From: Sebastian Lackner sebastian@fds-team.de
Signed-off-by: Zebediah Figura z.figura12@gmail.com --- dlls/ntdll/signal_x86_64.c | 82 +++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 81 insertions(+), 1 deletion(-)
diff --git a/dlls/ntdll/signal_x86_64.c b/dlls/ntdll/signal_x86_64.c index 169793b..7b82083 100644 --- a/dlls/ntdll/signal_x86_64.c +++ b/dlls/ntdll/signal_x86_64.c @@ -2721,6 +2721,86 @@ static void raise_generic_exception( EXCEPTION_RECORD *rec, CONTEXT *context )
/*********************************************************************** + * is_privileged_instr + * + * Check if the fault location is a privileged instruction. + */ +static inline DWORD is_privileged_instr( CONTEXT *context ) +{ + const BYTE *instr = (BYTE *)context->Rip; + unsigned int prefix_count = 0; + + for (;;) switch(*instr) + { + /* instruction prefixes */ + case 0x2e: /* %cs: */ + case 0x36: /* %ss: */ + case 0x3e: /* %ds: */ + case 0x26: /* %es: */ + case 0x40: /* rex */ + case 0x41: /* rex */ + case 0x42: /* rex */ + case 0x43: /* rex */ + case 0x44: /* rex */ + case 0x45: /* rex */ + case 0x46: /* rex */ + case 0x47: /* rex */ + case 0x48: /* rex */ + case 0x49: /* rex */ + case 0x4a: /* rex */ + case 0x4b: /* rex */ + case 0x4c: /* rex */ + case 0x4d: /* rex */ + case 0x4e: /* rex */ + case 0x4f: /* rex */ + case 0x64: /* %fs: */ + case 0x65: /* %gs: */ + case 0x66: /* opcode size */ + case 0x67: /* addr size */ + case 0xf0: /* lock */ + case 0xf2: /* repne */ + case 0xf3: /* repe */ + if (++prefix_count >= 15) return EXCEPTION_ILLEGAL_INSTRUCTION; + instr++; + continue; + + case 0x0f: /* extended instruction */ + switch(instr[1]) + { + case 0x06: /* clts */ + case 0x08: /* invd */ + case 0x09: /* wbinvd */ + case 0x20: /* mov crX, reg */ + case 0x21: /* mov drX, reg */ + case 0x22: /* mov reg, crX */ + case 0x23: /* mov reg drX */ + return EXCEPTION_PRIV_INSTRUCTION; + } + return 0; + case 0x6c: /* insb (%dx) */ + case 0x6d: /* insl (%dx) */ + case 0x6e: /* outsb (%dx) */ + case 0x6f: /* outsl (%dx) */ + case 0xcd: /* int $xx */ + case 0xe4: /* inb al,XX */ + case 0xe5: /* in (e)ax,XX */ + case 0xe6: /* outb XX,al */ + case 0xe7: /* out XX,(e)ax */ + case 0xec: /* inb (%dx),%al */ + case 0xed: /* inl (%dx),%eax */ + case 0xee: /* outb %al,(%dx) */ + case 0xef: /* outl %eax,(%dx) */ + case 0xf4: /* hlt */ + case 0xfa: /* cli */ + case 0xfb: /* sti */ + return EXCEPTION_PRIV_INSTRUCTION; + default: + return 0; + } +} + + +/*********************************************************************** * handle_interrupt * * Handle an interrupt. @@ -2790,8 +2870,8 @@ static void segv_handler( int signal, siginfo_t *siginfo, void *sigcontext ) { CONTEXT *win_context = get_exception_context( rec ); WORD err = ERROR_sig(ucontext); + if (!err && (rec->ExceptionCode = is_privileged_instr( win_context ))) break; if ((err & 7) == 2 && handle_interrupt( err >> 3, rec, win_context )) break; - rec->ExceptionCode = err ? EXCEPTION_ACCESS_VIOLATION : EXCEPTION_PRIV_INSTRUCTION; rec->ExceptionCode = EXCEPTION_ACCESS_VIOLATION; } break;