[PATCH 5.10 47/73] lsm: fix default return value of the socket_getpeersec_*() hooks

Sasha Levin
2024-03-13T16:47:34Z

From: Ondrej Mosnacek <omosnace@redhat.com>

[ Upstream commit 5a287d3d2b9de2b3e747132c615599907ba5c3c1 ]

For these hooks the true "neutral" value is -EOPNOTSUPP, which is
currently what is returned when no LSM provides this hook and what LSMs
return when there is no security context set on the socket. Correct the
value in <linux/lsm_hooks.h> and adjust the dispatch functions in
security/security.c to avoid issues when the BPF LSM is enabled.

Cc: stable@vger.kernel.org
Fixes: 98e828a0650f ("security: Refactor declaration of LSM hooks")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
[PM: subject line tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
include/linux/lsm_hook_defs.h | 4 ++--
security/security.c | 31 +++++++++++++++++++++++++++----
2 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index 9f550eab8ebdb..07abcd384975b 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h
@@ -293,9 +293,9 @@ LSM_HOOK(int, 0, socket_getsockopt, struct socket *sock, int level, int optname)
LSM_HOOK(int, 0, socket_setsockopt, struct socket *sock, int level, int optname)
LSM_HOOK(int, 0, socket_shutdown, struct socket *sock, int how)
LSM_HOOK(int, 0, socket_sock_rcv_skb, struct sock *sk, struct sk_buff *skb)
-LSM_HOOK(int, 0, socket_getpeersec_stream, struct socket *sock,
+LSM_HOOK(int, -ENOPROTOOPT, socket_getpeersec_stream, struct socket *sock,
sockptr_t optval, sockptr_t optlen, unsigned int len)
-LSM_HOOK(int, 0, socket_getpeersec_dgram, struct socket *sock,
+LSM_HOOK(int, -ENOPROTOOPT, socket_getpeersec_dgram, struct socket *sock,
struct sk_buff *skb, u32 *secid)
LSM_HOOK(int, 0, sk_alloc_security, struct sock *sk, int family, gfp_t priority)
LSM_HOOK(void, LSM_RET_VOID, sk_free_security, struct sock *sk)
diff --git a/security/security.c b/security/security.c
index e9dcde3c4f14b..0bbcb100ba8e9 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2227,14 +2227,37 @@ EXPORT_SYMBOL(security_sock_rcv_skb);
int security_socket_getpeersec_stream(struct socket *sock, sockptr_t optval,
sockptr_t optlen, unsigned int len)
{
- return call_int_hook(socket_getpeersec_stream, -ENOPROTOOPT, sock,
- optval, optlen, len);
+ struct security_hook_list *hp;
+ int rc;
+
+ /*
+ * Only one module will provide a security context.
+ */
+ hlist_for_each_entry(hp, &security_hook_heads.socket_getpeersec_stream,
+ list) {
+ rc = hp->hook.socket_getpeersec_stream(sock, optval, optlen,
+ len);
+ if (rc != LSM_RET_DEFAULT(socket_getpeersec_stream))
+ return rc;
+ }
+ return LSM_RET_DEFAULT(socket_getpeersec_stream);
}

int security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb, u32 *secid)
{
- return call_int_hook(socket_getpeersec_dgram, -ENOPROTOOPT, sock,
- skb, secid);
+ struct security_hook_list *hp;
+ int rc;
+
+ /*
+ * Only one module will provide a security context.
+ */
+ hlist_for_each_entry(hp, &security_hook_heads.socket_getpeersec_dgram,
+ list) {
+ rc = hp->hook.socket_getpeersec_dgram(sock, skb, secid);
+ if (rc != LSM_RET_DEFAULT(socket_getpeersec_dgram))
+ return rc;
+ }
+ return LSM_RET_DEFAULT(socket_getpeersec_dgram);
}
EXPORT_SYMBOL(security_socket_getpeersec_dgram);

--
2.43.0