mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-29 15:43:59 +08:00
21c7eae21a
Smack used to use a mix of smack_known struct and char* throughout its APIs and implementation. This patch unifies the behaviour and makes it store and operate exclusively on smack_known struct pointers when managing labels. Signed-off-by: Lukasz Pawelczyk <l.pawelczyk@samsung.com> Conflicts: security/smack/smack_access.c security/smack/smack_lsm.c
593 lines
14 KiB
C
593 lines
14 KiB
C
/*
|
|
* Copyright (C) 2007 Casey Schaufler <casey@schaufler-ca.com>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation, version 2.
|
|
*
|
|
* Author:
|
|
* Casey Schaufler <casey@schaufler-ca.com>
|
|
*
|
|
*/
|
|
|
|
#include <linux/types.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/sched.h>
|
|
#include "smack.h"
|
|
|
|
struct smack_known smack_known_huh = {
|
|
.smk_known = "?",
|
|
.smk_secid = 2,
|
|
};
|
|
|
|
struct smack_known smack_known_hat = {
|
|
.smk_known = "^",
|
|
.smk_secid = 3,
|
|
};
|
|
|
|
struct smack_known smack_known_star = {
|
|
.smk_known = "*",
|
|
.smk_secid = 4,
|
|
};
|
|
|
|
struct smack_known smack_known_floor = {
|
|
.smk_known = "_",
|
|
.smk_secid = 5,
|
|
};
|
|
|
|
struct smack_known smack_known_invalid = {
|
|
.smk_known = "",
|
|
.smk_secid = 6,
|
|
};
|
|
|
|
struct smack_known smack_known_web = {
|
|
.smk_known = "@",
|
|
.smk_secid = 7,
|
|
};
|
|
|
|
LIST_HEAD(smack_known_list);
|
|
|
|
/*
|
|
* The initial value needs to be bigger than any of the
|
|
* known values above.
|
|
*/
|
|
static u32 smack_next_secid = 10;
|
|
|
|
/*
|
|
* what events do we log
|
|
* can be overwritten at run-time by /smack/logging
|
|
*/
|
|
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
|
|
* @rule_list: the list of rules to search
|
|
*
|
|
* This function looks up the subject/object pair in the
|
|
* access rule list and returns the access mode. If no
|
|
* entry is found returns -ENOENT.
|
|
*
|
|
* NOTE:
|
|
*
|
|
* Earlier versions of this function allowed for labels that
|
|
* were not on the label list. This was done to allow for
|
|
* labels to come over the network that had never been seen
|
|
* before on this host. Unless the receiving socket has the
|
|
* star label this will always result in a failure check. The
|
|
* star labeled socket case is now handled in the networking
|
|
* hooks so there is no case where the label is not on the
|
|
* label list. Checking to see if the address of two labels
|
|
* is the same is now a reliable test.
|
|
*
|
|
* Do the object check first because that is more
|
|
* likely to differ.
|
|
*
|
|
* Allowing write access implies allowing locking.
|
|
*/
|
|
int smk_access_entry(char *subject_label, char *object_label,
|
|
struct list_head *rule_list)
|
|
{
|
|
int may = -ENOENT;
|
|
struct smack_rule *srp;
|
|
|
|
list_for_each_entry_rcu(srp, rule_list, list) {
|
|
if (srp->smk_object->smk_known == object_label &&
|
|
srp->smk_subject->smk_known == subject_label) {
|
|
may = srp->smk_access;
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* MAY_WRITE implies MAY_LOCK.
|
|
*/
|
|
if ((may & MAY_WRITE) == MAY_WRITE)
|
|
may |= MAY_LOCK;
|
|
return may;
|
|
}
|
|
|
|
/**
|
|
* smk_access - determine if a subject has a specific access to an object
|
|
* @subject: a pointer to the subject's Smack label entry
|
|
* @object: a pointer to the object's Smack label entry
|
|
* @request: the access requested, in "MAY" format
|
|
* @a : a pointer to the audit data
|
|
*
|
|
* This function looks up the subject/object pair in the
|
|
* access rule list and returns 0 if the access is permitted,
|
|
* non zero otherwise.
