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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: "Björn Töpel" <bjorn.topel@intel.com>,
	"Jonathan Lemon" <jonathan.lemon@gmail.com>,
	"Daniel Borkmann" <daniel@iogearbox.net>,
	"Sasha Levin" <sashal@kernel.org>,
	netdev@vger.kernel.org, bpf@vger.kernel.org
Subject: [PATCH AUTOSEL 4.19 530/671] xsk: avoid store-tearing when assigning umem
Date: Thu, 16 Jan 2020 12:02:48 -0500
Message-ID: <20200116170509.12787-267-sashal@kernel.org> (raw)
In-Reply-To: <20200116170509.12787-1-sashal@kernel.org>

From: Björn Töpel <bjorn.topel@intel.com>

[ Upstream commit 9764f4b301c3e7eb3b75eec85b73cad449cdbb0d ]

The umem member of struct xdp_sock is read outside of the control
mutex, in the mmap implementation, and needs a WRITE_ONCE to avoid
potential store-tearing.

Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Fixes: 423f38329d26 ("xsk: add umem fill queue support and mmap")
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/xdp/xsk.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index b580078f04d1..72caa4fb13f4 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -454,7 +454,7 @@ static int xsk_bind(struct socket *sock, struct sockaddr *addr, int addr_len)
 		}
 
 		xdp_get_umem(umem_xs->umem);
-		xs->umem = umem_xs->umem;
+		WRITE_ONCE(xs->umem, umem_xs->umem);
 		sockfd_put(sock);
 	} else if (!xs->umem || !xdp_umem_validate_queues(xs->umem)) {
 		err = -EINVAL;
@@ -534,7 +534,7 @@ static int xsk_setsockopt(struct socket *sock, int level, int optname,
 
 		/* Make sure umem is ready before it can be seen by others */
 		smp_wmb();
-		xs->umem = umem;
+		WRITE_ONCE(xs->umem, umem);
 		mutex_unlock(&xs->mutex);
 		return 0;
 	}
-- 
2.20.1


  parent reply index

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20200116170509.12787-1-sashal@kernel.org>
2020-01-16 16:58 ` [PATCH AUTOSEL 4.19 280/671] bpf: Add missed newline in verifier verbose log Sasha Levin
2020-01-16 16:59 ` [PATCH AUTOSEL 4.19 353/671] nfp: bpf: fix static check error through tightening shift amount adjustment Sasha Levin
2020-01-16 17:00 ` [PATCH AUTOSEL 4.19 383/671] signal/bpfilter: Fix bpfilter_kernl to use send_sig not force_sig Sasha Levin
2020-01-16 17:00 ` [PATCH AUTOSEL 4.19 390/671] net: core: support XDP generic on stacked devices Sasha Levin
2020-01-16 17:00 ` [PATCH AUTOSEL 4.19 417/671] bpf: fix the check that forwarding is enabled in bpf_ipv6_fib_lookup Sasha Levin
2020-01-16 17:01 ` [PATCH AUTOSEL 4.19 437/671] tools: bpftool: use correct argument in cgroup errors Sasha Levin
2020-01-16 17:01 ` [PATCH AUTOSEL 4.19 461/671] xdp: fix possible cq entry leak Sasha Levin
2020-01-16 17:02 ` [PATCH AUTOSEL 4.19 483/671] net: fix bpf_xdp_adjust_head regression for generic-XDP Sasha Levin
2020-01-16 17:02 ` [PATCH AUTOSEL 4.19 494/671] tools: bpftool: fix arguments for p_err() in do_event_pipe() Sasha Levin
2020-01-16 17:02 ` [PATCH AUTOSEL 4.19 495/671] tools: bpftool: fix format strings and arguments for jsonw_printf() Sasha Levin
2020-01-16 17:02 ` [PATCH AUTOSEL 4.19 529/671] xsk: avoid store-tearing when assigning queues Sasha Levin
2020-01-16 17:02 ` Sasha Levin [this message]
2020-01-16 17:03 ` [PATCH AUTOSEL 4.19 558/671] bpf: fix BTF limits Sasha Levin
2020-01-16 17:04 ` [PATCH AUTOSEL 4.19 602/671] xsk: Fix registration of Rx-only sockets Sasha Levin
2020-01-16 17:04 ` [PATCH AUTOSEL 4.19 603/671] bpf, offload: Unlock on error in bpf_offload_dev_create() Sasha Levin
2020-01-16 17:05 ` [PATCH AUTOSEL 4.19 666/671] samples/bpf: Fix broken xdp_rxq_info due to map order assumptions Sasha Levin

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