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 2C78551E42B for ; Fri, 4 Sep 2026 18:35:17 +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=1788546924; cv=none; b=nyjDlFhK6CC1xHCQjGQnc5J5wNhlvmsdPa8xy6Q6bypvTYsN+kSHEduyGylwqZC27nlpqqh7ePzg89PPV9AYxbQyUFUJLYGTK0ZBEDDkrQeM/nOa/1edDY0DVLVT1OFoXxaAXOAYeTzBaeS3IzmrxQI3x/RF7uBHxQnM9MSTNSk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788546924; c=relaxed/simple; bh=WYgXGktuRjobafyL5MvKI84Atzaq256crnQ2j/Abijs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=OFUW6SZjmPI0j+reaJRVC5YUuz3evRFvDU2amf/8bOWRigZJSw8WwkpAAZWIRhYZzFf5cxVUjbza7D+VDrn2nqNMqgeIM2Pm2dVG836PC9PTiQKzVfl2xZFxH+3k6dzX+krFG0aiOh8g+w/nHTShqE1fk+ZtEmEJY1LM1C5+1L8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=YIdNLMpV; 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="YIdNLMpV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 267A11F00ADB; Fri, 4 Sep 2026 18:35:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788546913; bh=+BC0BYeObthNICC7r6fNuVsswfI/HMrA8OfRYovXsJA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=YIdNLMpVNtsJIq5q8X4MiQuP7p/MeZe0pkCKkih9WrkYmRyao4z6yteD7umRfNPug UXvqBriKABqGhe02woaqloTyvJOf6txkQopWm7GBSiDrlmboXxDnk42iBt0OYgsAfA p8CzNu6t2sSZJMN2Oj3etReBVdcsXxoVmIEg5e7QM46K6yntq6sNWCIY2ET5Za7Re0 BskXCiAizJCHPBeT4ut3v06ODYzDfQ5n/U1Ot6vFaujo3kjQ4eYKqZRYfw6mHofHca eMKKLFMp1poEMT4YCH1Q6gKxjYrT6I8UK2azcSi/Ajp1POh+ftoycp/3Quu9fZVnh8 2JyW3DRn+OngQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Neill Kapron , Xingyu Jin , Greg Kroah-Hartman , Sasha Levin Subject: [PATCH 5.10.y 4/4] usb: gadget: f_fs: Fix Use-After-Free in AIO error path Date: Fri, 4 Sep 2026 14:35:09 -0400 Message-ID: <20260904183509.1323404-4-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260904183509.1323404-1-sashal@kernel.org> References: <2026090334-tiring-good-fffe@gregkh> <20260904183509.1323404-1-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 19d7b0cec0b03..3d4b8d9b355ac 100644 --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -1225,8 +1225,10 @@ 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; } @@ -1276,9 +1278,11 @@ 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