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-rw-r--r--security/integrity/ima/ima.h11
-rw-r--r--security/integrity/ima/ima_appraise.c33
-rw-r--r--security/integrity/ima/ima_main.c70
-rw-r--r--security/integrity/ima/ima_policy.c12
4 files changed, 102 insertions, 24 deletions
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 3689081aaf38..df4ca482fb53 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -217,6 +217,9 @@ void ima_store_measurement(struct integrity_iint_cache *iint, struct file *file,
struct evm_ima_xattr_data *xattr_value,
int xattr_len, const struct modsig *modsig, int pcr,
struct ima_template_desc *template_desc);
+void process_buffer_measurement(const void *buf, int size,
+ const char *eventname, enum ima_hooks func,
+ int pcr);
void ima_audit_measurement(struct integrity_iint_cache *iint,
const unsigned char *filename);
int ima_alloc_init_template(struct ima_event_data *event_data,
@@ -253,6 +256,8 @@ int ima_policy_show(struct seq_file *m, void *v);
#define IMA_APPRAISE_KEXEC 0x40
#ifdef CONFIG_IMA_APPRAISE
+int ima_check_blacklist(struct integrity_iint_cache *iint,
+ const struct modsig *modsig, int pcr);
int ima_appraise_measurement(enum ima_hooks func,
struct integrity_iint_cache *iint,
struct file *file, const unsigned char *filename,
@@ -268,6 +273,12 @@ int ima_read_xattr(struct dentry *dentry,
struct evm_ima_xattr_data **xattr_value);
#else
+static inline int ima_check_blacklist(struct integrity_iint_cache *iint,
+ const struct modsig *modsig, int pcr)
+{
+ return 0;
+}
+
static inline int ima_appraise_measurement(enum ima_hooks func,
struct integrity_iint_cache *iint,
struct file *file,
diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index 136ae4e0ee92..300c8d2943c5 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -12,6 +12,7 @@
#include <linux/magic.h>
#include <linux/ima.h>
#include <linux/evm.h>
+#include <keys/system_keyring.h>
#include "ima.h"
@@ -304,6 +305,38 @@ static int modsig_verify(enum ima_hooks func, const struct modsig *modsig,
}
/*
+ * ima_check_blacklist - determine if the binary is blacklisted.
+ *
+ * Add the hash of the blacklisted binary to the measurement list, based
+ * on policy.
+ *
+ * Returns -EPERM if the hash is blacklisted.
+ */
+int ima_check_blacklist(struct integrity_iint_cache *iint,
+ const struct modsig *modsig, int pcr)
+{
+ enum hash_algo hash_algo;
+ const u8 *digest = NULL;
+ u32 digestsize = 0;
+ int rc = 0;
+
+ if (!(iint->flags & IMA_CHECK_BLACKLIST))
+ return 0;
+
+ if (iint->flags & IMA_MODSIG_ALLOWED && modsig) {
+ ima_get_modsig_digest(modsig, &hash_algo, &digest, &digestsize);
+
+ rc = is_binary_blacklisted(digest, digestsize);
+ if ((rc == -EPERM) && (iint->flags & IMA_MEASURE))
+ process_buffer_measurement(digest, digestsize,
+ "blacklisted-hash", NONE,
+ pcr);
+ }
+
+ return rc;
+}
+
+/*
* ima_appraise_measurement - appraise file measurement
*
* Call evm_verifyxattr() to verify the integrity of 'security.ima'.
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 60027c643ecd..d7e987baf127 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -335,10 +335,14 @@ static int process_measurement(struct file *file, const struct cred *cred,
xattr_value, xattr_len, modsig, pcr,
template_desc);
if (rc == 0 && (action & IMA_APPRAISE_SUBMASK)) {
- inode_lock(inode);
- rc = ima_appraise_measurement(func, iint, file, pathname,
- xattr_value, xattr_len, modsig);
- inode_unlock(inode);
+ rc = ima_check_blacklist(iint, modsig, pcr);
+ if (rc != -EPERM) {
+ inode_lock(inode);
+ rc = ima_appraise_measurement(func, iint, file,
+ pathname, xattr_value,
+ xattr_len, modsig);
+ inode_unlock(inode);
+ }
if (!rc)
rc = mmap_violation_check(func, file, &pathbuf,
&pathname, filename);
@@ -626,14 +630,14 @@ int ima_load_data(enum kernel_load_data_id id)
* @buf: pointer to the buffer that needs to be added to the log.
* @size: size of buffer(in bytes).
* @eventname: event name to be used for the buffer entry.
- * @cred: a pointer to a credentials structure for user validation.
- * @secid: the secid of the task to be validated.
+ * @func: IMA hook
+ * @pcr: pcr to extend the measurement
*
* Based on policy, the buffer is measured into the ima log.
