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Diffstat (limited to 'security/smack/smackfs.c')
-rw-r--r--security/smack/smackfs.c329
1 files changed, 201 insertions, 128 deletions
diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index d9682985349e..5e0a64ebdf23 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -87,16 +87,6 @@ int smack_cipso_direct = SMACK_CIPSO_DIRECT_DEFAULT;
*/
int smack_cipso_mapped = SMACK_CIPSO_MAPPED_DEFAULT;
-/*
- * Unless a process is running with this label even
- * having CAP_MAC_OVERRIDE isn't enough to grant
- * privilege to violate MAC policy. If no label is
- * designated (the NULL case) capabilities apply to
- * everyone. It is expected that the hat (^) label
- * will be used if any label is used.
- */
-struct smack_known *smack_onlycap;
-
#ifdef CONFIG_SECURITY_SMACK_BRINGUP
/*
* Allow one label to be unconfined. This is for
@@ -338,8 +328,7 @@ static int smk_perm_from_str(const char *string)
* @import: if non-zero, import labels
* @len: label length limit
*
- * Returns 0 on success, -EINVAL on failure and -ENOENT when either subject
- * or object is missing.
+ * Returns 0 on success, appropriate error code on failure.
*/
static int smk_fill_rule(const char *subject, const char *object,
const char *access1, const char *access2,
@@ -351,16 +340,16 @@ static int smk_fill_rule(const char *subject, const char *object,
if (import) {
rule->smk_subject = smk_import_entry(subject, len);
- if (rule->smk_subject == NULL)
- return -EINVAL;
+ if (IS_ERR(rule->smk_subject))
+ return PTR_ERR(rule->smk_subject);
rule->smk_object = smk_import_entry(object, len);
- if (rule->smk_object == NULL)
- return -EINVAL;
+ if (IS_ERR(rule->smk_object))
+ return PTR_ERR(rule->smk_object);
} else {
cp = smk_parse_smack(subject, len);
- if (cp == NULL)
- return -EINVAL;
+ if (IS_ERR(cp))
+ return PTR_ERR(cp);
skp = smk_find_entry(cp);
kfree(cp);
if (skp == NULL)
@@ -368,8 +357,8 @@ static int smk_fill_rule(const char *subject, const char *object,
rule->smk_subject = skp;
cp = smk_parse_smack(object, len);
- if (cp == NULL)
- return -EINVAL;
+ if (IS_ERR(cp))
+ return PTR_ERR(cp);
skp = smk_find_entry(cp);
kfree(cp);
if (skp == NULL)
@@ -412,7 +401,7 @@ static int smk_parse_rule(const char *data, struct smack_parsed_rule *rule,
* @import: if non-zero, import labels
* @tokens: numer of substrings expected in data
*
- * Returns number of processed bytes on success, -1 on failure.
+ * Returns number of processed bytes on success, -ERRNO on failure.
*/
static ssize_t smk_parse_long_rule(char *data, struct smack_parsed_rule *rule,
int import, int tokens)
@@ -431,7 +420,7 @@ static ssize_t smk_parse_long_rule(char *data, struct smack_parsed_rule *rule,
if (data[cnt] == '\0')
/* Unexpected end of data */
- return -1;
+ return -EINVAL;
tok[i] = data + cnt;
@@ -529,14 +518,14 @@ static ssize_t smk_write_rules_list(struct file *file, const char __user *buf,
while (cnt < count) {
if (format == SMK_FIXED24_FMT) {
rc = smk_parse_rule(data, &rule, 1);
- if (rc != 0) {
- rc = -EINVAL;
+ if (rc < 0)
goto out;
- }
cnt = count;
} else {
rc = smk_parse_long_rule(data + cnt, &rule, 1, tokens);
- if (rc <= 0) {
+ if (rc < 0)
+ goto out;
+ if (rc == 0) {
rc = -EINVAL;
goto out;
}
@@ -567,23 +556,17 @@ static void *smk_seq_start(struct seq_file *s, loff_t *pos,
struct list_head *head)
{
struct list_head *list;
+ int i = *pos;
+
+ rcu_read_lock();
+ for (list = rcu_dereference(list_next_rcu(head));
+ list != head;
+ list = rcu_dereference(list_next_rcu(list))) {
+ if (i-- == 0)
+ return list;
+ }
- /*
- * This is 0 the first time through.
