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[Linux-ima-devel] [RFC PATCH 3/5] ima: mamespace audit status flags
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From: Mehmet K. <mka...@li...> - 2017-07-20 22:55:57
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The iint cache stores whether the file is measured, appraised, audited
etc. This patch moves the IMA_AUDITED flag into the per-namespace
ns_status, enabling IMA audit mechanism to audit the same file each time
it is accessed in a new namespace.
The ns_status is not looked up if the CONFIG_IMA_NS is disabled or if
none of the IMA_NS_STATUS_ACTIONS (currently only IMA_AUDIT) are enabled.
Read and write operations on the iint flags is replaced with function
calls. For reading, iint_flags() returns the bitwise AND of iint->flags
and ns_status->flags. The ns_status flags are masked with
IMA_NS_STATUS_FLAGS (currently only IMA_AUDITED). Similarly
set_iint_flags() only writes the masked portion to the ns_status flags,
while the iint flags is set as before. The ns_status parameter added to
ima_audit_measurement() is used with the above functions to query and
set the ns_status flags.
Signed-off-by: Mehmet Kayaalp <mka...@li...>
---
init/Kconfig | 4 +++-
security/integrity/ima/ima.h | 24 +++++++++++++++++++++++-
security/integrity/ima/ima_api.c | 8 +++++---
security/integrity/ima/ima_main.c | 15 ++++++++++++---
security/integrity/ima/ima_ns.c | 21 +++++++++++++++++++++
5 files changed, 64 insertions(+), 8 deletions(-)
diff --git a/init/Kconfig b/init/Kconfig
index 339f84d..6bfc579 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1294,7 +1294,9 @@ config IMA_NS
help
Allow the creation of IMA namespaces for each mount namespace.
Namespaced IMA data enables having IMA features work separately
- for each mount namespace.
+ for each mount namespace. Currently, only the audit status flags
+ are stored in the namespace, which allows the same file to be
+ audited each time it is accessed in a new namespace.
endif # NAMESPACES
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 5ab769a..78921b7 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -210,7 +210,8 @@ void ima_store_measurement(struct integrity_iint_cache *iint, struct file *file,
struct evm_ima_xattr_data *xattr_value,
int xattr_len, int pcr);
void ima_audit_measurement(struct integrity_iint_cache *iint,
- const unsigned char *filename);
+ const unsigned char *filename,
+ struct ns_status *status);
int ima_alloc_init_template(struct ima_event_data *event_data,
struct ima_template_entry **entry);
int ima_store_template(struct ima_template_entry *entry, int violation,
@@ -299,10 +300,17 @@ static inline int ima_read_xattr(struct dentry *dentry,
#endif /* CONFIG_IMA_APPRAISE */
+#define IMA_NS_STATUS_ACTIONS IMA_AUDIT
+#define IMA_NS_STATUS_FLAGS IMA_AUDITED
+
#ifdef CONFIG_IMA_NS
int ima_ns_init(void);
struct ns_status *ima_get_ns_status(struct ima_namespace *ns,
struct inode *inode);
+unsigned long iint_flags(struct integrity_iint_cache *iint,
+ struct ns_status *status);
+unsigned long set_iint_flags(struct integrity_iint_cache *iint,
+ struct ns_status *status, unsigned long flags);
#else
static inline int ima_ns_init(void)
{
@@ -314,6 +322,20 @@ static inline struct ns_status *ima_get_ns_status(struct ima_namespace *ns,
{
return NULL;
}
+
+static inline unsigned long iint_flags(struct integrity_iint_cache *iint,
+ struct ns_status *status)
+{
+ return iint->flags;
+}
+
+static inline unsigned long set_iint_flags(struct integrity_iint_cache *iint,
+ struct ns_status *status,
+ unsigned long flags)
+{
+ iint->flags = flags;
+ return flags;
+}
#endif /* CONFIG_IMA_NS */
/* LSM based policy rules require audit */
diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c
