fix: corner case for x87 context restore on execve

[lunaix-os.git] / lunaix-os / kernel / asm / x86 / pfault.c

diff --git a/lunaix-os/kernel/asm/x86/pfault.c b/lunaix-os/kernel/asm/x86/pfault.c
index 0d5a6fa661b908d901e625a5911f61dddabd6f3a..f527e12c3dcc0f81c292c3761c78c125943faa80 100644 (file)
--- a/lunaix-os/kernel/asm/x86/pfault.c
+++ b/lunaix-os/kernel/asm/x86/pfault.c
@@ -11,6 +11,19 @@
 
 #include <klibc/string.h>
 
 
 #include <klibc/string.h>
 

+static u32_t
+get_ptattr(struct mm_region* vmr)
+{
+    u32_t vmr_attr = vmr->attr;
+    u32_t ptattr = PG_PRESENT | PG_ALLOW_USER;
+
+    if ((vmr_attr & PROT_WRITE)) {
+        ptattr |= PG_WRITE;
+    }
+
+    return ptattr & 0xfff;
+}
+

 static void
 kprintf(const char* fmt, ...)
 {
 static void
 kprintf(const char* fmt, ...)
 {


@@ -28,6 +41,7 @@ __print_panic_msg(const char* msg, const isr_param* param);
 void
 intr_routine_page_fault(const isr_param* param)
 {
 void
 intr_routine_page_fault(const isr_param* param)
 {

+    uint32_t errcode = param->execp->err_code;

     ptr_t ptr = cpu_rcr2();
     if (!ptr) {
         goto segv_term;
     ptr_t ptr = cpu_rcr2();
     if (!ptr) {
         goto segv_term;


@@ -52,6 +66,14 @@ intr_routine_page_fault(const isr_param* param)
 
     volatile x86_pte_t* pte = &PTE_MOUNTED(VMS_SELF, ptr >> 12);
     if (PG_IS_PRESENT(*pte)) {
 
     volatile x86_pte_t* pte = &PTE_MOUNTED(VMS_SELF, ptr >> 12);
     if (PG_IS_PRESENT(*pte)) {

+        if (((errcode ^ mapping.flags) & PG_ALLOW_USER)) {
+            // invalid access
+            kprintf(KDEBUG "invalid user access. (%p->%p, attr:0x%x)\n",
+                    mapping.va,
+                    mapping.pa,
+                    mapping.flags);
+            goto segv_term;
+        }

         if ((hit_region->attr & COW_MASK) == COW_MASK) {
             // normal page fault, do COW
             cpu_invplg((ptr_t)pte);
         if ((hit_region->attr & COW_MASK) == COW_MASK) {
             // normal page fault, do COW
             cpu_invplg((ptr_t)pte);


@@ -78,7 +100,7 @@ intr_routine_page_fault(const isr_param* param)
                 goto oom;
             }
 
                 goto oom;
             }
 

-            *pte = *pte | pa | PG_PRESENT;
+            *pte = *pte | pa | get_ptattr(hit_region);

             memset((void*)PG_ALIGN(ptr), 0, PG_SIZE);
             goto resolved;
         }
             memset((void*)PG_ALIGN(ptr), 0, PG_SIZE);
             goto resolved;
         }


@@ -101,7 +123,7 @@ intr_routine_page_fault(const isr_param* param)
         }
 
         cpu_invplg((ptr_t)pte);
         }
 
         cpu_invplg((ptr_t)pte);

-        *pte = (*pte & 0xFFF) | pa | PG_PRESENT;
+        *pte = (*pte & 0xFFF) | pa | get_ptattr(hit_region);

 
         memset((void*)ptr, 0, PG_SIZE);
 
 
         memset((void*)ptr, 0, PG_SIZE);
 


@@ -128,13 +150,17 @@ intr_routine_page_fault(const isr_param* param)
 
 oom:
     kprintf(KERROR "out of memory\n");
 
 oom:
     kprintf(KERROR "out of memory\n");

+

 segv_term:
 segv_term:

-    kprintf(KERROR "(pid: %d) Segmentation fault on %p (%p:%p)\n",
+    kprintf(KERROR "(pid: %d) Segmentation fault on %p (%p:%p,e=0x%x)\n",

             __current->pid,
             ptr,
             param->execp->cs,
             __current->pid,
             ptr,
             param->execp->cs,

-            param->execp->eip);
-    __SIGSET(__current->sig_pending, _SIGSEGV);
+            param->execp->eip,
+            param->execp->err_code);
+
+    sigset_add(__current->sigctx.sig_pending, _SIGSEGV);
+

     schedule();
     // should not reach
     while (1)
     schedule();
     // should not reach
     while (1)