Commit 1880eff7 authored by Casey Schaufler's avatar Casey Schaufler
Browse files

Smack: onlycap limits on CAP_MAC_ADMIN 

Smack is integrated with the POSIX capabilities scheme,
using the capabilities CAP_MAC_OVERRIDE and CAP_MAC_ADMIN to
determine if a process is allowed to ignore Smack checks or
change Smack related data respectively. Smack provides an
additional restriction that if an onlycap value is set
by writing to /smack/onlycap only tasks with that Smack
label are allowed to use CAP_MAC_OVERRIDE.

This change adds CAP_MAC_ADMIN as a capability that is affected
by the onlycap mechanism.

Targeted for git://git.gitorious.org/smack-next/kernel.git



Signed-off-by: default avatarCasey Schaufler <casey@schaufler-ca.com>
parent eb982cb4

security/smack/smack.h

+13 −0
Original line number Diff line number Diff line
@@ -282,6 +282,19 @@ static inline char *smk_of_current(void) 
	return smk_of_task(current_security());

}



/*

 * Is the task privileged and allowed to be privileged

 * by the onlycap rule.

 */

static inline int smack_privileged(int cap)

{

	if (!capable(cap))

		return 0;

	if (smack_onlycap == NULL || smack_onlycap == smk_of_current())

		return 1;

	return 0;

}



/*

 * logging functions

 */

security/smack/smack_access.c

+2 −7
Original line number Diff line number Diff line
@@ -220,14 +220,9 @@ int smk_curacc(char *obj_label, u32 mode, struct smk_audit_info *a) 
	}



	/*

	 * Return if a specific label has been designated as the

	 * only one that gets privilege and current does not

	 * have that label.

	 * Allow for priviliged to override policy.

	 */

	if (smack_onlycap != NULL && smack_onlycap != sp)

		goto out_audit;



	if (capable(CAP_MAC_OVERRIDE))

	if (rc != 0 && smack_privileged(CAP_MAC_OVERRIDE))

		rc = 0;



out_audit:

security/smack/smack_lsm.c

+9 −8
Original line number Diff line number Diff line
@@ -217,7 +217,7 @@ static int smack_syslog(int typefrom_file) 
	int rc = 0;

	char *sp = smk_of_current();



	if (capable(CAP_MAC_OVERRIDE))

	if (smack_privileged(CAP_MAC_OVERRIDE))

		return 0;



	 if (sp != smack_known_floor.smk_known)
@@ -821,7 +821,7 @@ static int smack_inode_setxattr(struct dentry *dentry, const char *name, 
	    strcmp(name, XATTR_NAME_SMACKIPOUT) == 0 ||

	    strcmp(name, XATTR_NAME_SMACKEXEC) == 0 ||

	    strcmp(name, XATTR_NAME_SMACKMMAP) == 0) {

		if (!capable(CAP_MAC_ADMIN))

		if (!smack_privileged(CAP_MAC_ADMIN))

			rc = -EPERM;

		/*

		 * check label validity here so import wont fail on
@@ -831,7 +831,7 @@ static int smack_inode_setxattr(struct dentry *dentry, const char *name, 
		    smk_import(value, size) == NULL)

			rc = -EINVAL;

	} else if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0) {

		if (!capable(CAP_MAC_ADMIN))

		if (!smack_privileged(CAP_MAC_ADMIN))

			rc = -EPERM;

		if (size != TRANS_TRUE_SIZE ||

		    strncmp(value, TRANS_TRUE, TRANS_TRUE_SIZE) != 0)
@@ -927,7 +927,7 @@ static int smack_inode_removexattr(struct dentry *dentry, const char *name) 
	    strcmp(name, XATTR_NAME_SMACKEXEC) == 0 ||

	    strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0 ||

	    strcmp(name, XATTR_NAME_SMACKMMAP)) {

		if (!capable(CAP_MAC_ADMIN))

		if (!smack_privileged(CAP_MAC_ADMIN))

			rc = -EPERM;

	} else

		rc = cap_inode_removexattr(dentry, name);
@@ -1716,7 +1716,8 @@ static int smack_task_wait(struct task_struct *p) 
	 * state into account in the decision as well as

	 * the smack value.

