[PATCH v24 13/25] IMA: Change internal interfaces to use lsmblobs

Casey Schaufler
2021-01-26T18:11:40Z

The IMA interfaces ima_get_action() and ima_match_policy()
call LSM functions that use lsmblobs. Change the IMA functions
to pass the lsmblob to be compatible with the LSM functions.

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: John Johansen <john.johansen@canonical.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: linux-integrity@vger.kernel.org
To: Mimi Zohar <zohar@linux.ibm.com>
---
security/integrity/ima/ima.h | 11 ++++----
security/integrity/ima/ima_api.c | 10 +++----
security/integrity/ima/ima_appraise.c | 6 ++---
security/integrity/ima/ima_main.c | 38 +++++++++++----------------
security/integrity/ima/ima_policy.c | 16 +++++------
5 files changed, 36 insertions(+), 45 deletions(-)

diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 0c520ea21677..c0c225335cb1 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -253,9 +253,9 @@ static inline void ima_process_queued_keys(void) {}
#endif /* CONFIG_IMA_QUEUE_EARLY_BOOT_KEYS */

/* LIM API function definitions */
-int ima_get_action(struct inode *inode, const struct cred *cred, u32 secid,
- int mask, enum ima_hooks func, int *pcr,
- struct ima_template_desc **template_desc,
+int ima_get_action(struct inode *inode, const struct cred *cred,
+ struct lsmblob *blob, int mask, enum ima_hooks func,
+ int *pcr, struct ima_template_desc **template_desc,
const char *keyring);
int ima_must_measure(struct inode *inode, int mask, enum ima_hooks func);
int ima_collect_measurement(struct integrity_iint_cache *iint,
@@ -281,8 +281,9 @@ void ima_free_template_entry(struct ima_template_entry *entry);
const char *ima_d_path(const struct path *path, char **pathbuf, char *filename);

/* IMA policy related functions */
-int ima_match_policy(struct inode *inode, const struct cred *cred, u32 secid,
- enum ima_hooks func, int mask, int flags, int *pcr,
+int ima_match_policy(struct inode *inode, const struct cred *cred,
+ struct lsmblob *blob, enum ima_hooks func, int mask,
+ int flags, int *pcr,
struct ima_template_desc **template_desc,
const char *keyring);
void ima_init_policy(void);
diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c
index 4f39fb93f278..e83fa1c32843 100644
--- a/security/integrity/ima/ima_api.c
+++ b/security/integrity/ima/ima_api.c
@@ -164,7 +164,7 @@ void ima_add_violation(struct file *file, const unsigned char *filename,
* ima_get_action - appraise & measure decision based on policy.
* @inode: pointer to the inode associated with the object being validated
* @cred: pointer to credentials structure to validate
- * @secid: secid of the task being validated
+ * @blob: LSM data of the task being validated
* @mask: contains the permission mask (MAY_READ, MAY_WRITE, MAY_EXEC,
* MAY_APPEND)
* @func: caller identifier
@@ -183,16 +183,16 @@ void ima_add_violation(struct file *file, const unsigned char *filename,
* Returns IMA_MEASURE, IMA_APPRAISE mask.
*
*/
-int ima_get_action(struct inode *inode, const struct cred *cred, u32 secid,
- int mask, enum ima_hooks func, int *pcr,
- struct ima_template_desc **template_desc,
+int ima_get_action(struct inode *inode, const struct cred *cred,
+ struct lsmblob *blob, int mask, enum ima_hooks func,
+ int *pcr, struct ima_template_desc **template_desc,
const char *keyring)
{
int flags = IMA_MEASURE | IMA_AUDIT | IMA_APPRAISE | IMA_HASH;

flags &= ima_policy_flag;

