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-rw-r--r--security/smack/smack.h17
-rw-r--r--security/smack/smack_access.c54
-rw-r--r--security/smack/smack_lsm.c74
-rw-r--r--security/smack/smackfs.c37
4 files changed, 139 insertions, 43 deletions
diff --git a/security/smack/smack.h b/security/smack/smack.h
index a2e2cdfab4ef..129c4eb8ffb1 100644
--- a/security/smack/smack.h
+++ b/security/smack/smack.h
@@ -62,6 +62,7 @@ struct task_smack {
};
#define SMK_INODE_INSTANT 0x01 /* inode is instantiated */
+#define SMK_INODE_TRANSMUTE 0x02 /* directory is transmuting */
/*
* A label access rule.
@@ -167,6 +168,10 @@ struct smack_known {
#define SMACK_CIPSO_MAXCATNUM 239 /* CIPSO 2.2 standard */
/*
+ * Flag for transmute access
+ */
+#define MAY_TRANSMUTE 64
+/*
* Just to make the common cases easier to deal with
*/
#define MAY_ANY (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
@@ -197,6 +202,7 @@ struct inode_smack *new_inode_smack(char *);
/*
* These functions are in smack_access.c
*/
+int smk_access_entry(char *, char *);
int smk_access(char *, char *, int, struct smk_audit_info *);
int smk_curacc(char *, u32, struct smk_audit_info *);
int smack_to_cipso(const char *, struct smack_cipso *);
@@ -240,6 +246,15 @@ static inline void smack_catset_bit(int cat, char *catsetp)
}
/*
+ * Is the directory transmuting?
+ */
+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;
+}
+
+/*
* Present a pointer to the smack label in an inode blob.
*/
static inline char *smk_of_inode(const struct inode *isp)
@@ -265,7 +280,7 @@ static inline char *smk_of_forked(const struct task_smack *tsp)
}
/*
- * Present a pointer to the smack label in the curren task blob.
+ * Present a pointer to the smack label in the current task blob.
*/
static inline char *smk_of_current(void)
{
diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c
index 42becbc1ce33..7ba8478f599e 100644
--- a/security/smack/smack_access.c
+++ b/security/smack/smack_access.c
@@ -67,6 +67,46 @@ static u32 smack_next_secid = 10;
int log_policy = SMACK_AUDIT_DENIED;
/**
+ * smk_access_entry - look up matching access rule
+ * @subject_label: a pointer to the subject's Smack label
+ * @object_label: a pointer to the object's Smack label
+ *
+ * This function looks up the subject/object pair in the
+ * access rule list and returns pointer to the matching rule if found,
+ * NULL otherwise.
+ *
+ * NOTE:
+ * Even though Smack labels are usually shared on smack_list
+ * labels that come in off the network can't be imported
+ * and added to the list for locking reasons.
+ *
+ * Therefore, it is necessary to check the contents of the labels,
+ * not just the pointer values. Of course, in most cases the labels
+ * will be on the list, so checking the pointers may be a worthwhile
+ * optimization.
+ */
+int smk_access_entry(char *subject_label, char *object_label)
+{
+ u32 may = MAY_NOT;
+ struct smack_rule *srp;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(srp, &smack_rule_list, list) {
+ if (srp->smk_subject == subject_label ||
+ strcmp(srp->smk_subject, subject_label) == 0) {
+ if (srp->smk_object == object_label ||
+ strcmp(srp->smk_object, object_label) == 0) {
+ may = srp->smk_access;
+ break;
+ }
+ }
+ }
+ rcu_read_unlock();
+
+ return may;
+}
+
+/**
* smk_access - determine if a subject has a specific access to an object
* @subject_label: a pointer to the subject's Smack label
* @object_label: a pointer to the object's Smack label
@@ -90,7 +130,6 @@ int smk_access(char *subject_label, char *object_label, int request,
struct smk_audit_info *a)
{
u32 may = MAY_NOT;
- struct smack_rule *srp;
int rc = 0;
/*
@@ -144,18 +183,7 @@ int smk_access(char *subject_label, char *object_label, int request,
* access (e.g. read is included in readwrite) it's
* good.
*/
- rcu_read_lock();
- list_for_each_entry_rcu(srp, &smack_rule_list, list) {
- if (srp->smk_subject == subject_label ||
- strcmp(srp->smk_subject, subject_label) == 0) {
- if (srp->smk_object == object_label ||
- strcmp(srp->smk_object, object_label) == 0) {
- may = srp->smk_access;
- break;
- }
- }
- }
- rcu_read_unlock();
+ may = smk_access_entry(subject_label, object_label);
/*
* This is a bit map operation.
*/
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 7e19afe0e738..05dc4da2e25f 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -3,12 +3,14 @@
*
* This file contains the smack hook function implementations.
