Truncate all ALU32 except for bit-endianess

Signed-off-by: Alan Jowett <[email protected]>
iovisor · May 18, 2024 · 5f4c21a · 5f4c21a
1 parent 5a4f6c6
commit 5f4c21a
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Showing 3 changed files with 11 additions and 3 deletions.
diff --git a/external/bpf_conformance b/external/bpf_conformance
diff --git a/vm/ubpf_jit_x86_64.c b/vm/ubpf_jit_x86_64.c
@@ -769,6 +769,12 @@ translate(struct ubpf_vm* vm, struct jit_state* state, char** errmsg)
             state->jit_status = UnknownInstruction;
             *errmsg = ubpf_error("Unknown instruction at PC %d: opcode %02x", i, inst.opcode);
         }
+
+        // If this is a ALU32 instruction, truncate the target register to 32 bits.
+        if (((inst.opcode & EBPF_CLS_MASK) == EBPF_CLS_ALU) &&
+            (inst.opcode & EBPF_ALU_OP_MASK) != 0xd0) {
+            emit_truncate_u32(state, dst);
+        }
     }
 
     if (state->jit_status != NoError) {

diff --git a/vm/ubpf_vm.c b/vm/ubpf_vm.c
@@ -737,7 +737,7 @@ ubpf_exec_ex(
             }
             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;
@@ -1003,6 +1003,9 @@ ubpf_exec_ex(
             // valid.
             break;
         }
+        if (((inst.opcode & EBPF_CLS_MASK) == EBPF_CLS_ALU) && (inst.opcode & EBPF_ALU_OP_MASK) != 0xd0) {
+            reg[inst.dst] &= UINT32_MAX;
+        }
     }
 
 cleanup:
@@ -1371,7 +1374,6 @@ ubpf_get_registers(const struct ubpf_vm* vm)
     fprintf(stderr, "uBPF warning: registers are not exposed in release mode. Please recompile in debug mode\n");
     return NULL;
 }
-
 #endif
 
 typedef struct _ebpf_encoded_inst
+2 −2		.github/workflows/Build.yml
+1 −1		.github/workflows/CICD.yml
+4 −4		.github/workflows/codeql-analysis.yml
+2 −2		.github/workflows/dependency-review.yml
+3 −3		.github/workflows/scorecards.yml
+1 −1		Docker/Linux/Dockerfile
+32 −0		tests/j-signed-imm.data
+8 −4		tests/mov.data