1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
|
diff --git a/dlls/ntdll/tests/exception.c b/dlls/ntdll/tests/exception.c
index 9b5ca2ca5086c27344152eef0f296e71a57cbac3..13ef9b693bf862dd60daa3738bc37a15cac27660 100644
--- a/dlls/ntdll/tests/exception.c
+++ b/dlls/ntdll/tests/exception.c
@@ -2673,24 +2673,21 @@ static const struct exception
/* It is observed that fs/gs base is reset
on some CPUs when setting the segment value
even to 0 (regardless of CPU spec
- saying otherwise) and it is not currently
- handled in Wine.
+ saying otherwise) and the fs base case
+ is not currently handled in Wine.
Disable this part to avoid crashing the test. */
0x8e, 0xe0, /* mov %eax,%fs */
- 0x8e, 0xe8, /* mov %eax,%gs */
#else
0x90, 0x90, /* nop */
- 0x90, 0x90, /* nop */
#endif
+ 0x8e, 0xe8, /* mov %eax,%gs */
0xfa, /* cli */
0x58, /* pop %rax */
-#if 0
0x8e, 0xe8, /* mov %eax,%gs */
0x58, /* pop %rax */
+#if 0
0x8e, 0xe0, /* mov %eax,%fs */
#else
- 0x58, /* pop %rax */
- 0x90, 0x90, /* nop */
0x90, 0x90, /* nop */
#endif
0x58, /* pop %rax */
@@ -2711,6 +2708,12 @@ static const struct exception
{ { 0xb8, 0x01, 0x00, 0x00, 0x00, /* mov $0x01, %eax */
0xcd, 0x2d, 0xfa, 0xc3 }, /* int $0x2d; cli; ret */
8, 0, STATUS_SUCCESS, 0 },
+ { { 0x66, 0x0f, 0xa8, /* push %gs */
+ 0x66, 0x0f, 0xa9, /* pop %gs */
+ 0x65, 0x48, 0x8b, 0x04, 0x25, /* movq %gs:0x30,%rax (NtCurrentTeb) */
+ 0x30, 0x00, 0x00, 0x00,
+ 0xc3 }, /* ret */
+ 8, 0, STATUS_SUCCESS, 0 },
};
static int got_exception;
diff --git a/dlls/ntdll/unix/signal_x86_64.c b/dlls/ntdll/unix/signal_x86_64.c
index caa85249896fb9580f1f50dd62b6c0b7a84ee89f..46c70adc83be8112befc7e39cad5ce8b4511cb29 100644
--- a/dlls/ntdll/unix/signal_x86_64.c
+++ b/dlls/ntdll/unix/signal_x86_64.c
@@ -1967,6 +1967,102 @@ static BOOL handle_syscall_trap( ucontext_t *sigcontext, siginfo_t *siginfo )
}
+/***********************************************************************
+ * check_invalid_gsbase
+ *
+ * Check for fault caused by invalid %gs value (some copy protection schemes mess with it).
+ */
+static inline BOOL check_invalid_gsbase( ucontext_t *sigcontext, CONTEXT *context )
+{
+ unsigned int prefix_count = 0;
+ const BYTE *instr = (const BYTE *)context->Rip;
+ TEB *teb = NtCurrentTeb();
+ ULONG_PTR cur_gsbase = 0;
+
+#ifdef __linux__
+ if (syscall_flags & SYSCALL_HAVE_WRFSGSBASE)
+ __asm__ volatile ("rdgsbase %0" : "=r" (cur_gsbase));
+ else
+ arch_prctl( ARCH_GET_GS, &cur_gsbase );
+#elif defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
+ amd64_get_gsbase( &cur_gsbase );
+#elif defined(__NetBSD__)
+ sysarch( X86_64_GET_GSBASE, &cur_gsbase );
+#elif defined(__APPLE__)
+ cur_gsbase = (ULONG_PTR)teb->ThreadLocalStoragePointer;
+#else
+# error Please define getting %gs for your architecture
+#endif
+
+ if (cur_gsbase == (ULONG_PTR)teb) return FALSE;
+
+ 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 0x66: /* opcode size */
+ case 0x67: /* addr size */
+ case 0xf0: /* lock */
+ case 0xf2: /* repne */
+ case 0xf3: /* repe */
+ if (++prefix_count >= 15) return FALSE;
+ instr++;
+ continue;
+ case 0x65: /* %gs: */
+ GS_sig(sigcontext) = ds64_sel;
+ break;
+ default:
+ return FALSE;
+ }
+ break; /* %gs: */
+ }
+
+ TRACE( "gsbase %016lx teb %p at instr %p, fixing up\n", cur_gsbase, teb, instr );
+
+#ifdef __linux__
+ if (syscall_flags & SYSCALL_HAVE_WRFSGSBASE)
+ __asm__ volatile ("wrgsbase %0" :: "r" (teb));
+ else
+ arch_prctl( ARCH_SET_GS, teb );
+#elif defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
+ amd64_set_gsbase( teb );
+#elif defined(__NetBSD__)
+ sysarch( X86_64_SET_GSBASE, &teb );
+#elif defined(__APPLE__)
+ __asm__ volatile ("movq %0,%%gs:%c1" :: "r" (teb->Tib.Self),
+ "n" (FIELD_OFFSET(TEB, Tib.Self)));
+ __asm__ volatile ("movq %0,%%gs:%c1" :: "r" (teb->ThreadLocalStoragePointer),
+ "n" (FIELD_OFFSET(TEB, ThreadLocalStoragePointer)));
+#else
+# error Please define setting %gs for your architecture
+#endif
+
+ return TRUE;
+}
+
+
/**********************************************************************
* segv_handler
*
@@ -2025,6 +2121,11 @@ static void segv_handler( int signal, siginfo_t *siginfo, void *sigcontext )
/* send EXCEPTION_EXECUTE_FAULT only if data execution prevention is enabled */
if (!(flags & MEM_EXECUTE_OPTION_DISABLE)) rec.ExceptionInformation[0] = EXCEPTION_READ_FAULT;
}
+ if (CS_sig(ucontext) == cs64_sel && check_invalid_gsbase( ucontext, &context.c ))
+ {
+ leave_handler( ucontext );
+ return;
+ }
break;
case TRAP_x86_ALIGNFLT: /* Alignment check exception */
if (EFL_sig(ucontext) & 0x00040000)
|