linux-kernel - [PATCH 5.15 057/106] io_uring: fix races with file table unregister

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20220620124726.091379885@linuxfoundation.org>
Date:   Mon, 20 Jun 2022 14:51:16 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Pavel Begunkov <asml.silence@...il.com>,
        Sasha Levin <sashal@...nel.org>,
        van fantasy <g1042620637@...il.com>
Subject: [PATCH 5.15 057/106] io_uring: fix races with file table unregister

From: Pavel Begunkov <asml.silence@...il.com>

[ Upstream commit b0380bf6dad4601d92025841e2b7a135d566c6e3 ]

Fixed file table quiesce might unlock ->uring_lock, potentially letting
new requests to be submitted, don't allow those requests to use the
table as they will race with unregistration.

Reported-and-tested-by: van fantasy <g1042620637@...il.com>
Fixes: 05f3fb3c53975 ("io_uring: avoid ring quiesce for fixed file set unregister and update")
Signed-off-by: Pavel Begunkov <asml.silence@...il.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 fs/io_uring.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index b8e6398d9430..5f111a660fff 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -7933,11 +7933,19 @@ static void __io_sqe_files_unregister(struct io_ring_ctx *ctx)
 
 static int io_sqe_files_unregister(struct io_ring_ctx *ctx)
 {
+	unsigned nr = ctx->nr_user_files;
 	int ret;
 
 	if (!ctx->file_data)
 		return -ENXIO;
+
+	/*
+	 * Quiesce may unlock ->uring_lock, and while it's not held
+	 * prevent new requests using the table.
+	 */
+	ctx->nr_user_files = 0;
 	ret = io_rsrc_ref_quiesce(ctx->file_data, ctx);
+	ctx->nr_user_files = nr;
 	if (!ret)
 		__io_sqe_files_unregister(ctx);
 	return ret;
-- 
2.35.1