diff options
Diffstat (limited to 'security/selinux/hooks.c')
-rw-r--r-- | security/selinux/hooks.c | 281 |
1 files changed, 212 insertions, 69 deletions
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 5b52310..57b0b49 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -53,6 +53,7 @@ #include <net/ip.h> /* for local_port_range[] */ #include <net/sock.h> #include <net/tcp.h> /* struct or_callable used in sock_rcv_skb */ +#include <net/inet_connection_sock.h> #include <net/net_namespace.h> #include <net/netlabel.h> #include <linux/uaccess.h> @@ -95,8 +96,6 @@ #include "audit.h" #include "avc_ss.h" -#define NUM_SEL_MNT_OPTS 5 - extern struct security_operations *security_ops; /* SECMARK reference count */ @@ -139,12 +138,28 @@ static struct kmem_cache *sel_inode_cache; * This function checks the SECMARK reference counter to see if any SECMARK * targets are currently configured, if the reference counter is greater than * zero SECMARK is considered to be enabled. Returns true (1) if SECMARK is - * enabled, false (0) if SECMARK is disabled. + * enabled, false (0) if SECMARK is disabled. If the always_check_network + * policy capability is enabled, SECMARK is always considered enabled. * */ static int selinux_secmark_enabled(void) { - return (atomic_read(&selinux_secmark_refcount) > 0); + return (selinux_policycap_alwaysnetwork || atomic_read(&selinux_secmark_refcount)); +} + +/** + * selinux_peerlbl_enabled - Check to see if peer labeling is currently enabled + * + * Description: + * This function checks if NetLabel or labeled IPSEC is enabled. Returns true + * (1) if any are enabled or false (0) if neither are enabled. If the + * always_check_network policy capability is enabled, peer labeling + * is always considered enabled. + * + */ +static int selinux_peerlbl_enabled(void) +{ + return (selinux_policycap_alwaysnetwork || netlbl_enabled() || selinux_xfrm_enabled()); } /* @@ -219,6 +234,14 @@ static int inode_alloc_security(struct inode *inode) return 0; } +static void inode_free_rcu(struct rcu_head *head) +{ + struct inode_security_struct *isec; + + isec = container_of(head, struct inode_security_struct, rcu); + kmem_cache_free(sel_inode_cache, isec); +} + static void inode_free_security(struct inode *inode) { struct inode_security_struct *isec = inode->i_security; @@ -229,8 +252,16 @@ static void inode_free_security(struct inode *inode) list_del_init(&isec->list); spin_unlock(&sbsec->isec_lock); - inode->i_security = NULL; - kmem_cache_free(sel_inode_cache, isec); + /* + * The inode may still be referenced in a path walk and + * a call to selinux_inode_permission() can be made + * after inode_free_security() is called. Ideally, the VFS + * wouldn't do this, but fixing that is a much harder + * job. For now, simply free the i_security via RCU, and + * leave the current inode->i_security pointer intact. + * The inode will be freed after the RCU grace period too. + */ + call_rcu(&isec->rcu, inode_free_rcu); } static int file_alloc_security(struct file *file) @@ -309,8 +340,11 @@ enum { Opt_defcontext = 3, Opt_rootcontext = 4, Opt_labelsupport = 5, + Opt_nextmntopt = 6, }; +#define NUM_SEL_MNT_OPTS (Opt_nextmntopt - 1) + static const match_table_t tokens = { {Opt_context, CONTEXT_STR "%s"}, {Opt_fscontext, FSCONTEXT_STR "%s"}, @@ -355,6 +389,29 @@ static int may_context_mount_inode_relabel(u32 sid, return rc; } +static int