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Date: Fri, 01 Aug 2008 15:20:32 -0400
From: Mimi Zohar <zohar@...ux.vnet.ibm.com>
To: linux-kernel@...r.kernel.org
Cc: linux-security-module@...r.kernel.org, safford@...son.ibm.com,
serue@...ux.vnet.ibm.com, sailer@...son.ibm.com, zohar@...ibm.com
Subject: [Patch]integrity: ima policy update patch
- This patch adds support for policy definitions defined in terms of
LSM subj_role, subj_type, and obj_role.
- Support for uid measurement policy definitions.
- Constrain the default INODE_PERMISSION measurement to only measure
files opened for read by root.
Signed-off-by: Mimi Zohar <zohar@...ibm.com>
Index: security-testing-2.6/security/integrity/ima/ima_policy.c
===================================================================
--- security-testing-2.6.orig/security/integrity/ima/ima_policy.c
+++ security-testing-2.6/security/integrity/ima/ima_policy.c
@@ -20,29 +20,51 @@
#include "ima.h"
+#define MAX_LSM_RULES 6
+enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE,
+ LSM_SUBJ_USER, LSM_SUBJ_ROLE, LSM_SUBJ_TYPE
+};
+
+#define audit_type(type) AUDIT_ ##type
+#define lsm_type(type) LSM_ ##type
+
struct ima_measure_rule_entry {
struct list_head list;
int action;
- void *lsm_obj_rule;
- void *lsm_subj_rule;
- void *lsm_type_rule;
+ struct {
+ void *rule;
+ int type; /* audit type */
+ } lsm_field[MAX_LSM_RULES];
+ uint flags;
enum lim_hooks func;
int mask;
ulong fsmagic;
+ uid_t uid;
};
+/* flags definitions */
+#define IMA_FUNC 0x0001
+#define IMA_MASK 0x0002
+#define IMA_FSMAGIC 0x0004
+#define IMA_UID 0x0008
+
/* Without LSM specific knowledge, default policy can only
* be written in terms of .action, .func, .mask and .fsmagic.
*/
static struct ima_measure_rule_entry default_rules[] = {
- {.action = DONT_MEASURE,.fsmagic = PROC_SUPER_MAGIC},
- {.action = DONT_MEASURE,.fsmagic = SYSFS_MAGIC},
- {.action = DONT_MEASURE,.fsmagic = DEBUGFS_MAGIC},
- {.action = DONT_MEASURE,.fsmagic = TMPFS_MAGIC},
- {.action = DONT_MEASURE,.fsmagic = SECURITYFS_MAGIC},
- {.action = MEASURE,.func = FILE_MMAP,.mask = MAY_EXEC},
- {.action = MEASURE,.func = BPRM_CHECK,.mask = MAY_EXEC},
- {.action = MEASURE,.func = INODE_PERMISSION,.mask = MAY_READ},
+ {.action = DONT_MEASURE,.fsmagic = PROC_SUPER_MAGIC,
+ .flags = IMA_FSMAGIC},
+ {.action = DONT_MEASURE,.fsmagic = SYSFS_MAGIC,.flags = IMA_FSMAGIC},
+ {.action = DONT_MEASURE,.fsmagic = DEBUGFS_MAGIC,.flags = IMA_FSMAGIC},
+ {.action = DONT_MEASURE,.fsmagic = TMPFS_MAGIC,.flags = IMA_FSMAGIC},
+ {.action = DONT_MEASURE,.fsmagic = SECURITYFS_MAGIC,
+ .flags = IMA_FSMAGIC},
+ {.action = MEASURE,.func = FILE_MMAP,.mask = MAY_EXEC,
+ .flags = IMA_FUNC | IMA_MASK},
+ {.action = MEASURE,.func = BPRM_CHECK,.mask = MAY_EXEC,
+ .flags = IMA_FUNC | IMA_MASK},
+ {.action = MEASURE,.func = INODE_PERMISSION,.mask = MAY_READ,.uid = 0,
+ .flags = IMA_FUNC | IMA_MASK | IMA_UID}
};
static struct list_head measure_default_rules;
@@ -61,45 +83,50 @@ static DEFINE_MUTEX(ima_measure_mutex);
* Returns true on rule match, false on failure.