|
|
*
|
|
* Smack labels are shared on smack_list
|
|
*/
|
|
int smk_access(struct smack_known *subject, struct smack_known *object,
|
|
int request, struct smk_audit_info *a)
|
|
{
|
|
int may = MAY_NOT;
|
|
int rc = 0;
|
|
|
|
/*
|
|
* Hardcoded comparisons.
|
|
*
|
|
* A star subject can't access any object.
|
|
*/
|
|
if (subject == &smack_known_star) {
|
|
rc = -EACCES;
|
|
goto out_audit;
|
|
}
|
|
/*
|
|
* An internet object can be accessed by any subject.
|
|
* Tasks cannot be assigned the internet label.
|
|
* An internet subject can access any object.
|
|
*/
|
|
if (object == &smack_known_web ||
|
|
subject == &smack_known_web)
|
|
goto out_audit;
|
|
/*
|
|
* A star object can be accessed by any subject.
|
|
*/
|
|
if (object == &smack_known_star)
|
|
goto out_audit;
|
|
/*
|
|
* An object can be accessed in any way by a subject
|
|
* with the same label.
|
|
*/
|
|
if (subject->smk_known == object->smk_known)
|
|
goto out_audit;
|
|
/*
|
|
* A hat subject can read any object.
|
|
* A floor object can be read by any subject.
|
|
*/
|
|
if ((request & MAY_ANYREAD) == request) {
|
|
if (object == &smack_known_floor)
|
|
goto out_audit;
|
|
if (subject == &smack_known_hat)
|
|
goto out_audit;
|
|
}
|
|
/*
|
|
* Beyond here an explicit relationship is required.
|
|
* If the requested access is contained in the available
|
|
* access (e.g. read is included in readwrite) it's
|
|
* good. A negative response from smk_access_entry()
|
|
* indicates there is no entry for this pair.
|
|
*/
|
|
rcu_read_lock();
|
|
may = smk_access_entry(subject->smk_known, object->smk_known,
|
|
&subject->smk_rules);
|
|
rcu_read_unlock();
|
|
|
|
if (may <= 0 || (request & may) != request) {
|
|
rc = -EACCES;
|
|
goto out_audit;
|
|
}
|
|
#ifdef CONFIG_SECURITY_SMACK_BRINGUP
|
|
/*
|
|
* Return a positive value if using bringup mode.
|
|
* This allows the hooks to identify checks that
|
|
* succeed because of "b" rules.
|
|
*/
|
|
if (may & MAY_BRINGUP)
|
|
rc = MAY_BRINGUP;
|
|
#endif
|
|
|
|
out_audit:
|
|
#ifdef CONFIG_AUDIT
|
|
if (a)
|
|
smack_log(subject->smk_known, object->smk_known,
|
|
request, rc, a);
|
|
#endif
|
|
|
|
return rc;
|
|
}
|
|
|
|
/**
|
|
* smk_tskacc - determine if a task has a specific access to an object
|
|
* @tsp: a pointer to the subject's task
|
|
* @obj_known: a pointer to the object's label entry
|
|
* @mode: the access requested, in "MAY" format
|
|
* @a : common audit data
|
|
*
|
|
* This function checks the subject task's label/object label pair
|
|
* in the access rule list and returns 0 if the access is permitted,
|
|
* 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,
|
|
u32 mode, struct smk_audit_info *a)
|
|
{
|
|
struct smack_known *sbj_known = smk_of_task(tsp);
|
|
int may;
|
|
int rc;
|
|
|
|
/*
|
|
* Check the global rule list
|
|
*/
|
|
rc = smk_access(sbj_known, obj_known, mode, NULL);
|
|
if (rc >= 0) {
|
|
/*
|
|
* If there is an entry in the task's rule list
|
|
* it can further restrict access.
|
|
*/
|
|
may = smk_access_entry(sbj_known->smk_known,
|
|
obj_known->smk_known,
|
|
&tsp->smk_rules);
|
|
if (may < 0)
|
|
goto out_audit;
|
|
if ((mode & may) == mode)
|
|
goto out_audit;
|
|
rc = -EACCES;
|
|
}
|
|
|
|
/*
|
|
* Allow for priviliged to override policy.
