diff options
| author | Mike Rapoport <[email protected]> | 2023-06-12 17:11:07 -0700 |
|---|---|---|
| committer | Dave Hansen <[email protected]> | 2023-08-02 15:01:51 -0700 |
| commit | 680ed2f15e70d079c8148589a3ce9426fc0ff914 (patch) | |
| tree | c22c5326d8e7770ad97377f44714a005333f5147 /arch/x86/kernel/shstk.c | |
| parent | 2fab02b25ae7cf5f714ab456b03d9a3fe5ae98c9 (diff) | |
x86/shstk: Add ARCH_SHSTK_UNLOCK
Userspace loaders may lock features before a CRIU restore operation has
the chance to set them to whatever state is required by the process
being restored. Allow a way for CRIU to unlock features. Add it as an
arch_prctl() like the other shadow stack operations, but restrict it being
called by the ptrace arch_pctl() interface.
[Merged into recent API changes, added commit log and docs]
Signed-off-by: Mike Rapoport <[email protected]>
Signed-off-by: Rick Edgecombe <[email protected]>
Signed-off-by: Dave Hansen <[email protected]>
Reviewed-by: Borislav Petkov (AMD) <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Reviewed-by: David Hildenbrand <[email protected]>
Tested-by: Pengfei Xu <[email protected]>
Tested-by: John Allen <[email protected]>
Tested-by: Kees Cook <[email protected]>
Link: https://lore.kernel.org/all/20230613001108.3040476-42-rick.p.edgecombe%40intel.com
Diffstat (limited to 'arch/x86/kernel/shstk.c')
| -rw-r--r-- | arch/x86/kernel/shstk.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/arch/x86/kernel/shstk.c b/arch/x86/kernel/shstk.c index d723cdc93474..d43b7a9c57ce 100644 --- a/arch/x86/kernel/shstk.c +++ b/arch/x86/kernel/shstk.c @@ -489,9 +489,14 @@ long shstk_prctl(struct task_struct *task, int option, unsigned long features) return 0; } - /* Don't allow via ptrace */ - if (task != current) + /* Only allow via ptrace */ + if (task != current) { + if (option == ARCH_SHSTK_UNLOCK && IS_ENABLED(CONFIG_CHECKPOINT_RESTORE)) { + task->thread.features_locked &= ~features; + return 0; + } return -EINVAL; + } /* Do not allow to change locked features */ if (features & task->thread.features_locked) |