- */
- if (s->index == 0)
- s->private = head;
-
- if (s->private == NULL)
- return NULL;
-
- list = s->private;
- if (list_empty(list))
- return NULL;
-
- if (s->index == 0)
- return list->next;
- return list;
+ return NULL;
}
static void *smk_seq_next(struct seq_file *s, void *v, loff_t *pos,
@@ -591,17 +574,15 @@ static void *smk_seq_next(struct seq_file *s, void *v, loff_t *pos,
{
struct list_head *list = v;
- if (list_is_last(list, head)) {
- s->private = NULL;
- return NULL;
- }
- s->private = list->next;
- return list->next;
+ ++*pos;
+ list = rcu_dereference(list_next_rcu(list));
+
+ return (list == head) ? NULL : list;
}
static void smk_seq_stop(struct seq_file *s, void *v)
{
- /* No-op */
+ rcu_read_unlock();
}
static void smk_rule_show(struct seq_file *s, struct smack_rule *srp, int max)
@@ -661,7 +642,7 @@ static int load_seq_show(struct seq_file *s, void *v)
{
struct list_head *list = v;
struct smack_master_list *smlp =
- list_entry(list, struct smack_master_list, list);
+ list_entry_rcu(list, struct smack_master_list, list);
smk_rule_show(s, smlp->smk_rule, SMK_LABELLEN);
@@ -809,7 +790,7 @@ static int cipso_seq_show(struct seq_file *s, void *v)
{
struct list_head *list = v;
struct smack_known *skp =
- list_entry(list, struct smack_known, list);
+ list_entry_rcu(list, struct smack_known, list);
struct netlbl_lsm_catmap *cmp = skp->smk_netlabel.attr.mls.cat;
char sep = '/';
int i;
@@ -915,8 +896,10 @@ static ssize_t smk_set_cipso(struct file *file, const char __user *buf,
mutex_lock(&smack_cipso_lock);
skp = smk_import_entry(rule, 0);
- if (skp == NULL)
+ if (IS_ERR(skp)) {
+ rc = PTR_ERR(skp);
goto out;
+ }
if (format == SMK_FIXED24_FMT)
rule += SMK_LABELLEN;
@@ -998,7 +981,7 @@ static int cipso2_seq_show(struct seq_file *s, void *v)
{
struct list_head *list = v;
struct smack_known *skp =
- list_entry(list, struct smack_known, list);
+ list_entry_rcu(list, struct smack_known, list);
struct netlbl_lsm_catmap *cmp = skp->smk_netlabel.attr.mls.cat;
char sep = '/';
int i;
@@ -1082,7 +1065,7 @@ static int netlbladdr_seq_show(struct seq_file *s, void *v)
{
struct list_head *list = v;
struct smk_netlbladdr *skp =
- list_entry(list, struct smk_netlbladdr, list);
+ list_entry_rcu(list, struct smk_netlbladdr, list);
unsigned char *hp = (char *) &skp->smk_host.sin_addr.s_addr;
int maskn;
u32 temp_mask = be32_to_cpu(skp->smk_mask.s_addr);
@@ -1237,8 +1220,8 @@ static ssize_t smk_write_netlbladdr(struct file *file, const char __user *buf,
*/
if (smack[0] != '-') {
skp = smk_import_entry(smack, 0);
- if (skp == NULL) {
- rc = -EINVAL;
+ if (IS_ERR(skp)) {
+ rc = PTR_ERR(skp);
goto free_out;
}
} else {
@@ -1619,8 +1602,8 @@ static ssize_t smk_write_ambient(struct file *file, const char __user *buf,
}
skp = smk_import_entry(data, count);
- if (skp == NULL) {
- rc = -EINVAL;
+ if (IS_ERR(skp)) {
+ rc = PTR_ERR(skp);
goto out;
}
@@ -1643,34 +1626,79 @@ static const struct file_operations smk_ambient_ops = {
.llseek = default_llseek,
};
-/**
- * smk_read_onlycap - read() for smackfs/onlycap
- * @filp: file pointer, not actually used
