The following commit has been merged into the x86/shstk branch of tip: Commit-ID: 2883f01ec37dd8668e7222dfdb5980c86fdfe277 Gitweb: https://git.kernel.org/tip/2883f01ec37dd8668e7222dfdb5980c86fdfe277 Author: H.J. Lu <hjl.tools@xxxxxxxxx> AuthorDate: Fri, 15 Mar 2024 07:04:33 -07:00 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitterDate: Fri, 22 Mar 2024 10:17:11 +01:00 x86/shstk: Enable shadow stacks for x32 1. Add shadow stack support to x32 signal. 2. Use the 64-bit map_shadow_stack syscall for x32. 3. Set up shadow stack for x32. Tested with shadow stack enabled x32 glibc on Intel Tiger Lake: I configured x32 glibc with --enable-cet, build glibc and run all glibc tests with shadow stack enabled. There are no regressions. I verified that shadow stack is enabled via /proc/pid/status. Signed-off-by: H.J. Lu <hjl.tools@xxxxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Tested-by: H.J. Lu <hjl.tools@xxxxxxxxx> Cc: "Edgecombe, Rick P" <rick.p.edgecombe@xxxxxxxxx> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Andy Lutomirski <luto@xxxxxxxxxx> Link: https://lore.kernel.org/r/20240315140433.1966543-1-hjl.tools@xxxxxxxxx --- arch/x86/entry/syscalls/syscall_64.tbl | 2 +- arch/x86/kernel/shstk.c | 4 ++-- arch/x86/kernel/signal_64.c | 6 ++++++ 3 files changed, 9 insertions(+), 3 deletions(-) diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl index 7e8d46f..cc78226 100644 --- a/arch/x86/entry/syscalls/syscall_64.tbl +++ b/arch/x86/entry/syscalls/syscall_64.tbl @@ -374,7 +374,7 @@ 450 common set_mempolicy_home_node sys_set_mempolicy_home_node 451 common cachestat sys_cachestat 452 common fchmodat2 sys_fchmodat2 -453 64 map_shadow_stack sys_map_shadow_stack +453 common map_shadow_stack sys_map_shadow_stack 454 common futex_wake sys_futex_wake 455 common futex_wait sys_futex_wait 456 common futex_requeue sys_futex_requeue diff --git a/arch/x86/kernel/shstk.c b/arch/x86/kernel/shstk.c index 59e15dd..6f1e988 100644 --- a/arch/x86/kernel/shstk.c +++ b/arch/x86/kernel/shstk.c @@ -163,8 +163,8 @@ static int shstk_setup(void) if (features_enabled(ARCH_SHSTK_SHSTK)) return 0; - /* Also not supported for 32 bit and x32 */ - if (!cpu_feature_enabled(X86_FEATURE_USER_SHSTK) || in_32bit_syscall()) + /* Also not supported for 32 bit */ + if (!cpu_feature_enabled(X86_FEATURE_USER_SHSTK) || in_ia32_syscall()) return -EOPNOTSUPP; size = adjust_shstk_size(0); diff --git a/arch/x86/kernel/signal_64.c b/arch/x86/kernel/signal_64.c index 23d8aaf..8a94053 100644 --- a/arch/x86/kernel/signal_64.c +++ b/arch/x86/kernel/signal_64.c @@ -315,6 +315,9 @@ int x32_setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs) uc_flags = frame_uc_flags(regs); + if (setup_signal_shadow_stack(ksig)) + return -EFAULT; + if (!user_access_begin(frame, sizeof(*frame))) return -EFAULT; @@ -377,6 +380,9 @@ COMPAT_SYSCALL_DEFINE0(x32_rt_sigreturn) if (!restore_sigcontext(regs, &frame->uc.uc_mcontext, uc_flags)) goto badframe; + if (restore_signal_shadow_stack()) + goto badframe; + if (compat_restore_altstack(&frame->uc.uc_stack)) goto badframe;
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