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Fix memory leak in lmdb.cc + improve performance while reading collections in resolveMultiMatches #2520

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Fix memory leak in lmdb.cc + improve performance while reading collections in resolveMultiMatches #2520

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064b626
Remove memory leak in lmdb.cc while passing data from MDB_val to Vari…
ziollek Feb 24, 2021
f1c5f6b
Optimize fetching collection in resolveMultiMatches
ziollek Feb 24, 2021
440e3c9
Fix static-check violations
ziollek Feb 24, 2021
d980bef
Merge branch 'SpiderLabs:v3/master' into v3/master
ziollek Mar 6, 2022
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15 changes: 15 additions & 0 deletions headers/modsecurity/variable_value.h
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Original file line number Diff line number Diff line change
Expand Up @@ -47,6 +47,13 @@ class VariableValue {
m_value(value != nullptr?*value:"")
{ }

VariableValue(std::string&& key,
std::string&& value)
: m_collection(""),
m_key(std::move(key)),
m_value(std::move(value))
{ m_keyWithCollection = m_key; }

VariableValue(const std::string *collection,
const std::string *key,
const std::string *value)
Expand All @@ -56,6 +63,14 @@ class VariableValue {
m_value(*value)
{ }

VariableValue(const std::string *collection,
std::string&& key,
std::string&& value)
: m_collection(*collection),
m_key(std::move(key)),
m_value(std::move(value))
{ m_keyWithCollection = m_collection + ":" + m_key; }

explicit VariableValue(const VariableValue *o) :
m_collection(o->m_collection),
m_key(o->m_key),
Expand Down
35 changes: 21 additions & 14 deletions src/collection/backend/lmdb.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -291,6 +291,7 @@ void LMDB::resolveSingleMatch(const std::string& var,
reinterpret_cast<char *>(mdb_value_ret.mv_data),
mdb_value_ret.mv_size);
VariableValue *v = new VariableValue(&var, a);
delete a;
l->push_back(v);
}

Expand Down Expand Up @@ -498,22 +499,28 @@ void LMDB::resolveMultiMatches(const std::string& var,
while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) {
l->insert(l->begin(), new VariableValue(
&m_name,
new std::string(reinterpret_cast<char *>(key.mv_data),
std::string(reinterpret_cast<char *>(key.mv_data),
key.mv_size),
new std::string(reinterpret_cast<char *>(data.mv_data),
std::string(reinterpret_cast<char *>(data.mv_data),
data.mv_size)));
}
} else {
while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) {
char *a = reinterpret_cast<char *>(key.mv_data);
if (strncmp(var.c_str(), a, keySize) == 0) {
l->insert(l->begin(), new VariableValue(
&m_name,
new std::string(reinterpret_cast<char *>(key.mv_data),
key.mv_size),
new std::string(reinterpret_cast<char *>(data.mv_data),
data.mv_size)));
}
string2val(var, &key);
rc = mdb_cursor_get(cursor, &key, &data, MDB_SET_RANGE);
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@sobczak-m sobczak-m Mar 24, 2021 •
edited
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@ziollek replace MDB_SET_RANGE to MDB_SET_KEY
MDB_SET_RANGE - getting first key greater than or equal to specified key http://www.lmdb.tech/doc/group__mdb.html#ga1206b2af8b95e7f6b0ef6b28708c9127
If you are looking for none exist samplekey you get key containing samplekey like samplekey2 (if such key exist)
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@zimmerle zimmerle May 27, 2021

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Workable link for @sobczak-m comment's - http://www.lmdb.tech/doc/group__mdb.html#gga1206b2af8b95e7f6b0ef6b28708c9127af9feb0557c2954dbf7732eee5e1b59e7
if (rc == 0) {
do {
char *a = reinterpret_cast<char *>(key.mv_data);
if (strncmp(var.c_str(), a, keySize) == 0) {
l->insert(l->begin(), new VariableValue(
&m_name,
std::string(reinterpret_cast<char *>(key.mv_data),
key.mv_size),
std::string(reinterpret_cast<char *>(data.mv_data),
data.mv_size)));
} else {
break;
}
} while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0);
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@sobczak-m sobczak-m Apr 13, 2021

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replace MDB_NEXT to MDB_NEXT_DUB to iterate only over current key
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@zimmerle zimmerle May 27, 2021

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MDB_NEXT_DUP -
http://www.lmdb.tech/doc/group__mdb.html#gga1206b2af8b95e7f6b0ef6b28708c9127a37d22eecd320d77fbba9f905483f99e5
}
}

Expand Down Expand Up @@ -569,9 +576,9 @@ void LMDB::resolveRegularExpression(const std::string& var,
}

VariableValue *v = new VariableValue(
new std::string(reinterpret_cast<char *>(key.mv_data),
std::string(reinterpret_cast<char *>(key.mv_data),
key.mv_size),
new std::string(reinterpret_cast<char *>(data.mv_data),
std::string(reinterpret_cast<char *>(data.mv_data),
data.mv_size));
l->insert(l->begin(), v);
}
Expand Down