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DHCPClient: Avoid unaligned access when parsing options

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Just casting a void* to a T* and dereferencing it is not particularly
safe. Also UBSAN was complaining. Use memcpy into a default constructed
T instead and require that the T be trivially copyable.
This commit is contained in:
Andrew Kaster 2021-05-24 08:00:59 -06:00 • committed by Andreas Kling
parent 723b8586ec
commit 1a0eed705c
1 changed files with 4 additions and 2 deletions
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6
Userland/Services/DHCPClient/DHCPv4.h
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@ -114,7 +114,7 @@ struct AK::Traits<DHCPOption> : public GenericTraits<DHCPOption> {
struct ParsedDHCPv4Options {
template<typename T>
Optional<const T> get(DHCPOption option_name) const
Optional<const T> get(DHCPOption option_name) const requires(IsTriviallyCopyable<T>)
{
auto option = options.get(option_name);
if (!option.has_value()) {
@ -123,7 +123,9 @@ struct ParsedDHCPv4Options {
auto& value = option.value();
if (value.length != sizeof(T))
return {};
return *(const T*)value.value;
T t;
__builtin_memcpy(&t, value.value, value.length);
return t;
}
template<typename T>