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x86: vdso: Expose sigreturn address on vdso to the kernel

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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.

Suggested-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20201127193238.821364-2-krisman@collabora.com
This commit is contained in:
Gabriel Krisman Bertazi
2020-11-27 14:32:32 -05:00
committed by Thomas Gleixner
parent 01fe185d95
commit c5c878125a
5 changed files with 23 additions and 0 deletions
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2
arch/x86/include/asm/vdso.h
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@ -27,6 +27,8 @@ struct vdso_image {
long sym___kernel_rt_sigreturn;
long sym___kernel_vsyscall;
long sym_int80_landing_pad;
long sym_vdso32_sigreturn_landing_pad;
long sym_vdso32_rt_sigreturn_landing_pad;
};
#ifdef CONFIG_X86_64