- * @buf: where to put the result
- * @cn: maximum to send along
- * @ppos: where to start
- *
- * Returns number of bytes read or error code, as appropriate
+/*
+ * Seq_file operations for /smack/onlycap
*/
-static ssize_t smk_read_onlycap(struct file *filp, char __user *buf,
- size_t cn, loff_t *ppos)
+static void *onlycap_seq_start(struct seq_file *s, loff_t *pos)
{
- char *smack = "";
- ssize_t rc = -EINVAL;
- int asize;
+ return smk_seq_start(s, pos, &smack_onlycap_list);
+}
- if (*ppos != 0)
- return 0;
+static void *onlycap_seq_next(struct seq_file *s, void *v, loff_t *pos)
+{
+ return smk_seq_next(s, v, pos, &smack_onlycap_list);
+}
- if (smack_onlycap != NULL)
- smack = smack_onlycap->smk_known;
+static int onlycap_seq_show(struct seq_file *s, void *v)
+{
+ struct list_head *list = v;
+ struct smack_onlycap *sop =
+ list_entry_rcu(list, struct smack_onlycap, list);
- asize = strlen(smack) + 1;
+ seq_puts(s, sop->smk_label->smk_known);
+ seq_putc(s, ' ');
- if (cn >= asize)
- rc = simple_read_from_buffer(buf, cn, ppos, smack, asize);
+ return 0;
+}
- return rc;
+static const struct seq_operations onlycap_seq_ops = {
+ .start = onlycap_seq_start,
+ .next = onlycap_seq_next,
+ .show = onlycap_seq_show,
+ .stop = smk_seq_stop,
+};
+
+static int smk_open_onlycap(struct inode *inode, struct file *file)
+{
+ return seq_open(file, &onlycap_seq_ops);
+}
+
+/**
+ * smk_list_swap_rcu - swap public list with a private one in RCU-safe way
+ * The caller must hold appropriate mutex to prevent concurrent modifications
+ * to the public list.
+ * Private list is assumed to be not accessible to other threads yet.
+ *
+ * @public: public list
+ * @private: private list
+ */
+static void smk_list_swap_rcu(struct list_head *public,
+ struct list_head *private)
+{
+ struct list_head *first, *last;
+
+ if (list_empty(public)) {
+ list_splice_init_rcu(private, public, synchronize_rcu);
+ } else {
+ /* Remember public list before replacing it */
+ first = public->next;
+ last = public->prev;
+
+ /* Publish private list in place of public in RCU-safe way */
+ private->prev->next = public;
+ private->next->prev = public;
+ rcu_assign_pointer(public->next, private->next);
+ public->prev = private->prev;
+
+ synchronize_rcu();
+
+ /* When all readers are done with the old public list,
+ * attach it in place of private */
+ private->next = first;
+ private->prev = last;
+ first->prev = private;
+ last->next = private;
+ }
}
/**
@@ -1686,47 +1714,79 @@ static ssize_t smk_write_onlycap(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
char *data;
- struct smack_known *skp = smk_of_task(current->cred->security);
+ char *data_parse;
+ char *tok;
+ struct smack_known *skp;
+ struct smack_onlycap *sop;
+ struct smack_onlycap *sop2;
+ LIST_HEAD(list_tmp);
int rc = count;
if (!smack_privileged(CAP_MAC_ADMIN))
return -EPERM;
- /*
- * This can be done using smk_access() but is done
- * explicitly for clarity. The smk_access() implementation
- * would use smk_access(smack_onlycap, MAY_WRITE)
- */
- if (smack_onlycap != NULL && smack_onlycap != skp)
