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bdshemu: Fix edge case with unsupported instrs

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Fixes https://github.com/bitdefender/bddisasm/issues/106
This commit is contained in:
Eugen Podrug 2024-09-23 16:47:52 +02:00
parent b67fd766a1
commit 7136b64c6c
1 changed files with 9 additions and 8 deletions
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17
bdshemu/bdshemu_x86.c
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@ -1793,13 +1793,6 @@ ShemuX86Emulate(
nd_memzero(&dst, sizeof(dst)); nd_memzero(&dst, sizeof(dst));
nd_memzero(&src, sizeof(src)); nd_memzero(&src, sizeof(src));
// The stop flag has been set, this means we've reached a valid instruction, but that instruction cannot be
// emulated (for example, SYSCALL, INT, system instructions, etc).
if (stop)
{
return SHEMU_ABORT_CANT_EMULATE;
}
// If we already have a detection and we wish to stop on detections, do so now. // If we already have a detection and we wish to stop on detections, do so now.
if ((0 != Context->Flags) && (0 != (Context->Options & SHEMU_OPT_STOP_ON_EXPLOIT))) if ((0 != Context->Flags) && (0 != (Context->Options & SHEMU_OPT_STOP_ON_EXPLOIT)))
{ {
@ -1942,7 +1935,7 @@ ShemuX86Emulate(
} }
} }
continue; goto post_emulate;
} }
// This flag can only be set for APX instructions. // This flag can only be set for APX instructions.
@ -3557,6 +3550,14 @@ check_far_branch:
break; break;
} }
post_emulate:
// The stop flag has been set, this means we've reached a valid instruction, but that instruction cannot be
// emulated (for example, SYSCALL, INT, system instructions, etc).
if (stop)
{
return SHEMU_ABORT_CANT_EMULATE;
}
} }
// Minimum percent of the instructions were NOPs => consider we have a NOP sled. Note that we get here only if // Minimum percent of the instructions were NOPs => consider we have a NOP sled. Note that we get here only if