|
|
*/
|
|
if (rc != 0 && smack_privileged(CAP_MAC_OVERRIDE))
|
|
rc = 0;
|
|
|
|
out_audit:
|
|
#ifdef CONFIG_AUDIT
|
|
if (a)
|
|
smack_log(sbj_known->smk_known, obj_known->smk_known,
|
|
mode, rc, a);
|
|
#endif
|
|
return rc;
|
|
}
|
|
|
|
/**
|
|
* smk_curacc - determine if current has a specific access to an object
|
|
* @obj_known: a pointer to the object's Smack label entry
|
|
* @mode: the access requested, in "MAY" format
|
|
* @a : common audit data
|
|
*
|
|
* This function checks the current subject label/object label pair
|
|
* in the access rule list and returns 0 if the access is permitted,
|
|
* non zero otherwise. It allows that current may have the capability
|
|
* to override the rules.
|
|
*/
|
|
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);
|
|
}
|
|
|
|
#ifdef CONFIG_AUDIT
|
|
/**
|
|
* smack_str_from_perm : helper to transalate an int to a
|
|
* readable string
|
|
* @string : the string to fill
|
|
* @access : the int
|
|
*
|
|
*/
|
|
static inline void smack_str_from_perm(char *string, int access)
|
|
{
|
|
int i = 0;
|
|
|
|
if (access & MAY_READ)
|
|
string[i++] = 'r';
|
|
if (access & MAY_WRITE)
|
|
string[i++] = 'w';
|
|
if (access & MAY_EXEC)
|
|
string[i++] = 'x';
|
|
if (access & MAY_APPEND)
|
|
string[i++] = 'a';
|
|
if (access & MAY_TRANSMUTE)
|
|
string[i++] = 't';
|
|
if (access & MAY_LOCK)
|
|
string[i++] = 'l';
|
|
string[i] = '\0';
|
|
}
|
|
/**
|
|
* smack_log_callback - SMACK specific information
|
|
* will be called by generic audit code
|
|
* @ab : the audit_buffer
|
|
* @a : audit_data
|
|
*
|
|
*/
|
|
static void smack_log_callback(struct audit_buffer *ab, void *a)
|
|
{
|
|
struct common_audit_data *ad = a;
|
|
struct smack_audit_data *sad = ad->smack_audit_data;
|
|
audit_log_format(ab, "lsm=SMACK fn=%s action=%s",
|
|
ad->smack_audit_data->function,
|
|
sad->result ? "denied" : "granted");
|
|
audit_log_format(ab, " subject=");
|
|
audit_log_untrustedstring(ab, sad->subject);
|
|
audit_log_format(ab, " object=");
|
|
audit_log_untrustedstring(ab, sad->object);
|
|
if (sad->request[0] == '\0')
|
|
audit_log_format(ab, " labels_differ");
|
|
else
|
|
audit_log_format(ab, " requested=%s", sad->request);
|
|
}
|
|
|
|
/**
|
|
* smack_log - Audit the granting or denial of permissions.
|
|
* @subject_label : smack label of the requester
|
|
* @object_label : smack label of the object being accessed
|
|
* @request: requested permissions
|
|
* @result: result from smk_access
|
|
* @a: auxiliary audit data
|
|
*
|
|
* Audit the granting or denial of permissions in accordance
|
|
* with the policy.
|
|
*/
|
|
void smack_log(char *subject_label, char *object_label, int request,
|
|
int result, struct smk_audit_info *ad)
|
|
{
|
|
char request_buffer[SMK_NUM_ACCESS_TYPE + 1];
|
|
struct smack_audit_data *sad;
|
|
struct common_audit_data *a = &ad->a;
|
|
|
|
#ifdef CONFIG_SECURITY_SMACK_BRINGUP
|
|
/*
|
|
* The result may be positive in bringup mode.
