Emulation of the legacy vsyscall page is required by some programs built before 2013. Newer programs after 2013 don't use it. Disable vsyscall emulation when Control-flow Enforcement (CET) is enabled to enhance security.
Signed-off-by: Yu-cheng Yu <[email protected]> --- v12: - Disable vsyscall emulation only when it is attempted (vs. at compile time). arch/x86/entry/vsyscall/vsyscall_64.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/arch/x86/entry/vsyscall/vsyscall_64.c b/arch/x86/entry/vsyscall/vsyscall_64.c index 44c33103a955..3196e963e365 100644 --- a/arch/x86/entry/vsyscall/vsyscall_64.c +++ b/arch/x86/entry/vsyscall/vsyscall_64.c @@ -150,6 +150,15 @@ bool emulate_vsyscall(unsigned long error_code, WARN_ON_ONCE(address != regs->ip); +#ifdef CONFIG_X86_INTEL_CET + if (current->thread.cet.shstk_size || + current->thread.cet.ibt_enabled) { + warn_bad_vsyscall(KERN_INFO, regs, + "vsyscall attempted with cet enabled"); + return false; + } +#endif + if (vsyscall_mode == NONE) { warn_bad_vsyscall(KERN_INFO, regs, "vsyscall attempted with vsyscall=none"); -- 2.21.0
