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
166
167
|
Index: VirtualBox-5.1.22/src/VBox/HostDrivers/Support/posix/SUPR3HardenedMain-posix.cpp
===================================================================
--- VirtualBox-5.1.22/src/VBox/HostDrivers/Support/posix/SUPR3HardenedMain-posix.cpp (revision 115126)
+++ VirtualBox-5.1.22/src/VBox/HostDrivers/Support/posix/SUPR3HardenedMain-posix.cpp (revision 115307)
@@ -341,6 +341,7 @@
* Patch 64-bit hosts.
*/
uint32_t cRipRelMovs = 0;
+ uint32_t cRelCalls = 0;
/* Just use the disassembler to skip 12 bytes or more, we might need to
rewrite mov instructions using RIP relative addressing. */
@@ -349,7 +350,8 @@
cbInstr = 1;
int rc = DISInstr(pbTarget + offJmpBack, DISCPUMODE_64BIT, &Dis, &cbInstr);
if ( RT_FAILURE(rc)
- || (Dis.pCurInstr->fOpType & DISOPTYPE_CONTROLFLOW)
+ || ( Dis.pCurInstr->fOpType & DISOPTYPE_CONTROLFLOW
+ && Dis.pCurInstr->uOpcode != OP_CALL)
|| ( Dis.ModRM.Bits.Mod == 0
&& Dis.ModRM.Bits.Rm == 5 /* wrt RIP */
&& Dis.pCurInstr->uOpcode != OP_MOV))
@@ -357,15 +359,23 @@
if (Dis.ModRM.Bits.Mod == 0 && Dis.ModRM.Bits.Rm == 5 /* wrt RIP */)
cRipRelMovs++;
+ if ( Dis.pCurInstr->uOpcode == OP_CALL
+ && (Dis.pCurInstr->fOpType & DISOPTYPE_RELATIVE_CONTROLFLOW))
+ cRelCalls++;
offJmpBack += cbInstr;
cbPatchMem += cbInstr;
}
+ /*
+ * Each relative call requires extra bytes as it is converted to a pushq imm32
+ * + mov [RSP+4], imm32 + a jmp qword [$+8 wrt RIP] to avoid clobbering registers.
+ */
+ cbPatchMem += cRelCalls * RT_ALIGN_32(13 + 6 + 8, 8);
cbPatchMem += 14; /* jmp qword [$+8 wrt RIP] + 8 byte address to jump to. */
cbPatchMem = RT_ALIGN_32(cbPatchMem, 8);
- /* Allocate suitable exectuable memory available. */
+ /* Allocate suitable executable memory available. */
bool fConvRipRelMovs = false;
uint8_t *pbPatchMem = supR3HardenedMainPosixExecMemAlloc(cbPatchMem, pbTarget, cRipRelMovs > 0);
if (!pbPatchMem)
@@ -396,7 +406,8 @@
cbInstr = 1;
int rc = DISInstr(pbTarget + offInsn, DISCPUMODE_64BIT, &Dis, &cbInstr);
if ( RT_FAILURE(rc)
- || (Dis.pCurInstr->fOpType & DISOPTYPE_CONTROLFLOW))
+ || ( Dis.pCurInstr->fOpType & DISOPTYPE_CONTROLFLOW
+ && Dis.pCurInstr->uOpcode != OP_CALL))
return VERR_SUPLIB_UNEXPECTED_INSTRUCTION;
if ( Dis.ModRM.Bits.Mod == 0
@@ -439,6 +450,34 @@
pbPatchMem += sizeof(int32_t);
}
}
+ else if ( Dis.pCurInstr->uOpcode == OP_CALL
+ && (Dis.pCurInstr->fOpType & DISOPTYPE_RELATIVE_CONTROLFLOW))
+ {
+ /* Convert to absolute jump. */
+ uintptr_t uAddr = (uintptr_t)&pbTarget[offInsn + cbInstr] + (intptr_t)Dis.Param1.uValue;
+
+ /* Skip the push instructions till the return address is known. */
+ uint8_t *pbPatchMemPush = pbPatchMem;
+ pbPatchMem += 13;
+
+ *pbPatchMem++ = 0xff; /* jmp qword [$+8 wrt RIP] */
+ *pbPatchMem++ = 0x25;
+ *(uint32_t *)pbPatchMem = (uint32_t)(RT_ALIGN_PT(pbPatchMem + 4, 8, uint8_t *) - (pbPatchMem + 4));
+ pbPatchMem = RT_ALIGN_PT(pbPatchMem + 4, 8, uint8_t *);
