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/*
* Copyright (c) 2015-2017, Intel Corporation
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of Intel Corporation nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include "fdr_internal.h"
#include "fdr_confirm.h"
#include "fdr_compile_internal.h"
#include "fdr_engine_description.h"
#include "grey.h"
#include "ue2common.h"
#include "util/alloc.h"
#include "util/bitutils.h"
#include "util/charreach.h"
#include "util/compare.h"
#include "util/ue2string.h"
#include "util/verify_types.h"
#include <cstring>
#include <map>
#include <memory>
#include <string>
#include <vector>
using namespace std;
namespace ue2 {
namespace {
struct FloodComparator {
bool operator()(const FDRFlood &f1, const FDRFlood &f2) const {
return std::memcmp(&f1, &f2, sizeof(f1)) < 0;
}
};
}
static
bool isDifferent(u8 oldC, u8 c, bool caseless) {
if (caseless) {
return mytolower(oldC) != mytolower(c);
} else {
return oldC != c;
}
}
static
void updateFloodSuffix(vector<FDRFlood> &tmpFlood, u8 c, u32 suffix) {
FDRFlood &fl = tmpFlood[c];
fl.suffix = MAX(fl.suffix, suffix + 1);
DEBUG_PRINTF("Updated Flood Suffix for char 0x%02x to %u\n", c, fl.suffix);
}
static
void addFlood(vector<FDRFlood> &tmpFlood, u8 c, const hwlmLiteral &lit,
u32 suffix) {
FDRFlood &fl = tmpFlood[c];
fl.suffix = MAX(fl.suffix, suffix + 1);
if (fl.idCount < FDR_FLOOD_MAX_IDS) {
fl.ids[fl.idCount] = lit.id;
fl.allGroups |= lit.groups;
fl.groups[fl.idCount] = lit.groups;
// when idCount gets to max_ids this flood no longer happens
// only incremented one more time to avoid arithmetic overflow
DEBUG_PRINTF("Added Flood for char '%c' suffix=%u len[%hu]=%u\n",
c, fl.suffix, fl.idCount, suffix);
fl.idCount++;
}
}
bytecode_ptr<u8> setupFDRFloodControl(const vector<hwlmLiteral> &lits,
const EngineDescription &eng,
const Grey &grey) {
vector<FDRFlood> tmpFlood(N_CHARS);
u32 default_suffix = eng.getDefaultFloodSuffixLength();
// zero everything to avoid spurious distinctions in the compares
memset(&tmpFlood[0], 0, N_CHARS * sizeof(FDRFlood));
for (u32 c = 0; c < N_CHARS; c++) {
tmpFlood[c].suffix = default_suffix;
}
for (const auto &lit : lits) {
DEBUG_PRINTF("lit: '%s'%s\n", escapeString(lit.s).c_str(),
lit.nocase ? " (nocase)" : "");
u32 litSize = verify_u32(lit.s.size());
u32 maskSize = (u32)lit.msk.size();
u8 c = lit.s[litSize - 1];
bool nocase = ourisalpha(c) ? lit.nocase : false;
if (nocase && maskSize && (lit.msk[maskSize - 1] & CASE_BIT)) {
c = (lit.cmp[maskSize - 1] & CASE_BIT) ? mytolower(c) : mytoupper(c);
nocase = false;
}
u32 iEnd = MAX(litSize, maskSize);
u32 upSuffix = iEnd; // upSuffix is used as an upper case suffix length
// for case-less, or as a suffix length for case-sensitive;
u32 loSuffix = iEnd; // loSuffix used only for case-less as a lower case suffix
// length;
for (u32 i = 0; i < iEnd; i++) {
if (i < litSize) {
if (isDifferent(c, lit.s[litSize - i - 1], lit.nocase)) {
DEBUG_PRINTF("non-flood char in literal[%u]: "
"0x%02x != 0x%02x\n",
i, c, lit.s[litSize - i - 1]);
upSuffix = MIN(upSuffix, i);
loSuffix = MIN(loSuffix, i); // makes sense only for case-less
break;
}
}
if (i < maskSize) {
u8 m = lit.msk[maskSize - i - 1];
u8 cm = lit.cmp[maskSize - i - 1] & m;
if(nocase) {
if ((mytoupper(c) & m) != cm) {
DEBUG_PRINTF("non-flood char in mask[%u] %c != %c\n",
i, mytoupper(c), cm);
upSuffix = MIN(upSuffix, i);
}
if ((mytolower(c) & m) != cm) {
DEBUG_PRINTF("non-flood char in mask[%u] %c != %c\n",
i, mytolower(c), cm);
loSuffix = MIN(loSuffix, i);
}
if (loSuffix != iEnd && upSuffix != iEnd) {
break;
}
} else if ((c & m) != cm) {
DEBUG_PRINTF("non-flood char in mask[%u] %c != %c\n", i, c, cm);
upSuffix = MIN(upSuffix, i);
break;
}
}
}
if(upSuffix != iEnd) {
updateFloodSuffix(tmpFlood, nocase ? mytoupper(c) : c, upSuffix);
} else {
addFlood(tmpFlood, nocase ? mytoupper(c) : c, lit, upSuffix);
}
if (nocase) {
if(loSuffix != iEnd) {
updateFloodSuffix(tmpFlood, mytolower(c), loSuffix);
} else {
addFlood(tmpFlood, mytolower(c), lit, loSuffix);
}
}
}
#ifdef DEBUG
for (u32 i = 0; i < N_CHARS; i++) {
FDRFlood &fl = tmpFlood[i];
if (!fl.idCount) {
continue;
}
printf("i is %02x fl->idCount is %hd fl->suffix is %d fl->allGroups is "
"%016llx\n", i, fl.idCount, fl.suffix, fl.allGroups);
for (u32 j = 0; j < fl.idCount; j++) {
printf("j is %d fl.groups[j] %016llx\n", j, fl.groups[j]);
}
}
#endif
// If flood detection has been switched off in the grey box, we comply by
// setting idCount too high for all floods.
if (!grey.fdrAllowFlood) {
for (auto &fl : tmpFlood) {
fl.idCount = FDR_FLOOD_MAX_IDS;
}
}
map<FDRFlood, CharReach, FloodComparator> flood2chars;
for (u32 i = 0; i < N_CHARS; i++) {
FDRFlood fl = tmpFlood[i];
flood2chars[fl].set(i);
}
u32 nDistinctFloods = flood2chars.size();
size_t floodHeaderSize = sizeof(u32) * N_CHARS;
size_t floodStructSize = sizeof(FDRFlood) * nDistinctFloods;
size_t totalSize = ROUNDUP_16(floodHeaderSize + floodStructSize);
auto buf = make_zeroed_bytecode_ptr<u8>(totalSize, 16);
assert(buf); // otherwise would have thrown std::bad_alloc
u32 *floodHeader = (u32 *)buf.get();
FDRFlood *layoutFlood = (FDRFlood *)(buf.get() + floodHeaderSize);
u32 currentFloodIndex = 0;
for (const auto &m : flood2chars) {
const FDRFlood &fl = m.first;
const CharReach &cr = m.second;
layoutFlood[currentFloodIndex] = fl;
for (size_t c = cr.find_first(); c != cr.npos; c = cr.find_next(c)) {
floodHeader[c] = currentFloodIndex;
}
currentFloodIndex++;
}
DEBUG_PRINTF("made a flood structure with %zu + %zu = %zu\n",
floodHeaderSize, floodStructSize, totalSize);
return buf;
}
} // namespace ue2
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