- return ima_match_policy(inode, cred, secid, func, mask, flags, pcr,
+ return ima_match_policy(inode, cred, blob, func, mask, flags, pcr,
template_desc, keyring);
}

diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index afcf715de585..1309d2092dc9 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -76,10 +76,8 @@ int ima_must_appraise(struct inode *inode, int mask, enum ima_hooks func)
return 0;

security_task_getsecid(current, &blob);
- /* scaffolding the .secid[0] */
- return ima_match_policy(inode, current_cred(), blob.secid[0], func,
- mask, IMA_APPRAISE | IMA_HASH, NULL, NULL,
- NULL);
+ return ima_match_policy(inode, current_cred(), &blob, func, mask,
+ IMA_APPRAISE | IMA_HASH, NULL, NULL, NULL);
}

static int ima_fix_xattr(struct dentry *dentry,
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index e4ed01b1919a..f3400605292d 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -194,8 +194,8 @@ void ima_file_free(struct file *file)
}

static int process_measurement(struct file *file, const struct cred *cred,
- u32 secid, char *buf, loff_t size, int mask,
- enum ima_hooks func)
+ struct lsmblob *blob, char *buf, loff_t size,
+ int mask, enum ima_hooks func)
{
struct inode *inode = file_inode(file);
struct integrity_iint_cache *iint = NULL;
@@ -218,7 +218,7 @@ static int process_measurement(struct file *file, const struct cred *cred,
* bitmask based on the appraise/audit/measurement policy.
* Included is the appraise submask.
*/
- action = ima_get_action(inode, cred, secid, mask, func, &pcr,
+ action = ima_get_action(inode, cred, blob, mask, func, &pcr,
&template_desc, NULL);
violation_check = ((func == FILE_CHECK || func == MMAP_CHECK) &&
(ima_policy_flag & IMA_MEASURE));
@@ -392,8 +392,7 @@ int ima_file_mmap(struct file *file, unsigned long prot)

if (file && (prot & PROT_EXEC)) {
security_task_getsecid(current, &blob);
- /* scaffolding - until process_measurement changes */
- return process_measurement(file, current_cred(), blob.secid[0],
+ return process_measurement(file, current_cred(), &blob,
NULL, 0, MAY_EXEC, MMAP_CHECK);
}

@@ -432,8 +431,7 @@ int ima_file_mprotect(struct vm_area_struct *vma, unsigned long prot)

security_task_getsecid(current, &blob);
inode = file_inode(vma->vm_file);
- /* scaffolding */
- action = ima_get_action(NULL, current_cred(), blob.secid[0], 0,
+ action = ima_get_action(NULL, current_cred(), &blob, 0,
MMAP_CHECK, &pcr, &template, 0);

/* Is the mmap'ed file in policy? */
@@ -472,16 +470,14 @@ int ima_bprm_check(struct linux_binprm *bprm)
struct lsmblob blob;

security_task_getsecid(current, &blob);
- /* scaffolding until process_measurement changes */
- ret = process_measurement(bprm->file, current_cred(), blob.secid[0],
- NULL, 0, MAY_EXEC, BPRM_CHECK);
+ ret = process_measurement(bprm->file, current_cred(), &blob, NULL, 0,
+ MAY_EXEC, BPRM_CHECK);
if (ret)
return ret;

security_cred_getsecid(bprm->cred, &blob);
- /* scaffolding until process_measurement changes */
- return process_measurement(bprm->file, bprm->cred, blob.secid[0],
- NULL, 0, MAY_EXEC, CREDS_CHECK);
+ return process_measurement(bprm->file, bprm->cred, &blob, NULL, 0,
+ MAY_EXEC, CREDS_CHECK);
}

