Merge branch 'smack-for-3.16' of git://git.gitorious.org/smack-next/kernel into next

2014-05-20 14:50:09 +10:00
parent fab71a90ed ec554fa75e
commit 2fd4e6698f
5 changed files with 307 additions and 73 deletions
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -157,6 +157,74 @@ static int smk_copy_rules(struct list_head *nhead, struct list_head *ohead,
 	return rc;
 }

+/**
+ * smk_ptrace_mode - helper function for converting PTRACE_MODE_* into MAY_*
+ * @mode - input mode in form of PTRACE_MODE_*
+ *
+ * Returns a converted MAY_* mode usable by smack rules
+ */
+static inline unsigned int smk_ptrace_mode(unsigned int mode)
+{
+	switch (mode) {
+	case PTRACE_MODE_READ:
+		return MAY_READ;
+	case PTRACE_MODE_ATTACH:
+		return MAY_READWRITE;
+	}
+
+	return 0;
+}
+
+/**
+ * smk_ptrace_rule_check - helper for ptrace access
+ * @tracer: tracer process
+ * @tracee_label: label of the process that's about to be traced,
+ *                the pointer must originate from smack structures
+ * @mode: ptrace attachment mode (PTRACE_MODE_*)
+ * @func: name of the function that called us, used for audit
+ *
+ * Returns 0 on access granted, -error on error
+ */
+static int smk_ptrace_rule_check(struct task_struct *tracer, char *tracee_label,
+				 unsigned int mode, const char *func)
+{
+	int rc;
+	struct smk_audit_info ad, *saip = NULL;
+	struct task_smack *tsp;
+	struct smack_known *skp;
+
+	if ((mode & PTRACE_MODE_NOAUDIT) == 0) {
+		smk_ad_init(&ad, func, LSM_AUDIT_DATA_TASK);
+		smk_ad_setfield_u_tsk(&ad, tracer);
+		saip = &ad;
+	}
+
+	tsp = task_security(tracer);
+	skp = smk_of_task(tsp);
+
+	if ((mode & PTRACE_MODE_ATTACH) &&
+	    (smack_ptrace_rule == SMACK_PTRACE_EXACT ||
+	     smack_ptrace_rule == SMACK_PTRACE_DRACONIAN)) {
+		if (skp->smk_known == tracee_label)
+			rc = 0;
+		else if (smack_ptrace_rule == SMACK_PTRACE_DRACONIAN)
+			rc = -EACCES;
+		else if (capable(CAP_SYS_PTRACE))
+			rc = 0;
+		else
+			rc = -EACCES;
+
+		if (saip)
+			smack_log(skp->smk_known, tracee_label, 0, rc, saip);
+
+		return rc;
+	}
+
+	/* In case of rule==SMACK_PTRACE_DEFAULT or mode==PTRACE_MODE_READ */
+	rc = smk_tskacc(tsp, tracee_label, smk_ptrace_mode(mode), saip);
+	return rc;
+}
+
 /*
 * LSM hooks.
 * We he, that is fun!
@@ -165,16 +233,15 @@ static int smk_copy_rules(struct list_head *nhead, struct list_head *ohead,
 /**
 * smack_ptrace_access_check - Smack approval on PTRACE_ATTACH
 * @ctp: child task pointer
- * @mode: ptrace attachment mode
+ * @mode: ptrace attachment mode (PTRACE_MODE_*)
 *
 * Returns 0 if access is OK, an error code otherwise
 *
- * Do the capability checks, and require read and write.
+ * Do the capability checks.
 */
 static int smack_ptrace_access_check(struct task_struct *ctp, unsigned int mode)
 {
 	int rc;
-	struct smk_audit_info ad;
 	struct smack_known *skp;

 	rc = cap_ptrace_access_check(ctp, mode);
@@ -182,10 +249,8 @@ static int smack_ptrace_access_check(struct task_struct *ctp, unsigned int mode)
 		return rc;

 	skp = smk_of_task(task_security(ctp));
-	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
-	smk_ad_setfield_u_tsk(&ad, ctp);

