1 files changed, 85 insertions, 11 deletions

diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 9d0abedeae77..8a91711ca79b 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -394,6 +394,58 @@ int ima_file_mmap(struct file *file, unsigned long prot)
 }
 
 /**
+ * ima_file_mprotect - based on policy, limit mprotect change
+ * @prot: contains the protection that will be applied by the kernel.
+ *
+ * Files can be mmap'ed read/write and later changed to execute to circumvent
+ * IMA's mmap appraisal policy rules.  Due to locking issues (mmap semaphore
+ * would be taken before i_mutex), files can not be measured or appraised at
+ * this point.  Eliminate this integrity gap by denying the mprotect
+ * PROT_EXECUTE change, if an mmap appraise policy rule exists.
+ *
+ * On mprotect change success, return 0.  On failure, return -EACESS.
+ */
+int ima_file_mprotect(struct vm_area_struct *vma, unsigned long prot)
+{
+	struct ima_template_desc *template;
+	struct file *file = vma->vm_file;
+	char filename[NAME_MAX];
+	char *pathbuf = NULL;
+	const char *pathname = NULL;
+	struct inode *inode;
+	int result = 0;
+	int action;
+	u32 secid;
+	int pcr;
+
+	/* Is mprotect making an mmap'ed file executable? */
+	if (!(ima_policy_flag & IMA_APPRAISE) || !vma->vm_file ||
+	    !(prot & PROT_EXEC) || (vma->vm_flags & VM_EXEC))
+		return 0;
+
+	security_task_getsecid(current, &secid);
+	inode = file_inode(vma->vm_file);
+	action = ima_get_action(inode, current_cred(), secid, MAY_EXEC,
+				MMAP_CHECK, &pcr, &template, 0);
+
+	/* Is the mmap'ed file in policy? */
+	if (!(action & (IMA_MEASURE | IMA_APPRAISE_SUBMASK)))
+		return 0;
+
+	if (action & IMA_APPRAISE_SUBMASK)
+		result = -EPERM;
+
+	file = vma->vm_file;
+	pathname = ima_d_path(&file->f_path, &pathbuf, filename);
+	integrity_audit_msg(AUDIT_INTEGRITY_DATA, inode, pathname,
+			    "collect_data", "failed-mprotect", result, 0);
+	if (pathbuf)
+		__putname(pathbuf);
+
+	return result;
+}
+
+/**
  * ima_bprm_check - based on policy, collect/store measurement.
  * @bprm: contains the linux_binprm structure
  *
@@ -674,6 +726,7 @@ int ima_load_data(enum kernel_load_data_id id)
 
 /*
  * process_buffer_measurement - Measure the buffer to ima log.
+ * @inode: inode associated with the object being measured (NULL for KEY_CHECK)
  * @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.
@@ -683,11 +736,12 @@ int ima_load_data(enum kernel_load_data_id id)
  *
  * Based on policy, the buffer is measured into the ima log.
  */
-void process_buffer_measurement(const void *buf, int size,
+void process_buffer_measurement(struct inode *inode, const void *buf, int size,
 				const char *eventname, enum ima_hooks func,
 				int pcr, const char *keyring)
 {
 	int ret = 0;
+	const char *audit_cause = "ENOMEM";
 	struct ima_template_entry *entry = NULL;
 	struct integrity_iint_cache iint = {};
 	struct ima_event_data event_data = {.iint = &iint,
@@ -715,7 +769,7 @@ void process_buffer_measurement(const void *buf, int size,
 	 */
 	if (func) {
 		security_task_getsecid(current, &secid);
-		action = ima_get_action(NULL, current_cred(), secid, 0, func,
+		action = ima_get_action(inode, current_cred(), secid, 0, func,
 					&pcr, &template, keyring);
 		if (!(action & IMA_MEASURE))
 			return;
@@ -742,37 +796,54 @@ void process_buffer_measurement(const void *buf, int size,
 	iint.ima_hash->length = hash_digest_size[ima_hash_algo];
 
 	ret = ima_calc_buffer_hash(buf, size, iint.ima_hash);
-	if (ret < 0)
+	if (ret < 0) {
+		audit_cause = "hashing_error";
 		goto out;
+	}
 
 	ret = ima_alloc_init_template(&event_data, &entry, template);
-	if (ret < 0)
+	if (ret < 0) {
+		audit_cause = "alloc_entry";
 		goto out;
+	}
 
 	ret = ima_store_template(entry, violation, NULL, buf, pcr);
-
-	if (ret < 0)
+	if (ret < 0) {
+		audit_cause = "store_entry";
 		ima_free_template_entry(entry);
+	}
 
 out:
 	if (ret < 0)
-		pr_devel("%s: failed, result: %d\n", __func__, ret);
+		integrity_audit_message(AUDIT_INTEGRITY_PCR, NULL, eventname,
+					func_measure_str(func),
+					audit_cause, ret, 0, ret);
 
 	return;
 }
 
 /**
  * ima_kexec_cmdline - measure kexec cmdline boot args
+ * @kernel_fd: file descriptor of the kexec kernel being loaded
  * @buf: pointer to buffer
  * @size: size of buffer
  *
  * Buffers can only be measured, not appraised.
  */
-void ima_kexec_cmdline(const void *buf, int size)
+void ima_kexec_cmdline(int kernel_fd, const void *buf, int size)
 {
-	if (buf && size != 0)
-		process_buffer_measurement(buf, size, "kexec-cmdline",
-					   KEXEC_CMDLINE, 0, NULL);
+	struct fd f;
+
+	if (!buf || !size)
+		return;
+
+	f = fdget(kernel_fd);
+	if (!f.file)
+		return;
+
+	process_buffer_measurement(file_inode(f.file), buf, size,
+				   "kexec-cmdline", KEXEC_CMDLINE, 0, NULL);
+	fdput(f);
 }
 
 static int __init init_ima(void)
@@ -792,6 +863,9 @@ static int __init init_ima(void)
 		error = ima_init();
 	}
 
+	if (error)
+		return error;
+
 	error = register_blocking_lsm_notifier(&ima_lsm_policy_notifier);
 	if (error)
 		pr_warn("Couldn't register LSM notifier, error %d\n", error);