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1 // Copyright (c) 2010 The Chromium Authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 #include "debug.h" | |
6 #include "sandbox_impl.h" | |
7 | |
8 namespace playground { | |
9 | |
10 long Sandbox::sandbox_madvise(void* start, size_t length, int advice) { | |
11 long long tm; | |
12 Debug::syscall(&tm, __NR_madvise, "Executing handler"); | |
13 struct { | |
14 int sysnum; | |
15 long long cookie; | |
16 MAdvise madvise_req; | |
17 } __attribute__((packed)) request; | |
18 request.sysnum = __NR_madvise; | |
19 request.cookie = cookie(); | |
20 request.madvise_req.start = start; | |
21 request.madvise_req.len = length; | |
22 request.madvise_req.advice = advice; | |
23 | |
24 long rc; | |
25 SysCalls sys; | |
26 if (write(sys, processFdPub(), &request, sizeof(request)) != | |
27 sizeof(request) || | |
28 read(sys, threadFdPub(), &rc, sizeof(rc)) != sizeof(rc)) { | |
29 die("Failed to forward madvise() request [sandbox]"); | |
30 } | |
31 Debug::elapsed(tm, __NR_madvise); | |
32 return rc; | |
33 } | |
34 | |
35 bool Sandbox::process_madvise(int parentMapsFd, int sandboxFd, int threadFdPub, | |
36 int threadFd, SecureMem::Args* mem) { | |
37 // Read request | |
38 MAdvise madvise_req; | |
39 SysCalls sys; | |
40 if (read(sys, sandboxFd, &madvise_req, sizeof(madvise_req)) != | |
41 sizeof(madvise_req)) { | |
42 die("Failed to read parameters for madvise() [process]"); | |
43 } | |
44 int rc = -EINVAL; | |
45 switch (madvise_req.advice) { | |
46 case MADV_NORMAL: | |
47 case MADV_RANDOM: | |
48 case MADV_SEQUENTIAL: | |
49 case MADV_WILLNEED: | |
50 ok: | |
51 SecureMem::sendSystemCall(threadFdPub, false, -1, mem, __NR_madvise, | |
52 madvise_req.start, madvise_req.len, | |
53 madvise_req.advice); | |
54 return true; | |
55 default: | |
56 // All other flags to madvise() are potential dangerous (as opposed to | |
57 // merely affecting overall performance). Do not allow them on memory | |
58 // ranges that were part of the original mappings. | |
59 void *stop = reinterpret_cast<void *>( | |
60 (char *)madvise_req.start + madvise_req.len); | |
61 ProtectedMap::const_iterator iter = protectedMap_.lower_bound( | |
62 (void *)madvise_req.start); | |
63 if (iter != protectedMap_.begin()) { | |
64 --iter; | |
65 } | |
66 for (; iter != protectedMap_.end() && iter->first < stop; ++iter) { | |
67 if (madvise_req.start < reinterpret_cast<void *>( | |
68 reinterpret_cast<char *>(iter->first) + iter->second) && | |
69 stop > iter->first) { | |
70 SecureMem::abandonSystemCall(threadFd, rc); | |
71 return false; | |
72 } | |
73 } | |
74 | |
75 // Changing attributes on memory regions that were newly mapped inside of | |
76 // the sandbox is OK. | |
77 goto ok; | |
78 } | |
79 } | |
80 | |
81 } // namespace | |
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