From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E3DCD4A2A75 for ; Fri, 4 Sep 2026 15:53:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788537224; cv=none; b=WPmleKpVBoak5iYzbiQROojPCQvFQFFXtQNxHzDOk/Sr9fCA6NaknsMXut/9bvDZah4aaHEQ3UIIaHaipGnLu4TkCU8xCzSAFep7kwZDJcaS6PnC/OblIUYJE9vju9/xV7xZBqF63iQbDMF35I2F82EXjxUBZw4Qzp04fSu6N58= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788537224; c=relaxed/simple; bh=xLKp4Wdh8kmBY+q4hDd3N9IejIIHC9Eu+M57ezHvBQo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=fxZL9KxoewptJRgYCONd9I9ieBCBBJZiPVBLDo8UEECoDGf3gpBQr5daSlIVdSw00LpxSBVaeGwQm1wKgtsfQ4cymKxLW7gi3exFR3vXlNZ7hjvG/NtknY2ZzdNnZcqFWCw/YtUf+HBZ1AeULNh49pHRQOV7YIdO49u8xETmq40= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=R9oS3Cgr; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="R9oS3Cgr" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C3AC41F00ACA; Fri, 4 Sep 2026 15:53:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788537222; bh=IyknKemI1Af/VSFwaEoIbQSUtCu7vvFSYWo6zi69R2k=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=R9oS3CgrzTvotlWxLGahQgBy6sLLJ0RVLb4qzqxGira/Dgk3thU0WbeQKdmJPZql3 kkmXuOKKxR8ASzxoBfw1IUISSsIUYAX/i0LsVSXtZchkOlLNaX320AsPE5zFwrqm28 yP2pJNI3jzoq2mNkAJOYnYDvQ9MD2LyBA/AWmIY6ocdniau4gG8OJZd15gPAWL8Bd5 XHBaQXJAdGrXTvzgVSe+WaqZEeAuNOlEQjg7y17GtGRoiBffwTS7gHgi0K5iG72R5f /huc8AfYVV0pKJeA6AMU4TsHKI577CwJ9jl/bDmX4QJ97thQAhj+hlrFIwbSlYsAZW eZ/l9+XWxxNgg== From: Sasha Levin To: stable@vger.kernel.org Cc: Neill Kapron , Xingyu Jin , Greg Kroah-Hartman , Sasha Levin Subject: [PATCH 5.15.y 6/6] usb: gadget: f_fs: Fix Use-After-Free in AIO error path Date: Fri, 4 Sep 2026 11:53:36 -0400 Message-ID: <20260904155336.1042108-6-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260904155336.1042108-1-sashal@kernel.org> References: <2026090333-willfully-art-ea0b@gregkh> <20260904155336.1042108-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Neill Kapron [ Upstream commit e78dcb1f7ec271449c54984dc90c62a5ba272de7 ] In ffs_epfile_write_iter() and ffs_epfile_read_iter(), when ffs_epfile_io() fails with an error other than -EIOCBQUEUED, the io_data structure (`p`) is freed. However, for AIO operations, the kiocb cancel function was already armed and kiocb->private was set to `p`. If a concurrent cancel operation (such as sys_io_cancel()) executes after ffs_epfile_io() fails but before the function frees `p`, a Use-After-Free can occur when the cancellation handler accesses the freed pointer. To securely fix this race condition, we must properly un-arm the cancellation. Invoking `kiocb->ki_complete()` does exactly this by acquiring `ctx->ctx_lock` and safely removing the kiocb from the active sequence. In doing so, it ensures that a parallel io_cancel can no longer discover the kiocb, effectively closing the race window. We then return -EIOCBQUEUED to notify the VFS layer that the kiocb has been consumed and it should avoid attempting to complete the request again or triggering subsequent completion handlers. Fixes: de2080d41b5d ("gadget/function/f_fs.c: close leaks") Cc: stable@vger.kernel.org Reported-by: Xingyu Jin Assisted-by: Antigravity:gemini-3.1-pro Signed-off-by: Neill Kapron Link: https://patch.msgid.link/20260724235100.106011-1-nkapron@google.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/usb/gadget/function/f_fs.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c index 7edfa788e6836..cc728a830197d 100644 --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -1238,8 +1238,10 @@ static ssize_t ffs_epfile_write_iter(struct kiocb *kiocb, struct iov_iter *from) if (res == -EIOCBQUEUED) return res; if (p->aio) { + kiocb->ki_complete(kiocb, res); mmdrop(p->mm); kfree(p); + return -EIOCBQUEUED; } else { *from = p->data; } @@ -1289,9 +1291,11 @@ static ssize_t ffs_epfile_read_iter(struct kiocb *kiocb, struct iov_iter *to) return res; if (p->aio) { + kiocb->ki_complete(kiocb, res); mmdrop(p->mm); kfree(p->to_free); kfree(p); + return -EIOCBQUEUED; } else { *to = p->data; } -- 2.53.0