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ntdll: Handle invalid %gs fault in signal handler on i386. 

Signed-off-by: Alexandre Julliard <julliard@winehq.org>
This commit is contained in:
Alexandre Julliard 2019-09-12 20:00:48 +02:00
parent 0bd2465326
commit 58139dcb12
1 changed files with 13 additions and 10 deletions
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23
dlls/ntdll/signal_i386.c
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@ -1594,18 +1594,19 @@ static inline DWORD is_privileged_instr( CONTEXT *context )
*
* Check for fault caused by invalid %gs value (some copy protection schemes mess with it).
*/
static inline BOOL check_invalid_gs( CONTEXT *context )
static inline BOOL check_invalid_gs( ucontext_t *sigcontext, CONTEXT *context )
{
unsigned int prefix_count = 0;
const BYTE *instr = (BYTE *)context->Eip;
BYTE instr[14];
unsigned int i, len;
WORD system_gs = x86_thread_data()->gs;
if (context->SegGs == system_gs) return FALSE;
if (!wine_ldt_is_system( context->SegCs )) return FALSE;
/* only handle faults in system libraries */
if (virtual_is_valid_code_address( instr, 1 )) return FALSE;
if (virtual_is_valid_code_address( (BYTE *)context->Eip, 1 )) return FALSE;
for (;;) switch(*instr)
len = virtual_uninterrupted_read_memory( (BYTE *)context->Eip, instr, sizeof(instr) );
for (i = 0; i < len; i++) switch (instr[i])
{
/* instruction prefixes */
case 0x2e: /* %cs: */
@ -1618,16 +1619,17 @@ static inline BOOL check_invalid_gs( CONTEXT *context )
case 0xf0: /* lock */
case 0xf2: /* repne */
case 0xf3: /* repe */
if (++prefix_count >= 15) return FALSE;
instr++;
continue;
case 0x65: /* %gs: */
TRACE( "%04x/%04x at %p, fixing up\n", context->SegGs, system_gs, instr );
context->SegGs = system_gs;
#ifdef GS_sig
GS_sig(sigcontext) = system_gs;
#endif
return TRUE;
default:
return FALSE;
}
return FALSE;
}
@ -1911,8 +1913,6 @@ static void WINAPI raise_segv_exception( EXCEPTION_RECORD *rec, CONTEXT *context
case EXCEPTION_ACCESS_VIOLATION:
if (rec->NumberParameters == 2)
{
if (rec->ExceptionInformation[1] == 0xffffffff && check_invalid_gs( context ))
goto done;
if (!(rec->ExceptionCode = virtual_handle_fault( (void *)rec->ExceptionInformation[1],
rec->ExceptionInformation[0], FALSE )))
goto done;
@ -2059,7 +2059,10 @@ static void segv_handler( int signal, siginfo_t *siginfo, void *sigcontext )
if ((err & 7) == 4 && !wine_ldt_is_system( err | 7 ))
stack->rec.ExceptionInformation[1] = err & ~7;
else
{
stack->rec.ExceptionInformation[1] = 0xffffffff;
if (check_invalid_gs( context, &stack->context )) return;
}
}
break;
case TRAP_x86_PAGEFLT: /* Page fault */