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-rw-r--r--security/selinux/hooks.c212
1 files changed, 154 insertions, 58 deletions
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 794c3ca49eac..4b34847208cc 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>
@@ -81,7 +82,6 @@
#include <linux/syslog.h>
#include <linux/user_namespace.h>
#include <linux/export.h>
-#include <linux/security.h>
#include <linux/msg.h>
#include <linux/shm.h>
@@ -95,10 +95,6 @@
#include "audit.h"
#include "avc_ss.h"
-#define SB_TYPE_FMT "%s%s%s"
-#define SB_SUBTYPE(sb) (sb->s_subtype && sb->s_subtype[0])
-#define SB_TYPE_ARGS(sb) sb->s_type->name, SB_SUBTYPE(sb) ? "." : "", SB_SUBTYPE(sb) ? sb->s_subtype : ""
-
extern struct security_operations *security_ops;
/* SECMARK reference count */
@@ -237,6 +233,14 @@ 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;
@@ -247,8 +251,16 @@ 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)
@@ -413,8 +425,8 @@ static int sb_finish_set_opts(struct super_block *sb)
the first boot of the SELinux kernel before we have
assigned xattr values to the filesystem. */
if (!root_inode->i_op->getxattr) {
- printk(KERN_WARNING "SELinux: (dev %s, type "SB_TYPE_FMT") has no "
- "xattr support\n", sb->s_id, SB_TYPE_ARGS(sb));
+ printk(KERN_WARNING "SELinux: (dev %s, type %s) has no "
+ "xattr support\n", sb->s_id, sb->s_type->name);
rc = -EOPNOTSUPP;
goto out;
}
@@ -422,22 +434,22 @@ static int sb_finish_set_opts(struct super_block *sb)
if (rc < 0 && rc != -ENODATA) {
if (rc == -EOPNOTSUPP)
printk(KERN_WARNING "SELinux: (dev %s, type "
- SB_TYPE_FMT") has no security xattr handler\n",
- sb->s_id, SB_TYPE_ARGS(sb));
+ "%s) has no security xattr handler\n",
+ sb->s_id, sb->s_type->name);
else
printk(KERN_WARNING "SELinux: (dev %s, type "
- SB_TYPE_FMT") getxattr errno %d\n", sb->s_id,
- SB_TYPE_ARGS(sb), -rc);
+ "%s) getxattr errno %d\n", sb->s_id,
+ sb->s_type->name, -rc);
goto out;
}
}
if (sbsec->behavior > ARRAY_SIZE(labeling_behaviors))
- printk(KERN_ERR "SELinux: initialized (dev %s, type "SB_TYPE_FMT"), unknown behavior\n",
- sb->s_id, SB_TYPE_ARGS(sb));
+ printk(KERN_ERR "SELinux: initialized (dev %s, type %s), unknown behavior\n",
+ sb->s_id, sb->s_type->name);
else
- printk(KERN_DEBUG "SELinux: initialized (dev %s, type "SB_TYPE_FMT"), %s\n",
- sb->s_id, SB_TYPE_ARGS(sb),
+ printk(KERN_DEBUG "SELinux: initialized (dev %s, type %s), %s\n",
+ sb->s_id, sb->s_type->name,
labeling_behaviors[sbsec->behavior-1]);
sbsec->flags |= SE_SBINITIALIZED;
@@ -600,6 +612,7 @@ static int selinux_set_mnt_opts(struct super_block *sb,
const struct cred *cred = current_cred();
int rc = 0, i;
struct superblock_security_struct *sbsec = sb->s_security;
+ const char *name = sb->s_type->name;
struct inode *inode = sbsec->sb->s_root->d_inode;
struct inode_security_struct *root_isec = inode->i_security;
u32 fscontext_sid = 0, context_sid = 0, rootcontext_sid = 0;
@@ -658,8 +671,8 @@ static int selinux_set_mnt_opts(struct super_block *sb,
strlen(mount_options[i]), &sid);
if (rc) {
printk(KERN_WARNING "SELinux: security_context_to_sid"
- "(%s) failed for (dev %s, type "SB_TYPE_FMT") errno=%d\n",
- mount_options[i], sb->s_id, SB_TYPE_ARGS(sb), rc);
+ "(%s) failed for (dev %s, type %s) errno=%d\n",
+ mount_options[i], sb->s_id, name, rc);
goto out;
}
switch (flags[i]) {
@@ -806,8 +819,7 @@ out:
out_double_mount:
rc = -EINVAL;
printk(KERN_WARNING "SELinux: mount invalid. Same superblock, different "
- "security settings for (dev %s, type "SB_TYPE_FMT")\n", sb->s_id,
- SB_TYPE_ARGS(sb));
+ "security settings for (dev %s, type %s)\n", sb->s_id, name);
goto out;
}
@@ -2480,8 +2492,8 @@ static int selinux_sb_remount(struct super_block *sb, void *data)
rc = security_context_to_sid(mount_options[i], len, &sid);
if (rc) {
printk(KERN_WARNING "SELinux: security_context_to_sid"
- "(%s) failed for (dev %s, type "SB_TYPE_FMT") errno=%d\n",
- mount_options[i], sb->s_id, SB_TYPE_ARGS(sb), rc);
+ "(%s) failed for (dev %s, type %s) errno=%d\n",
+ mount_options[i], sb->s_id, sb->s_type->name, rc);
goto out_free_opts;
}
rc = -EINVAL;
@@ -2519,8 +2531,8 @@ out_free_secdata:
return rc;
out_bad_option:
printk(KERN_WARNING "SELinux: unable to change security options "
- "during remount (dev %s, type "SB_TYPE_FMT")\n", sb->s_id,
- SB_TYPE_ARGS(sb));
+ "during remount (dev %s, type=%s)\n", sb->s_id,
+ sb->s_type->name);
goto out_free_opts;
}
@@ -3828,7 +3840,7 @@ static int selinux_skb_peerlbl_sid(struct sk_buff *skb, u16 family, u32 *sid)
u32 nlbl_sid;
u32 nlbl_type;
- err = selinux_skb_xfrm_sid(skb, &xfrm_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);
@@ -3846,6 +3858,30 @@ 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,
@@ -4313,8 +4349,10 @@ 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) {
@@ -4451,27 +4489,18 @@ 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;
+ u16 family = req->rsk_ops->family;
+ u32 connsid;
u32 peersid;
- /* handle mapped IPv4 packets arriving via IPv6 sockets */
- if (family == PF_INET6 && skb->protocol == htons(ETH_P_IP))
- family = PF_INET;
-
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);
}
@@ -4731,6 +4760,7 @@ static unsigned int selinux_ipv6_forward(const struct nf_hook_ops *ops,
static unsigned int selinux_ip_output(struct sk_buff *skb,
u16 family)
{
+ struct sock *sk;
u32 sid;
if (!netlbl_enabled())
@@ -4739,8 +4769,27 @@ 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;
@@ -4810,27 +4859,36 @@ 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 = selinux_peerlbl_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))
@@ -4839,7 +4897,45 @@ 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;
@@ -5503,11 +5599,11 @@ 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,
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-19 06:34:57 +0100