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| author | Sami Tolvanen <samitolvanen@google.com> | 2020-04-27 18:00:07 +0200 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2020-05-15 17:35:45 +0200 |
| commit | d08b9f0ca6605e13dcb48f04e55a30545b3c71eb (patch) | |
| tree | 177893706ae16d9302dda4ee5f4894ac02e9b24e /kernel/fork.c | |
| parent | Linux 5.7-rc3 (diff) | |
| download | linux-d08b9f0ca6605e13dcb48f04e55a30545b3c71eb.tar.xz linux-d08b9f0ca6605e13dcb48f04e55a30545b3c71eb.zip | |
scs: Add support for Clang's Shadow Call Stack (SCS)
This change adds generic support for Clang's Shadow Call Stack,
which uses a shadow stack to protect return addresses from being
overwritten by an attacker. Details are available here:
https://clang.llvm.org/docs/ShadowCallStack.html
Note that security guarantees in the kernel differ from the ones
documented for user space. The kernel must store addresses of
shadow stacks in memory, which means an attacker capable reading
and writing arbitrary memory may be able to locate them and hijack
control flow by modifying the stacks.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
[will: Numerous cosmetic changes]
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'kernel/fork.c')
| -rw-r--r-- | kernel/fork.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/kernel/fork.c b/kernel/fork.c index 8c700f881d92..f6339f9d232d 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -94,6 +94,7 @@ #include <linux/thread_info.h> #include <linux/stackleak.h> #include <linux/kasan.h> +#include <linux/scs.h> #include <asm/pgtable.h> #include <asm/pgalloc.h> @@ -456,6 +457,8 @@ void put_task_stack(struct task_struct *tsk) void free_task(struct task_struct *tsk) { + scs_release(tsk); + #ifndef CONFIG_THREAD_INFO_IN_TASK /* * The task is finally done with both the stack and thread_info, @@ -840,6 +843,8 @@ void __init fork_init(void) NULL, free_vm_stack_cache); #endif + scs_init(); + lockdep_init_task(&init_task); uprobes_init(); } @@ -899,6 +904,10 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node) if (err) goto free_stack; + err = scs_prepare(tsk, node); + if (err) + goto free_stack; + #ifdef CONFIG_SECCOMP /* * We must handle setting up seccomp filters once we're under |