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| author | Kees Cook <keescook@chromium.org> | 2018-05-01 15:07:31 -0700 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2018-10-03 04:09:42 +0100 |
| commit | 284aa1550489336c3e5fd7b7ea3269b6ad96fe01 (patch) | |
| tree | 198509ac498a5ada8b604a098b25914f03bc28d6 /kernel | |
| parent | c0f77718114bfdc56711dbaa411825839b7a190e (diff) | |
| download | linux-284aa1550489336c3e5fd7b7ea3269b6ad96fe01.tar.gz linux-284aa1550489336c3e5fd7b7ea3269b6ad96fe01.tar.bz2 linux-284aa1550489336c3e5fd7b7ea3269b6ad96fe01.zip | |
seccomp: Enable speculation flaw mitigations
commit 5c3070890d06ff82eecb808d02d2ca39169533ef upstream.
When speculation flaw mitigations are opt-in (via prctl), using seccomp
will automatically opt-in to these protections, since using seccomp
indicates at least some level of sandboxing is desired.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[bwh: Backported to 3.16:
- Apply to current task
- Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/seccomp.c | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/kernel/seccomp.c b/kernel/seccomp.c index d2596136b0d1..816cdfe9b592 100644 --- a/kernel/seccomp.c +++ b/kernel/seccomp.c @@ -16,6 +16,8 @@ #include <linux/atomic.h> #include <linux/audit.h> #include <linux/compat.h> +#include <linux/nospec.h> +#include <linux/prctl.h> #include <linux/sched.h> #include <linux/seccomp.h> #include <linux/syscalls.h> @@ -205,9 +207,24 @@ static inline bool seccomp_may_assign_mode(unsigned long seccomp_mode) return true; } +/* + * If a given speculation mitigation is opt-in (prctl()-controlled), + * select it, by disabling speculation (enabling mitigation). + */ +static inline void spec_mitigate(struct task_struct *task, + unsigned long which) +{ + int state = arch_prctl_spec_ctrl_get(task, which); + + if (state > 0 && (state & PR_SPEC_PRCTL)) + arch_prctl_spec_ctrl_set(task, which, PR_SPEC_DISABLE); +} + static inline void seccomp_assign_mode(unsigned long seccomp_mode) { current->seccomp.mode = seccomp_mode; + /* Assume seccomp processes want speculation flaw mitigation. */ + spec_mitigate(current, PR_SPEC_STORE_BYPASS); set_tsk_thread_flag(current, TIF_SECCOMP); } |