diff options
| author | Kees Cook <keescook@chromium.org> | 2020-10-02 10:38:23 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-10-05 13:37:03 +0200 |
| commit | 2039bda1fa8dad3f4275b29eeaffef545bcbc85d (patch) | |
| tree | 68a81272505370153df7eca21780bf3f91f0f2eb /security/loadpin | |
| parent | 38f901735a9e2b3d182fc04a1dfcdb0d3325ea5d (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 <keescook@chromium.org>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
Link: https://lore.kernel.org/r/20201002173828.2099543-12-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'security/loadpin')
| -rw-r--r-- | security/loadpin/loadpin.c | 14 |
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 = { |