[PATCH 74/90] LSM: Change error detection for UDP peer security
Casey Schaufler
casey at schaufler-ca.com
Fri Apr 19 00:46:01 UTC 2019
security_socket_getpeercred_dgram() supplies secids for use
by security_secid_to_secctx(). Sometimes a secid will be invalid.
Move the check for an invalid secid from the LSM specific
socket_getpeercred_dgram hooks into the secid_to_secctx hooks.
This allows for the case where one LSM (Smack) will provide a
secid and another (SELinux) to have an error for the same call.
Regardless of which LSM the caller wants to see the peer security
attributes for the correct result will be provided.
As there is no longer any reason for security_secid_to_secctx()
to return a value make all the secid_to_secctx functions void
instead of int. Add checking for a invalid secid to the Smack
and SELinux secid_to_secctx hooks.
Signed-off-by: Casey Schaufler <casey at schaufler-ca.com>
---
include/linux/lsm_hooks.h | 3 +--
include/linux/security.h | 11 +++++------
net/ipv4/ip_sockglue.c | 4 +---
security/security.c | 7 +++----
security/selinux/hooks.c | 13 +++++++------
security/smack/smack_lsm.c | 17 ++++++++---------
6 files changed, 25 insertions(+), 30 deletions(-)
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index 34f98cfe2ffd..0bb064c8b2dd 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -883,7 +883,6 @@
* @sock is the socket
* @skb is the skbuff for the packet being queried
* @l is a pointer to a buffer in which to copy the security data
- * Return 0 on success, error on failure.
* @sk_alloc_security:
* Allocate and attach a security structure to the sk->sk_security field,
* which is used to copy security attributes between local stream sockets.
@@ -1699,7 +1698,7 @@ union security_list_options {
int (*socket_getpeersec_stream)(struct socket *sock,
char __user *optval,
int __user *optlen, unsigned len);
- int (*socket_getpeersec_dgram)(struct socket *sock,
+ void (*socket_getpeersec_dgram)(struct socket *sock,
struct sk_buff *skb,
struct lsm_export *l);
int (*sk_alloc_security)(struct sock *sk, int family, gfp_t priority);
diff --git a/include/linux/security.h b/include/linux/security.h
index 8eb849d71e9d..99f9824ec230 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -1288,8 +1288,8 @@ int security_socket_shutdown(struct socket *sock, int how);
int security_sock_rcv_skb(struct sock *sk, struct sk_buff *skb);
int security_socket_getpeersec_stream(struct socket *sock, char __user *optval,
int __user *optlen, unsigned len);
-int security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb,
- struct lsm_export *l);
+void security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb,
+ struct lsm_export *l);
int security_sk_alloc(struct sock *sk, int family, gfp_t priority);
void security_sk_free(struct sock *sk);
void security_sk_clone(const struct sock *sk, struct sock *newsk);
@@ -1427,11 +1427,10 @@ static inline int security_socket_getpeersec_stream(struct socket *sock, char __
return -ENOPROTOOPT;
}
-static inline int security_socket_getpeersec_dgram(struct socket *sock,
- struct sk_buff *skb,
- struct lsm_export *l)
+static inline void security_socket_getpeersec_dgram(struct socket *sock,
+ struct sk_buff *skb,
+ struct lsm_export *l)
{
- return -ENOPROTOOPT;
}
static inline int security_sk_alloc(struct sock *sk, int family, gfp_t priority)
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 56035b53952d..ae69718d87ae 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -134,9 +134,7 @@ static void ip_cmsg_recv_security(struct msghdr *msg, struct sk_buff *skb)
struct lsm_context lc;
int err;
