alonid/llvm-experimental

Description

This project demonstrate an experimental Clang feature named RANDSTRUCT which does similar work to the existing RANDSTRUCT GCC plugin in the Linux kernel. See lwn article. In the process of contributing this Clang feature upstream, the implementation is in github.com/clang-randstruct.

The built packages include:

• A modified version of Clang 9.0.0
• A modified Fedora Linux kernel enabled with RANDSTRUCT

Installation Instructions

dnf copr enable alonid/llvm-experimentall
dnf install kernel-5.3.14-200.randstruct.fc30.x86_64.rpm

Reboot to the new kernel.

Randomization is reflected in the debuginfo, unlike in the GCC plugin (with gcc 9.2.0 and the plugin from Linux 5.3).

dnf install dwarves kernel-{devel,debuginfo}-5.3.14-200.randstruct.fc30.x86_64
pahole  /usr/lib/debug/lib/modules/5.3.14-200.randstruct.fc30.x86_64/kernel/fs/xfs/xfs.ko.debug | less -R

struct signal_struct {
        long unsigned int          cnivcsw;              /*     0     8 */
        struct hlist_head  multiprocess;                 /*     8     8 */
        u64                        cutime;               /*    16     8 */
        long unsigned int          nivcsw;               /*    24     8 */
        int                        notify_count;         /*    32     4 */
        int                        group_stop_count;     /*    36     4 */
        long unsigned int          cmin_flt;             /*    40     8 */
        u64                        cgtime;               /*    48     8 */
        wait_queue_head_t          wait_chldexit;        /*    56    24 */
        /* --- cacheline 1 boundary (64 bytes) was 16 bytes ago --- */
        struct tty_audit_buf *     tty_audit_buf;        /*    80     8 */
        struct mm_struct *         oom_mm;               /*    88     8 */
        struct pid *               pids[4];              /*    96    32 */
        /* --- cacheline 2 boundary (128 bytes) --- */
        struct mutex       cred_guard_mutex;             /*   128    32 */
...

See the struct definition (from /usr/src/kernels/5.3.14-200.randstruct.fc30.x86_64/include/linux/sched/signal.h):

struct signal_struct {
        refcount_t              sigcnt;
        atomic_t                live;
        int                     nr_threads;
        struct list_head        thread_head;

        wait_queue_head_t       wait_chldexit;  /* for wait4() */

        /* current thread group signal load-balancing target: */
        struct task_struct      *curr_target;

        /* shared signal handling: */
        struct sigpending       shared_pending;

        /* For collecting multiprocess signals during fork */
        struct hlist_head       multiprocess;

Active Releases

The following unofficial repositories are provided as-is by owner of this project. Contact the owner directly for bugs or issues (IE: not bugzilla).

* Total number of downloaded packages.