selinux_is_sblabel_mnt(struct super_block *sb) +{ + struct superblock_security_struct *sbsec = sb->s_security; + + if (sbsec->behavior == SECURITY_FS_USE_XATTR || + sbsec->behavior == SECURITY_FS_USE_TRANS || + sbsec->behavior == SECURITY_FS_USE_TASK) + return 1; + + /* Special handling for sysfs. Is genfs but also has setxattr handler*/ + if (strncmp(sb->s_type->name, "sysfs", sizeof("sysfs")) == 0) + return 1; + + /* + * Special handling for rootfs. Is genfs but supports + * setting SELinux context on in-core inodes. + */ + if (strncmp(sb->s_type->name, "rootfs", sizeof("rootfs")) == 0) + return 1; + + return 0; +} + static int sb_finish_set_opts(struct super_block *sb) { struct superblock_security_struct *sbsec = sb->s_security; @@ -388,8 +445,6 @@ static int sb_finish_set_opts(struct super_block *sb) } } - sbsec->flags |= (SE_SBINITIALIZED | SE_SBLABELSUPP); - if (sbsec->behavior > ARRAY_SIZE(labeling_behaviors)) printk(KERN_ERR "SELinux: initialized (dev %s, type %s), unknown behavior\n", sb->s_id, sb->s_type->name); @@ -398,15 +453,9 @@ static int sb_finish_set_opts(struct super_block *sb) sb->s_id, sb->s_type->name, labeling_behaviors[sbsec->behavior-1]); - if (sbsec->behavior == SECURITY_FS_USE_GENFS || - sbsec->behavior == SECURITY_FS_USE_MNTPOINT || - sbsec->behavior == SECURITY_FS_USE_NONE || - sbsec->behavior > ARRAY_SIZE(labeling_behaviors)) - sbsec->flags &= ~SE_SBLABELSUPP; - - /* Special handling for sysfs. Is genfs but also has setxattr handler*/ - if (strncmp(sb->s_type->name, "sysfs", sizeof("sysfs")) == 0) - sbsec->flags |= SE_SBLABELSUPP; + sbsec->flags |= SE_SBINITIALIZED; + if (selinux_is_sblabel_mnt(sb)) + sbsec->flags |= SBLABEL_MNT; /* Initialize the root inode. */ rc = inode_doinit_with_dentry(root_inode, root); @@ -460,15 +509,18 @@ static int selinux_get_mnt_opts(const struct super_block *sb, if (!ss_initialized) return -EINVAL; + /* make sure we always check enough bits to cover the mask */ + BUILD_BUG_ON(SE_MNTMASK >= (1 << NUM_SEL_MNT_OPTS)); + tmp = sbsec->flags & SE_MNTMASK; /* count the number of mount options for this sb */ - for (i = 0; i < 8; i++) { + for (i = 0; i < NUM_SEL_MNT_OPTS; i++) { if (tmp & 0x01) opts->num_mnt_opts++; tmp >>= 1; } /* Check if the Label support flag is set */ - if (sbsec->flags & SE_SBLABELSUPP) + if (sbsec->flags & SBLABEL_MNT) opts->num_mnt_opts++; opts->mnt_opts = kcalloc(opts->num_mnt_opts, sizeof(char *), GFP_ATOMIC); @@ -515,9 +567,9 @@ static int selinux_get_mnt_opts(const struct super_block *sb, opts->mnt_opts[i] = context; opts->mnt_opts_flags[i++] = ROOTCONTEXT_MNT; } - if (sbsec->flags & SE_SBLABELSUPP) { + if (sbsec->flags & SBLABEL_MNT) { opts->mnt_opts[i] = NULL; - opts->mnt_opts_flags[i++] = SE_SBLABELSUPP; + opts->mnt_opts_flags[i++] = SBLABEL_MNT; } BUG_ON(i != opts->num_mnt_opts); @@ -614,7 +666,7 @@ static int selinux_set_mnt_opts(struct super_block *sb, for (i = 0; i < num_opts; i++) { u32 sid; - if (flags[i] == SE_SBLABELSUPP) + if (flags[i] == SBLABEL_MNT) continue; rc = security_context_to_sid(mount_options[i], strlen(mount_options[i]), &sid); @@ -685,9 +737,7 @@ static int selinux_set_mnt_opts(struct super_block *sb, * Determine the labeling behavior to use for this * filesystem type. */ - rc = security_fs_use((sbsec->flags & SE_SBPROC) ? - "proc" : sb->s_type->name, - &sbsec->behavior, &sbsec->sid); + rc = security_fs_use(sb); if (rc) { printk(KERN_WARNING "%s: security_fs_use(%s) returned %d\n", @@ -1037,7 +1087,7 @@ static void selinux_write_opts(struct seq_file *m, case DEFCONTEXT_MNT: prefix = DEFCONTEXT_STR; break; - case SE_SBLABELSUPP: + case SBLABEL_MNT: seq_putc(m, ','); seq_puts(m, LABELSUPP_STR); continue; @@ -1649,7 +1699,7 @@ static int may_create(struct inode *dir, if (rc) return rc; - if (!newsid || !