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Kernel: Fix stack pointer OOB check 

i686 does not push the stack pointer on interrupt when no CPL change
happens.
This commit is contained in:
Bananymous 2024-07-22 00:27:08 +03:00
parent 1ee37cb671
commit 9f90eeab05
1 changed files with 21 additions and 23 deletions
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16
kernel/kernel/IDT.cpp
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@ -173,15 +173,17 @@ namespace Kernel
if (tid) if (tid)
{ {
auto& thread = Thread::current();
#if __enable_sse #if __enable_sse
Thread::current().save_sse(); thread.save_sse();
#endif #endif
if (isr == ISR::PageFault) if (isr == ISR::PageFault && Thread::current().is_userspace())
{ {
// Check if stack is OOB // Check if stack is OOB
auto& thread = Thread::current(); if (ARCH(i686) && !GDT::is_user_segment(interrupt_stack->cs))
if (thread.userspace_stack_bottom() < interrupt_stack->sp && interrupt_stack->sp <= thread.userspace_stack_top()) ; // 32 bit does not push stack pointer when no CPL change happens
else if (thread.userspace_stack_bottom() < interrupt_stack->sp && interrupt_stack->sp <= thread.userspace_stack_top())
; // using userspace stack ; // using userspace stack
else if (thread.kernel_stack_bottom() < interrupt_stack->sp && interrupt_stack->sp <= thread.kernel_stack_top()) else if (thread.kernel_stack_bottom() < interrupt_stack->sp && interrupt_stack->sp <= thread.kernel_stack_top())
; // using kernel stack ; // using kernel stack
@ -198,13 +200,10 @@ namespace Kernel
goto done; goto done;
} }
// Demand paging is only supported in userspace
if (thread.is_userspace())
{
// Try demand paging on non present pages // Try demand paging on non present pages
PageFaultError page_fault_error; PageFaultError page_fault_error;
page_fault_error.raw = error; page_fault_error.raw = error;
if (!page_fault_error.present) if (pid && !page_fault_error.present)
{ {
Processor::set_interrupt_state(InterruptState::Enabled); Processor::set_interrupt_state(InterruptState::Enabled);
auto result = Process::current().allocate_page_for_demand_paging(regs->cr2); auto result = Process::current().allocate_page_for_demand_paging(regs->cr2);
@ -222,7 +221,6 @@ namespace Kernel
} }
} }
} }
}
Debug::s_debug_lock.lock(); Debug::s_debug_lock.lock();