1 files changed, 122 insertions, 27 deletions

diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 584019728660..9fe949c6a530 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -202,6 +202,7 @@ static int process_measurement(struct file *file, const struct cred *cred,
 	int rc = 0, action, must_appraise = 0;
 	int pcr = CONFIG_IMA_MEASURE_PCR_IDX;
 	struct evm_ima_xattr_data *xattr_value = NULL;
+	struct modsig *modsig = NULL;
 	int xattr_len = 0;
 	bool violation_check;
 	enum hash_algo hash_algo;
@@ -214,7 +215,7 @@ static int process_measurement(struct file *file, const struct cred *cred,
 	 * Included is the appraise submask.
 	 */
 	action = ima_get_action(inode, cred, secid, mask, func, &pcr,
-				&template_desc);
+				&template_desc, NULL);
 	violation_check = ((func == FILE_CHECK || func == MMAP_CHECK) &&
 			   (ima_policy_flag & IMA_MEASURE));
 	if (!action && !violation_check)
@@ -302,13 +303,27 @@ static int process_measurement(struct file *file, const struct cred *cred,
 	}
 
 	if ((action & IMA_APPRAISE_SUBMASK) ||
-		    strcmp(template_desc->name, IMA_TEMPLATE_IMA_NAME) != 0)
+	    strcmp(template_desc->name, IMA_TEMPLATE_IMA_NAME) != 0) {
 		/* read 'security.ima' */
 		xattr_len = ima_read_xattr(file_dentry(file), &xattr_value);
 
+		/*
+		 * Read the appended modsig if allowed by the policy, and allow
+		 * an additional measurement list entry, if needed, based on the
+		 * template format and whether the file was already measured.
+		 */
+		if (iint->flags & IMA_MODSIG_ALLOWED) {
+			rc = ima_read_modsig(func, buf, size, &modsig);
+
+			if (!rc && ima_template_has_modsig(template_desc) &&
+			    iint->flags & IMA_MEASURED)
+				action |= IMA_MEASURE;
+		}
+	}
+
 	hash_algo = ima_get_hash_algo(xattr_value, xattr_len);
 
-	rc = ima_collect_measurement(iint, file, buf, size, hash_algo);
+	rc = ima_collect_measurement(iint, file, buf, size, hash_algo, modsig);
 	if (rc != 0 && rc != -EBADF && rc != -EINVAL)
 		goto out_locked;
 
@@ -317,13 +332,17 @@ static int process_measurement(struct file *file, const struct cred *cred,
 
 	if (action & IMA_MEASURE)
 		ima_store_measurement(iint, file, pathname,
-				      xattr_value, xattr_len, pcr,
+				      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);
-		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);
@@ -339,6 +358,7 @@ out_locked:
 		rc = -EACCES;
 	mutex_unlock(&iint->mutex);
 	kfree(xattr_value);
+	ima_free_modsig(modsig);
 out:
 	if (pathbuf)
 		__putname(pathbuf);
@@ -426,6 +446,55 @@ int ima_file_check(struct file *file, int mask)
 EXPORT_SYMBOL_GPL(ima_file_check);
 
 /**
+ * ima_file_hash - return the stored measurement if a file has been hashed and
+ * is in the iint cache.
+ * @file: pointer to the file
+ * @buf: buffer in which to store the hash
+ * @buf_size: length of the buffer
+ *
+ * On success, return the hash algorithm (as defined in the enum hash_algo).
+ * If buf is not NULL, this function also outputs the hash into buf.
+ * If the hash is larger than buf_size, then only buf_size bytes will be copied.
+ * It generally just makes sense to pass a buffer capable of holding the largest
+ * possible hash: IMA_MAX_DIGEST_SIZE.
+ * The file hash returned is based on the entire file, including the appended
+ * signature.
+ *
+ * If IMA is disabled or if no measurement is available, return -EOPNOTSUPP.
+ * If the parameters are incorrect, return -EINVAL.
+ */
+int ima_file_hash(struct file *file, char *buf, size_t buf_size)
+{
+	struct inode *inode;
+	struct integrity_iint_cache *iint;
+	int hash_algo;
+
+	if (!file)
+		return -EINVAL;
+
+	if (!ima_policy_flag)
+		return -EOPNOTSUPP;
+
+	inode = file_inode(file);
+	iint = integrity_iint_find(inode);
+	if (!iint)
+		return -EOPNOTSUPP;
+
+	mutex_lock(&iint->mutex);
+	if (buf) {
+		size_t copied_size;
+
+		copied_size = min_t(size_t, iint->ima_hash->length, buf_size);
+		memcpy(buf, iint->ima_hash->digest, copied_size);
+	}
+	hash_algo = iint->ima_hash->algo;
+	mutex_unlock(&iint->mutex);
+
+	return hash_algo;
+}
+EXPORT_SYMBOL_GPL(ima_file_hash);
+
+/**
  * ima_post_create_tmpfile - mark newly created tmpfile as new
  * @file : newly created tmpfile
  *
@@ -502,7 +571,7 @@ int ima_read_file(struct file *file, enum kernel_read_file_id read_id)
 	return 0;
 }
 
-static const int read_idmap[READING_MAX_ID] = {
+const int read_idmap[READING_MAX_ID] = {
 	[READING_FIRMWARE] = FIRMWARE_CHECK,
 	[READING_FIRMWARE_PREALLOC_BUFFER] = FIRMWARE_CHECK,
 	[READING_MODULE] = MODULE_CHECK,
@@ -574,7 +643,7 @@ int ima_load_data(enum kernel_load_data_id id)
 
 	switch (id) {
 	case LOADING_KEXEC_IMAGE:
-		if (IS_ENABLED(CONFIG_KEXEC_VERIFY_SIG)
+		if (IS_ENABLED(CONFIG_KEXEC_SIG)
 		    && arch_ima_get_secureboot()) {
 			pr_err("impossible to appraise a kernel image without a file descriptor; try using kexec_file_load syscall.\n");
 			return -EACCES;
@@ -610,14 +679,15 @@ 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
+ * @keyring: keyring name to determine the action to be performed
  *
  * 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, const char *keyring)
 {
 	int ret = 0;
 	struct ima_template_entry *entry = NULL;
@@ -626,20 +696,49 @@ 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))
+	if (!ima_policy_flag)
 		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, keyring);
+		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;
 	iint.ima_hash->length = hash_digest_size[ima_hash_algo];
@@ -648,7 +747,7 @@ 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;
 
@@ -670,13 +769,9 @@ 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, NULL);
 }
 
 static int __init init_ima(void)