*/
-static void process_buffer_measurement(const void *buf, int size,
- const char *eventname,
- const struct cred *cred, u32 secid)
+void process_buffer_measurement(const void *buf, int size,
+ const char *eventname, enum ima_hooks func,
+ int pcr)
{
int ret = 0;
struct ima_template_entry *entry = NULL;
@@ -642,19 +646,45 @@ static void process_buffer_measurement(const void *buf, int size,
.filename = eventname,
.buf = buf,
.buf_len = size};
- struct ima_template_desc *template_desc = NULL;
+ struct ima_template_desc *template = NULL;
struct {
struct ima_digest_data hdr;
char digest[IMA_MAX_DIGEST_SIZE];
} hash = {};
int violation = 0;
- int pcr = CONFIG_IMA_MEASURE_PCR_IDX;
int action = 0;
+ u32 secid;
- action = ima_get_action(NULL, cred, secid, 0, KEXEC_CMDLINE, &pcr,
- &template_desc);
- if (!(action & IMA_MEASURE))
- return;
+ /*
+ * Both LSM hooks and auxilary based buffer measurements are
+ * based on policy. To avoid code duplication, differentiate
+ * between the LSM hooks and auxilary buffer measurements,
+ * retrieving the policy rule information only for the LSM hook
+ * buffer measurements.
+ */
+ if (func) {
+ security_task_getsecid(current, &secid);
+ action = ima_get_action(NULL, current_cred(), secid, 0, func,
+ &pcr, &template);
+ if (!(action & IMA_MEASURE))
+ return;
+ }
+
+ if (!pcr)
+ pcr = CONFIG_IMA_MEASURE_PCR_IDX;
+
+ if (!template) {
+ template = lookup_template_desc("ima-buf");
+ ret = template_desc_init_fields(template->fmt,
+ &(template->fields),
+ &(template->num_fields));
+ if (ret < 0) {
+ pr_err("template %s init failed, result: %d\n",
+ (strlen(template->name) ?
+ template->name : template->fmt), ret);
+ return;
+ }
+ }
iint.ima_hash = &hash.hdr;
iint.ima_hash->algo = ima_hash_algo;
@@ -664,7 +694,7 @@ static void process_buffer_measurement(const void *buf, int size,
if (ret < 0)
goto out;
- ret = ima_alloc_init_template(&event_data, &entry, template_desc);
+ ret = ima_alloc_init_template(&event_data, &entry, template);
if (ret < 0)
goto out;
@@ -686,13 +716,9 @@ out:
*/
void ima_kexec_cmdline(const void *buf, int size)
{
- u32 secid;
-
- if (buf && size != 0) {
- security_task_getsecid(current, &secid);
+ if (buf && size != 0)
process_buffer_measurement(buf, size, "kexec-cmdline",
- current_cred(), secid);
- }
+ KEXEC_CMDLINE, 0);
}
static int __init init_ima(void)
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 5380aca2b351..f19a895ad7cd 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -765,8 +765,8 @@ enum {
Opt_fsuuid, Opt_uid_eq, Opt_euid_eq, Opt_fowner_eq,
Opt_uid_gt, Opt_euid_gt, Opt_fowner_gt,
Opt_uid_lt, Opt_euid_lt, Opt_fowner_lt,
- Opt_appraise_type, Opt_permit_directio,
- Opt_pcr, Opt_template, Opt_err
+ Opt_appraise_type, Opt_appraise_flag,
+ Opt_permit_directio, Opt_pcr, Opt_template, Opt_err
};
static const match_table_t policy_tokens = {
@@ -798,6 +798,7 @@ static const match_table_t policy_tokens = {
{Opt_euid_lt, "euid<%s"},
{Opt_fowner_lt, "fowner<%s"},
{Opt_appraise_type, "appraise_type=%s"},
+ {Opt_appraise_flag, "appraise_flag=%s"},
{Opt_permit_directio, "permit_directio"},
{Opt_pcr, "pcr=%s"},
{Opt_template, "template=%s"},
@@ -1172,6 +1173,11 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
else
result = -EINVAL;
break;
+ case Opt_appraise_flag:
+ ima_log_string(ab, "appraise_flag", args[0].from);
+ if (strstr(args[0].from, "blacklist"))
+ entry->flags |= IMA_CHECK_BLACKLIST;
+ break;
case Opt_permit_directio:
entry->flags |= IMA_PERMIT_DIRECTIO;
break;
@@ -1500,6 +1506,8 @@ int ima_policy_show(struct seq_file *m, void *v)
else
seq_puts(m, "appraise_type=imasig ");
}
+ if (entry->flags & IMA_CHECK_BLACKLIST)
+ seq_puts(m, "appraise_flag=check_blacklist ");
if (entry->flags & IMA_PERMIT_DIRECTIO)
seq_puts(m, "permit_directio ");
rcu_read_unlock();
generated by cgit (git 2.34.1) at 2024-06-11 02:03:45 +0000