index c2edba8..4a77072 100644
--- a/security/integrity/ima/ima_api.c
+++ b/security/integrity/ima/ima_api.c
@@ -287,15 +287,17 @@ void ima_store_measurement(struct integrity_iint_cache *iint,
}
void ima_audit_measurement(struct integrity_iint_cache *iint,
- const unsigned char *filename)
+ const unsigned char *filename,
+ struct ns_status *status)
{
struct audit_buffer *ab;
char hash[(iint->ima_hash->length * 2) + 1];
const char *algo_name = hash_algo_name[iint->ima_hash->algo];
char algo_hash[sizeof(hash) + strlen(algo_name) + 2];
int i;
+ unsigned long flags = iint_flags(iint, status);
- if (iint->flags & IMA_AUDITED)
+ if (flags & IMA_AUDITED)
return;
for (i = 0; i < iint->ima_hash->length; i++)
@@ -316,7 +318,7 @@ void ima_audit_measurement(struct integrity_iint_cache *iint,
audit_log_task_info(ab, current);
audit_log_end(ab);
- iint->flags |= IMA_AUDITED;
+ set_iint_flags(iint, status, flags | IMA_AUDITED);
}
/*
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 2aebb79..fb002f2 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -160,6 +160,7 @@ static int process_measurement(struct file *file, char *buf, loff_t size,
{
struct inode *inode = file_inode(file);
struct integrity_iint_cache *iint = NULL;
+ struct ns_status *status = NULL;
struct ima_template_desc *template_desc;
char *pathbuf = NULL;
char filename[NAME_MAX];
@@ -170,6 +171,7 @@ static int process_measurement(struct file *file, char *buf, loff_t size,
int xattr_len = 0;
bool violation_check;
enum hash_algo hash_algo;
+ unsigned long flags;
if (!ima_policy_flag || !S_ISREG(inode->i_mode))
return 0;
@@ -196,6 +198,12 @@ static int process_measurement(struct file *file, char *buf, loff_t size,
iint = integrity_inode_get(inode);
if (!iint)
goto out;
+
+ if (action & IMA_NS_STATUS_ACTIONS) {
+ status = ima_get_ns_status(get_current_ns(), inode);
+ if (IS_ERR(status))
+ goto out;
+ }
}
if (violation_check) {
@@ -211,9 +219,10 @@ static int process_measurement(struct file *file, char *buf, loff_t size,
* (IMA_MEASURE, IMA_MEASURED, IMA_XXXX_APPRAISE, IMA_XXXX_APPRAISED,
* IMA_AUDIT, IMA_AUDITED)
*/
- iint->flags |= action;
+ flags = iint_flags(iint, status);
+ flags = set_iint_flags(iint, status, flags | action);
action &= IMA_DO_MASK;
- action &= ~((iint->flags & (IMA_DONE_MASK ^ IMA_MEASURED)) >> 1);
+ action &= ~((flags & (IMA_DONE_MASK ^ IMA_MEASURED)) >> 1);
/* If target pcr is already measured, unset IMA_MEASURE action */
if ((action & IMA_MEASURE) && (iint->measured_pcrs & (0x1 << pcr)))
@@ -251,7 +260,7 @@ static int process_measurement(struct file *file, char *buf, loff_t size,
rc = ima_appraise_measurement(func, iint, file, pathname,
xattr_value, xattr_len, opened);
if (action & IMA_AUDIT)
- ima_audit_measurement(iint, pathname);
+ ima_audit_measurement(iint, pathname, status);
out_digsig:
if ((mask & MAY_WRITE) && (iint->flags & IMA_DIGSIG) &&
diff --git a/security/integrity/ima/ima_ns.c b/security/integrity/ima/ima_ns.c
index 5ec5a4b..562a0812 100644
--- a/security/integrity/ima/ima_ns.c
+++ b/security/integrity/ima/ima_ns.c
@@ -301,3 +301,24 @@ struct ns_status *ima_get_ns_status(struct ima_namespace *ns,
return status;
}
+
+#define IMA_NS_STATUS_ACTIONS IMA_AUDIT
+#define IMA_NS_STATUS_FLAGS IMA_AUDITED
+
+unsigned long iint_flags(struct integrity_iint_cache *iint,
+ struct ns_status *status)
+{
+ if (!status)
+ return iint->flags;
+
+ return iint->flags & (status->flags & IMA_NS_STATUS_FLAGS);
+}
+
+unsigned long set_iint_flags(struct integrity_iint_cache *iint,
+ struct ns_status *status, unsigned long flags)
+{
+ iint->flags = flags;
+ if (status)
+ status->flags = flags & IMA_NS_STATUS_FLAGS;
+ return flags;
+}
--
2.9.4
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