(sbsec->flags & SE_SBLABELSUPP)) { + if (!newsid || !(sbsec->flags & SBLABEL_MNT)) { rc = security_transition_sid(sid, dsec->sid, tclass, &dentry->d_name, &newsid); if (rc) @@ -2437,7 +2487,7 @@ static int selinux_sb_remount(struct super_block *sb, void *data) u32 sid; size_t len; - if (flags[i] == SE_SBLABELSUPP) + if (flags[i] == SBLABEL_MNT) continue; len = strlen(mount_options[i]); rc = security_context_to_sid(mount_options[i], len, &sid); @@ -2606,7 +2656,7 @@ static int selinux_inode_init_security(struct inode *inode, struct inode *dir, if ((sbsec->flags & SE_SBINITIALIZED) && (sbsec->behavior == SECURITY_FS_USE_MNTPOINT)) newsid = sbsec->mntpoint_sid; - else if (!newsid || !(sbsec->flags & SE_SBLABELSUPP)) { + else if (!newsid || !(sbsec->flags & SBLABEL_MNT)) { rc = security_transition_sid(sid, dsec->sid, inode_mode_to_security_class(inode->i_mode), qstr, &newsid); @@ -2628,7 +2678,7 @@ static int selinux_inode_init_security(struct inode *inode, struct inode *dir, isec->initialized = 1; } - if (!ss_initialized || !(sbsec->flags & SE_SBLABELSUPP)) + if (!ss_initialized || !(sbsec->flags & SBLABEL_MNT)) return -EOPNOTSUPP; if (name) @@ -2830,7 +2880,7 @@ static int selinux_inode_setxattr(struct dentry *dentry, const char *name, return selinux_inode_setotherxattr(dentry, name); sbsec = inode->i_sb->s_security; - if (!(sbsec->flags & SE_SBLABELSUPP)) + if (!(sbsec->flags & SBLABEL_MNT)) return -EOPNOTSUPP; if (!inode_owner_or_capable(inode)) @@ -3791,8 +3841,12 @@ static int selinux_skb_peerlbl_sid(struct sk_buff *skb, u16 family, u32 *sid) u32 nlbl_sid; u32 nlbl_type; - selinux_skb_xfrm_sid(skb, &xfrm_sid); - selinux_netlbl_skbuff_getsid(skb, family, &nlbl_type, &nlbl_sid); + err = selinux_xfrm_skb_sid(skb, &xfrm_sid); + if (unlikely(err)) + return -EACCES; + err = selinux_netlbl_skbuff_getsid(skb, family, &nlbl_type, &nlbl_sid); + if (unlikely(err)) + return -EACCES; err = security_net_peersid_resolve(nlbl_sid, nlbl_type, xfrm_sid, sid); if (unlikely(err)) { @@ -3805,6 +3859,30 @@ static int selinux_skb_peerlbl_sid(struct sk_buff *skb, u16 family, u32 *sid) return 0; } +/** + * selinux_conn_sid - Determine the child socket label for a connection + * @sk_sid: the parent socket's SID + * @skb_sid: the packet's SID + * @conn_sid: the resulting connection SID + * + * If @skb_sid is valid then the user:role:type information from @sk_sid is + * combined with the MLS information from @skb_sid in order to create + * @conn_sid. If @skb_sid is not valid then then @conn_sid is simply a copy + * of @sk_sid. Returns zero on success, negative values on failure. + * + */ +static int selinux_conn_sid(u32 sk_sid, u32 skb_sid, u32 *conn_sid) +{ + int err = 0; + + if (skb_sid != SECSID_NULL) + err = security_sid_mls_copy(sk_sid, skb_sid, conn_sid); + else + *conn_sid = sk_sid; + + return err; +} + /* socket security operations */ static int socket_sockcreate_sid(const struct task_security_struct *tsec, @@ -3928,7 +4006,7 @@ static int selinux_socket_bind(struct socket *sock, struct sockaddr *address, in if (snum) { int low, high; - inet_get_local_port_range(&low, &high); + inet_get_local_port_range(sock_net(sk), &low, &high); if (snum < max(PROT_SOCK, low) || snum > high) { err = sel_netport_sid(sk->sk_protocol, @@ -4246,7 +4324,7 @@ static int selinux_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb) return selinux_sock_rcv_skb_compat(sk, skb, family); secmark_active = selinux_secmark_enabled(); - peerlbl_active = netlbl_enabled() || selinux_xfrm_enabled(); + peerlbl_active = selinux_peerlbl_enabled(); if (!secmark_active && !peerlbl_active) return 0; @@ -4272,8 +4350,10 @@ static int selinux_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb) } err = avc_has_perm(sk_sid, peer_sid, SECCLASS_PEER, PEER__RECV, &ad); - if (err) + if (err) { selinux_netlbl_err(skb, err, 0); + return err; + } } if (secmark_active) { @@ -4411,7 +4491,7 @@ static int selinux_inet_conn_request(struct sock *sk, struct sk_buff *skb, struct sk_security_struct *sksec = sk->sk_security; int err; u16 family = sk->sk_family; - u32 newsid; + u32 connsid; u32 peersid; /* handle mapped IPv4 packets arriving via IPv6 sockets */ @@ -4421,16 +4501,11 @@ static int selinux_inet_conn_request(struct sock *sk, struct sk_buff *skb, err = selinux_skb_peerlbl_sid(skb, family, &peersid); if (err) return err; - if (peersid == SECSID_NULL) { - req->secid = sksec->sid; - req->peer_secid = SECSID_NULL; - } else { - err = security_sid_mls_copy(sksec->sid, peersid, &newsid); - if (err) - return err; - req->secid = newsid; - req->peer_secid = peersid; - } + err = selinux_conn_sid(sksec->sid, peersid, &connsid); + if (err) + return err; + req->secid = connsid; + req->peer_secid = peersid; return selinux_netlbl_inet_conn_request(req, family); } @@ -4628,7 +4703,7 @@ static unsigned int selinux_ip_forward(struct sk_buff *skb, int ifindex, secmark_active = selinux_secmark_enabled(); netlbl_active = netlbl_enabled(); - peerlbl_active = netlbl_active || selinux_xfrm_enabled(); + peerlbl_active = selinux_peerlbl_enabled(); if (!secmark_active && !peerlbl_active) return NF_ACCEPT; @@ -4667,7 +4742,7 @@ static unsigned int selinux_ip_forward(struct sk_buff *skb, int ifindex, return NF_ACCEPT; } -static unsigned int selinux_ipv4_forward(unsigned int hooknum, +static unsigned int selinux_ipv4_forward(const struct nf_hook_ops *ops, struct sk_buff *skb, const struct net_device *in, const struct net_device *out, @@ -4677,7 +4752,7 @@ static unsigned int selinux_ipv4_forward(unsigned int hooknum, } #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) -static unsigned int selinux_ipv6_forward(unsigned int hooknum, +static unsigned int selinux_ipv6_forward(const struct nf_hook_ops *ops, struct sk_buff *skb, const struct net_device *in, const struct net_device *out, @@ -4690,6 +4765,7 @@ static unsigned int selinux_ipv6_forward(unsigned int hooknum, static unsigned int selinux_ip_output(struct sk_buff *skb, u16 family) { + struct sock *sk; u32 sid; if (!netlbl_enabled()) @@ -4698,8 +4774,27 @@ static unsigned int selinux_ip_output(struct sk_buff *skb, /* we do this in the LOCAL_OUT path and not the POST_ROUTING path * because we want to make sure we apply the necessary labeling * before IPsec is applied so we can leverage AH protection */ - if (skb->sk) { - struct sk_security_struct *sksec = skb->sk->sk_security; + sk = skb->sk; + if (sk) { + struct