+ *(uint64_t *)pbPatchMem = uAddr;
+ pbPatchMem += sizeof(uint64_t);
+
+ /* Push the return address onto stack. Difficult on amd64 without clobbering registers... */
+ uintptr_t uAddrReturn = (uintptr_t)pbPatchMem;
+ *pbPatchMemPush++ = 0x68; /* push imm32 sign-extended as 64-bit*/
+ *(uint32_t *)pbPatchMemPush = RT_LO_U32(uAddrReturn);
+ pbPatchMemPush += sizeof(uint32_t);
+ *pbPatchMemPush++ = 0xc7;
+ *pbPatchMemPush++ = 0x44;
+ *pbPatchMemPush++ = 0x24;
+ *pbPatchMemPush++ = 0x04; /* movl [RSP+4], imm32 */
+ *(uint32_t *)pbPatchMemPush = RT_HI_U32(uAddrReturn);
+ }
else
{
memcpy(pbPatchMem, pbTarget + offInsn, cbInstr);
Index: VirtualBox-5.1.22/src/VBox/HostDrivers/Support/SUPR3HardenedVerify.cpp
===================================================================
--- VirtualBox-5.1.22/src/VBox/HostDrivers/Support/SUPR3HardenedVerify.cpp (revision 115126)
+++ VirtualBox-5.1.22/src/VBox/HostDrivers/Support/SUPR3HardenedVerify.cpp (revision 115307)
@@ -86,6 +86,9 @@
/** The max path length acceptable for a trusted path. */
#define SUPR3HARDENED_MAX_PATH 260U
+/** Enable to resolve symlinks using realpath() instead of cooking our own stuff. */
+#define SUP_HARDENED_VERIFY_FOLLOW_SYMLINKS_USE_REALPATH 1
+
#ifdef RT_OS_SOLARIS
# define dirfd(d) ((d)->d_fd)
#endif
@@ -1091,7 +1094,8 @@
#endif
-#if defined(RT_OS_DARWIN) || defined(RT_OS_LINUX)
+#ifndef SUP_HARDENED_VERIFY_FOLLOW_SYMLINKS_USE_REALPATH
+# if defined(RT_OS_DARWIN) || defined(RT_OS_LINUX)
/**
* Copies the error message to the error buffer and returns @a rc.
*
@@ -1104,6 +1108,7 @@
{
return supR3HardenedSetErrorN(rc, pErrInfo, 1, pszMsg);
}
+# endif
#endif
@@ -1893,7 +1898,9 @@
/*
* Verify each component from the root up.
*/
+#ifndef SUP_HARDENED_VERIFY_FOLLOW_SYMLINKS_USE_REALPATH
uint32_t iLoops = 0;
+#endif
SUPR3HARDENEDFSOBJSTATE FsObjState;
uint32_t iComponent = 0;
while (iComponent < Info.cComponents)
@@ -1915,6 +1922,24 @@
if ( RT_SUCCESS(rc)
&& S_ISLNK(FsObjState.Stat.st_mode))
{
+#if SUP_HARDENED_VERIFY_FOLLOW_SYMLINKS_USE_REALPATH /* Another approach using realpath() and verifying the result when encountering a symlink. */
+ char *pszFilenameResolved = realpath(pszFilename, NULL);
+ if (pszFilenameResolved)
+ {
+ rc = supR3HardenedVerifyFile(pszFilenameResolved, hNativeFile, fMaybe3rdParty, pErrInfo);
+ free(pszFilenameResolved);
+ return rc;
+ }
+ else
+ {
+ int iErr = errno;
+ supR3HardenedError(VERR_ACCESS_DENIED, false /*fFatal*/,
+ "supR3HardenedVerifyFileFollowSymlinks: Failed to resolve the real path '%s': %s (%d)\n",
+ pszFilename, strerror(iErr), iErr);
+ return supR3HardenedSetError4(VERR_ACCESS_DENIED, pErrInfo,
+ "realpath failed for '", pszFilename, "': ", strerror(iErr));
+ }
+#else
/* Don't loop forever. */
iLoops++;
if (iLoops < 8)
@@ -1989,6 +2014,7 @@
else
return supR3HardenedSetError3(VERR_TOO_MANY_SYMLINKS, pErrInfo,
"Too many symbolic links: '", pszFilename, "'");
+#endif
}
}
if (RT_FAILURE(rc))
|
