ima: pass 'opened' flag to identify newly created files

Empty files and missing xattrs do not guarantee that a file was
just created. This patch passes FILE_CREATED flag to IMA to
reliably identify new files.

Signed-off-by: Dmitry Kasatkin <[e-mail]>
Signed-off-by: Mimi Zohar <[e-mail]>
Cc: <[e-mail]> 3.14+

fs/namei.c

···
 	error = open_check_o_direct(file);
 	if (error)
 		goto exit_fput;
-	error = ima_file_check(file, op->acc_mode);
+	error = ima_file_check(file, op->acc_mode, *opened);
 	if (error)
 		goto exit_fput;
 

fs/nfsd/vfs.c

···
 		host_err = PTR_ERR(*filp);
 		*filp = NULL;
 	} else {
-		host_err = ima_file_check(*filp, may_flags);
+		host_err = ima_file_check(*filp, may_flags, 0);
 
 		if (may_flags & NFSD_MAY_64BIT_COOKIE)
 			(*filp)->f_mode |= FMODE_64BITHASH;

include/linux/ima.h

···
 
 #ifdef CONFIG_IMA
 extern int ima_bprm_check(struct linux_binprm *bprm);
-extern int ima_file_check(struct file *file, int mask);
+extern int ima_file_check(struct file *file, int mask, int opened);
 extern void ima_file_free(struct file *file);
 extern int ima_file_mmap(struct file *file, unsigned long prot);
 extern int ima_module_check(struct file *file);
···
 	return 0;
 }
 
-static inline int ima_file_check(struct file *file, int mask)
+static inline int ima_file_check(struct file *file, int mask, int opened)
 {
 	return 0;
 }

security/integrity/ima/ima.h

···
 int ima_appraise_measurement(int func, struct integrity_iint_cache *iint,
 			     struct file *file, const unsigned char *filename,
 			     struct evm_ima_xattr_data *xattr_value,
-			     int xattr_len);
+			     int xattr_len, int opened);
 int ima_must_appraise(struct inode *inode, int mask, enum ima_hooks func);
 void ima_update_xattr(struct integrity_iint_cache *iint, struct file *file);
 enum integrity_status ima_get_cache_status(struct integrity_iint_cache *iint,
···
 					   struct file *file,
 					   const unsigned char *filename,
 					   struct evm_ima_xattr_data *xattr_value,
-					   int xattr_len)
+					   int xattr_len, int opened)
 {
 	return INTEGRITY_UNKNOWN;
 }

security/integrity/ima/ima_appraise.c

···
 int ima_appraise_measurement(int func, struct integrity_iint_cache *iint,
 			     struct file *file, const unsigned char *filename,
 			     struct evm_ima_xattr_data *xattr_value,
-			     int xattr_len)
+			     int xattr_len, int opened)
 {
 	static const char op[] = "appraise_data";
 	char *cause = "unknown";
···
 
 		cause = "missing-hash";
 		status = INTEGRITY_NOLABEL;
-		if (inode->i_size == 0) {
+		if (opened & FILE_CREATED) {
 			iint->flags |= IMA_NEW_FILE;
 			status = INTEGRITY_PASS;
 		}

security/integrity/ima/ima_main.c

···
 }
 
 static int process_measurement(struct file *file, const char *filename,
-			       int mask, int function)
+			       int mask, int function, int opened)
 {
 	struct inode *inode = file_inode(file);
 	struct integrity_iint_cache *iint;
···
 				      xattr_value, xattr_len);
 	if (action & IMA_APPRAISE_SUBMASK)
 		rc = ima_appraise_measurement(_func, iint, file, pathname,
-					      xattr_value, xattr_len);
+					      xattr_value, xattr_len, opened);
 	if (action & IMA_AUDIT)
 		ima_audit_measurement(iint, pathname);
 	kfree(pathbuf);
···
 int ima_file_mmap(struct file *file, unsigned long prot)
 {
 	if (file && (prot & PROT_EXEC))
-		return process_measurement(file, NULL, MAY_EXEC, MMAP_CHECK);
+		return process_measurement(file, NULL, MAY_EXEC, MMAP_CHECK, 0);
 	return 0;
 }
 
···
 	return process_measurement(bprm->file,
 				   (strcmp(bprm->filename, bprm->interp) == 0) ?
 				   bprm->filename : bprm->interp,
-				   MAY_EXEC, BPRM_CHECK);
+				   MAY_EXEC, BPRM_CHECK, 0);
 }
 
 /**
···
  * On success return 0.  On integrity appraisal error, assuming the file
  * is in policy and IMA-appraisal is in enforcing mode, return -EACCES.
  */
-int ima_file_check(struct file *file, int mask)
+int ima_file_check(struct file *file, int mask, int opened)
 {
 	ima_rdwr_violation_check(file);
 	return process_measurement(file, NULL,
 				   mask & (MAY_READ | MAY_WRITE | MAY_EXEC),
-				   FILE_CHECK);
+				   FILE_CHECK, opened);
 }
 EXPORT_SYMBOL_GPL(ima_file_check);
 
···
 #endif
 		return 0;	/* We rely on module signature checking */
 	}
-	return process_measurement(file, NULL, MAY_EXEC, MODULE_CHECK);
+	return process_measurement(file, NULL, MAY_EXEC, MODULE_CHECK, 0);
 }
 
 int ima_fw_from_file(struct file *file, char *buf, size_t size)
···
 			return -EACCES;	/* INTEGRITY_UNKNOWN */
 		return 0;
 	}
-	return process_measurement(file, NULL, MAY_EXEC, FIRMWARE_CHECK);
+	return process_measurement(file, NULL, MAY_EXEC, FIRMWARE_CHECK, 0);
 }
 
 static int __init init_ima(void)