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LibIMAP: Make parsing of atom data fallible

We now return an error where `parse_atom()` would have previously
returned an empty StringView. This is consistent with RFC3501, which
says that an atom consists of one or more characters.

This prevents a few cases where parsing an invalid atom could lead to
an infinite loop.
This commit is contained in:
Tim Ledbetter 2023-11-07 13:34:12 +00:00 committed by Andreas Kling
parent b96a5f4265
commit 4b995542c4
2 changed files with 11 additions and 9 deletions

View File

@ -147,7 +147,7 @@ ErrorOr<void> Parser::parse_untagged()
auto number = try_parse_number();
if (number.has_value()) {
TRY(consume(" "sv));
auto data_type = parse_atom();
auto data_type = TRY(parse_atom());
if (data_type == "EXISTS"sv) {
m_response.data().set_exists(number.value());
TRY(consume("\r\n"sv));
@ -180,7 +180,7 @@ ErrorOr<void> Parser::parse_untagged()
} else if (consume_if("OK"sv)) {
TRY(consume(" "sv));
if (consume_if("["sv)) {
auto actual_type = parse_atom();
auto actual_type = TRY(parse_atom());
if (actual_type == "CLOSED"sv) {
// No-op.
} else if (actual_type == "UIDNEXT"sv) {
@ -230,7 +230,7 @@ ErrorOr<void> Parser::parse_untagged()
auto status_item = StatusItem();
status_item.set_mailbox(mailbox);
while (!consume_if(")"sv)) {
auto status_att = parse_atom();
auto status_att = TRY(parse_atom());
TRY(consume(" "sv));
auto value = TRY(parse_number());
@ -582,14 +582,13 @@ ErrorOr<void> Parser::parse_capability_response()
auto capability = AK::Vector<DeprecatedString>();
while (!consume_if("\r\n"sv)) {
TRY(consume(" "sv));
auto x = DeprecatedString(parse_atom());
capability.append(x);
capability.append(TRY(parse_atom()));
}
m_response.data().add_capabilities(move(capability));
return {};
}
StringView Parser::parse_atom()
ErrorOr<StringView> Parser::parse_atom()
{
dbgln_if(IMAP_PARSER_DEBUG, "p: {}, parse_atom()", m_position);
auto is_non_atom_char = [](u8 x) {
@ -604,6 +603,9 @@ StringView Parser::parse_atom()
m_position++;
}
if (count == 0)
return Error::from_string_literal("Invalid atom value");
StringView s = StringView(m_buffer.data() + start, count);
dbgln_if(IMAP_PARSER_DEBUG, "p: {}, ret \"{}\"", m_position, s);
return s;
@ -611,7 +613,7 @@ StringView Parser::parse_atom()
ErrorOr<ResponseStatus> Parser::parse_status()
{
auto atom = parse_atom();
auto atom = TRY(parse_atom());
if (atom == "OK"sv) {
return ResponseStatus::OK;
@ -733,7 +735,7 @@ ErrorOr<FetchCommand::DataItem> Parser::parse_fetch_data_item()
data_item.section->parts->append(num.value());
continue;
}
auto atom = parse_atom();
auto atom = TRY(parse_atom());
if (atom.equals_ignoring_ascii_case("MIME"sv)) {
data_item.section->ends_with_mime = true;
continue;

View File

@ -41,7 +41,7 @@ private:
ErrorOr<void> parse_untagged();
ErrorOr<void> parse_capability_response();
StringView parse_atom();
ErrorOr<StringView> parse_atom();
ErrorOr<StringView> parse_quoted_string();
ErrorOr<StringView> parse_literal_string();
ErrorOr<StringView> parse_string();