	 */

	if (capable(CAP_MAC_OVERRIDE) || has_capability(p, CAP_MAC_OVERRIDE))

	if (smack_privileged(CAP_MAC_OVERRIDE) ||

	    has_capability(p, CAP_MAC_OVERRIDE))

		rc = 0;

	/* we log only if we didn't get overriden */

 out_log:
@@ -2717,7 +2718,7 @@ static int smack_setprocattr(struct task_struct *p, char *name, 
	if (p != current)

		return -EPERM;



	if (!capable(CAP_MAC_ADMIN))

	if (!smack_privileged(CAP_MAC_ADMIN))

		return -EPERM;



	if (value == NULL || size == 0 || size >= SMK_LONGLABEL)
@@ -2780,7 +2781,7 @@ static int smack_unix_stream_connect(struct sock *sock, 
	smk_ad_setfield_u_net_sk(&ad, other);

#endif



	if (!capable(CAP_MAC_OVERRIDE))

	if (!smack_privileged(CAP_MAC_OVERRIDE))

		rc = smk_access(ssp->smk_out, osp->smk_in, MAY_WRITE, &ad);



	/*
@@ -2816,7 +2817,7 @@ static int smack_unix_may_send(struct socket *sock, struct socket *other) 
	smk_ad_setfield_u_net_sk(&ad, other->sk);

#endif



	if (!capable(CAP_MAC_OVERRIDE))

	if (!smack_privileged(CAP_MAC_OVERRIDE))

		rc = smk_access(ssp->smk_out, osp->smk_in, MAY_WRITE, &ad);



	return rc;

security/smack/smackfs.c

+10 −11
Original line number Diff line number Diff line
@@ -595,13 +595,12 @@ static int smk_open_load(struct inode *inode, struct file *file) 
static ssize_t smk_write_load(struct file *file, const char __user *buf,

			      size_t count, loff_t *ppos)

{



	/*

	 * Must have privilege.

	 * No partial writes.

	 * Enough data must be present.

	 */

	if (!capable(CAP_MAC_ADMIN))

	if (!smack_privileged(CAP_MAC_ADMIN))

		return -EPERM;



	return smk_write_rules_list(file, buf, count, ppos, NULL, NULL,
@@ -787,7 +786,7 @@ static ssize_t smk_set_cipso(struct file *file, const char __user *buf, 
	 * No partial writes.

	 * Enough data must be present.

	 */

	if (!capable(CAP_MAC_ADMIN))

	if (!smack_privileged(CAP_MAC_ADMIN))

		return -EPERM;

	if (*ppos != 0)

		return -EINVAL;
@@ -1090,7 +1089,7 @@ static ssize_t smk_write_netlbladdr(struct file *file, const char __user *buf, 
	 * "<addr/mask, as a.b.c.d/e><space><label>"

	 * "<addr, as a.b.c.d><space><label>"

	 */

	if (!capable(CAP_MAC_ADMIN))

	if (!smack_privileged(CAP_MAC_ADMIN))

		return -EPERM;

	if (*ppos != 0)

		return -EINVAL;
@@ -1267,7 +1266,7 @@ static ssize_t smk_write_doi(struct file *file, const char __user *buf, 
	char temp[80];

	int i;



	if (!capable(CAP_MAC_ADMIN))

	if (!smack_privileged(CAP_MAC_ADMIN))

		return -EPERM;



	if (count >= sizeof(temp) || count == 0)
@@ -1334,7 +1333,7 @@ static ssize_t smk_write_direct(struct file *file, const char __user *buf, 
	char temp[80];

	int i;



	if (!capable(CAP_MAC_ADMIN))

	if (!smack_privileged(CAP_MAC_ADMIN))

		return -EPERM;



	if (count >= sizeof(temp) || count == 0)
@@ -1412,7 +1411,7 @@ static ssize_t smk_write_mapped(struct file *file, const char __user *buf, 
	char temp[80];

	int i;



	if (!capable(CAP_MAC_ADMIN))

	if (!smack_privileged(CAP_MAC_ADMIN))

		return -EPERM;



	if (count >= sizeof(temp) || count == 0)
@@ -1503,7 +1502,7 @@ static ssize_t smk_write_ambient(struct file *file, const char __user *buf, 
	char *data;

	int rc = count;



	if (!capable(CAP_MAC_ADMIN))

	if (!smack_privileged(CAP_MAC_ADMIN))

		return -EPERM;



	data = kzalloc(count + 1, GFP_KERNEL);
@@ -1586,7 +1585,7 @@ static ssize_t smk_write_onlycap(struct file *file, const char __user *buf, 
	char *sp = smk_of_task(current->cred->security);

	int rc = count;



	if (!capable(CAP_MAC_ADMIN))

	if (!smack_privileged(CAP_MAC_ADMIN))

		return -EPERM;



	/*
@@ -1664,7 +1663,7 @@ static ssize_t smk_write_logging(struct file *file, const char __user *buf, 
	char temp[32];

	int i;



	if (!capable(CAP_MAC_ADMIN))

	if (!smack_privileged(CAP_MAC_ADMIN))

		return -EPERM;



	if (count >= sizeof(temp) || count == 0)
@@ -1885,7 +1884,7 @@ static ssize_t smk_write_load2(struct file *file, const char __user *buf, 
	/*

	 * Must have privilege.

	 */

	if (!capable(CAP_MAC_ADMIN))

	if (!smack_privileged(CAP_MAC_ADMIN))

		return -EPERM;



	return smk_write_rules_list(file, buf, count, ppos, NULL, NULL,

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