/* Given an instruction corresponding to a call, validate that the generated
* return address is safe.
* Parameters:
* vstate - The state of the validator.
*/
static void NaClValidateCallAlignment(NaClValidatorState* vstate) {
/* The return is safe only if it begins at an aligned address (since
* return instructions are not explicit jumps).
*/
NaClPcAddress next_addr = vstate->cur_inst_state->inst_addr
+ NaClInstStateLength(vstate->cur_inst_state);
if (next_addr & vstate->bundle_mask) {
NaClPcAddress printable_next_addr =
NaClInstStatePrintableAddress(vstate->cur_inst_state) +
NaClInstStateLength(vstate->cur_inst_state);
/* NOTE: Previously the validator recorded an error for call instructions
* that were not aligned against the end of a bundle, as these, while
* safe, are not correct with the current code generation idioms.
* This #if defined(ERROR_ON_CALL_BUNDLE_ALIGNMENT) was added to allow
* experimentation with different call/return idioms.
*/
if (!NACL_FLAGS_unsafe_single_inst_mode) {
NaClValidatorInstMessage(
#if defined(ERROR_ON_CALL_BUNDLE_ALIGNMENT)
LOG_ERROR,
#else
LOG_WARNING,
#endif
vstate, vstate->cur_inst_state,
"Bad call alignment, return pc = %"NACL_PRIxNaClPcAddress"\n",
printable_next_addr);
}
}
}
void NaClInstStateInstPrint(struct Gio* file, NaClInstState* state) {
int i;
const NaClInst* inst;
/* Print out the address and the inst bytes. */
int length = NaClInstStateLength(state);
DEBUG_OR_ERASE(
NaClInstPrint(file, state->decoder_tables, NaClInstStateInst(state)));
DEBUG(NaClExpVectorPrint(file, state));
gprintf(file, "%"NACL_PRIxNaClPcAddressAll": ",
NaClInstStatePrintableAddress(state));
for (i = 0; i < length; ++i) {
gprintf(file, "%02"NACL_PRIx8" ", NaClInstStateByte(state, i));
}
for (i = length; i < NACL_MAX_BYTES_PER_X86_INSTRUCTION; ++i) {
gprintf(file, " ");
}
/* Print out the assembly instruction it disassembles to. */
inst = NaClInstStateInst(state);
NaClPrintDisassembled(file, state, inst);
gprintf(file, "\n");
}
/* Print out the given constant expression node to the given file. */
static void NaClPrintDisassembledConst(
struct Gio* file, NaClInstState* state, NaClExp* node) {
assert(node->kind == ExprConstant);
if (node->flags & NACL_EFLAG(ExprJumpTarget)) {
NaClPcAddress target = NaClInstStatePrintableAddress(state)
+ state->bytes.length + (NaClPcNumber) NaClGetExprSignedValue(node);
gprintf(file, "0x%"NACL_PRIxNaClPcAddress, target);
}else if (node->flags & NACL_EFLAG(ExprUnsignedHex)) {
gprintf(file, "0x%"NACL_PRIx64, NaClGetExprUnsignedValue(node));
} else if (node->flags & NACL_EFLAG(ExprSignedHex)) {
int64_t val = NaClGetExprSignedValue(node);
if (val < 0) {
val = -val;
gprintf(file, "-0x%"NACL_PRIx64, val);
} else {
gprintf(file, "0x%"NACL_PRIx64, val);
}
} else if (node->flags & NACL_EFLAG(ExprUnsignedInt)) {
gprintf(file, "%"NACL_PRIu64, NaClGetExprUnsignedValue(node));
} else {
/* Assume ExprSignedInt. */
gprintf(file, "%"NACL_PRId64, NaClGetExprSignedValue(node));
}
}