*
- * Author:
+ * Authors:
* Casey Schaufler <casey@schaufler-ca.com>
+ * Jarkko Sakkinen <ext-jarkko.2.sakkinen@nokia.com>
*
* Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.com>
* Copyright (C) 2009 Hewlett-Packard Development Company, L.P.
* Paul Moore <paul.moore@hp.com>
+ * Copyright (C) 2010 Nokia Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2,
@@ -35,6 +37,9 @@
#define task_security(task) (task_cred_xxx((task), security))
+#define TRANS_TRUE "TRUE"
+#define TRANS_TRUE_SIZE 4
+
/**
* smk_fetch - Fetch the smack label from a file.
* @ip: a pointer to the inode
@@ -468,6 +473,8 @@ static int smack_inode_init_security(struct inode *inode, struct inode *dir,
char **name, void **value, size_t *len)
{
char *isp = smk_of_inode(inode);
+ char *dsp = smk_of_inode(dir);
+ u32 may;
if (name) {
*name = kstrdup(XATTR_SMACK_SUFFIX, GFP_KERNEL);
@@ -476,6 +483,16 @@ static int smack_inode_init_security(struct inode *inode, struct inode *dir,
}
if (value) {
+ may = smk_access_entry(smk_of_current(), dsp);
+
+ /*
+ * If the access rule allows transmutation and
+ * the directory requests transmutation then
+ * by all means transmute.
+ */
+ if (((may & MAY_TRANSMUTE) != 0) && smk_inode_transmutable(dir))
+ isp = dsp;
+
*value = kstrdup(isp, GFP_KERNEL);
if (*value == NULL)
return -ENOMEM;
@@ -709,6 +726,12 @@ static int smack_inode_setxattr(struct dentry *dentry, const char *name,
if (size == 0 || size >= SMK_LABELLEN ||
smk_import(value, size) == NULL)
rc = -EINVAL;
+ } else if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0) {
+ if (!capable(CAP_MAC_ADMIN))
+ rc = -EPERM;
+ if (size != TRANS_TRUE_SIZE ||
+ strncmp(value, TRANS_TRUE, TRANS_TRUE_SIZE) != 0)
+ rc = -EINVAL;
} else
rc = cap_inode_setxattr(dentry, name, value, size, flags);
@@ -735,35 +758,23 @@ static int smack_inode_setxattr(struct dentry *dentry, const char *name,
static void smack_inode_post_setxattr(struct dentry *dentry, const char *name,
const void *value, size_t size, int flags)
{
- struct inode_smack *isp;
char *nsp;
-
- /*
- * Not SMACK or SMACKEXEC
- */
- if (strcmp(name, XATTR_NAME_SMACK) &&
- strcmp(name, XATTR_NAME_SMACKEXEC))
- return;
-
- isp = dentry->d_inode->i_security;
-
- /*
- * No locking is done here. This is a pointer
- * assignment.
- */
- nsp = smk_import(value, size);
+ struct inode_smack *isp = dentry->d_inode->i_security;
if (strcmp(name, XATTR_NAME_SMACK) == 0) {
+ nsp = smk_import(value, size);
if (nsp != NULL)
isp->smk_inode = nsp;
else
isp->smk_inode = smack_known_invalid.smk_known;
- } else {
+ } else if (strcmp(name, XATTR_NAME_SMACKEXEC) == 0) {
+ nsp = smk_import(value, size);
if (nsp != NULL)
isp->smk_task = nsp;
else
isp->smk_task = smack_known_invalid.smk_known;
- }
+ } else if (strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0)
+ isp->smk_flags |= SMK_INODE_TRANSMUTE;
return;
}
@@ -803,7 +814,8 @@ static int smack_inode_removexattr(struct dentry *dentry, const char *name)
if (strcmp(name, XATTR_NAME_SMACK) == 0 ||
strcmp(name, XATTR_NAME_SMACKIPIN) == 0 ||
strcmp(name, XATTR_NAME_SMACKIPOUT) == 0 ||
- strcmp(name, XATTR_NAME_SMACKEXEC) == 0) {
+ strcmp(name, XATTR_NAME_SMACKEXEC) == 0 ||
+ strcmp(name, XATTR_NAME_SMACKTRANSMUTE) == 0) {
if (!capable(CAP_MAC_ADMIN))
rc = -EPERM;
} else
@@ -2274,6 +2286,8 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode)
char *csp = smk_of_current();
char *fetched;
char *final;
+ char trattr[TRANS_TRUE_SIZE];
+ int transflag = 0;
struct dentry *dp;
if (inode == NULL)
@@ -2392,10 +2406,19 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode)
