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 is the first attempt at resolving 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. Although this patch set defines two new security hooks for pre and post file read, it does not attempt to merge the existing security hooks. That is left as future work. These patches are based on top of the "ima: measuring/appraising files read by the kernel". The latest version of these patches can be found in the next-kernel-read branch of: git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity.git Mimi Zohar (5): vfs: define a generic function to read a file from the kernel firmware: replace call to fw_read_file_contents() with kernel version kexec: replace call to copy_file_from_fd() with kernel version ima: replace call to integrity_read_file() with kernel version module: replace copy_module_from_fd with kernel version drivers/base/firmware_class.c | 51 +++++-------------- fs/exec.c | 96 +++++++++++++++++++++++++++++++++++ include/linux/fs.h | 3 ++ include/linux/ima.h | 7 +-- include/linux/lsm_hooks.h | 19 +++++++ include/linux/security.h | 14 +++-- kernel/kexec_file.c | 76 +++------------------------ kernel/module.c | 67 +++--------------------- security/integrity/ima/ima.h | 1 - security/integrity/ima/ima_appraise.c | 7 --- security/integrity/ima/ima_fs.c | 15 +++--- security/integrity/ima/ima_main.c | 21 ++++---- security/integrity/ima/ima_policy.c | 16 +++--- security/integrity/integrity.h | 12 ++--- security/security.c | 46 ++++++++++++----- 15 files changed, 217 insertions(+), 234 deletions(-) -- 2.1.0
