Add option to disable ldabs* and ldind* instructions

Part of the SBF cleanup effort.
solana-labs · Jan 7, 2022 · ea9a33a · ea9a33a
1 parent f1d696f
commit ea9a33a
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Showing 3 changed files with 71 additions and 5 deletions.
diff --git a/src/jit.rs b/src/jit.rs
@@ -1020,8 +1020,25 @@ impl JitCompiler {
             let src = REGISTER_MAP[insn.src as usize];
             let target_pc = (self.pc as isize + insn.off as isize + 1) as usize;
 
-            match insn.opc {
+            if self.config.disable_deprecated_load_instructions {
+                match insn.opc {
+                    ebpf::LD_ABS_B
+                    | ebpf::LD_ABS_H
+                    | ebpf::LD_ABS_W
+                    | ebpf::LD_ABS_DW
+                    | ebpf::LD_IND_B
+                    | ebpf::LD_IND_H
+                    | ebpf::LD_IND_W
+                    | ebpf::LD_IND_DW => {
+                        return Err(EbpfError::UnsupportedInstruction(
+                            self.pc + ebpf::ELF_INSN_DUMP_OFFSET,
+                        ))
+                    }
+                    _ => {}
+                };
+            }
 
+            match insn.opc {
                 // BPF_LD class
                 ebpf::LD_ABS_B   => {
                     emit_address_translation(self, R11, Value::Constant64(ebpf::MM_INPUT_START.wrapping_add(insn.imm as u32 as u64) as i64, true), 1, AccessType::Load)?;

diff --git a/src/vm.rs b/src/vm.rs
@@ -207,6 +207,8 @@ pub struct Config {
     pub verify_mul64_imm_nonzero: bool,
     /// Feature flag for the SHIFT_IMM >= 32 verification check
     pub verify_shift32_imm: bool,
+    /// Disable ldabs* and ldind* instructions
+    pub disable_deprecated_load_instructions: bool,
 }
 impl Default for Config {
     fn default() -> Self {
@@ -221,6 +223,7 @@ impl Default for Config {
             reject_unresolved_syscalls: false,
             reject_section_virtual_address_file_offset_mismatch: false,
             reject_all_writable_sections: false,
+            disable_deprecated_load_instructions: false,
             noop_instruction_ratio: 1.0 / 256.0,
             sanitize_user_provided_values: true,
             encrypt_environment_registers: true,
@@ -668,6 +671,7 @@ impl<'a, E: UserDefinedError, I: InstructionMeter> EbpfVm<'a, E, I> {
         // Check config outside of the instruction loop
         let instruction_meter_enabled = self.executable.get_config().enable_instruction_meter;
         let instruction_tracing_enabled = self.executable.get_config().enable_instruction_tracing;
+        let disable_deprecated_load_instructions = self.executable.get_config().disable_deprecated_load_instructions;
 
         // Loop on instructions
         let entry = self.executable.get_entrypoint_instruction_offset()?;
@@ -691,6 +695,24 @@ impl<'a, E: UserDefinedError, I: InstructionMeter> EbpfVm<'a, E, I> {
                 self.tracer.trace(state);
             }
 
+            if disable_deprecated_load_instructions {
+                match insn.opc {
+                    ebpf::LD_ABS_B
+                    | ebpf::LD_ABS_H
+                    | ebpf::LD_ABS_W
+                    | ebpf::LD_ABS_DW
+                    | ebpf::LD_IND_B
+                    | ebpf::LD_IND_H
+                    | ebpf::LD_IND_W
+                    | ebpf::LD_IND_DW => {
+                        return Err(EbpfError::UnsupportedInstruction(
+                            pc + ebpf::ELF_INSN_DUMP_OFFSET,
+                        ))
+                    }
+                    _ => {}
+                };
+            }
+
             match insn.opc {
 
                 // BPF_LD class

diff --git a/tests/ubpf_execution.rs b/tests/ubpf_execution.rs
@@ -76,17 +76,23 @@ macro_rules! test_interpreter_and_jit {
 }
 
 macro_rules! test_interpreter_and_jit_asm {
+    ($source:tt, $config:tt, $mem:tt, ($($location:expr => $syscall_function:expr; $syscall_context_object:expr),* $(,)?), $check:block, $expected_instruction_count:expr) => {
+        #[allow(unused_mut)]
+        {
+            let mut syscall_registry = SyscallRegistry::default();
+            $(test_interpreter_and_jit!(register, syscall_registry, $location => $syscall_function; $syscall_context_object);)*
+            let mut executable = assemble($source, None, $config, syscall_registry).unwrap();
+            test_interpreter_and_jit!(executable, $mem, ($($location => $syscall_function; $syscall_context_object),*), $check, $expected_instruction_count);
+        }
+    };
     ($source:tt, $mem:tt, ($($location:expr => $syscall_function:expr; $syscall_context_object:expr),* $(,)?), $check:block, $expected_instruction_count:expr) => {
         #[allow(unused_mut)]
         {
             let config = Config {
                 enable_instruction_tracing: true,
                 ..Config::default()
             };
-            let mut syscall_registry = SyscallRegistry::default();
-            $(test_interpreter_and_jit!(register, syscall_registry, $location => $syscall_function; $syscall_context_object);)*
-            let mut executable = assemble($source, None, config, syscall_registry).unwrap();
-            test_interpreter_and_jit!(executable, $mem, ($($location => $syscall_function; $syscall_context_object),*), $check, $expected_instruction_count);
+            test_interpreter_and_jit_asm!($source, config, $mem, ($($location => $syscall_function; $syscall_context_object),*), $check, $expected_instruction_count);
         }
     };
 }
@@ -1009,6 +1015,27 @@ fn test_err_ldabsb_nomem() {
     );
 }
 
+#[test]
+fn test_err_ldabsb_disabled() {
+    let config = Config {
+        disable_deprecated_load_instructions: true,
+        ..Config::default()
+    };
+
+    test_interpreter_and_jit_asm!(
+        "
+        ldabsb 0x3
+        exit",
+        config,
+        [],
+        (),
+        {
+            |_vm, res: Result| matches!(res.unwrap_err(), EbpfError::UnsupportedInstruction(pc) if pc == 29)
+        },
+        1
+    );
+}
+
 #[test]
 fn test_ldindb() {
     test_interpreter_and_jit_asm!(