mirror of
https://github.com/clearlinux/graphene.git
synced 2026-09-06 13:51:28 +00:00
Isaku Yamahata
0dd84ddf94
First, this commit enables the usage of alternative stack by using SA_ONSTACK during sigaction() and fixes the bug with ss.ss_sp (it should point not to the top of the altstack but to its bottom). Also, the size of the alternative stack is increased to normal Linux value of 64KB (otherwise stack corruptions ensued). Second, this commit consolidates the logic of Linux-SGX PAL of allocating data on the untrusted stack. The normal OCALL handling used `enclave_tls.ustack` to copy syscall arguments from enclave memory to untrusted memory and back. On the other hand, the AEX signal handling used `SGX_GRP.ursp` to operate on the same untrusted stack. This could clobber the stack if AEX happened during OCALL processing, and result in corrupted data. This commit consolidates this logic to always use `SGX_GPR.ursp` and allocate new stack frames on the untrusted stack. This commit also adds a corresponding PAL test to validate that the normal stack and the altstack are different.
141 lines
3.4 KiB
C
141 lines
3.4 KiB
C
/* This Hello World simply print out "Hello World" */
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#include <stdatomic.h>
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#include <inttypes.h>
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#include "pal.h"
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#include "pal_debug.h"
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static void* get_stack(void) {
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void* stack;
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__asm__ volatile("mov %%rsp, %0" : "=r"(stack) :: "memory");
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return stack;
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}
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void handler1 (PAL_PTR event, PAL_NUM arg, PAL_CONTEXT * context)
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{
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pal_printf("Arithmetic Exception Handler 1: 0x%08lx, rip = 0x%08lx\n",
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arg, context->rip);
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pal_printf("Stack in handler: %p\n", get_stack());
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while (*(unsigned char *) context->rip != 0x90)
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context->rip++;
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DkExceptionReturn(event);
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}
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void handler2 (PAL_PTR event, PAL_NUM arg, PAL_CONTEXT * context)
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{
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pal_printf("Arithmetic Exception Handler 2: 0x%08lx, rip = 0x%08lx\n",
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arg, context->rip);
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while (*(unsigned char *) context->rip != 0x90)
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context->rip++;
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DkExceptionReturn(event);
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}
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void handler3 (PAL_PTR event, PAL_NUM arg, PAL_CONTEXT * context)
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{
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pal_printf("Memory Fault Exception Handler: 0x%08lx, rip = 0x%08lx\n",
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arg, context->rip);
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while (*(unsigned char *) context->rip != 0x90)
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context->rip++;
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DkExceptionReturn(event);
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}
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atomic_bool handler4_called = false;
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void handler4(PAL_PTR event, PAL_NUM arg, PAL_CONTEXT * context)
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{
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pal_printf("Arithmetic Exception Handler 4: 0x%" PRIx64 ", rip = 0x%" PRIx64 "\n", arg, context->rip);
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while (*(unsigned char *) context->rip != 0x90)
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context->rip++;
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handler4_called = true;
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DkExceptionReturn(event);
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}
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static void red_zone_test(void) {
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uint64_t res = 0;
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// First call some function to ensure that gcc doesn't use the red zone
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// itself.
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pal_printf("Testing red zone...\n");
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__asm__ volatile (
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// Fill the red zone with a pattern (0xaa 0xa9 0xa8 ...)
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"movq $-128, %%rax\n"
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"movq $0xaa, %%rbx\n"
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"1:\n"
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"movb %%bl, (%%rsp, %%rax, 1)\n"
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"decq %%rbx\n"
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"incq %%rax\n"
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"jnz 1b\n"
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// Trigger exception
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"movq $1, %%rax\n"
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"cqo\n"
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"movq $0, %%rbx\n"
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"divq %%rbx\n"
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"nop\n"
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// Calculate sum of pattern
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"movq $-128, %%rax\n"
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"movq $0, %%rbx\n"
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"movq $0, %%rcx\n"
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"1:\n"
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"movb (%%rsp, %%rax, 1), %%bl\n"
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"addq %%rbx, %%rcx\n"
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"incq %%rax\n"
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"jnz 1b\n"
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"movq %%rcx, %q0\n"
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: "=rm"(res)
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:
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: "rax", "rbx", "rcx", "rdx", "cc", "memory");
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if (!handler4_called) {
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pal_printf("Exception handler was not called!\n");
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return;
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}
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if (res != 13632) {
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pal_printf("Sum over red zone (%lu) doesn't match!\n", res);
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return;
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}
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pal_printf("Red zone test ok.\n");
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}
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int main (void)
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{
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volatile long i;
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pal_printf("Stack in main: %p\n", get_stack());
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DkSetExceptionHandler(handler1, PAL_EVENT_ARITHMETIC_ERROR);
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i = 0;
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i = 1 / i;
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__asm__ volatile("nop");
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DkSetExceptionHandler(handler2, PAL_EVENT_ARITHMETIC_ERROR);
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i = 0;
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i = 1 / i;
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__asm__ volatile("nop");
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DkSetExceptionHandler(handler3, PAL_EVENT_MEMFAULT);
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*(volatile long *) 0x1000 = 0;
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__asm__ volatile("nop");
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DkSetExceptionHandler(handler4, PAL_EVENT_ARITHMETIC_ERROR);
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red_zone_test();
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return 0;
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}
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