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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
	Alexei Starovoitov <ast@kernel.org>,
	"David S . Miller" <davem@davemloft.net>,
	Sasha Levin <sashal@kernel.org>,
	netdev@vger.kernel.org, bpf@vger.kernel.org
Subject: [PATCH AUTOSEL 4.19 383/671] signal/bpfilter: Fix bpfilter_kernl to use send_sig not force_sig
Date: Thu, 16 Jan 2020 12:00:21 -0500
Message-ID: <20200116170509.12787-120-sashal@kernel.org> (raw)
In-Reply-To: <20200116170509.12787-1-sashal@kernel.org>

From: "Eric W. Biederman" <ebiederm@xmission.com>

[ Upstream commit 1dfd1711de2952fd1bfeea7152bd1687a4eea771 ]

The locking in force_sig_info is not prepared to deal with
a task that exits or execs (as sighand may change).  As force_sig
is only built to handle synchronous exceptions.

Further the function force_sig_info changes the signal state if the
signal is ignored, or blocked or if SIGNAL_UNKILLABLE will prevent the
delivery of the signal.  The signal SIGKILL can not be ignored and can
not be blocked and SIGNAL_UNKILLABLE won't prevent it from being
delivered.

So using force_sig rather than send_sig for SIGKILL is pointless.

Because it won't impact the sending of the signal and and because
using force_sig is wrong, replace force_sig with send_sig.

Cc: Alexei Starovoitov <ast@kernel.org>
Cc: David S. Miller <davem@davemloft.net>
Fixes: d2ba09c17a06 ("net: add skeleton of bpfilter kernel module")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/bpfilter/bpfilter_kern.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/bpfilter/bpfilter_kern.c b/net/bpfilter/bpfilter_kern.c
index 94e88f510c5b..450b257afa84 100644
--- a/net/bpfilter/bpfilter_kern.c
+++ b/net/bpfilter/bpfilter_kern.c
@@ -25,7 +25,7 @@ static void shutdown_umh(struct umh_info *info)
 		return;
 	tsk = get_pid_task(find_vpid(info->pid), PIDTYPE_PID);
 	if (tsk) {
-		force_sig(SIGKILL, tsk);
+		send_sig(SIGKILL, tsk, 1);
 		put_task_struct(tsk);
 	}
 	fput(info->pipe_to_umh);
-- 
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 ` Sasha Levin [this message]
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 ` [PATCH AUTOSEL 4.19 530/671] xsk: avoid store-tearing when assigning umem Sasha Levin
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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