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// Copyright (c) 2010 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "debug.h"
#include "sandbox_impl.h"
namespace playground {
int Sandbox::sandbox_mprotect(const void *addr, size_t len, int prot) {
Debug::syscall(__NR_mprotect, "Executing handler");
struct {
int sysnum;
long long cookie;
MProtect mprotect_req;
} __attribute__((packed)) request;
request.sysnum = __NR_mprotect;
request.cookie = cookie();
request.mprotect_req.addr = addr;
request.mprotect_req.len = len;
request.mprotect_req.prot = prot;
long rc;
SysCalls sys;
if (write(sys, processFdPub(), &request, sizeof(request)) !=
sizeof(request) ||
read(sys, threadFdPub(), &rc, sizeof(rc)) != sizeof(rc)) {
die("Failed to forward mprotect() request [sandbox]");
}
return static_cast<int>(rc);
}
bool Sandbox::process_mprotect(int parentMapsFd, int sandboxFd,
int threadFdPub, int threadFd,
SecureMem::Args* mem) {
// Read request
SysCalls sys;
MProtect mprotect_req;
if (read(sys, sandboxFd, &mprotect_req, sizeof(mprotect_req)) !=
sizeof(mprotect_req)) {
die("Failed to read parameters for mprotect() [process]");
}
// Cannot change permissions on any memory region that was part of the
// original memory mappings.
int rc = -EINVAL;
void *stop = reinterpret_cast<void *>(
(char *)mprotect_req.addr + mprotect_req.len);
ProtectedMap::const_iterator iter = protectedMap_.lower_bound(
(void *)mprotect_req.addr);
if (iter != protectedMap_.begin()) {
--iter;
}
for (; iter != protectedMap_.end() && iter->first < stop; ++iter) {
if (mprotect_req.addr < reinterpret_cast<void *>(
reinterpret_cast<char *>(iter->first) + iter->second) &&
stop > iter->first) {
SecureMem::abandonSystemCall(threadFd, rc);
return false;
}
}
// Changing permissions on memory regions that were newly mapped inside of
// the sandbox is OK.
SecureMem::sendSystemCall(threadFdPub, false, -1, mem, __NR_mprotect,
mprotect_req.addr, mprotect_req.len,
mprotect_req.prot);
return true;
}
} // namespace
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