*/
static bool ima_match_rules(struct ima_measure_rule_entry *rule,
- struct inode *inode, enum lim_hooks func, int mask)
+ struct inode *inode, enum lim_hooks func, int mask)
{
- if (rule->func && rule->func != func)
+ struct task_struct *tsk = current;
+ int i;
+
+ if ((rule->flags & IMA_FUNC) && rule->func != func)
return false;
- if (rule->mask && rule->mask != mask)
+ if ((rule->flags & IMA_MASK) && rule->mask != mask)
return false;
- if (rule->fsmagic && rule->fsmagic != inode->i_sb->s_magic)
+ if ((rule->flags & IMA_FSMAGIC)
+ && rule->fsmagic != inode->i_sb->s_magic)
return false;
- if (rule->lsm_subj_rule) {
- struct task_struct *tsk = current;
- u32 sid;
- int rc;
-
- security_task_getsecid(tsk, &sid);
- rc = security_filter_rule_match(sid, AUDIT_SUBJ_USER,
- AUDIT_EQUAL,
- rule->lsm_subj_rule, NULL);
- if (!rc)
- return false;
- }
- if (rule->lsm_obj_rule) {
- u32 osid;
+ if ((rule->flags & IMA_UID) && rule->uid != tsk->uid)
+ return false;
+ for (i = 0; i < MAX_LSM_RULES; i++) {
int rc;
+ u32 osid, sid;
- security_inode_getsecid(inode, &osid);
- rc = security_filter_rule_match(osid, AUDIT_OBJ_USER,
- AUDIT_EQUAL,
- rule->lsm_obj_rule, NULL);
- if (!rc)
- return false;
- }
- if (rule->lsm_type_rule) {
- u32 osid;
- int rc;
+ if (!rule->lsm_field[i].rule)
+ continue;
- security_inode_getsecid(inode, &osid);
- rc = security_filter_rule_match(osid, AUDIT_OBJ_TYPE,
- AUDIT_EQUAL,
- rule->lsm_type_rule, NULL);
+ switch (i) {
+ case LSM_OBJ_USER:
+ case LSM_OBJ_ROLE:
+ case LSM_OBJ_TYPE:
+ security_inode_getsecid(inode, &osid);
+ rc = security_filter_rule_match(osid,
+ rule->lsm_field[i].type,
+ AUDIT_EQUAL,
+ rule->lsm_field[i].rule,
+ NULL);
+ break;
+ case LSM_SUBJ_USER:
+ case LSM_SUBJ_ROLE:
+ case LSM_SUBJ_TYPE:
+ security_task_getsecid(tsk, &sid);
+ rc = security_filter_rule_match(sid,
+ rule->lsm_field[i].type,
+ AUDIT_EQUAL,
+ rule->lsm_field[i].rule,
+ NULL);
+ default:
+ break;
+ }
if (!rc)
return false;
}
@@ -180,11 +207,13 @@ void ima_update_policy(void)
*
* Returns 0 on success, an error code on failure.
*/
-int ima_add_rule(int action, char *subj, char *obj, char *type,
- char *func, char *mask, char *fsmagic)
+int ima_add_rule(int action,
+ char *subj_user, char *subj_role, char *subj_type,
+ char *obj_user, char *obj_role, char *obj_type,
+ char *func, char *mask, char *fsmagic, char *uid)
{
struct ima_measure_rule_entry *entry;
- int result = 0;
+ int i, result = 0;
/* Prevent installed policy from changing */
if (ima_measure != &measure_default_rules) {
@@ -199,15 +228,49 @@ int ima_add_rule(int action, char *subj,
result = -EINVAL;
else
entry->action = action;
- if (!result && subj)
- result = security_filter_rule_init(AUDIT_SUBJ_USER, AUDIT_EQUAL,
- subj, &entry->lsm_subj_rule);
- if (!result && obj)
- result = security_filter_rule_init(AUDIT_OBJ_USER, AUDIT_EQUAL,
- obj, &entry->lsm_obj_rule);
- if (!result && type)
- result = security_filter_rule_init(AUDIT_OBJ_TYPE, AUDIT_EQUAL,
- obj, &entry->lsm_obj_rule);
+
+ if (!result && subj_user) {
+ i = lsm_type(SUBJ_USER);
+ entry->lsm_field[i].type = audit_type(SUBJ_USER);
+ result = security_filter_rule_init(entry->lsm_field[i].type,
+ AUDIT_EQUAL, subj_user,
+ &entry->lsm_field[i].rule);
+ }
+ if (!result && subj_role) {
+ i = lsm_type(SUBJ_ROLE);
+ entry->lsm_field[i].type = audit_type(SUBJ_ROLE);