- return -EPERM;
-
data = kzalloc(count + 1, GFP_KERNEL);
if (data == NULL)
return -ENOMEM;
+ if (copy_from_user(data, buf, count) != 0) {
+ kfree(data);
+ return -EFAULT;
+ }
+
+ data_parse = data;
+ while ((tok = strsep(&data_parse, " ")) != NULL) {
+ if (!*tok)
+ continue;
+
+ skp = smk_import_entry(tok, 0);
+ if (IS_ERR(skp)) {
+ rc = PTR_ERR(skp);
+ break;
+ }
+
+ sop = kzalloc(sizeof(*sop), GFP_KERNEL);
+ if (sop == NULL) {
+ rc = -ENOMEM;
+ break;
+ }
+
+ sop->smk_label = skp;
+ list_add_rcu(&sop->list, &list_tmp);
+ }
+ kfree(data);
+
/*
- * Should the null string be passed in unset the onlycap value.
- * This seems like something to be careful with as usually
- * smk_import only expects to return NULL for errors. It
- * is usually the case that a nullstring or "\n" would be
- * bad to pass to smk_import but in fact this is useful here.
+ * Clear the smack_onlycap on invalid label errors. This means
+ * that we can pass a null string to unset the onlycap value.
*
- * smk_import will also reject a label beginning with '-',
+ * Importing will also reject a label beginning with '-',
* so "-usecapabilities" will also work.
+ *
+ * But do so only on invalid label, not on system errors.
+ * The invalid label must be first to count as clearing attempt.
*/
- if (copy_from_user(data, buf, count) != 0)
- rc = -EFAULT;
- else
- smack_onlycap = smk_import_entry(data, count);
+ if (rc == -EINVAL && list_empty(&list_tmp))
+ rc = count;
+
+ if (rc >= 0) {
+ mutex_lock(&smack_onlycap_lock);
+ smk_list_swap_rcu(&smack_onlycap_list, &list_tmp);
+ mutex_unlock(&smack_onlycap_lock);
+ }
+
+ list_for_each_entry_safe(sop, sop2, &list_tmp, list)
+ kfree(sop);
- kfree(data);
return rc;
}
static const struct file_operations smk_onlycap_ops = {
- .read = smk_read_onlycap,
+ .open = smk_open_onlycap,
+ .read = seq_read,
.write = smk_write_onlycap,
- .llseek = default_llseek,
+ .llseek = seq_lseek,
+ .release = seq_release,
};
#ifdef CONFIG_SECURITY_SMACK_BRINGUP
@@ -1773,6 +1833,7 @@ static ssize_t smk_write_unconfined(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
char *data;
+ struct smack_known *skp;
int rc = count;
if (!smack_privileged(CAP_MAC_ADMIN))
@@ -1782,21 +1843,31 @@ static ssize_t smk_write_unconfined(struct file *file, const char __user *buf,
if (data == NULL)
return -ENOMEM;
+ if (copy_from_user(data, buf, count) != 0) {
+ rc = -EFAULT;
+ goto freeout;
+ }
+
/*
- * Should the null string be passed in unset the unconfined value.
- * This seems like something to be careful with as usually
- * smk_import only expects to return NULL for errors. It
- * is usually the case that a nullstring or "\n" would be
- * bad to pass to smk_import but in fact this is useful here.
+ * Clear the smack_unconfined on invalid label errors. This means
+ * that we can pass a null string to unset the unconfined value.
*
- * smk_import will also reject a label beginning with '-',
+ * Importing will also reject a label beginning with '-',
* so "-confine" will also work.
+ *
+ * But do so only on invalid label, not on system errors.
