On Wed, Feb 3, 2016 at 11:06 AM, Mimi Zohar <zohar at linux.vnet.ibm.com> wrote: > For a while it was looked down upon to directly read files from Linux. > These days there exists a few mechanisms in the kernel that do just this > though to load a file into a local buffer. There are minor but important > checks differences on each, we should take all the best practices from > each of them, generalize them and make all places in the kernel that > read a file use it.[1] > > One difference is the method for opening the file. In some cases we > have a file, while in other cases we have a pathname or a file descriptor. > > Another difference is the security hook calls, or lack of them. In > some versions there is a post file read hook, while in others there > is a pre file read hook. > > This patch set attempts to resolve these differences. It does not attempt > to merge the different methods of opening a file, but defines a single > common kernel file read function with two wrappers. In addition, as none > of the upstreamed LSMs define either a kernel_module_from_file or a > kernel_fw_from_file hook, this patch set removes these hooks and the > associated functions. The ima_module_check() and ima_fw_from_file() > functions are renamed and called from the pre and post kernel_read_file > security functions respectively. I'm very happy about the pre and post hooks; this solves the primary problem I'd had when comparing the firmware and module hooks. Thanks! Once this series is in -next, I'll resend my rebased "loadpin" LSM. -Kees > > Changelog: > - Rebased on top of some of the "firmware_class: extensible firmware API" > patches posted by Luis. > - Removed the kernel_module_from_file and kernel_fw_from_file security > hooks and functions. > - Defined "kernel_read_file_id" enumeration, independently of "ima_hooks". > - Split patches for ease of review. > > The latest version of these patches can be found in the next-kernel-read-v3 > branch of: > git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity.git > > [1] Taken from Luis Rodriguez's wiki - > http://kernelnewbies.org/KernelProjects/common-kernel-loader > > Mimi > > David Howells (1): > firmware: fold successful fw read early > > Dmitry Kasatkin (3): > ima: separate 'security.ima' reading functionality from collect > ima: provide buffer hash calculation function > ima: load policy using path > > Luis R. Rodriguez (2): > firmware: simplify dev_*() print messages for generic helpers > firmware: move completing fw into a helper > > Mimi Zohar (16): > ima: refactor ima_policy_show() to display "ima_hooks" rules > ima: use "ima_hooks" enum as function argument > vfs: define a generic function to read a file from the kernel > vfs: define kernel_read_file_id enumeration > ima: calculate the hash of a buffer using aynchronous hash(ahash) > ima: define a new hook to measure and appraise a file already in > memory > vfs: define kernel_read_file_from_path > firmware: replace call to fw_read_file_contents() with kernel version > security: define kernel_read_file hook > vfs: define kernel_copy_file_from_fd() > module: replace copy_module_from_fd with kernel version > ima: remove firmware and module specific cached status info > kexec: replace call to copy_file_from_fd() with kernel version > ima: support for kexec image and initramfs > ima: measure and appraise the IMA policy itself > ima: require signed IMA policy > > Documentation/ABI/testing/ima_policy | 2 +- > drivers/base/firmware_class.c | 76 ++++++------------- > fs/exec.c | 95 +++++++++++++++++++++++ > include/linux/fs.h | 15 ++++ > include/linux/ima.h | 10 ++- > include/linux/lsm_hooks.h | 35 ++++----- > include/linux/security.h | 16 ++-- > kernel/kexec_file.c | 73 +++--------------- > kernel/module.c | 68 ++--------------- > security/integrity/iint.c | 4 +- > security/integrity/ima/ima.h | 49 ++++++++---- > security/integrity/ima/ima_api.c | 25 +++---- > security/integrity/ima/ima_appraise.c | 69 ++++++++--------- > security/integrity/ima/ima_crypto.c | 120 +++++++++++++++++++++++++++++- > security/integrity/ima/ima_fs.c | 50 ++++++++++++- > security/integrity/ima/ima_init.c | 2 +- > security/integrity/ima/ima_main.c | 104 +++++++++++++++++++------- > security/integrity/ima/ima_policy.c | 107 +++++++++++++++++--------- > security/integrity/ima/ima_template.c | 2 - > security/integrity/ima/ima_template_lib.c | 1 - > security/integrity/integrity.h | 15 ++-- > security/security.c | 32 ++++---- > 22 files changed, 605 insertions(+), 365 deletions(-) > > -- > 2.1.0 > -- Kees Cook Chrome OS & Brillo Security
