path: root/security/loadpin
diff options
authorKees Cook <>2020-10-02 10:38:23 -0700
committerGreg Kroah-Hartman <>2020-10-05 13:37:03 +0200
commit2039bda1fa8dad3f4275b29eeaffef545bcbc85d (patch)
tree68a81272505370153df7eca21780bf3f91f0f2eb /security/loadpin
parent38f901735a9e2b3d182fc04a1dfcdb0d3325ea5d (diff)
LSM: Add "contents" flag to kernel_read_file hook
As with the kernel_load_data LSM hook, add a "contents" flag to the kernel_read_file LSM hook that indicates whether the LSM can expect a matching call to the kernel_post_read_file LSM hook with the full contents of the file. With the coming addition of partial file read support for kernel_read_file*() API, the LSM will no longer be able to always see the entire contents of a file during the read calls. For cases where the LSM must read examine the complete file contents, it will need to do so on its own every time the kernel_read_file hook is called with contents=false (or reject such cases). Adjust all existing LSMs to retain existing behavior. Signed-off-by: Kees Cook <> Reviewed-by: Mimi Zohar <> Link: Signed-off-by: Greg Kroah-Hartman <>
Diffstat (limited to 'security/loadpin')
1 files changed, 12 insertions, 2 deletions
diff --git a/security/loadpin/loadpin.c b/security/loadpin/loadpin.c
index 28782412febb..b12f7d986b1e 100644
--- a/security/loadpin/loadpin.c
+++ b/security/loadpin/loadpin.c
@@ -118,11 +118,21 @@ static void loadpin_sb_free_security(struct super_block *mnt_sb)
-static int loadpin_read_file(struct file *file, enum kernel_read_file_id id)
+static int loadpin_read_file(struct file *file, enum kernel_read_file_id id,
+ bool contents)
struct super_block *load_root;
const char *origin = kernel_read_file_id_str(id);
+ /*
+ * If we will not know that we'll be seeing the full contents
+ * then we cannot trust a load will be complete and unchanged
+ * off disk. Treat all contents=false hooks as if there were
+ * no associated file struct.
+ */
+ if (!contents)
+ file = NULL;
/* If the file id is excluded, ignore the pinning. */
if ((unsigned int)id < ARRAY_SIZE(ignore_read_file_id) &&
ignore_read_file_id[id]) {
@@ -179,7 +189,7 @@ static int loadpin_read_file(struct file *file, enum kernel_read_file_id id)
static int loadpin_load_data(enum kernel_load_data_id id, bool contents)
- return loadpin_read_file(NULL, (enum kernel_read_file_id) id);
+ return loadpin_read_file(NULL, (enum kernel_read_file_id) id, contents);
static struct security_hook_list loadpin_hooks[] __lsm_ro_after_init = {