diff options
| author | Kees Cook <keescook@chromium.org> | 2020-10-02 19:38:23 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-10-05 13:37:03 +0200 |
| commit | 2039bda1fa8dad3f4275b29eeaffef545bcbc85d (patch) | |
| tree | 68a81272505370153df7eca21780bf3f91f0f2eb /security/integrity | |
| parent | module: Call security_kernel_post_load_data() (diff) | |
| download | linux-2039bda1fa8dad3f4275b29eeaffef545bcbc85d.tar.xz linux-2039bda1fa8dad3f4275b29eeaffef545bcbc85d.zip | |
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/integrity')
| -rw-r--r-- | security/integrity/ima/ima_main.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index 6f2b8352573a..939f53d02627 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -602,6 +602,7 @@ void ima_post_path_mknod(struct dentry *dentry) * ima_read_file - pre-measure/appraise hook decision based on policy * @file: pointer to the file to be measured/appraised/audit * @read_id: caller identifier + * @contents: whether a subsequent call will be made to ima_post_read_file() * * Permit reading a file based on policy. The policy rules are written * in terms of the policy identifier. Appraising the integrity of @@ -609,8 +610,15 @@ void ima_post_path_mknod(struct dentry *dentry) * * For permission return 0, otherwise return -EACCES. */ -int ima_read_file(struct file *file, enum kernel_read_file_id read_id) +int ima_read_file(struct file *file, enum kernel_read_file_id read_id, + bool contents) { + /* Reject all partial reads during appraisal. */ + if (!contents) { + if (ima_appraise & IMA_APPRAISE_ENFORCE) + return -EACCES; + } + /* * Do devices using pre-allocated memory run the risk of the * firmware being accessible to the device prior to the completion |