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From: Kuniyuki Iwashima To: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: Simon Horman , Kuniyuki Iwashima , Kuniyuki Iwashima , netdev@vger.kernel.org, "D. Wythe" , Dust Li , Sidraya Jayagond , Wenjia Zhang , Mahanta Jambigi , Tony Lu , Wen Gu , Ursula Braun Content-Type: text/plain; charset="UTF-8" smc_clc_prfx_match() is called from smc_listen_work() and not under RCU nor RTNL. Using sk_dst_get(sk)->dev could trigger UAF. Let's use __sk_dst_get() and dst_dev_rcu(). Note that the returned value of smc_clc_prfx_match() is not used in the caller. Fixes: a046d57da19f ("smc: CLC handshake (incl. preparation steps)") Signed-off-by: Kuniyuki Iwashima --- Cc: "D. Wythe" Cc: Dust Li Cc: Sidraya Jayagond Cc: Wenjia Zhang Cc: Mahanta Jambigi Cc: Tony Lu Cc: Wen Gu Cc: Ursula Braun --- net/smc/smc_clc.c | 26 +++++++++++++------------- 1 file changed, 13 insertions(+), 13 deletions(-) diff --git a/net/smc/smc_clc.c b/net/smc/smc_clc.c index 976b2102bdfc..09745baa1017 100644 --- a/net/smc/smc_clc.c +++ b/net/smc/smc_clc.c @@ -657,26 +657,26 @@ static int smc_clc_prfx_match6_rcu(struct net_device *dev, int smc_clc_prfx_match(struct socket *clcsock, struct smc_clc_msg_proposal_prefix *prop) { - struct dst_entry *dst = sk_dst_get(clcsock->sk); + struct net_device *dev; + struct dst_entry *dst; int rc; - if (!dst) { - rc = -ENOTCONN; - goto out; - } - if (!dst->dev) { + rcu_read_lock(); + + dst = __sk_dst_get(clcsock->sk); + dev = dst ? dst_dev_rcu(dst) : NULL; + if (!dev) { rc = -ENODEV; - goto out_rel; + goto out; } - rcu_read_lock(); + if (!prop->ipv6_prefixes_cnt) - rc = smc_clc_prfx_match4_rcu(dst->dev, prop); + rc = smc_clc_prfx_match4_rcu(dev, prop); else - rc = smc_clc_prfx_match6_rcu(dst->dev, prop); - rcu_read_unlock(); -out_rel: - dst_release(dst); + rc = smc_clc_prfx_match6_rcu(dev, prop); out: + rcu_read_unlock(); + return rc; } -- 2.51.0.384.g4c02a37b29-goog