- err = security_socket_getpeersec_dgram(NULL, skb, &le);
- if (err)
- return;
+ security_socket_getpeersec_dgram(NULL, skb, &le);
err = security_secid_to_secctx(&le, &lc);
if (err)
diff --git a/security/security.c b/security/security.c
index 1a54e7b1196e..0bbe0dfd3cfc 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2402,12 +2402,11 @@ int security_socket_getpeersec_stream(struct socket *sock, char __user *optval,
optval, optlen, len);
}
-int security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb,
- struct lsm_export *l)
+void security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb,
+ struct lsm_export *l)
{
lsm_export_init(l);
- return call_int_hook(socket_getpeersec_dgram, -ENOPROTOOPT, sock, skb,
- l);
+ call_void_hook(socket_getpeersec_dgram, sock, skb, l);
}
EXPORT_SYMBOL(security_socket_getpeersec_dgram);
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 86578f7de131..93c3982d940c 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -4939,9 +4939,9 @@ static int selinux_socket_getpeersec_stream(struct socket *sock,
return err;
}
-static int selinux_socket_getpeersec_dgram(struct socket *sock,
- struct sk_buff *skb,
- struct lsm_export *l)
+static void selinux_socket_getpeersec_dgram(struct socket *sock,
+ struct sk_buff *skb,
+ struct lsm_export *l)
{
u32 peer_secid = SECSID_NULL;
u16 family;
@@ -4964,9 +4964,7 @@ static int selinux_socket_getpeersec_dgram(struct socket *sock,
out:
selinux_export_secid(l, peer_secid);
- if (peer_secid == SECSID_NULL)
- return -EINVAL;
- return 0;
+ return;
}
static int selinux_sk_alloc_security(struct sock *sk, int family, gfp_t priority)
@@ -6313,6 +6311,9 @@ static int selinux_secid_to_secctx(struct lsm_export *l, struct lsm_context *cp)
u32 secid;
selinux_import_secid(l, &secid);
+ if (secid == SECSID_NULL)
+ return -EINVAL;
+
cp->release = selinux_release_secctx;
if (l->flags & LSM_EXPORT_LENGTH)
return security_sid_to_context(&selinux_state, secid,
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 3fd46cd2c4b1..e18245a52e80 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -3988,9 +3988,9 @@ static int smack_socket_getpeersec_stream(struct socket *sock,
*
* Sets the netlabel socket state on sk from parent
*/
-static int smack_socket_getpeersec_dgram(struct socket *sock,
- struct sk_buff *skb,
- struct lsm_export *l)
+static void smack_socket_getpeersec_dgram(struct socket *sock,
+ struct sk_buff *skb,
+ struct lsm_export *l)
{
struct netlbl_lsm_secattr secattr;
@@ -3998,7 +3998,6 @@ static int smack_socket_getpeersec_dgram(struct socket *sock,
struct smack_known *skp;
int family = PF_UNSPEC;
u32 s = 0; /* 0 is the invalid secid */
- int rc;
if (skb != NULL) {
if (skb->protocol == htons(ETH_P_IP))
@@ -4028,8 +4027,7 @@ static int smack_socket_getpeersec_dgram(struct socket *sock,
if (sock != NULL && sock->sk != NULL)
ssp = smack_sock(sock->sk);
netlbl_secattr_init(&secattr);
- rc = netlbl_skbuff_getattr(skb, family, &secattr);
- if (rc == 0) {
+ if (netlbl_skbuff_getattr(skb, family, &secattr) == 0) {
skp = smack_from_secattr(&secattr, ssp);
s = skp->smk_secid;
}
@@ -4044,9 +4042,7 @@ static int smack_socket_getpeersec_dgram(struct socket *sock,
break;
}
smack_export_secid(l, s);
- if (s == 0)
- return -EINVAL;
- return 0;
+ return;
}
/**
@@ -4458,6 +4454,9 @@ static int smack_secid_to_secctx(struct lsm_export *l, struct lsm_context *cp)
u32 secid;
smack_import_secid(l, &secid);
+ if (secid == 0)
+ return -EINVAL;
+
skp = smack_from_secid(secid);
cp->context = (l->flags & LSM_EXPORT_LENGTH) ? NULL : skp->smk_known;
--
2.19.1
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