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ConfigParser: fix use-out-of-scope leaks #1661

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merged 2 commits into from
May 10, 2024
Merged

ConfigParser: fix use-out-of-scope leaks #1661

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06e8f09
ConfigParser: fix use-out-of-scope leaks
evan-goode May 7, 2024
aed770e
Add tests for shell-style variable expansion
evan-goode May 7, 2024
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48 changes: 32 additions & 16 deletions libdnf/conf/ConfigParser.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -95,25 +95,32 @@ std::pair<std::string, size_t> ConfigParser::substitute_expression(const std::st
const auto & variable_key = res.substr(pos_variable, pos_after_variable - pos_variable);
const auto variable_mapping = substitutions.find(variable_key);

const std::string * variable_value = nullptr;
// No std::optional here.
bool variable_value_has_value{false};
std::string variable_value{""};

if (variable_mapping == substitutions.end()) {
if (variable_key == "releasever_major" || variable_key == "releasever_minor") {
const auto releasever_mapping = substitutions.find("releasever");
if (releasever_mapping != substitutions.end()) {
const auto & releasever_split = ConfigParser::split_releasever(releasever_mapping->second);
if (variable_key == "releasever_major") {
variable_value = &std::get<0>(releasever_split);
variable_value = std::get<0>(releasever_split);
variable_value_has_value = true;
} else {
variable_value = &std::get<1>(releasever_split);
variable_value = std::get<1>(releasever_split);
variable_value_has_value = true;
}
}
}
} else {
variable_value = &variable_mapping->second;
variable_value = variable_mapping->second;
variable_value_has_value = true;
}

const std::string * subst_str = nullptr;
// No std::optional here
std::string subst_str{""};
bool subst_str_has_value{false};

size_t pos_after_variable_expression;

Expand Down Expand Up @@ -153,20 +160,23 @@ std::pair<std::string, size_t> ConfigParser::substitute_expression(const std::st
// If variable is unset or empty, the expansion of word is
// substituted. Otherwise, the value of variable is
// substituted.
if (variable_value == nullptr || variable_value->empty()) {
subst_str = &expanded_word;
if (!variable_value_has_value || variable_value.empty()) {
subst_str = expanded_word;
subst_str_has_value = true;
} else {
subst_str = variable_value;
subst_str_has_value = true;
}
} else if (expansion_mode == '+') {
// ${variable:+word} (alternate value)
// If variable is unset or empty nothing is substituted.
// Otherwise, the expansion of word is substituted.
if (variable_value == nullptr || variable_value->empty()) {
const std::string empty{};
subst_str = &empty;
if (!variable_value_has_value || variable_value.empty()) {
subst_str = "";
subst_str_has_value = true;
} else {
subst_str = &expanded_word;
subst_str = expanded_word;
subst_str_has_value = true;
}
} else {
// Unknown expansion mode, continue after the ':'
Expand All @@ -176,7 +186,10 @@ std::pair<std::string, size_t> ConfigParser::substitute_expression(const std::st
pos_after_variable_expression = pos_after_word + 1;
} else if (res[pos_after_variable] == '}') {
// ${variable}
subst_str = variable_value;
if (variable_value_has_value) {
subst_str = variable_value;
subst_str_has_value = true;
}
// Move past the closing '}'
pos_after_variable_expression = pos_after_variable + 1;
} else {
Expand All @@ -186,20 +199,23 @@ std::pair<std::string, size_t> ConfigParser::substitute_expression(const std::st
}
} else {
// No braces, we have a $variable
subst_str = variable_value;
if (variable_value_has_value) {
subst_str = variable_value;
subst_str_has_value = true;
}
pos_after_variable_expression = pos_after_variable;
}

// If there is no substitution to make, move past the variable expression and continue.
if (subst_str == nullptr) {
if (!subst_str_has_value) {
total_scanned += pos_after_variable_expression - pos;
pos = pos_after_variable_expression;
continue;
}

res.replace(pos, pos_after_variable_expression - pos, *subst_str);
res.replace(pos, pos_after_variable_expression - pos, subst_str);
total_scanned += pos_after_variable_expression - pos;
pos += subst_str->length();
pos += subst_str.length();
} else {
total_scanned += 1;
pos += 1;
Expand Down
17 changes: 17 additions & 0 deletions tests/libdnf/conf/ConfigParserTest.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -30,4 +30,21 @@ void ConfigParserTest::testConfigParserReleasever()
libdnf::ConfigParser::substitute(text, substitutions);
CPPUNIT_ASSERT(text == "major: , minor: ");
}
{
std::map<std::string, std::string> substitutions = {
{"var1", "value123"},
{"var2", "456"},
};
std::string text = "foo$var1-bar";
libdnf::ConfigParser::substitute(text, substitutions);
CPPUNIT_ASSERT(text == "foovalue123-bar");

text = "${var1:+alternate}-${unset:-default}-${nn:+n${nn:-${nnn:}";
libdnf::ConfigParser::substitute(text, substitutions);
CPPUNIT_ASSERT(text == "alternate-default-${nn:+n${nn:-${nnn:}");

text = "${unset:-${var1:+${var2:+$var2}}}";
libdnf::ConfigParser::substitute(text, substitutions);
CPPUNIT_ASSERT(text == "456");
}
}
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