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LibDNS: Make DNS packet parsing fallible
Previously, a DNS packet containing an invalid name would be returned with an empty name. With this change, an error is returned if any error is encountered during parsing.
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parent
95d62822bf
commit
1793f51bc6
8 changed files with 29 additions and 40 deletions
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@ -21,15 +21,15 @@ Name::Name(DeprecatedString const& name)
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m_name = name;
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}
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Name Name::parse(ReadonlyBytes data, size_t& offset, size_t recursion_level)
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ErrorOr<Name> Name::parse(ReadonlyBytes data, size_t& offset, size_t recursion_level)
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{
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if (recursion_level > 4)
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return {};
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return Name {};
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StringBuilder builder;
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while (true) {
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if (offset >= data.size())
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return {};
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return Error::from_string_literal("Unexpected EOF when parsing name");
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u8 b = data[offset++];
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if (b == '\0') {
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// This terminates the name.
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@ -37,15 +37,15 @@ Name Name::parse(ReadonlyBytes data, size_t& offset, size_t recursion_level)
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} else if ((b & 0xc0) == 0xc0) {
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// The two bytes tell us the offset when to continue from.
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if (offset >= data.size())
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return {};
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return Error::from_string_literal("Unexpected EOF when parsing name");
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size_t dummy = (b & 0x3f) << 8 | data[offset++];
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auto rest_of_name = parse(data, dummy, recursion_level + 1);
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auto rest_of_name = TRY(parse(data, dummy, recursion_level + 1));
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builder.append(rest_of_name.as_string());
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return builder.to_deprecated_string();
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} else {
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// This is the length of a part.
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if (offset + b >= data.size())
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return {};
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return Error::from_string_literal("Unexpected EOF when parsing name");
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builder.append({ data.offset_pointer(offset), b });
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builder.append('.');
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offset += b;
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