/**
@@ -499,8 +495,7 @@ int ima_file_check(struct file *file, int mask)
struct lsmblob blob;

security_task_getsecid(current, &blob);
- /* scaffolding until process_measurement changes */
- return process_measurement(file, current_cred(), blob.secid[0], NULL, 0,
+ return process_measurement(file, current_cred(), &blob, NULL, 0,
mask & (MAY_READ | MAY_WRITE | MAY_EXEC |
MAY_APPEND), FILE_CHECK);
}
@@ -685,8 +680,7 @@ int ima_read_file(struct file *file, enum kernel_read_file_id read_id,
/* Read entire file for all partial reads. */
func = read_idmap[read_id] ?: FILE_CHECK;
security_task_getsecid(current, &blob);
- /* scaffolding - until process_measurement changes */
- return process_measurement(file, current_cred(), blob.secid[0], NULL,
+ return process_measurement(file, current_cred(), &blob, NULL,
0, MAY_READ, func);
}

@@ -729,9 +723,8 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size,

func = read_idmap[read_id] ?: FILE_CHECK;
security_task_getsecid(current, &blob);
- /* scaffolding until process_measurement changes */
- return process_measurement(file, current_cred(), blob.secid[0], buf,
- size, MAY_READ, func);
+ return process_measurement(file, current_cred(), &blob, buf, size,
+ MAY_READ, func);
}

/**
@@ -867,9 +860,8 @@ void process_buffer_measurement(struct inode *inode, const void *buf, int size,
*/
if (func) {
security_task_getsecid(current, &blob);
- /* scaffolding */
- action = ima_get_action(inode, current_cred(), blob.secid[0],
- 0, func, &pcr, &template, keyring);
+ action = ima_get_action(inode, current_cred(), &blob, 0, func,
+ &pcr, &template, keyring);
if (!(action & IMA_MEASURE))
return;
}
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index ab66266fe932..9ac673472781 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -522,7 +522,7 @@ static bool ima_match_keyring(struct ima_rule_entry *rule,
* @rule: a pointer to a rule
* @inode: a pointer to an inode
* @cred: a pointer to a credentials structure for user validation
- * @secid: the secid of the task to be validated
+ * @blob: the lsm data of the task to be validated
* @func: LIM hook identifier
* @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
* @keyring: keyring name to check in policy for KEY_CHECK func
@@ -530,7 +530,7 @@ static bool ima_match_keyring(struct ima_rule_entry *rule,
* Returns true on rule match, false on failure.
*/
static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
- const struct cred *cred, u32 secid,
+ const struct cred *cred, struct lsmblob *blob,
enum ima_hooks func, int mask,
const char *keyring)
{
@@ -595,8 +595,7 @@ static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode,
case LSM_SUBJ_USER:
case LSM_SUBJ_ROLE:
case LSM_SUBJ_TYPE:
- lsmblob_init(&lsmdata, secid);
- rc = ima_filter_rule_match(&lsmdata, rule->lsm[i].type,
+ rc = ima_filter_rule_match(blob, rule->lsm[i].type,
Audit_equal,
rule->lsm[i].rules);
default:
@@ -638,7 +637,7 @@ static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func)
* @inode: pointer to an inode for which the policy decision is being made
* @cred: pointer to a credentials structure for which the policy decision is
* being made
- * @secid: LSM secid of the task to be validated
+ * @blob: LSM data of the task to be validated
* @func: IMA hook identifier
* @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
* @pcr: set the pcr to extend
@@ -653,8 +652,9 @@ static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func)
* list when walking it. Reads are many orders of magnitude more numerous
* than writes so ima_match_policy() is classical RCU candidate.
*/
-int ima_match_policy(struct inode *inode, const struct cred *cred, u32 secid,
- enum ima_hooks func, int mask, int flags, int *pcr,
+int ima_match_policy(struct inode *inode, const struct cred *cred,
+ struct lsmblob *blob, enum ima_hooks func, int mask,
+ int flags, int *pcr,
struct ima_template_desc **template_desc,
const char *keyring)
{
@@ -670,7 +670,7 @@ int ima_match_policy(struct inode *inode, const struct cred *cred, u32 secid,
if (!(entry->action & actmask))
continue;

- if (!ima_match_rules(entry, inode, cred, secid, func, mask,
+ if (!ima_match_rules(entry, inode, cred, blob, func, mask,
keyring))
continue;

--
2.25.4