ima: define a new hook to measure and appraise a file already in memory

This patch defines a new IMA hook ima_post_read_file() for measuring
and appraising files read by the kernel. The caller loads the file into
memory before calling this function, which calculates the hash followed by
the normal IMA policy based processing.

Changelog v5:
- fail ima_post_read_file() if either file or buf is NULL
v3:
- rename ima_hash_and_process_file() to ima_post_read_file()

v1:
- split patch

Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: Dmitry Kasatkin <dmitry.kasatkin@huawei.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/include/linux/ima.h b/include/linux/ima.h
index 120ccc53fcb7..d29a6a23fc19 100644
--- a/include/linux/ima.h
+++ b/include/linux/ima.h
@@ -20,6 +20,8 @@ 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);
 extern int ima_fw_from_file(struct file *file, char *buf, size_t size);
+extern int ima_post_read_file(struct file *file, void *buf, loff_t size,
+			      enum kernel_read_file_id id);
 
 #else
 static inline int ima_bprm_check(struct linux_binprm *bprm)
@@ -52,6 +54,12 @@ static inline int ima_fw_from_file(struct file *file, char *buf, size_t size)
 	return 0;
 }
 
+static inline int ima_post_read_file(struct file *file, void *buf, loff_t size,
+				     enum kernel_read_file_id id)
+{
+	return 0;
+}
+
 #endif /* CONFIG_IMA */
 
 #ifdef CONFIG_IMA_APPRAISE