-	rc = smk_curacc(skp->smk_known, mode, &ad);
+	rc = smk_ptrace_rule_check(current, skp->smk_known, mode, __func__);
 	return rc;
 }

@@ -195,23 +260,21 @@ static int smack_ptrace_access_check(struct task_struct *ctp, unsigned int mode)
 *
 * Returns 0 if access is OK, an error code otherwise
 *
- * Do the capability checks, and require read and write.
+ * Do the capability checks, and require PTRACE_MODE_ATTACH.
 */
 static int smack_ptrace_traceme(struct task_struct *ptp)
 {
 	int rc;
-	struct smk_audit_info ad;
 	struct smack_known *skp;

 	rc = cap_ptrace_traceme(ptp);
 	if (rc != 0)
 		return rc;

-	skp = smk_of_task(task_security(ptp));
-	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_TASK);
-	smk_ad_setfield_u_tsk(&ad, ptp);
+	skp = smk_of_task(current_security());

-	rc = smk_curacc(skp->smk_known, MAY_READWRITE, &ad);
+	rc = smk_ptrace_rule_check(ptp, skp->smk_known,
+				   PTRACE_MODE_ATTACH, __func__);
 	return rc;
 }

@@ -413,9 +476,11 @@ static int smack_sb_kern_mount(struct super_block *sb, int flags, void *data)
 	 * Initialize the root inode.
 	 */
 	isp = inode->i_security;
-	if (inode->i_security == NULL) {
-		inode->i_security = new_inode_smack(sp->smk_root);
-		isp = inode->i_security;
+	if (isp == NULL) {
+		isp = new_inode_smack(sp->smk_root);
+		if (isp == NULL)
+			return -ENOMEM;
+		inode->i_security = isp;
 	} else
 		isp->smk_inode = sp->smk_root;

@@ -453,7 +518,7 @@ static int smack_sb_statfs(struct dentry *dentry)
 * smack_bprm_set_creds - set creds for exec
 * @bprm: the exec information
 *
- * Returns 0 if it gets a blob, -ENOMEM otherwise
+ * Returns 0 if it gets a blob, -EPERM if exec forbidden and -ENOMEM otherwise
 */
 static int smack_bprm_set_creds(struct linux_binprm *bprm)
 {
@@ -473,7 +538,22 @@ static int smack_bprm_set_creds(struct linux_binprm *bprm)
 	if (isp->smk_task == NULL || isp->smk_task == bsp->smk_task)
 		return 0;

-	if (bprm->unsafe)
+	if (bprm->unsafe & (LSM_UNSAFE_PTRACE | LSM_UNSAFE_PTRACE_CAP)) {
+		struct task_struct *tracer;
+		rc = 0;
+
+		rcu_read_lock();
+		tracer = ptrace_parent(current);
+		if (likely(tracer != NULL))
+			rc = smk_ptrace_rule_check(tracer,
+						   isp->smk_task->smk_known,
+						   PTRACE_MODE_ATTACH,
+						   __func__);
+		rcu_read_unlock();
+
+		if (rc != 0)
+			return rc;
+	} else if (bprm->unsafe)
 		return -EPERM;

 	bsp->smk_task = isp->smk_task;
@@ -880,18 +960,20 @@ static void smack_inode_post_setxattr(struct dentry *dentry, const char *name,
 		return;
 	}

