These changes fix two corner cases related to internal handling of types
in package rlp: The "tail" struct tag can only be applied to the last field.
The check for this was wrong and didn't allow for private fields after the
field with the tag. Unsupported types (e.g. structs containing int) which
implement either the Encoder or Decoder interface but not both
couldn't be encoded/decoded.
Also fixes#19367
The bug can cause crashes if Read is called after EOF has been returned.
No code performs such calls right now, but hitting the bug gets more
likely as rlp.EncodeToReader gets used in more places.
Decoding did not reject byte arrays of length one with a single element
b where 55 < b < 128. Such byte arrays must be rejected because
they must be encoded as the single byte b instead.
The list size checking overflowed if the size information
for a value was bigger than the list. This is resolved by
always performing the check before reading.
The rules have changed as follows:
* When decoding into pointers, empty values no longer produce
a nil pointer. This can be overriden for struct fields using the
struct tag "nil".
* When decoding into structs, the input list must contain an element
for each field.
All integers (including size information in type tags) need to be
encoded using the smallest possible encoding. This commit expands the
stricter validation introduced for *big.Int in commit 59597d23a5
to all integer types and size tags.
A single zero byte carries information and should not set the pointer
to nil. This is arguably a corner case. While here, fix the comment
to explain pointer reuse.
This is a preliminary fix for #420 (SEC-18 RLP decoder unsafe
allocation). If a sane input limit is set on the rlp.Stream,
it should no longer be possible to cause huge []byte allocations.
The encoder was missing a special case for one element strings whose
element is below 0x7f. Such strings must be encoded as a single byte
without a string header.
This needs to be supported because []someInterface does occur sometimes.
Funny enough, the fix involves changes to the decoder. makeDecoder
cannot return an error for non-empty interfaces anymore because the type
cache builds both decoder and writer. Do the check at 'runtime' instead.
I'm reasonably confident that the encoding matches the output of
ethutil.Encode for values that it supports. Some of the tests have been
adpated from the Ethereum testing repository.
There are still TODOs in the code.
