From 3610cda53f247e176bcbb7a7cca64bc53b12acdb Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Wed, 5 Jan 2011 15:38:53 -0800 Subject: [PATCH] af_unix: Avoid socket->sk NULL OOPS in stream connect security hooks. unix_release() can asynchornously set socket->sk to NULL, and it does so without holding the unix_state_lock() on "other" during stream connects. However, the reverse mapping, sk->sk_socket, is only transitioned to NULL under the unix_state_lock(). Therefore make the security hooks follow the reverse mapping instead of the forward mapping. Reported-by: Jeremy Fitzhardinge Reported-by: Linus Torvalds Signed-off-by: David S. Miller --- include/linux/security.h | 15 +++++++-------- net/unix/af_unix.c | 2 +- security/capability.c | 2 +- security/security.c | 3 +-- security/selinux/hooks.c | 10 +++++----- security/smack/smack_lsm.c | 14 +++++++------- 6 files changed, 22 insertions(+), 24 deletions(-) diff --git a/include/linux/security.h b/include/linux/security.h index fd4d55fb8845..d47a4c24b3e4 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -796,8 +796,9 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts) * @unix_stream_connect: * Check permissions before establishing a Unix domain stream connection * between @sock and @other. - * @sock contains the socket structure. - * @other contains the peer socket structure. + * @sock contains the sock structure. + * @other contains the peer sock structure. + * @newsk contains the new sock structure. * Return 0 if permission is granted. * @unix_may_send: * Check permissions before connecting or sending datagrams from @sock to @@ -1568,8 +1569,7 @@ struct security_operations { int (*inode_getsecctx)(struct inode *inode, void **ctx, u32 *ctxlen); #ifdef CONFIG_SECURITY_NETWORK - int (*unix_stream_connect) (struct socket *sock, - struct socket *other, struct sock *newsk); + int (*unix_stream_connect) (struct sock *sock, struct sock *other, struct sock *newsk); int (*unix_may_send) (struct socket *sock, struct socket *other); int (*socket_create) (int family, int type, int protocol, int kern); @@ -2525,8 +2525,7 @@ static inline int security_inode_getsecctx(struct inode *inode, void **ctx, u32 #ifdef CONFIG_SECURITY_NETWORK -int security_unix_stream_connect(struct socket *sock, struct socket *other, - struct sock *newsk); +int security_unix_stream_connect(struct sock *sock, struct sock *other, struct sock *newsk); int security_unix_may_send(struct socket *sock, struct socket *other); int security_socket_create(int family, int type, int protocol, int kern); int security_socket_post_create(struct socket *sock, int family, @@ -2567,8 +2566,8 @@ void security_tun_dev_post_create(struct sock *sk); int security_tun_dev_attach(struct sock *sk); #else /* CONFIG_SECURITY_NETWORK */ -static inline int security_unix_stream_connect(struct socket *sock, - struct socket *other, +static inline int security_unix_stream_connect(struct sock *sock, + struct sock *other, struct sock *newsk) { return 0; diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 417d7a6c36cf..dd419d286204 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -1157,7 +1157,7 @@ static int unix_stream_connect(struct socket *sock, struct sockaddr *uaddr, goto restart; } - err = security_unix_stream_connect(sock, other->sk_socket, newsk); + err = security_unix_stream_connect(sk, other, newsk); if (err) { unix_state_unlock(sk); goto out_unlock; diff --git a/security/capability.c b/security/capability.c index c773635ca3a0..2a5df2b7da83 100644 --- a/security/capability.c +++ b/security/capability.c @@ -548,7 +548,7 @@ static int cap_sem_semop(struct sem_array *sma, struct sembuf *sops, } #ifdef CONFIG_SECURITY_NETWORK -static int cap_unix_stream_connect(struct socket *sock, struct socket *other, +static int cap_unix_stream_connect(struct sock *sock, struct sock *other, struct sock *newsk) { return 0; diff --git a/security/security.c b/security/security.c index 1b798d3df710..e5fb07a3052d 100644 --- a/security/security.c +++ b/security/security.c @@ -977,8 +977,7 @@ EXPORT_SYMBOL(security_inode_getsecctx); #ifdef CONFIG_SECURITY_NETWORK -int security_unix_stream_connect(struct socket *sock, struct socket *other, - struct sock *newsk) +int security_unix_stream_connect(struct sock *sock, struct sock *other, struct sock *newsk) { return security_ops->unix_stream_connect(sock, other, newsk); } diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index c82538a4b1a4..6f637d2678ac 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -3921,18 +3921,18 @@ static int selinux_socket_shutdown(struct socket *sock, int how) return sock_has_perm(current, sock->sk, SOCKET__SHUTDOWN); } -static int selinux_socket_unix_stream_connect(struct socket *sock, - struct socket *other, +static int selinux_socket_unix_stream_connect(struct sock *sock, + struct sock *other, struct sock *newsk) { - struct sk_security_struct *sksec_sock = sock->sk->sk_security; - struct sk_security_struct *sksec_other = other->sk->sk_security; + struct sk_security_struct *sksec_sock = sock->sk_security; + struct sk_security_struct *sksec_other = other->sk_security; struct sk_security_struct *sksec_new = newsk->sk_security; struct common_audit_data ad; int err; COMMON_AUDIT_DATA_INIT(&ad, NET); - ad.u.net.sk = other->sk; + ad.u.net.sk = other; err = avc_has_perm(sksec_sock->sid, sksec_other->sid, sksec_other->sclass, diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index 489a85afa477..ccb71a044a1a 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -2408,22 +2408,22 @@ static int smack_setprocattr(struct task_struct *p, char *name, /** * smack_unix_stream_connect - Smack access on UDS - * @sock: one socket - * @other: the other socket + * @sock: one sock + * @other: the other sock * @newsk: unused * * Return 0 if a subject with the smack of sock could access * an object with the smack of other, otherwise an error code */ -static int smack_unix_stream_connect(struct socket *sock, - struct socket *other, struct sock *newsk) +static int smack_unix_stream_connect(struct sock *sock, + struct sock *other, struct sock *newsk) { - struct inode *sp = SOCK_INODE(sock); - struct inode *op = SOCK_INODE(other); + struct inode *sp = SOCK_INODE(sock->sk_socket); + struct inode *op = SOCK_INODE(other->sk_socket); struct smk_audit_info ad; smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_NET); - smk_ad_setfield_u_net_sk(&ad, other->sk); + smk_ad_setfield_u_net_sk(&ad, other); return smk_access(smk_of_inode(sp), smk_of_inode(op), MAY_READWRITE, &ad); }