sk_security_struct *sksec; + + if (sk->sk_state == TCP_LISTEN) + /* if the socket is the listening state then this + * packet is a SYN-ACK packet which means it needs to + * be labeled based on the connection/request_sock and + * not the parent socket. unfortunately, we can't + * lookup the request_sock yet as it isn't queued on + * the parent socket until after the SYN-ACK is sent. + * the "solution" is to simply pass the packet as-is + * as any IP option based labeling should be copied + * from the initial connection request (in the IP + * layer). it is far from ideal, but until we get a + * security label in the packet itself this is the + * best we can do. */ + return NF_ACCEPT; + + /* standard practice, label using the parent socket */ + sksec = sk->sk_security; sid = sksec->sid; } else sid = SECINITSID_KERNEL; @@ -4709,7 +4804,7 @@ static unsigned int selinux_ip_output(struct sk_buff *skb, return NF_ACCEPT; } -static unsigned int selinux_ipv4_output(unsigned int hooknum, +static unsigned int selinux_ipv4_output(const struct nf_hook_ops *ops, struct sk_buff *skb, const struct net_device *in, const struct net_device *out, @@ -4769,27 +4864,36 @@ static unsigned int selinux_ip_postroute(struct sk_buff *skb, int ifindex, * as fast and as clean as possible. */ if (!selinux_policycap_netpeer) return selinux_ip_postroute_compat(skb, ifindex, family); + + secmark_active = selinux_secmark_enabled(); + peerlbl_active = selinux_peerlbl_enabled(); + if (!secmark_active && !peerlbl_active) + return NF_ACCEPT; + + sk = skb->sk; + #ifdef CONFIG_XFRM /* If skb->dst->xfrm is non-NULL then the packet is undergoing an IPsec * packet transformation so allow the packet to pass without any checks * since we'll have another chance to perform access control checks * when the packet is on it's final way out. * NOTE: there appear to be some IPv6 multicast cases where skb->dst - * is NULL, in this case go ahead and apply access control. */ - if (skb_dst(skb) != NULL && skb_dst(skb)->xfrm != NULL) + * is NULL, in this case go ahead and apply access control. + * NOTE: if this is a local socket (skb->sk != NULL) that is in the + * TCP listening state we cannot wait until the XFRM processing + * is done as we will miss out on the SA label if we do; + * unfortunately, this means more work, but it is only once per + * connection. */ + if (skb_dst(skb) != NULL && skb_dst(skb)->xfrm != NULL && + !(sk != NULL && sk->sk_state == TCP_LISTEN)) return NF_ACCEPT; #endif - secmark_active = selinux_secmark_enabled(); - peerlbl_active = netlbl_enabled() || selinux_xfrm_enabled(); - if (!secmark_active && !peerlbl_active) - return NF_ACCEPT; - /* if the packet is being forwarded then get the peer label from the - * packet itself; otherwise check to see if it is from a local - * application or the kernel, if from an application get the peer label - * from the sending socket, otherwise use the kernel's sid */ - sk = skb->sk; if (sk == NULL) { + /* Without an associated socket the packet is either coming + * from the kernel or it is being forwarded; check the packet + * to determine which and if the packet is being forwarded + * query the packet directly to determine the security label. */ if (skb->skb_iif) { secmark_perm = PACKET__FORWARD_OUT; if (selinux_skb_peerlbl_sid(skb, family, &peer_sid)) @@ -4798,7 +4902,45 @@ static unsigned int selinux_ip_postroute(struct sk_buff *skb, int ifindex, secmark_perm = PACKET__SEND; peer_sid = SECINITSID_KERNEL; } + } else if (sk->sk_state == TCP_LISTEN) { + /* Locally generated packet but the associated socket is in the + * listening state which means this is a SYN-ACK packet. In + * this particular case the correct security label is assigned + * to the connection/request_sock but unfortunately we can't + * query the request_sock as it isn't queued on the parent + * socket until after the SYN-ACK packet is sent; the only + * viable choice is to regenerate the label like we do in + * selinux_inet_conn_request(). See also selinux_ip_output() + * for similar problems. */ + u32 skb_sid; + struct sk_security_struct *sksec = sk->sk_security; + if (selinux_skb_peerlbl_sid(skb, family, &skb_sid)) + return NF_DROP; + /* At this point, if the returned skb peerlbl is SECSID_NULL + * and the packet has been through at least one XFRM + * transformation then we must be dealing with the "final" + * form of labeled IPsec packet; since we've already applied + * all of our access controls on this packet we can safely + * pass the packet. */ + if (skb_sid == SECSID_NULL) { + switch (family) { + case PF_INET: + if (IPCB(skb)->flags & IPSKB_XFRM_TRANSFORMED) + return NF_ACCEPT; + break; + case PF_INET6: + if (IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) + return NF_ACCEPT; + default: + return NF_DROP_ERR(-ECONNREFUSED); + } + } + if (selinux_conn_sid(sksec->sid, skb_sid, &peer_sid)) + return NF_DROP; + secmark_perm = PACKET__SEND; } else { + /* Locally generated packet, fetch the security label from the + * associated socket. */ struct sk_security_struct *sksec = sk->sk_security; peer_sid = sksec->sid; secmark_perm = PACKET__SEND; @@ -4836,7 +4978,7 @@ static unsigned int selinux_ip_postroute(struct sk_buff *skb, int ifindex, return NF_ACCEPT; } -static unsigned int selinux_ipv4_postroute(unsigned int hooknum, +static unsigned int selinux_ipv4_postroute(const struct nf_hook_ops *ops, struct sk_buff *skb, const struct net_device *in, const struct net_device *out, @@ -4846,7 +4988,7 @@ static unsigned int selinux_ipv4_postroute(unsigned int hooknum, } #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) -static unsigned int selinux_ipv6_postroute(unsigned int hooknum, +static unsigned int selinux_ipv6_postroute(const struct nf_hook_ops *ops, struct sk_buff *skb, const struct net_device *in, const struct net_device *out, @@ -5462,11 +5604,11 @@ static int selinux_setprocattr(struct task_struct *p, /* Check for ptracing, and update the task SID if ok. Otherwise, leave SID unchanged and fail. */ ptsid = 0; - task_lock(p); + rcu_read_lock(); tracer = ptrace_parent(p); if (tracer) ptsid = task_sid(tracer); - task_unlock(p); + rcu_read_unlock(); if (tracer) { error = avc_has_perm(ptsid, sid, SECCLASS_PROCESS, @@ -5784,7 +5926,8 @@ static struct security_operations selinux_ops = { .xfrm_policy_clone_security = selinux_xfrm_policy_clone, .xfrm_policy_free_security = selinux_xfrm_policy_free, .xfrm_policy_delete_security = selinux_xfrm_policy_delete, - .xfrm_state_alloc_security = selinux_xfrm_state_alloc, + .xfrm_state_alloc = selinux_xfrm_state_alloc, + .xfrm_state_alloc_acquire = selinux_xfrm_state_alloc_acquire, .xfrm_state_free_security = selinux_xfrm_state_free, .xfrm_state_delete_security = selinux_xfrm_state_delete, .xfrm_policy_lookup = selinux_xfrm_policy_lookup, |