-	skp = smk_import_entry(value, size);
 	if (strcmp(name, XATTR_NAME_SMACK) == 0) {
+		skp = smk_import_entry(value, size);
 		if (skp != NULL)
 			isp->smk_inode = skp->smk_known;
 		else
 			isp->smk_inode = smack_known_invalid.smk_known;
 	} else if (strcmp(name, XATTR_NAME_SMACKEXEC) == 0) {
+		skp = smk_import_entry(value, size);
 		if (skp != NULL)
 			isp->smk_task = skp;
 		else
 			isp->smk_task = &smack_known_invalid;
 	} else if (strcmp(name, XATTR_NAME_SMACKMMAP) == 0) {
+		skp = smk_import_entry(value, size);
 		if (skp != NULL)
 			isp->smk_mmap = skp;
 		else
@@ -938,24 +1020,37 @@ static int smack_inode_removexattr(struct dentry *dentry, const char *name)
 	    strcmp(name, XATTR_NAME_SMACKIPOUT) == 0 ||
 	    strcmp(name, XATTR_NAME_SMACKEXEC) == 0 ||
 	    strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0 ||
-	    strcmp(name, XATTR_NAME_SMACKMMAP)) {
+	    strcmp(name, XATTR_NAME_SMACKMMAP) == 0) {
 		if (!smack_privileged(CAP_MAC_ADMIN))
 			rc = -EPERM;
 	} else
 		rc = cap_inode_removexattr(dentry, name);

+	if (rc != 0)
+		return rc;
+
 	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_DENTRY);
 	smk_ad_setfield_u_fs_path_dentry(&ad, dentry);
-	if (rc == 0)
-		rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad);

-	if (rc == 0) {
-		isp = dentry->d_inode->i_security;
+	rc = smk_curacc(smk_of_inode(dentry->d_inode), MAY_WRITE, &ad);
+	if (rc != 0)
+		return rc;
+
+	isp = dentry->d_inode->i_security;
+	/*
+	 * Don't do anything special for these.
+	 *	XATTR_NAME_SMACKIPIN
+	 *	XATTR_NAME_SMACKIPOUT
+	 *	XATTR_NAME_SMACKEXEC
+	 */
+	if (strcmp(name, XATTR_NAME_SMACK) == 0)
 		isp->smk_task = NULL;
+	else if (strcmp(name, XATTR_NAME_SMACKMMAP) == 0)
 		isp->smk_mmap = NULL;
-	}
+	else if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0)
+		isp->smk_flags &= ~SMK_INODE_TRANSMUTE;

-	return rc;
+	return 0;
 }

 /**
@@ -1000,7 +1095,7 @@ static int smack_inode_getsecurity(const struct inode *inode,
 	ssp = sock->sk->sk_security;

 	if (strcmp(name, XATTR_SMACK_IPIN) == 0)
-		isp = ssp->smk_in;
+		isp = ssp->smk_in->smk_known;
 	else if (strcmp(name, XATTR_SMACK_IPOUT) == 0)
 		isp = ssp->smk_out->smk_known;
 	else
@@ -1367,19 +1462,32 @@ static int smack_file_receive(struct file *file)
 /**
 * smack_file_open - Smack dentry open processing
 * @file: the object
- * @cred: unused
+ * @cred: task credential
 *
 * Set the security blob in the file structure.
+ * Allow the open only if the task has read access. There are
+ * many read operations (e.g. fstat) that you can do with an
+ * fd even if you have the file open write-only.
 *
 * Returns 0
 */
 static int smack_file_open(struct file *file, const struct cred *cred)
 {
+	struct task_smack *tsp = cred->security;
 	struct inode_smack *isp = file_inode(file)->i_security;
+	struct smk_audit_info ad;
+	int rc;

-	file->f_security = isp->smk_inode;
+	if (smack_privileged(CAP_MAC_OVERRIDE))
+		return 0;

-	return 0;
+	smk_ad_init(&ad, __func__, LSM_AUDIT_DATA_PATH);
+	smk_ad_setfield_u_fs_path(&ad, file->f_path);
+	rc = smk_access(tsp->smk_task, isp->smk_inode, MAY_READ, &ad);
+	if (rc == 0)
+		file->f_security = isp->smk_inode;
+
+	return rc;
 }

 /*
@@ -1764,7 +1872,7 @@ static int smack_sk_alloc_security(struct sock *sk, int family, gfp_t gfp_flags)
 	if (ssp == NULL)
 		return -ENOMEM;

-	ssp->smk_in = skp->smk_known;
+	ssp->smk_in = skp;
 	ssp->smk_out = skp;
 	ssp->smk_packet = NULL;

