Size verification

src/hotspot/os_cpu/linux_riscv/os_linux_riscv.cpp

@@ -392,6 +392,16 @@ void os::print_context(outputStream *st, const void *context) {
     return;
   }
 
+  //size = sizeof(struct __riscv_ctx_hdr) + sizeof(struct __sc_riscv_v_state) + riscv_v_vsize;
+  uint32_t ext_size = ext->hdr.size;
+
+  if (ext_size < (sizeof(struct __riscv_ctx_hdr) + sizeof(*v_ext_state))) {
+    st->print_cr("Vector state: not found, invalid size");
+    return;
+  }
+
+  ext_size -= (sizeof(struct __riscv_ctx_hdr) + sizeof(*v_ext_state));
+
   v_ext_state = (struct redefine_riscv_v_ext_state *)((char *)(ext) + sizeof(*ext));
 
   st->print_cr("Vector state:");
@@ -401,9 +411,15 @@ void os::print_context(outputStream *st, const void *context) {
   st->print_cr("vcsr=" INTPTR_FORMAT, v_ext_state->vcsr);
   st->print_cr("vlenb=" INTPTR_FORMAT, v_ext_state->vlenb);
   st->print_cr("Vector registers:");
+
+  uint64_t vr_size = v_ext_state->vlenb;
+
+  if (ext_size < (32*vr_size)) {
+    st->print_cr("Vector registers: not found, invalid size");
+    return;
+  }
   // datap format is undocumented, but is generated by kernel function riscv_v_vstate_save().
   uint8_t *regp = (uint8_t *)v_ext_state->datap;
-  uint64_t vr_size = v_ext_state->vlenb;
   for (int r = 0; r < 32; r++) {
     st->print("v%d=0x", r);
     for (int i = vr_size; i > 0; i--) {