From 103ed1b17f30cf798b8c2411f962c3a4104ab8db Mon Sep 17 00:00:00 2001
From: jD91mZM2 <me@krake.one>
Date: Wed, 8 Jul 2020 10:54:34 +0200
Subject: [PATCH] Make interrupt stack readable on kernel signals
---
src/arch/x86_64/macros.rs | 42 +++++++++++++++++++++++----------------
src/lib.rs | 8 +++++++-
2 files changed, 32 insertions(+), 18 deletions(-)
diff --git a/src/arch/x86_64/macros.rs b/src/arch/x86_64/macros.rs
index 6271229..29d0d10 100644
--- a/src/arch/x86_64/macros.rs
+++ b/src/arch/x86_64/macros.rs
@@ -48,9 +48,8 @@ impl ScratchRegisters {
}
macro_rules! scratch_push {
- () => (asm!(
- "push rax
- push rcx
+ (without rax) => (asm!(
+ "push rcx
push rdx
push rdi
push rsi
@@ -60,6 +59,10 @@ macro_rules! scratch_push {
push r11"
: : : : "intel", "volatile"
));
+ () => ({
+ asm!("push rax" : : : : "intel", "volatile");
+ scratch_push!(without rax);
+ });
}
macro_rules! scratch_pop {
@@ -362,20 +365,14 @@ macro_rules! interrupt_stack {
#[derive(Default)]
#[repr(packed)]
pub struct InterruptErrorStack {
- pub fs: usize,
- pub preserved: PreservedRegisters,
- pub scratch: ScratchRegisters,
pub code: usize,
- pub iret: IretRegisters,
+ pub inner: InterruptStack,
}
impl InterruptErrorStack {
pub fn dump(&self) {
- self.iret.dump();
+ self.inner.dump();
println!("CODE: {:>016X}", { self.code });
- self.scratch.dump();
- self.preserved.dump();
- println!("FS: {:>016X}", { self.fs });
}
}
@@ -385,12 +382,23 @@ macro_rules! interrupt_error {
#[naked]
pub unsafe extern fn $name () {
#[inline(never)]
- unsafe fn inner($stack: &$crate::arch::x86_64::macros::InterruptErrorStack) {
+ unsafe fn inner($stack: &mut $crate::arch::x86_64::macros::InterruptErrorStack) {
+ let _guard = ptrace::set_process_regs(&mut $stack.inner);
$func
}
- // Push scratch registers
- interrupt_push!();
+ // Swap RAX and error code, in order to push the code later and be
+ // compatible with InterruptStack.
+ asm!("xchg [rsp], rax" : : : : "intel", "volatile");
+
+ // Push all the registers (except for rax which is already pushed,
+ // in place of the error code)
+ scratch_push!(without rax);
+ preserved_push!();
+ fs_push!();
+
+ // Finally, push rax (now containing error code)
+ asm!("push rax" : : : : "intel", "volatile");
// Get reference to stack variables
let rsp: usize;
@@ -400,14 +408,14 @@ macro_rules! interrupt_error {
$crate::arch::x86_64::pti::map();
// Call inner rust function
- inner(&*(rsp as *const $crate::arch::x86_64::macros::InterruptErrorStack));
+ inner(&mut *(rsp as *mut $crate::arch::x86_64::macros::InterruptErrorStack));
// Unmap kernel
$crate::arch::x86_64::pti::unmap();
- // Pop scratch registers, error code, and return
- interrupt_pop!();
+ // Pop error code, registers, and return
asm!("add rsp, 8" : : : : "intel", "volatile"); // pop error code
+ interrupt_pop!();
iret!();
}
};
diff --git a/src/lib.rs b/src/lib.rs
index 8627940..82004e7 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -274,5 +274,11 @@ pub extern fn ksignal(signal: usize) {
println!("NAME {}", unsafe { ::core::str::from_utf8_unchecked(&context.name.lock()) });
}
}
- syscall::exit(signal & 0x7F);
+
+ // Try running kill(getpid(), signal), but fallback to exiting
+ syscall::getpid()
+ .and_then(|pid| syscall::kill(pid, signal).map(|_| ()))
+ .unwrap_or_else(|_| {
+ syscall::exit(signal & 0x7F);
+ });
}
--
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