[PATCH 5/8] smack: misc cleanups in preparation for a namespace patch

Lukasz Pawelczyk
2015-05-21T11:54:14Z

This patch does some small miscellaneous cleanups and additions that
should not change the code behaviour in any way. Its only purpose is to
shape the code in a way that the smack namespace patches would be
smaller and easier to understand.

Changes:
- two small functions added
- one macro has been moved to a header
- minor code reformatting in several places for readability
- unnecessarily increasing string size has been fixed

This patch should not change the behaviour of the Smack in any way.

Signed-off-by: Lukasz Pawelczyk <l.pawelczyk@samsung.com>
---
security/smack/smack.h | 25 ++++++++++++++++++-
security/smack/smack_access.c | 18 +++++++++-----
security/smack/smack_lsm.c | 58 ++++++++++++++++---------------------------
3 files changed, 58 insertions(+), 43 deletions(-)

diff --git a/security/smack/smack.h b/security/smack/smack.h
index fa32495..3818d19 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -229,6 +229,7 @@ struct smk_audit_info {
struct smack_audit_data sad;
#endif
};
+
/*
* These functions are in smack_lsm.c
*/
@@ -240,7 +241,7 @@ struct inode_smack *new_inode_smack(struct smack_known *);
int smk_access_entry(char *, char *, struct list_head *);
int smk_access(struct smack_known *, struct smack_known *,
int, struct smk_audit_info *);
-int smk_tskacc(struct task_smack *, struct smack_known *,
+int smk_tskacc(struct task_struct *, struct smack_known *,
u32, struct smk_audit_info *);
int smk_curacc(struct smack_known *, u32, struct smk_audit_info *);
struct smack_known *smack_from_secid(const u32);
@@ -287,6 +288,7 @@ extern struct hlist_head smack_known_hash[SMACK_HASH_SLOTS];
static inline int smk_inode_transmutable(const struct inode *isp)
{
struct inode_smack *sip = isp->i_security;
+
return (sip->smk_flags & SMK_INODE_TRANSMUTE) != 0;
}

@@ -296,10 +298,31 @@ static inline int smk_inode_transmutable(const struct inode *isp)
static inline struct smack_known *smk_of_inode(const struct inode *isp)
{
struct inode_smack *sip = isp->i_security;
+
return sip->smk_inode;
}

/*
+ * Present a pointer to the smack label entry in an inode blob for an exec.
+ */
+static inline struct smack_known *smk_of_exec(const struct inode *isp)
+{
+ struct inode_smack *sip = isp->i_security;
+
+ return sip->smk_task;
+}
+
+/*
+ * Present a pointer to the smack label entry in an inode blob for an mmap.
+ */
+static inline struct smack_known *smk_of_mmap(const struct inode *isp)
+{
+ struct inode_smack *sip = isp->i_security;
+
+ return sip->smk_mmap;
+}
+
+/*
* Present a pointer to the smack label entry in an task blob.
*/
static inline struct smack_known *smk_of_task(const struct task_smack *tsp)
diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c
index 3bf4cad..47a9c92 100644
--- a/security/smack/smack_access.c
+++ b/security/smack/smack_access.c
@@ -167,6 +167,7 @@ int smk_access(struct smack_known *subject, struct smack_known *object,
if (subject == &smack_known_hat)
goto out_audit;
}
+
/*
* Beyond here an explicit relationship is required.
* If the requested access is contained in the available
@@ -183,6 +184,7 @@ int smk_access(struct smack_known *subject, struct smack_known *object,
rc = -EACCES;
goto out_audit;
}
+
#ifdef CONFIG_SECURITY_SMACK_BRINGUP
/*
* Return a positive value if using bringup mode.
@@ -225,10 +227,10 @@ out_audit:
* non zero otherwise. It allows that the task may have the capability
* to override the rules.
*/
-int smk_tskacc(struct task_smack *tsp, struct smack_known *obj_known,
+int smk_tskacc(struct task_struct *task, struct smack_known *obj_known,
u32 mode, struct smk_audit_info *a)
{
- struct smack_known *sbj_known = smk_of_task(tsp);
+ struct smack_known *sbj_known = smk_of_task_struct(task);
int may;
int rc;

@@ -237,13 +239,19 @@ int smk_tskacc(struct task_smack *tsp, struct smack_known *obj_known,
*/
rc = smk_access(sbj_known, obj_known, mode, NULL);
if (rc >= 0) {
+ struct task_smack *tsp;
+
/*
* If there is an entry in the task's rule list
* it can further restrict access.
*/
+ rcu_read_lock();
+ tsp = __task_cred(task)->security;
may = smk_access_entry(sbj_known->smk_known,
obj_known->smk_known,
&tsp->smk_rules);
+ rcu_read_unlock();
+
if (may < 0)
goto out_audit;
if ((mode & may) == mode)
@@ -280,9 +288,7 @@ out_audit:
int smk_curacc(struct smack_known *obj_known,
u32 mode, struct smk_audit_info *a)
{
- struct task_smack *tsp = current_security();
-
- return smk_tskacc(tsp, obj_known, mode, a);
+ return smk_tskacc(current, obj_known, mode, a);
}

#ifdef CONFIG_AUDIT
@@ -456,7 +462,7 @@ char *smk_parse_smack(const char *string, int len)
int i;

if (len <= 0)
- len = strlen(string) + 1;
+ len = strlen(string);

