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Subject[PATCH 3/3] IMA: add support to measure duplicate buffer for critical data hook
Date
process_buffer_measurement() and the underlying functions do not use the
policy condition to measure duplicate buffer entries for integrity
critical data.

Update process_buffer_measurement(), ima_add_template_entry(), and
ima_store_template() to use the policy condition to decide if a
duplicate buffer entry for integrity critical data should be measured.

Signed-off-by: Tushar Sugandhi <tusharsu@linux.microsoft.com>
---
security/integrity/ima/ima.h | 4 ++--
security/integrity/ima/ima_api.c | 9 +++++----
security/integrity/ima/ima_init.c | 2 +-
security/integrity/ima/ima_main.c | 5 +++--
security/integrity/ima/ima_queue.c | 5 +++--
5 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 59324173497f..b06732560949 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -139,7 +139,7 @@ int ima_init(void);
int ima_fs_init(void);
int ima_add_template_entry(struct ima_template_entry *entry, int violation,
const char *op, struct inode *inode,
- const unsigned char *filename);
+ const unsigned char *filename, bool allow_dup);
int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash);
int ima_calc_buffer_hash(const void *buf, loff_t len,
struct ima_digest_data *hash);
@@ -278,7 +278,7 @@ int ima_alloc_init_template(struct ima_event_data *event_data,
struct ima_template_desc *template_desc);
int ima_store_template(struct ima_template_entry *entry, int violation,
struct inode *inode,
- const unsigned char *filename, int pcr);
+ const unsigned char *filename, int pcr, bool allow_dup);
void ima_free_template_entry(struct ima_template_entry *entry);
const char *ima_d_path(const struct path *path, char **pathbuf, char *filename);

diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c
index d273373e6be9..f84369f9905e 100644
--- a/security/integrity/ima/ima_api.c
+++ b/security/integrity/ima/ima_api.c
@@ -101,7 +101,7 @@ int ima_alloc_init_template(struct ima_event_data *event_data,
*/
int ima_store_template(struct ima_template_entry *entry,
int violation, struct inode *inode,
- const unsigned char *filename, int pcr)
+ const unsigned char *filename, int pcr, bool allow_dup)
{
static const char op[] = "add_template_measure";
static const char audit_cause[] = "hashing_error";
@@ -119,7 +119,8 @@ int ima_store_template(struct ima_template_entry *entry,
}
}
entry->pcr = pcr;
- result = ima_add_template_entry(entry, violation, op, inode, filename);
+ result = ima_add_template_entry(entry, violation, op, inode, filename,
+ allow_dup);
return result;
}

@@ -152,7 +153,7 @@ void ima_add_violation(struct file *file, const unsigned char *filename,
goto err_out;
}
result = ima_store_template(entry, violation, inode,
- filename, CONFIG_IMA_MEASURE_PCR_IDX);
+ filename, CONFIG_IMA_MEASURE_PCR_IDX, false);
if (result < 0)
ima_free_template_entry(entry);
err_out:
@@ -330,7 +331,7 @@ void ima_store_measurement(struct integrity_iint_cache *iint,
return;
}

- result = ima_store_template(entry, violation, inode, filename, pcr);
+ result = ima_store_template(entry, violation, inode, filename, pcr, false);
if ((!result || result == -EEXIST) && !(file->f_flags & O_DIRECT)) {
iint->flags |= IMA_MEASURED;
iint->measured_pcrs |= (0x1 << pcr);
diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c
index 6e8742916d1d..d0a79d7b8d89 100644
--- a/security/integrity/ima/ima_init.c
+++ b/security/integrity/ima/ima_init.c
@@ -88,7 +88,7 @@ static int __init ima_add_boot_aggregate(void)

result = ima_store_template(entry, violation, NULL,
boot_aggregate_name,
- CONFIG_IMA_MEASURE_PCR_IDX);
+ CONFIG_IMA_MEASURE_PCR_IDX, false);
if (result < 0) {
ima_free_template_entry(entry);
audit_cause = "store_entry";
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 2774139845b6..ff6d15d7594c 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -843,6 +843,7 @@ void process_buffer_measurement(struct inode *inode, const void *buf, int size,
int digest_hash_len = hash_digest_size[ima_hash_algo];
int violation = 0;
int action = 0;
+ bool allow_dup = false;
u32 secid;

if (!ima_policy_flag)
@@ -865,7 +866,7 @@ void process_buffer_measurement(struct inode *inode, const void *buf, int size,
if (func) {
security_task_getsecid(current, &secid);
action = ima_get_action(inode, current_cred(), secid, 0, func,
- &pcr, &template, func_data, NULL);
+ &pcr, &template, func_data, &allow_dup);
if (!(action & IMA_MEASURE))
return;
}
@@ -903,7 +904,7 @@ void process_buffer_measurement(struct inode *inode, const void *buf, int size,
goto out;
}

- ret = ima_store_template(entry, violation, NULL, event_data.buf, pcr);
+ ret = ima_store_template(entry, violation, NULL, event_data.buf, pcr, allow_dup);
if (ret < 0) {
audit_cause = "store_entry";
ima_free_template_entry(entry);
diff --git a/security/integrity/ima/ima_queue.c b/security/integrity/ima/ima_queue.c
index c096ef8945c7..fbf359495fa8 100644
--- a/security/integrity/ima/ima_queue.c
+++ b/security/integrity/ima/ima_queue.c
@@ -158,7 +158,7 @@ static int ima_pcr_extend(struct tpm_digest *digests_arg, int pcr)
*/
int ima_add_template_entry(struct ima_template_entry *entry, int violation,
const char *op, struct inode *inode,
- const unsigned char *filename)
+ const unsigned char *filename, bool allow_dup)
{
u8 *digest = entry->digests[ima_hash_algo_idx].digest;
struct tpm_digest *digests_arg = entry->digests;
@@ -169,7 +169,8 @@ int ima_add_template_entry(struct ima_template_entry *entry, int violation,

mutex_lock(&ima_extend_list_mutex);
if (!violation) {
- if (ima_lookup_digest_entry(digest, entry->pcr)) {
+ if (!allow_dup &&
+ ima_lookup_digest_entry(digest, entry->pcr)) {
audit_cause = "hash_exists";
result = -EEXIST;
goto out;
--
2.17.1
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