*/
dp = dget(opt_dentry);
fetched = smk_fetch(XATTR_NAME_SMACK, inode, dp);
- if (fetched != NULL)
+ if (fetched != NULL) {
final = fetched;
- isp->smk_task = smk_fetch(XATTR_NAME_SMACKEXEC, inode,
- dp);
+ if (S_ISDIR(inode->i_mode)) {
+ trattr[0] = '\0';
+ inode->i_op->getxattr(dp,
+ XATTR_NAME_SMACKTRANSMUTE,
+ trattr, TRANS_TRUE_SIZE);
+ if (strncmp(trattr, TRANS_TRUE,
+ TRANS_TRUE_SIZE) == 0)
+ transflag = SMK_INODE_TRANSMUTE;
+ }
+ }
+ isp->smk_task = smk_fetch(XATTR_NAME_SMACKEXEC, inode, dp);
dput(dp);
break;
@@ -2406,7 +2429,7 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode)
else
isp->smk_inode = final;
- isp->smk_flags |= SMK_INODE_INSTANT;
+ isp->smk_flags |= (SMK_INODE_INSTANT | transflag);
unlockandout:
mutex_unlock(&isp->smk_lock);
@@ -2456,6 +2479,7 @@ static int smack_setprocattr(struct task_struct *p, char *name,
void *value, size_t size)
{
struct task_smack *tsp;
+ struct task_smack *oldtsp;
struct cred *new;
char *newsmack;
@@ -2485,6 +2509,7 @@ static int smack_setprocattr(struct task_struct *p, char *name,
if (newsmack == smack_known_web.smk_known)
return -EPERM;
+ oldtsp = p->cred->security;
new = prepare_creds();
if (new == NULL)
return -ENOMEM;
@@ -2494,6 +2519,7 @@ static int smack_setprocattr(struct task_struct *p, char *name,
return -ENOMEM;
}
tsp->smk_task = newsmack;
+ tsp->smk_forked = oldtsp->smk_forked;
new->security = tsp;
commit_creds(new);
return size;
diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index 01a0be93d8d0..362d5eda948b 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -109,9 +109,12 @@ const char *smack_cipso_option = SMACK_CIPSO_OPTION;
* SMK_ACCESSLEN: Maximum length for a rule access field
* SMK_LOADLEN: Smack rule length
*/
-#define SMK_ACCESS "rwxa"
-#define SMK_ACCESSLEN (sizeof(SMK_ACCESS) - 1)
-#define SMK_LOADLEN (SMK_LABELLEN + SMK_LABELLEN + SMK_ACCESSLEN)
+#define SMK_OACCESS "rwxa"
+#define SMK_ACCESS "rwxat"
+#define SMK_OACCESSLEN (sizeof(SMK_OACCESS) - 1)
+#define SMK_ACCESSLEN (sizeof(SMK_ACCESS) - 1)
+#define SMK_OLOADLEN (SMK_LABELLEN + SMK_LABELLEN + SMK_OACCESSLEN)
+#define SMK_LOADLEN (SMK_LABELLEN + SMK_LABELLEN + SMK_ACCESSLEN)
/**
* smk_netlabel_audit_set - fill a netlbl_audit struct
@@ -175,6 +178,8 @@ static int load_seq_show(struct seq_file *s, void *v)
seq_putc(s, 'x');
if (srp->smk_access & MAY_APPEND)
seq_putc(s, 'a');
+ if (srp->smk_access & MAY_TRANSMUTE)
+ seq_putc(s, 't');
if (srp->smk_access == 0)
seq_putc(s, '-');
@@ -273,10 +278,15 @@ static ssize_t smk_write_load(struct file *file, const char __user *buf,
if (!capable(CAP_MAC_ADMIN))
return -EPERM;
- if (*ppos != 0 || count != SMK_LOADLEN)
+ if (*ppos != 0)
+ return -EINVAL;
+ /*
+ * Minor hack for backward compatability
+ */
+ if (count < (SMK_OLOADLEN) || count > SMK_LOADLEN)
return -EINVAL;
- data = kzalloc(count, GFP_KERNEL);
+ data = kzalloc(SMK_LOADLEN, GFP_KERNEL);
if (data == NULL)
return -ENOMEM;
@@ -285,6 +295,12 @@ static ssize_t smk_write_load(struct file *file, const char __user *buf,
goto out;
}
+ /*
+ * More on the minor hack for backward compatability
+ */
+ if (count == (SMK_OLOADLEN))
+ data[SMK_OLOADLEN] = '-';
+
rule = kzalloc(sizeof(*rule), GFP_KERNEL);
if (rule == NULL) {
rc = -ENOMEM;
@@ -345,6 +361,17 @@ static ssize_t smk_write_load(struct file *file, const char __user *buf,
goto out_free_rule;
}
+ switch (data[SMK_LABELLEN + SMK_LABELLEN + 4]) {
+ case '-':
+ break;
+ case 't':
+ case 'T':
+ rule->smk_access |= MAY_TRANSMUTE;
+ break;
+ default:
+ goto out_free_rule;
+ }
+
rc = smk_set_access(rule);
if (!rc)