/*
* Reserve a leading '-' as an indicator that
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 4a197b6..bb74ca9 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -383,8 +383,6 @@ static int smk_ptrace_rule_check(struct task_struct *tracer,
{
int rc;
struct smk_audit_info ad, *saip = NULL;
- struct task_smack *tsp;
- struct smack_known *tracer_known;

if ((mode & PTRACE_MODE_NOAUDIT) == 0) {
smk_ad_init(&ad, func, LSM_AUDIT_DATA_TASK);
@@ -392,13 +390,12 @@ static int smk_ptrace_rule_check(struct task_struct *tracer,
saip = &ad;
}

- rcu_read_lock();
- tsp = __task_cred(tracer)->security;
- tracer_known = smk_of_task(tsp);

if ((mode & PTRACE_MODE_ATTACH) &&
(smack_ptrace_rule == SMACK_PTRACE_EXACT ||
smack_ptrace_rule == SMACK_PTRACE_DRACONIAN)) {
+ struct smack_known *tracer_known = smk_of_task_struct(tracer);
+
if (tracer_known->smk_known == tracee_known->smk_known)
rc = 0;
else if (smack_ptrace_rule == SMACK_PTRACE_DRACONIAN)
@@ -406,22 +403,18 @@ static int smk_ptrace_rule_check(struct task_struct *tracer,
else if (smack_has_privilege(tracer, CAP_SYS_PTRACE))
rc = 0;
else
- rc = -EACCES;
+ rc = -EPERM;

if (saip)
smack_log(tracer_known->smk_known,
tracee_known->smk_known,
0, rc, saip);

- rcu_read_unlock();
return rc;
}

/* In case of rule==SMACK_PTRACE_DEFAULT or mode==PTRACE_MODE_READ */
- rc = smk_tskacc(tsp, tracee_known, smk_ptrace_mode(mode), saip);
-
- rcu_read_unlock();
- return rc;
+ return smk_tskacc(tracer, tracee_known, smk_ptrace_mode(mode), saip);
}

/*
@@ -440,9 +433,7 @@ static int smk_ptrace_rule_check(struct task_struct *tracer,
*/
static int smack_ptrace_access_check(struct task_struct *ctp, unsigned int mode)
{
- struct smack_known *skp;
-
- skp = smk_of_task_struct(ctp);
+ struct smack_known *skp = smk_of_task_struct(ctp);

return smk_ptrace_rule_check(current, skp, mode, __func__);
}
@@ -457,13 +448,9 @@ static int smack_ptrace_access_check(struct task_struct *ctp, unsigned int mode)
*/
static int smack_ptrace_traceme(struct task_struct *ptp)
{
- int rc;
- struct smack_known *skp;
-
- skp = smk_of_task(current_security());
+ struct smack_known *skp = smk_of_current();

- rc = smk_ptrace_rule_check(ptp, skp, PTRACE_MODE_ATTACH, __func__);
- return rc;
+ return smk_ptrace_rule_check(ptp, skp, PTRACE_MODE_ATTACH, __func__);
}

/**
@@ -1529,13 +1516,14 @@ static int smack_mmap_file(struct file *file,
if (file == NULL)
return 0;

+ tsp = current_security();
+ skp = smk_of_task(tsp);
isp = file_inode(file)->i_security;
- if (isp->smk_mmap == NULL)
- return 0;
mkp = isp->smk_mmap;

- tsp = current_security();
- skp = smk_of_current();
+ if (mkp == NULL)
+ return 0;
+
rc = 0;

rcu_read_lock();
@@ -3348,11 +3336,13 @@ static int smack_setprocattr(struct task_struct *p, char *name,
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 smack_known *skp_out = ssp->smk_out;
+ struct smack_known *okp_out = osp->smk_out;
+ struct smack_known *skp_in = ssp->smk_in;
+ struct smack_known *okp_in = osp->smk_in;
struct smk_audit_info ad;
int rc = 0;
#ifdef CONFIG_AUDIT
@@ -3360,19 +3350,15 @@ static int smack_unix_stream_connect(struct sock *sock,
#endif

if (!smack_privileged(CAP_MAC_OVERRIDE)) {
- skp = ssp->smk_out;
- okp = osp->smk_in;
#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, MAY_WRITE, &ad);
- rc = smk_bu_note("UDS connect", skp, okp, MAY_WRITE, rc);
+ rc = smk_access(skp_out, okp_in, MAY_WRITE, &ad);
+ rc = smk_bu_note("UDS connect", skp_out, okp_in, MAY_WRITE, rc);
if (rc == 0) {
- okp = osp->smk_out;
- skp = ssp->smk_in;
- rc = smk_access(okp, skp, MAY_WRITE, &ad);
- rc = smk_bu_note("UDS connect", okp, skp,
+ rc = smk_access(okp_out, skp_in, MAY_WRITE, &ad);
+ rc = smk_bu_note("UDS connect", okp_out, skp_in,
MAY_WRITE, rc);
}
}
@@ -3381,8 +3367,8 @@ static int smack_unix_stream_connect(struct sock *sock,
* Cross reference the peer labels for SO_PEERSEC.
*/
if (rc == 0) {
- nsp->smk_packet = ssp->smk_out;
- ssp->smk_packet = osp->smk_out;
+ nsp->smk_packet = skp_out;
+ ssp->smk_packet = okp_out;
}

return rc;
--
2.1.0