*/
- if (copy_from_user(data, buf, count) != 0)
- rc = -EFAULT;
- else
- smack_unconfined = smk_import_entry(data, count);
+ skp = smk_import_entry(data, count);
+ if (PTR_ERR(skp) == -EINVAL)
+ skp = NULL;
+ else if (IS_ERR(skp)) {
+ rc = PTR_ERR(skp);
+ goto freeout;
+ }
+ smack_unconfined = skp;
+
+freeout:
kfree(data);
return rc;
}
@@ -1895,7 +1966,7 @@ static int load_self_seq_show(struct seq_file *s, void *v)
{
struct list_head *list = v;
struct smack_rule *srp =
- list_entry(list, struct smack_rule, list);
+ list_entry_rcu(list, struct smack_rule, list);
smk_rule_show(s, srp, SMK_LABELLEN);
@@ -1980,7 +2051,7 @@ static ssize_t smk_user_access(struct file *file, const char __user *buf,
res = smk_access(rule.smk_subject, rule.smk_object,
rule.smk_access1, NULL);
else if (res != -ENOENT)
- return -EINVAL;
+ return res;
/*
* smk_access() can return a value > 0 in the "bringup" case.
@@ -2024,7 +2095,7 @@ static int load2_seq_show(struct seq_file *s, void *v)
{
struct list_head *list = v;
struct smack_master_list *smlp =
- list_entry(list, struct smack_master_list, list);
+ list_entry_rcu(list, struct smack_master_list, list);
smk_rule_show(s, smlp->smk_rule, SMK_LONGLABEL);
@@ -2101,7 +2172,7 @@ static int load_self2_seq_show(struct seq_file *s, void *v)
{
struct list_head *list = v;
struct smack_rule *srp =
- list_entry(list, struct smack_rule, list);
+ list_entry_rcu(list, struct smack_rule, list);
smk_rule_show(s, srp, SMK_LONGLABEL);
@@ -2182,8 +2253,8 @@ static const struct file_operations smk_access2_ops = {
static ssize_t smk_write_revoke_subj(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
- char *data = NULL;
- const char *cp = NULL;
+ char *data;
+ const char *cp;
struct smack_known *skp;
struct smack_rule *sp;
struct list_head *rule_list;
@@ -2205,18 +2276,18 @@ static ssize_t smk_write_revoke_subj(struct file *file, const char __user *buf,
if (copy_from_user(data, buf, count) != 0) {
rc = -EFAULT;
- goto free_out;
+ goto out_data;
}
cp = smk_parse_smack(data, count);
- if (cp == NULL) {
- rc = -EINVAL;
- goto free_out;
+ if (IS_ERR(cp)) {
+ rc = PTR_ERR(cp);
+ goto out_data;
}
skp = smk_find_entry(cp);
if (skp == NULL)
- goto free_out;
+ goto out_cp;
rule_list = &skp->smk_rules;
rule_lock = &skp->smk_rules_lock;
@@ -2228,9 +2299,11 @@ static ssize_t smk_write_revoke_subj(struct file *file, const char __user *buf,
mutex_unlock(rule_lock);
-free_out:
- kfree(data);
+out_cp:
kfree(cp);
+out_data:
+ kfree(data);
+
return rc;
}
@@ -2341,10 +2414,10 @@ static ssize_t smk_write_syslog(struct file *file, const char __user *buf,
rc = -EFAULT;
else {
skp = smk_import_entry(data, count);
- if (skp == NULL)
- rc = -EINVAL;
+ if (IS_ERR(skp))
+ rc = PTR_ERR(skp);
else
- smack_syslog_label = smk_import_entry(data, count);
+ smack_syslog_label = skp;
}
kfree(data);
@@ -2547,7 +2620,7 @@ static int __init init_smk_fs(void)
int err;
int rc;
- if (!security_module_enable(&smack_ops))
+ if (!security_module_enable("smack"))
return 0;
err = smk_init_sysfs();