@@ -2004,7 +2112,7 @@ static int smk_ipv6_port_check(struct sock *sk, struct sockaddr_in6 *address,

 	if (act == SMK_RECEIVING) {
 		skp = smack_net_ambient;
-		object = ssp->smk_in;
+		object = ssp->smk_in->smk_known;
 	} else {
 		skp = ssp->smk_out;
 		object = smack_net_ambient->smk_known;
@@ -2034,9 +2142,9 @@ static int smk_ipv6_port_check(struct sock *sk, struct sockaddr_in6 *address,
 	list_for_each_entry(spp, &smk_ipv6_port_list, list) {
 		if (spp->smk_port != port)
 			continue;
-		object = spp->smk_in;
+		object = spp->smk_in->smk_known;
 		if (act == SMK_CONNECTING)
-			ssp->smk_packet = spp->smk_out->smk_known;
+			ssp->smk_packet = spp->smk_out;
 		break;
 	}

@@ -2076,7 +2184,7 @@ static int smack_inode_setsecurity(struct inode *inode, const char *name,
 	int rc = 0;

 	if (value == NULL || size > SMK_LONGLABEL || size == 0)
-		return -EACCES;
+		return -EINVAL;

 	skp = smk_import_entry(value, size);
 	if (skp == NULL)
@@ -2100,7 +2208,7 @@ static int smack_inode_setsecurity(struct inode *inode, const char *name,
 	ssp = sock->sk->sk_security;

 	if (strcmp(name, XATTR_SMACK_IPIN) == 0)
-		ssp->smk_in = skp->smk_known;
+		ssp->smk_in = skp;
 	else if (strcmp(name, XATTR_SMACK_IPOUT) == 0) {
 		ssp->smk_out = skp;
 		if (sock->sk->sk_family == PF_INET) {
@@ -2713,6 +2821,15 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode)
 	 * of the superblock.
 	 */
 	if (opt_dentry->d_parent == opt_dentry) {
+		if (sbp->s_magic == CGROUP_SUPER_MAGIC) {
+			/*
+			 * The cgroup filesystem is never mounted,
+			 * so there's no opportunity to set the mount
+			 * options.
+			 */
+			sbsp->smk_root = smack_known_star.smk_known;
+			sbsp->smk_default = smack_known_star.smk_known;
+		}
 		isp->smk_inode = sbsp->smk_root;
 		isp->smk_flags |= SMK_INODE_INSTANT;
 		goto unlockandout;
@@ -2726,16 +2843,20 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode)
 	 */
 	switch (sbp->s_magic) {
 	case SMACK_MAGIC:
+	case PIPEFS_MAGIC:
+	case SOCKFS_MAGIC:
+	case CGROUP_SUPER_MAGIC:
 		/*
 		 * Casey says that it's a little embarrassing
 		 * that the smack file system doesn't do
 		 * extended attributes.
-		 */
-		final = smack_known_star.smk_known;
-		break;
-	case PIPEFS_MAGIC:
-		/*
+		 *
 		 * Casey says pipes are easy (?)
+		 *
+		 * Socket access is controlled by the socket
+		 * structures associated with the task involved.
+		 *
+		 * Cgroupfs is special
 		 */
 		final = smack_known_star.smk_known;
 		break;
@@ -2747,13 +2868,6 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode)
 		 */
 		final = ckp->smk_known;
 		break;
-	case SOCKFS_MAGIC:
-		/*
-		 * Socket access is controlled by the socket
-		 * structures associated with the task involved.
-		 */
-		final = smack_known_star.smk_known;
-		break;
 	case PROC_SUPER_MAGIC:
 		/*
 		 * Casey says procfs appears not to care.
@@ -2959,30 +3073,34 @@ static int smack_unix_stream_connect(struct sock *sock,
 				     struct sock *other, struct sock *newsk)
 {
 	struct smack_known *skp;
+	struct smack_known *okp;
 	struct socket_smack *ssp = sock->sk_security;
 	struct socket_smack *osp = other->sk_security;
 	struct socket_smack *nsp = newsk->sk_security;
 	struct smk_audit_info ad;
 	int rc = 0;
-
 #ifdef CONFIG_AUDIT
 	struct lsm_network_audit net;
-
-	smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
-	smk_ad_setfield_u_net_sk(&ad, other);
 #endif

