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 D58863822A3 for ; Fri, 4 Sep 2026 14:32:45 +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=1788532367; cv=none; b=feLEXA3xglc+JisZ4JRtecE6FGew4+8Q9g/apvDcmMrjinQ8TyrTsXRNblFAxhSeZqWC72EwOktwrXdDq+m8fwcqn/ZQm5rKPXsRnsniRGkRYuJmi4oe6XWz9pqLnb+Hboodk2vldRdOu1/wXBTnd8R99f4pg7fb+5HhBrlU1M0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788532367; c=relaxed/simple; bh=xaUBdRDO+uViIivb33QBwlkmEXsjunmO1YdW1dJtxu0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ibf9PSwInwFKCoKN/m3zP4zsFJMirVCkQHo4an70NhO6V6/kXt+PbFR5N/4pY1magp6DOgOrLf0xDHEUJMIMPOaQ0LuYusvqLfuXbHa14wyJZM8xWckQaZtYngIa4vNGN5rrFIt1StcY4rS9xxWvTbrIwi+HnXSuKY5S8I0ZryM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=fE1SxaH/; 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="fE1SxaH/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2A8621F00A3E; Fri, 4 Sep 2026 14:32:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788532365; bh=CEsd3On9vJB4nteA5ndtbsxPcnsFVjkeOuyJRy6JTxI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=fE1SxaH/JhLCj81lMEtNBoyVQWXQiVqGm5Y9+cqk7y2w12sFMsX8HH559eJ1d+fAY 96fkz/aRLPmbSP4j1Glt1QZQKhYiME4qNAyrE4wpsu3LsVXyQje9/h5HbcHbOfkW08 U4YAocpE53qrqLWjkqwcErvgWZMBcCjZxwhNwRqkvDJtvXs8Z2AarDOeiKvYulD/p/ te3bX0nvEWCArU8x8MRYTNHVu0DXEqKuBWYfVT8do6zF4e88VZMBeTTkyFlnS0kUdu YcdGI9vdl86lFde7pxKfpaJUJgIlCqIbtOwy9Q85qrHdjOntMZamBuRVZoG70Epr89 HgaSGJXFHm8oA== From: Sasha Levin To: stable@vger.kernel.org Cc: Neill Kapron , Xingyu Jin , Greg Kroah-Hartman , Sasha Levin Subject: [PATCH 6.12.y 2/2] usb: gadget: f_fs: Fix Use-After-Free in AIO error path Date: Fri, 4 Sep 2026 10:32:42 -0400 Message-ID: <20260904143242.806049-2-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260904143242.806049-1-sashal@kernel.org> References: <2026090332-backlight-leggings-4547@gregkh> <20260904143242.806049-1-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 c6eadd3433f27..8cfcddc4dc160 100644 --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -1267,8 +1267,10 @@ 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; } @@ -1316,9 +1318,11 @@ 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