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authorMimi Zohar <zohar@linux.vnet.ibm.com>2012-12-03 17:08:11 -0500
committerMimi Zohar <zohar@linux.vnet.ibm.com>2013-01-22 16:10:36 -0500
commitd79d72e02485c00b886179538dc8deaffa3be507 (patch)
tree92690d5cbd6e4a0a3bee369033fe18d9b2d065f7 /security/integrity/ima
parentf578c08ec959cb0cdadf02bdc9689a4df3e9b9d4 (diff)
downloadlinux-linaro-stable-d79d72e02485c00b886179538dc8deaffa3be507.tar.gz
ima: per hook cache integrity appraisal status
With the new IMA policy 'appraise_type=' option, different hooks can require different methods for appraising a file's integrity. For example, the existing 'ima_appraise_tcb' policy defines a generic rule, requiring all root files to be appraised, without specfying the appraisal method. A more specific rule could require all kernel modules, for example, to be signed. appraise fowner=0 func=MODULE_CHECK appraise_type=imasig appraise fowner=0 As a result, the integrity appraisal results for the same inode, but for different hooks, could differ. This patch caches the integrity appraisal results on a per hook basis. Changelog v2: - Rename ima_cache_status() to ima_set_cache_status() - Rename and move get_appraise_status() to ima_get_cache_status() Changelog v0: - include IMA_APPRAISE/APPRAISED_SUBMASK in IMA_DO/DONE_MASK (Dmitry) - Support independent MODULE_CHECK appraise status. - fixed IMA_XXXX_APPRAISE/APPRAISED flags Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com> Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
Diffstat (limited to 'security/integrity/ima')
-rw-r--r--security/integrity/ima/ima.h13
-rw-r--r--security/integrity/ima/ima_appraise.c71
-rw-r--r--security/integrity/ima/ima_main.c19
-rw-r--r--security/integrity/ima/ima_policy.c22
4 files changed, 106 insertions, 19 deletions
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 991844db98d9..ab68bed8ac36 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -142,13 +142,16 @@ void ima_delete_rules(void);
#define IMA_APPRAISE_FIX 0x02
#ifdef CONFIG_IMA_APPRAISE
-int ima_appraise_measurement(struct integrity_iint_cache *iint,
+int ima_appraise_measurement(int func, struct integrity_iint_cache *iint,
struct file *file, const unsigned char *filename);
int ima_must_appraise(struct inode *inode, int mask, enum ima_hooks func);
void ima_update_xattr(struct integrity_iint_cache *iint, struct file *file);
+enum integrity_status ima_get_cache_status(struct integrity_iint_cache *iint,
+ int func);
#else
-static inline int ima_appraise_measurement(struct integrity_iint_cache *iint,
+static inline int ima_appraise_measurement(int func,
+ struct integrity_iint_cache *iint,
struct file *file,
const unsigned char *filename)
{
@@ -165,6 +168,12 @@ static inline void ima_update_xattr(struct integrity_iint_cache *iint,
struct file *file)
{
}
+
+static inline enum integrity_status ima_get_cache_status(struct integrity_iint_cache
+ *iint, int func)
+{
+ return INTEGRITY_UNKNOWN;
+}
#endif
/* LSM based policy rules require audit */
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index 8004332ccb8f..2d4becab8918 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -51,6 +51,62 @@ static int ima_fix_xattr(struct dentry *dentry,
sizeof(iint->ima_xattr), 0);
}
+/* Return specific func appraised cached result */
+enum integrity_status ima_get_cache_status(struct integrity_iint_cache *iint,
+ int func)
+{
+ switch(func) {
+ case MMAP_CHECK:
+ return iint->ima_mmap_status;
+ case BPRM_CHECK:
+ return iint->ima_bprm_status;
+ case MODULE_CHECK:
+ return iint->ima_module_status;
+ case FILE_CHECK:
+ default:
+ return iint->ima_file_status;
+ }
+}
+
+static void ima_set_cache_status(struct integrity_iint_cache *iint,
+ int func, enum integrity_status status)
+{
+ switch(func) {
+ case MMAP_CHECK:
+ iint->ima_mmap_status = status;
+ break;
+ case BPRM_CHECK:
+ iint->ima_bprm_status = status;
+ break;
+ case MODULE_CHECK:
+ iint->ima_module_status = status;
+ break;
+ case FILE_CHECK:
+ default:
+ iint->ima_file_status = status;
+ break;
+ }
+}
+
+static void ima_cache_flags(struct integrity_iint_cache *iint, int func)
+{
+ switch(func) {
+ case MMAP_CHECK:
+ iint->flags |= (IMA_MMAP_APPRAISED | IMA_APPRAISED);
+ break;
+ case BPRM_CHECK:
+ iint->flags |= (IMA_BPRM_APPRAISED | IMA_APPRAISED);
+ break;
+ case MODULE_CHECK:
+ iint->flags |= (IMA_MODULE_APPRAISED | IMA_APPRAISED);
+ break;
+ case FILE_CHECK:
+ default:
+ iint->flags |= (IMA_FILE_APPRAISED | IMA_APPRAISED);
+ break;
