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| author |   Mike Rapoport <rppt@linux.ibm.com> | 2023-06-12 17:11:07 -0700 |
|---|---|---|
| committer |   Dave Hansen <dave.hansen@linux.intel.com> | 2023-08-02 15:01:51 -0700 |
| commit | 680ed2f15e70d079c8148589a3ce9426fc0ff914 (patch) | |
| tree | c22c5326d8e7770ad97377f44714a005333f5147 /arch/x86/kernel | |
| parent | x86: Add PTRACE interface for shadow stack (diff) | |
| download | wireguard-linux-680ed2f15e70d079c8148589a3ce9426fc0ff914.tar.xz wireguard-linux-680ed2f15e70d079c8148589a3ce9426fc0ff914.zip | |
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 <rppt@linux.ibm.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Tested-by: Pengfei Xu <pengfei.xu@intel.com>
Tested-by: John Allen <john.allen@amd.com>
Tested-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/all/20230613001108.3040476-42-rick.p.edgecombe%40intel.com
Diffstat (limited to 'arch/x86/kernel')
| -rw-r--r-- | arch/x86/kernel/process_64.c | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/shstk.c | 9 |
2 files changed, 8 insertions, 2 deletions
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 0f89aa0186d1..e6db21c470aa 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -899,6 +899,7 @@ long do_arch_prctl_64(struct task_struct *task, int option, unsigned long arg2) case ARCH_SHSTK_ENABLE: case ARCH_SHSTK_DISABLE: case ARCH_SHSTK_LOCK: + case ARCH_SHSTK_UNLOCK: return shstk_prctl(task, option, arg2); default: ret = -EINVAL; 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) |