|
|
*/
|
|
if (result > 0)
|
|
result = 0;
|
|
#endif
|
|
/* check if we have to log the current event */
|
|
if (result != 0 && (log_policy & SMACK_AUDIT_DENIED) == 0)
|
|
return;
|
|
if (result == 0 && (log_policy & SMACK_AUDIT_ACCEPT) == 0)
|
|
return;
|
|
|
|
sad = a->smack_audit_data;
|
|
|
|
if (sad->function == NULL)
|
|
sad->function = "unknown";
|
|
|
|
/* end preparing the audit data */
|
|
smack_str_from_perm(request_buffer, request);
|
|
sad->subject = subject_label;
|
|
sad->object = object_label;
|
|
sad->request = request_buffer;
|
|
sad->result = result;
|
|
|
|
common_lsm_audit(a, smack_log_callback, NULL);
|
|
}
|
|
#else /* #ifdef CONFIG_AUDIT */
|
|
void smack_log(char *subject_label, char *object_label, int request,
|
|
int result, struct smk_audit_info *ad)
|
|
{
|
|
}
|
|
#endif
|
|
|
|
DEFINE_MUTEX(smack_known_lock);
|
|
|
|
struct hlist_head smack_known_hash[SMACK_HASH_SLOTS];
|
|
|
|
/**
|
|
* smk_insert_entry - insert a smack label into a hash map,
|
|
*
|
|
* this function must be called under smack_known_lock
|
|
*/
|
|
void smk_insert_entry(struct smack_known *skp)
|
|
{
|
|
unsigned int hash;
|
|
struct hlist_head *head;
|
|
|
|
hash = full_name_hash(skp->smk_known, strlen(skp->smk_known));
|
|
head = &smack_known_hash[hash & (SMACK_HASH_SLOTS - 1)];
|
|
|
|
hlist_add_head_rcu(&skp->smk_hashed, head);
|
|
list_add_rcu(&skp->list, &smack_known_list);
|
|
}
|
|
|
|
/**
|
|
* smk_find_entry - find a label on the list, return the list entry
|
|
* @string: a text string that might be a Smack label
|
|
*
|
|
* Returns a pointer to the entry in the label list that
|
|
* matches the passed string.
|
|
*/
|
|
struct smack_known *smk_find_entry(const char *string)
|
|
{
|
|
unsigned int hash;
|
|
struct hlist_head *head;
|
|
struct smack_known *skp;
|
|
|
|
hash = full_name_hash(string, strlen(string));
|
|
head = &smack_known_hash[hash & (SMACK_HASH_SLOTS - 1)];
|
|
|
|
hlist_for_each_entry_rcu(skp, head, smk_hashed)
|
|
if (strcmp(skp->smk_known, string) == 0)
|
|
return skp;
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* smk_parse_smack - parse smack label from a text string
|
|
* @string: a text string that might contain a Smack label
|
|
* @len: the maximum size, or zero if it is NULL terminated.
|
|
*
|
|
* Returns a pointer to the clean label, or NULL
|
|
*/
|
|
char *smk_parse_smack(const char *string, int len)
|
|
{
|
|
char *smack;
|
|
int i;
|
|
|
|
if (len <= 0)
|
|
len = strlen(string) + 1;
|
|
|
|
/*
|
|
* Reserve a leading '-' as an indicator that
|
|
* this isn't a label, but an option to interfaces
|
|
* including /smack/cipso and /smack/cipso2
|
|
*/
|
|
if (string[0] == '-')
|
|
return NULL;
|
|
|
|
for (i = 0; i < len; i++)
|
|
if (string[i] > '~' || string[i] <= ' ' || string[i] == '/' ||
|
|
string[i] == '"' || string[i] == '\\' || string[i] == '\'')
|
|
break;
|
|
|
|
if (i == 0 || i >= SMK_LONGLABEL)
|
|
return NULL;
|
|
|
|
smack = kzalloc(i + 1, GFP_KERNEL);
|
|
if (smack != NULL) {
|
|
strncpy(smack, string, i + 1);
|
|
smack[i] = '\0';
|
|
}
|
|
return smack;
|
|
}
|
|
|
|
/**
|
|
* smk_netlbl_mls - convert a catset to netlabel mls categories
|
|
* @catset: the Smack categories
|
|
* @sap: where to put the netlabel categories
|
|
*
|
|
* Allocates and fills attr.mls
|
|
* Returns 0 on success, error code on failure.
