Mark [r1-r5] as invalid on exit

Signed-off-by: Alan Jowett <alan.jowett@microsoft.com>
iovisor · May 7, 2024 · d83a876 · d83a876
1 parent f7016ab
commit d83a876
Showing 1 changed file with 8 additions and 6 deletions.
diff --git a/vm/ubpf_vm.c b/vm/ubpf_vm.c
@@ -542,13 +542,15 @@ ubpf_validate_shadow_register(const struct ubpf_vm* vm, uint16_t* shadow_registe
     if (inst.opcode == EBPF_OP_CALL) {
         // Mark the return address register as initialized.
         *shadow_registers |= 1 << 0;
-        // Mark r1-r5 as uninitialized.
-        *shadow_registers &= ~0x3e;
     }
 
-    if (inst.opcode == EBPF_OP_EXIT && !(*shadow_registers & (1 << 0))) {
-        vm->error_printf(stderr, "Error: Return address register r0 is not initialized.\n");
-        return false;
+    if (inst.opcode == EBPF_OP_EXIT) {
+        if (!(*shadow_registers & (1 << 0))) {
+            vm->error_printf(stderr, "Error: Return address register r0 is not initialized.\n");
+            return false;
+        }
+        // Mark r1-r5 as uninitialized.
+        *shadow_registers &= ~0x3e;
     }
 
     return true;
@@ -933,7 +935,7 @@ ubpf_exec(const struct ubpf_vm* vm, void* mem, size_t mem_len, uint64_t* bpf_ret
             }
             break;
         case EBPF_OP_JEQ32_REG:
-            if (u32(reg[inst.dst]) == reg[inst.src]) {
+            if (u32(reg[inst.dst]) == u32(reg[inst.src])) {
                 pc += inst.offset;
             }
             break;