+ }
+}
+
/*
* ima_appraise_measurement - appraise file measurement
*
@@ -59,7 +115,7 @@ static int ima_fix_xattr(struct dentry *dentry,
*
* Return 0 on success, error code otherwise
*/
-int ima_appraise_measurement(struct integrity_iint_cache *iint,
+int ima_appraise_measurement(int func, struct integrity_iint_cache *iint,
struct file *file, const unsigned char *filename)
{
struct dentry *dentry = file->f_dentry;
@@ -75,9 +131,6 @@ int ima_appraise_measurement(struct integrity_iint_cache *iint,
if (!inode->i_op->getxattr)
return INTEGRITY_UNKNOWN;
- if (iint->flags & IMA_APPRAISED)
- return iint->ima_status;
-
rc = vfs_getxattr_alloc(dentry, XATTR_NAME_IMA, (char **)&xattr_value,
0, GFP_NOFS);
if (rc <= 0) {
@@ -99,7 +152,6 @@ int ima_appraise_measurement(struct integrity_iint_cache *iint,
cause = "invalid-HMAC";
goto out;
}
-
switch (xattr_value->type) {
case IMA_XATTR_DIGEST:
if (iint->flags & IMA_DIGSIG_REQUIRED) {
@@ -148,9 +200,9 @@ out:
integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, filename,
op, cause, rc, 0);
} else {
- iint->flags |= IMA_APPRAISED;
+ ima_cache_flags(iint, func);
}
- iint->ima_status = status;
+ ima_set_cache_status(iint, func, status);
kfree(xattr_value);
return status;
}
@@ -196,10 +248,11 @@ void ima_inode_post_setattr(struct dentry *dentry)
must_appraise = ima_must_appraise(inode, MAY_ACCESS, POST_SETATTR);
iint = integrity_iint_find(inode);
if (iint) {
+ iint->flags &= ~(IMA_APPRAISE | IMA_APPRAISED |
+ IMA_APPRAISE_SUBMASK | IMA_APPRAISED_SUBMASK |
+ IMA_ACTION_FLAGS);
if (must_appraise)
iint->flags |= IMA_APPRAISE;
- else
- iint->flags &= ~(IMA_APPRAISE | IMA_APPRAISED);
}
if (!must_appraise)
rc = inode->i_op->removexattr(dentry, XATTR_NAME_IMA);
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 3cdd78768c29..66b7f408eff2 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -151,8 +151,10 @@ static int process_measurement(struct file *file, const char *filename,
if (!ima_initialized || !S_ISREG(inode->i_mode))
return 0;
- /* Determine if in appraise/audit/measurement policy,
- * returns IMA_MEASURE, IMA_APPRAISE, IMA_AUDIT bitmask. */
+ /* Return an IMA_MEASURE, IMA_APPRAISE, IMA_AUDIT action
+ * bitmask based on the appraise/audit/measurement policy.
+ * Included is the appraise submask.
+ */
action = ima_get_action(inode, mask, function);
if (!action)
return 0;
@@ -166,16 +168,17 @@ static int process_measurement(struct file *file, const char *filename,
goto out;
/* Determine if already appraised/measured based on bitmask
- * (IMA_MEASURE, IMA_MEASURED, IMA_APPRAISE, IMA_APPRAISED,
- * IMA_AUDIT, IMA_AUDITED) */
+ * (IMA_MEASURE, IMA_MEASURED, IMA_XXXX_APPRAISE, IMA_XXXX_APPRAISED,
+ * IMA_AUDIT, IMA_AUDITED)
+ */
iint->flags |= action;
action &= IMA_DO_MASK;
action &= ~((iint->flags & IMA_DONE_MASK) >> 1);
/* Nothing to do, just return existing appraised status */
if (!action) {
- if (iint->flags & IMA_APPRAISED)
- rc = iint->ima_status;
+ if (must_appraise)
+ rc = ima_get_cache_status(iint, function);
goto out_digsig;
}
@@ -191,8 +194,8 @@ static int process_measurement(struct file *file, const char *filename,
if (action & IMA_MEASURE)
ima_store_measurement(iint, file, pathname);
- if (action & IMA_APPRAISE)
- rc = ima_appraise_measurement(iint, file, pathname);
+ if (action & IMA_APPRAISE_SUBMASK)
+ rc = ima_appraise_measurement(function, iint, file, pathname);
if (action & IMA_AUDIT)
ima_audit_measurement(iint, pathname);
kfree(pathbuf);
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 1a2543a8ee53..4d7c0ae656d3 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -218,6 +218,25 @@ retry:
return true;
}
+/*
+ * In addition to knowing that we need to appraise the file in general,
+ * we need to differentiate between calling hooks.
+ */
+static int get_subaction(int func)
+{
+ switch(func) {
+ case MMAP_CHECK:
+ return IMA_MMAP_APPRAISE;
+ case BPRM_CHECK:
+ return IMA_BPRM_APPRAISE;
+ case MODULE_CHECK:
+ return IMA_MODULE_APPRAISE;
+ case FILE_CHECK:
+ default:
+ return IMA_FILE_APPRAISE;
+ }
+}
+
/**
* ima_match_policy - decision based on LSM and other conditions
* @inode: pointer to an inode for which the policy decision is being made
@@ -248,6 +267,9 @@ int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask,
action |= entry->flags & IMA_ACTION_FLAGS;
action |= entry->action & IMA_DO_MASK;
+ if (entry->action & IMA_APPRAISE)
+ action |= get_subaction(func);
+
if (entry->action & IMA_DO_MASK)
actmask &= ~(entry->action | entry->action << 1);
else