Re: [PATCH v6 3/9] x86: vdso: Expose sigreturn address on vdso to the kernel

On Fri, Sep 04, 2020 at 04:31:41PM -0400, Gabriel Krisman Bertazi wrote:

Syscall user redirection requires the signal trampoline code to not be captured, in order to support returning with a locked selector while avoiding recursion back into the signal handler. For ia-32, which has the trampoline in the vDSO, expose the entry points to the kernel, such that it can avoid dispatching syscalls from that region to userspace.

Changes since V1

• Change return address to bool (Andy)

Suggested-by: Andy Lutomirski luto@kernel.org Acked-by: Andy Lutomirski luto@kernel.org Signed-off-by: Gabriel Krisman Bertazi krisman@collabora.com

Look good to me; would anything else benefit from this information?

Reviewed-by: Kees Cook keescook@chromium.org