|
|
*/
|
|
int smk_netlbl_mls(int level, char *catset, struct netlbl_lsm_secattr *sap,
|
|
int len)
|
|
{
|
|
unsigned char *cp;
|
|
unsigned char m;
|
|
int cat;
|
|
int rc;
|
|
int byte;
|
|
|
|
sap->flags |= NETLBL_SECATTR_MLS_CAT;
|
|
sap->attr.mls.lvl = level;
|
|
sap->attr.mls.cat = NULL;
|
|
|
|
for (cat = 1, cp = catset, byte = 0; byte < len; cp++, byte++)
|
|
for (m = 0x80; m != 0; m >>= 1, cat++) {
|
|
if ((m & *cp) == 0)
|
|
continue;
|
|
rc = netlbl_catmap_setbit(&sap->attr.mls.cat,
|
|
cat, GFP_ATOMIC);
|
|
if (rc < 0) {
|
|
netlbl_catmap_free(sap->attr.mls.cat);
|
|
return rc;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* smk_import_entry - import a label, return the list entry
|
|
* @string: a text string that might be a Smack label
|
|
* @len: the maximum size, or zero if it is NULL terminated.
|
|
*
|
|
* Returns a pointer to the entry in the label list that
|
|
* matches the passed string, adding it if necessary.
|
|
*/
|
|
struct smack_known *smk_import_entry(const char *string, int len)
|
|
{
|
|
struct smack_known *skp;
|
|
char *smack;
|
|
int slen;
|
|
int rc;
|
|
|
|
smack = smk_parse_smack(string, len);
|
|
if (smack == NULL)
|
|
return NULL;
|
|
|
|
mutex_lock(&smack_known_lock);
|
|
|
|
skp = smk_find_entry(smack);
|
|
if (skp != NULL)
|
|
goto freeout;
|
|
|
|
skp = kzalloc(sizeof(*skp), GFP_KERNEL);
|
|
if (skp == NULL)
|
|
goto freeout;
|
|
|
|
skp->smk_known = smack;
|
|
skp->smk_secid = smack_next_secid++;
|
|
skp->smk_netlabel.domain = skp->smk_known;
|
|
skp->smk_netlabel.flags =
|
|
NETLBL_SECATTR_DOMAIN | NETLBL_SECATTR_MLS_LVL;
|
|
/*
|
|
* If direct labeling works use it.
|
|
* Otherwise use mapped labeling.
|
|
*/
|
|
slen = strlen(smack);
|
|
if (slen < SMK_CIPSOLEN)
|
|
rc = smk_netlbl_mls(smack_cipso_direct, skp->smk_known,
|
|
&skp->smk_netlabel, slen);
|
|
else
|
|
rc = smk_netlbl_mls(smack_cipso_mapped, (char *)&skp->smk_secid,
|
|
&skp->smk_netlabel, sizeof(skp->smk_secid));
|
|
|
|
if (rc >= 0) {
|
|
INIT_LIST_HEAD(&skp->smk_rules);
|
|
mutex_init(&skp->smk_rules_lock);
|
|
/*
|
|
* Make sure that the entry is actually
|
|
* filled before putting it on the list.
|
|
*/
|
|
smk_insert_entry(skp);
|
|
goto unlockout;
|
|
}
|
|
/*
|
|
* smk_netlbl_mls failed.
|
|
*/
|
|
kfree(skp);
|
|
skp = NULL;
|
|
freeout:
|
|
kfree(smack);
|
|
unlockout:
|
|
mutex_unlock(&smack_known_lock);
|
|
|
|
return skp;
|
|
}
|
|
|
|
/**
|
|
* smack_from_secid - find the Smack label associated with a secid
|
|
* @secid: an integer that might be associated with a Smack label
|
|
*
|
|
* Returns a pointer to the appropriate Smack label entry if there is one,
|
|
* otherwise a pointer to the invalid Smack label.
|
|
*/
|
|
struct smack_known *smack_from_secid(const u32 secid)
|
|
{
|
|
struct smack_known *skp;
|
|
|
|
rcu_read_lock();
|
|
list_for_each_entry_rcu(skp, &smack_known_list, list) {
|
|
if (skp->smk_secid == secid) {
|
|
rcu_read_unlock();
|
|
return skp;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If we got this far someone asked for the translation
|
|
* of a secid that is not on the list.
|
|
*/
|
|
rcu_read_unlock();
|
|
return &smack_known_invalid;
|
|
}
|