From dc49c1f94e3469d94b952e8f5160dd4ccd791d79 Mon Sep 17 00:00:00 2001 From: Catherine Zhang Date: Wed, 2 Aug 2006 14:12:06 -0700 Subject: [AF_UNIX]: Kernel memory leak fix for af_unix datagram getpeersec patch From: Catherine Zhang This patch implements a cleaner fix for the memory leak problem of the original unix datagram getpeersec patch. Instead of creating a security context each time a unix datagram is sent, we only create the security context when the receiver requests it. This new design requires modification of the current unix_getsecpeer_dgram LSM hook and addition of two new hooks, namely, secid_to_secctx and release_secctx. The former retrieves the security context and the latter releases it. A hook is required for releasing the security context because it is up to the security module to decide how that's done. In the case of Selinux, it's a simple kfree operation. Acked-by: Stephen Smalley Signed-off-by: David S. Miller --- security/dummy.c | 14 ++++++++++++-- security/selinux/hooks.c | 38 ++++++++++++++++++++++++-------------- 2 files changed, 36 insertions(+), 16 deletions(-) (limited to 'security') diff --git a/security/dummy.c b/security/dummy.c index bbbfda70e131..58c6d399c844 100644 --- a/security/dummy.c +++ b/security/dummy.c @@ -791,8 +791,7 @@ static int dummy_socket_getpeersec_stream(struct socket *sock, char __user *optv return -ENOPROTOOPT; } -static int dummy_socket_getpeersec_dgram(struct sk_buff *skb, char **secdata, - u32 *seclen) +static int dummy_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb, u32 *secid) { return -ENOPROTOOPT; } @@ -876,6 +875,15 @@ static int dummy_setprocattr(struct task_struct *p, char *name, void *value, siz return -EINVAL; } +static int dummy_secid_to_secctx(u32 secid, char **secdata, u32 *seclen) +{ + return -EOPNOTSUPP; +} + +static void dummy_release_secctx(char *secdata, u32 seclen) +{ +} + #ifdef CONFIG_KEYS static inline int dummy_key_alloc(struct key *key, struct task_struct *ctx, unsigned long flags) @@ -1028,6 +1036,8 @@ void security_fixup_ops (struct security_operations *ops) set_to_dummy_if_null(ops, d_instantiate); set_to_dummy_if_null(ops, getprocattr); set_to_dummy_if_null(ops, setprocattr); + set_to_dummy_if_null(ops, secid_to_secctx); + set_to_dummy_if_null(ops, release_secctx); #ifdef CONFIG_SECURITY_NETWORK set_to_dummy_if_null(ops, unix_stream_connect); set_to_dummy_if_null(ops, unix_may_send); diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index a91c961ba38b..5d1b8c733199 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -3524,25 +3524,21 @@ out: return err; } -static int selinux_socket_getpeersec_dgram(struct sk_buff *skb, char **secdata, u32 *seclen) +static int selinux_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb, u32 *secid) { + u32 peer_secid = SECSID_NULL; int err = 0; - u32 peer_sid; - if (skb->sk->sk_family == PF_UNIX) - selinux_get_inode_sid(SOCK_INODE(skb->sk->sk_socket), - &peer_sid); - else - peer_sid = selinux_socket_getpeer_dgram(skb); - - if (peer_sid == SECSID_NULL) - return -EINVAL; + if (sock && (sock->sk->sk_family == PF_UNIX)) + selinux_get_inode_sid(SOCK_INODE(sock), &peer_secid); + else if (skb) + peer_secid = selinux_socket_getpeer_dgram(skb); - err = security_sid_to_context(peer_sid, secdata, seclen); - if (err) - return err; + if (peer_secid == SECSID_NULL) + err = -EINVAL; + *secid = peer_secid; - return 0; + return err; } static int selinux_sk_alloc_security(struct sock *sk, int family, gfp_t priority) @@ -4407,6 +4403,17 @@ static int selinux_setprocattr(struct task_struct *p, return size; } +static int selinux_secid_to_secctx(u32 secid, char **secdata, u32 *seclen) +{ + return security_sid_to_context(secid, secdata, seclen); +} + +static void selinux_release_secctx(char *secdata, u32 seclen) +{ + if (secdata) + kfree(secdata); +} + #ifdef CONFIG_KEYS static int selinux_key_alloc(struct key *k, struct task_struct *tsk, @@ -4587,6 +4594,9 @@ static struct security_operations selinux_ops = { .getprocattr = selinux_getprocattr, .setprocattr = selinux_setprocattr, + .secid_to_secctx = selinux_secid_to_secctx, + .release_secctx = selinux_release_secctx, + .unix_stream_connect = selinux_socket_unix_stream_connect, .unix_may_send = selinux_socket_unix_may_send, -- cgit v1.2.3