Re: [PATCH] selinux: Read sk->sk_family once in selinux_socket_bind()
From: Stephen Smalley <stephen.smalley.work@gmail.com>
Date: 2025-01-07 20:13:54
Also in:
linux-security-module, selinux
On Thu, Dec 12, 2024 at 5:20 AM Mikhail Ivanov [off-list ref] wrote:
selinux_socket_bind() is called without holding the socket lock. Use READ_ONCE() to safely read sk->sk_family for IPv6 socket in case of lockless transformation to IPv4 socket via IPV6_ADDRFORM [1]. [1] https://lore.kernel.org/all/20240202095404.183274-1-edumazet@google.com/ (local) Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Mikhail Ivanov <redacted>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
quoted hunk ↗ jump to hunk
--- security/selinux/hooks.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 5e5f3398f39d..b7adff2cf5f6 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c@@ -4715,8 +4715,10 @@ static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, in if (err) goto out; + /* IPV6_ADDRFORM can change sk->sk_family under us. */ + family = READ_ONCE(sk->sk_family); + /* If PF_INET or PF_INET6, check name_bind permission for the port. */ - family = sk->sk_family; if (family == PF_INET || family == PF_INET6) { char *addrp; struct common_audit_data ad;base-commit: 034294fbfdf0ded4f931f9503d2ca5bbf8b9aebd -- 2.34.1