 	if (!smack_privileged(CAP_MAC_OVERRIDE)) {
 		skp = ssp->smk_out;
-		rc = smk_access(skp, osp->smk_in, MAY_WRITE, &ad);
+		okp = osp->smk_out;
+#ifdef CONFIG_AUDIT
+		smk_ad_init_net(&ad, __func__, LSM_AUDIT_DATA_NET, &net);
+		smk_ad_setfield_u_net_sk(&ad, other);
+#endif
+		rc = smk_access(skp, okp->smk_known, MAY_WRITE, &ad);
+		if (rc == 0)
+			rc = smk_access(okp, okp->smk_known, MAY_WRITE, NULL);
 	}

 	/*
 	 * Cross reference the peer labels for SO_PEERSEC.
 	 */
 	if (rc == 0) {
-		nsp->smk_packet = ssp->smk_out->smk_known;
-		ssp->smk_packet = osp->smk_out->smk_known;
+		nsp->smk_packet = ssp->smk_out;
+		ssp->smk_packet = osp->smk_out;
 	}

 	return rc;
@@ -3014,7 +3132,7 @@ static int smack_unix_may_send(struct socket *sock, struct socket *other)
 		return 0;

 	skp = ssp->smk_out;
-	return smk_access(skp, osp->smk_in, MAY_WRITE, &ad);
+	return smk_access(skp, osp->smk_in->smk_known, MAY_WRITE, &ad);
 }

 /**
@@ -3109,7 +3227,7 @@ static struct smack_known *smack_from_secattr(struct netlbl_lsm_secattr *sap,
 		if (found)
 			return skp;

-		if (ssp != NULL && ssp->smk_in == smack_known_star.smk_known)
+		if (ssp != NULL && ssp->smk_in == &smack_known_star)
 			return &smack_known_web;
 		return &smack_known_star;
 	}
@@ -3228,7 +3346,7 @@ static int smack_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
 		 * This is the simplist possible security model
 		 * for networking.
 		 */
-		rc = smk_access(skp, ssp->smk_in, MAY_WRITE, &ad);
+		rc = smk_access(skp, ssp->smk_in->smk_known, MAY_WRITE, &ad);
 		if (rc != 0)
 			netlbl_skbuff_err(skb, rc, 0);
 		break;
@@ -3263,7 +3381,7 @@ static int smack_socket_getpeersec_stream(struct socket *sock,

 	ssp = sock->sk->sk_security;
 	if (ssp->smk_packet != NULL) {
-		rcp = ssp->smk_packet;
+		rcp = ssp->smk_packet->smk_known;
 		slen = strlen(rcp) + 1;
 	}

@@ -3348,7 +3466,7 @@ static void smack_sock_graft(struct sock *sk, struct socket *parent)
 		return;

 	ssp = sk->sk_security;
-	ssp->smk_in = skp->smk_known;
+	ssp->smk_in = skp;
 	ssp->smk_out = skp;
 	/* cssp->smk_packet is already set in smack_inet_csk_clone() */
 }
@@ -3408,7 +3526,7 @@ static int smack_inet_conn_request(struct sock *sk, struct sk_buff *skb,
 	 * Receiving a packet requires that the other end be able to write
 	 * here. Read access is not required.
 	 */
-	rc = smk_access(skp, ssp->smk_in, MAY_WRITE, &ad);
+	rc = smk_access(skp, ssp->smk_in->smk_known, MAY_WRITE, &ad);
 	if (rc != 0)
 		return rc;

@@ -3452,7 +3570,7 @@ static void smack_inet_csk_clone(struct sock *sk,

 	if (req->peer_secid != 0) {
 		skp = smack_from_secid(req->peer_secid);
-		ssp->smk_packet = skp->smk_known;
+		ssp->smk_packet = skp;
 	} else
 		ssp->smk_packet = NULL;
 }