tls: fix missing memory barrier in tls_init
[ Upstream commit 91e61dd7 ] In tls_init(), a write memory barrier is missing, and store-store reordering may cause NULL dereference in tls_{setsockopt,getsockopt}. CPU0 CPU1 ----- ----- // In tls_init() // In tls_ctx_create() ctx = kzalloc() ctx->sk_proto = READ_ONCE(sk->sk_prot) -(1) // In update_sk_prot() WRITE_ONCE(sk->sk_prot, tls_prots) -(2) // In sock_common_setsockopt() READ_ONCE(sk->sk_prot)->setsockopt() // In tls_{setsockopt,getsockopt}() ctx->sk_proto->setsockopt() -(3) In the above scenario, when (1) and (2) are reordered, (3) can observe the NULL value of ctx->sk_proto, causing NULL dereference. To fix it, we rely on rcu_assign_pointer() which implies the release barrier semantic. By moving rcu_assign_pointer() after ctx->sk_proto is initialized, we can ensure that ctx->sk_proto are visible when changing sk->sk_prot. Fixes: d5bee737 ("net/tls: Annotate access to sk_prot with READ_ONCE/WRITE_ONCE") Signed-off-by:Yewon Choi <woni9911@gmail.com> Signed-off-by:
Dae R. Jeong <threeearcat@gmail.com> Link: https://lore.kernel.org/netdev/ZU4OJG56g2V9z_H7@dragonet/T/ Link: https://lore.kernel.org/r/Zkx4vjSFp0mfpjQ2@libra05 Signed-off-by:
Paolo Abeni <pabeni@redhat.com> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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cb95173e
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