+ result = security_filter_rule_init(entry->lsm_field[i].type,
+ AUDIT_EQUAL, subj_role,
+ &entry->lsm_field[i].rule);
+ }
+ if (!result && subj_type) {
+ i = lsm_type(SUBJ_TYPE);
+ entry->lsm_field[i].type = audit_type(SUBJ_TYPE);
+ result = security_filter_rule_init(entry->lsm_field[i].type,
+ AUDIT_EQUAL, subj_type,
+ &entry->lsm_field[i].rule);
+ }
+ if (!result && obj_user) {
+ i = lsm_type(OBJ_USER);
+ entry->lsm_field[i].type = audit_type(OBJ_USER);
+ result = security_filter_rule_init(entry->lsm_field[i].type,
+ AUDIT_EQUAL, obj_user,
+ &entry->lsm_field[i].rule);
+ }
+ if (!result && obj_role) {
+ i = lsm_type(OBJ_ROLE);
+ entry->lsm_field[i].type = audit_type(OBJ_ROLE);
+ result = security_filter_rule_init(entry->lsm_field[i].type,
+ AUDIT_EQUAL, obj_role,
+ &entry->lsm_field[i].rule);
+ }
+ if (!result && obj_type) {
+ i = lsm_type(OBJ_TYPE);
+ entry->lsm_field[i].type = audit_type(OBJ_TYPE);
+ result = security_filter_rule_init(entry->lsm_field[i].type,
+ AUDIT_EQUAL, obj_type,
+ &entry->lsm_field[i].rule);
+ }
if (!result && func) {
if (strcmp(func, "INODE_PERMISSION") == 0)
entry->func = INODE_PERMISSION;
@@ -217,6 +280,8 @@ int ima_add_rule(int action, char *subj,
entry->func = BPRM_CHECK;
else
result = -EINVAL;
+ if (!result)
+ entry->flags |= IMA_FUNC;
}
if (!result && mask) {
if (strcmp(mask, "MAY_EXEC") == 0)
@@ -229,6 +294,8 @@ int ima_add_rule(int action, char *subj,
entry->mask = MAY_APPEND;
else
result = -EINVAL;
+ if (!result)
+ entry->flags |= IMA_MASK;
}
if (!result && fsmagic) {
int rc;
@@ -236,6 +303,23 @@ int ima_add_rule(int action, char *subj,
rc = strict_strtoul(fsmagic, 16, &entry->fsmagic);
if (rc)
result = -EINVAL;
+ else
+ entry->flags |= IMA_FSMAGIC;
+ }
+ if (!result && uid) {
+ int rc;
+ ulong lnum;
+
+ rc = strict_strtoul(uid, 10, &lnum);
+ if (rc)
+ result = -EINVAL;
+ else {
+ entry->uid = (uid_t) lnum;
+ if (entry->uid != lnum)
+ result = -EINVAL;
+ else
+ entry->flags |= IMA_UID;
+ }
}
if (!result) {
mutex_lock(&ima_measure_mutex);
Index: security-testing-2.6/security/integrity/ima/ima_fs.c
===================================================================
--- security-testing-2.6.orig/security/integrity/ima/ima_fs.c
+++ security-testing-2.6/security/integrity/ima/ima_fs.c
@@ -313,8 +313,9 @@ static ssize_t ima_write_policy(struct f
size_t rc = 0, datalen;
int action = 0;
char *data, *datap, *dataend;
- char *subj = NULL, *obj = NULL, *type = NULL;
- char *func = NULL, *mask = NULL, *fsmagic = NULL;
+ char *subj_user = NULL, *subj_role = NULL, *subj_type = NULL;
+ char *obj_user = NULL, *obj_role = NULL, *obj_type = NULL;
+ char *func = NULL, *mask = NULL, *fsmagic = NULL, *uid = NULL;
int err = 0;
char *tag;
int taglen, i;
@@ -347,18 +348,26 @@ static ssize_t ima_write_policy(struct f
tag = get_tag(datap, dataend, ' ', &taglen);
if (!tag)
break;
- if (strncmp(tag, "obj=", 4) == 0)
- obj = tag + 4;
- else if (strncmp(tag, "subj=", 5) == 0)
- subj = tag + 5;
- else if (strncmp(tag, "type=", 5) == 0)
- type = tag + 5;
+ if (strncmp(tag, "obj_user=", 9) == 0)
+ obj_user = tag + 9;
+ else if (strncmp(tag, "obj_role=", 9) == 0)
+ obj_role = tag + 9;
+ else if (strncmp(tag, "obj_type=", 9) == 0)
+ obj_type = tag + 9;
+ else if (strncmp(tag, "subj_user=", 10) == 0)
+ subj_user = tag + 10;
+ else if (strncmp(tag, "subj_role=", 10) == 0)
+ subj_role = tag + 10;
