else { + ret = -EFAULT; + } + mmdrop(io_data->mm); } io_data->kiocb->ki_complete(io_data->kiocb, ret); @@ -1229,16 +1235,20 @@ static ssize_t ffs_epfile_write_iter(str kiocb->private = p; - if (p->aio) + if (p->aio) { + mmgrab(p->mm); kiocb_set_cancel_fn(kiocb, ffs_aio_cancel); + } res = ffs_epfile_io(kiocb->ki_filp, p); if (res == -EIOCBQUEUED) return res; - if (p->aio) + if (p->aio) { + mmdrop(p->mm); kfree(p); - else + } else { *from = p->data; + } return res; } @@ -1275,14 +1285,17 @@ static ssize_t ffs_epfile_read_iter(stru kiocb->private = p; - if (p->aio) + if (p->aio) { + mmgrab(p->mm); kiocb_set_cancel_fn(kiocb, ffs_aio_cancel); + } res = ffs_epfile_io(kiocb->ki_filp, p); if (res == -EIOCBQUEUED) return res; if (p->aio) { + mmdrop(p->mm); kfree(p->to_free); kfree(p); } else {