+ else if (strncmp(tag, "subj_type=", 10) == 0)
+ subj_type = tag + 10;
else if (strncmp(tag, "func=", 5) == 0)
func = tag + 5;
else if (strncmp(tag, "mask=", 5) == 0)
mask = tag + 5;
else if (strncmp(tag, "fsmagic=", 8) == 0)
fsmagic = tag + 8;
+ else if (strncmp(tag, "uid=", 4) == 0)
+ uid = tag + 4;
else { /* bad format */
err = 1;
break;
@@ -367,10 +376,14 @@ static ssize_t ima_write_policy(struct f
}
if (!err) {
- ima_info("%s %s %s %s %s %s %s\n",
+ ima_info("%s subj: %s %s %s obj: %s %s %s %s %s %s %s\n",
action ? "measure " : "dont_measure",
- subj, obj, type, func, mask, fsmagic);
- ima_add_rule(action, subj, obj, type, func, mask, fsmagic);
+ subj_user, subj_role, subj_type,
+ obj_user, obj_role, obj_type,
+ func, mask, fsmagic, uid);
+ ima_add_rule(action, subj_user, subj_role, subj_type,
+ obj_user, obj_role, obj_type,
+ func, mask, fsmagic, uid);
}
out:
if (!data)
Index: security-testing-2.6/security/integrity/ima/ima.h
===================================================================
--- security-testing-2.6.orig/security/integrity/ima/ima.h
+++ security-testing-2.6/security/integrity/ima/ima.h
@@ -78,7 +78,9 @@ void ima_add_violation(struct inode *ino
enum ima_action {DONT_MEASURE, MEASURE};
int ima_match_policy(struct inode *inode, enum lim_hooks func, int mask);
-int ima_add_rule(int, char *, char *, char *, char *, char *, char *);
+int ima_add_rule(int, char *subj_user, char *subj_role, char *subj_type,
+ char *obj_user, char *obj_role, char *obj_type,
+ char *func, char *mask, char *fsmagic, char *uid);
void ima_init_policy(void);
void ima_update_policy(void);
Index: security-testing-2.6/Documentation/ABI/testing/ima_policy
===================================================================
--- security-testing-2.6.orig/Documentation/ABI/testing/ima_policy
+++ security-testing-2.6/Documentation/ABI/testing/ima_policy
@@ -16,12 +16,14 @@ Description:
action: measure | dont_measure
condition:= base | lsm
- base: [[func=] [mask=] [fsmagic=]]
- lsm: [[subj=] [obj=] [type=]]
+ base: [[func=] [mask=] [fsmagic=] [uid=]]
+ lsm: [[subj_user=] [subj_role=] [subj_type=]
+ [obj_user=] [obj_role=] [obj_type=]]
base: func:= [BPRM_CHECK][FILE_MMAP][INODE_PERMISSION]
mask:= [MAY_READ] [MAY_WRITE] [MAY_APPEND] [MAY_EXEC]
fsmagic:= hex value
+ uid:= decimal value
lsm: are LSM specific
default policy:
@@ -35,21 +37,24 @@ Description:
dont_measure fsmagic=0x01021994
# SECURITYFS_MAGIC
dont_measure fsmagic=0x73636673
+ # SELINUX_MAGIC
+ dont_measure fsmagic=0xF97CFF8C
measure func=BPRM_CHECK
measure func=FILE_MMAP mask=MAY_EXEC
- measure func=INODE_PERM mask=MAY_READ
+ measure func=INODE_PERM mask=MAY_READ uid=0
The default policy measures all executables in bprm_check,
all files mmapped executable in file_mmap, and all files
- open for read in inode_permission.
+ open for read by root in inode_permission.
Examples of LSM specific definitions:
SELinux:
- dont_measure type=var_log_t
- dont_measure type=auditd_log_t
- measure subj=system_u func=INODE_PERM mask=MAY_READ
+ dont_measure obj_type=var_log_t
+ dont_measure obj_type=auditd_log_t
+ measure subj_user=system_u func=INODE_PERM mask=MAY_READ
+ measure subj_role=system_r func=INODE_PERM mask=MAY_READ
Smack:
- measure subj=_ func=INODE_PERM mask=MAY_READ
+ measure subj_user=_ func=INODE_PERM mask=MAY_READ
--
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