Error using parse_key! on key string

[joshbode]

I am getting an error using parse_key! on a string containing a key.

ERROR: MethodError: no method matching unsafe_convert(::Type{Ptr{Void}}, ::String)
...

The existing function is converting the key input to a String, but it looks like the C function needs an array of UInt8 which I've shown in my example below.

I am using Julia 0.5 and the latest version of MbedTLS.jl

Example

key = """\
-----BEGIN PRIVATE KEY-----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-----END PRIVATE KEY-----"""

Not Working

This doesn't work:

import MbedTLS
ctx = MbedTLS.PKContext()
MbedTLS.parse_key!(ctx, key)

with the error:

ERROR: MethodError: no method matching unsafe_convert(::Type{Ptr{Void}}, ::String)
Closest candidates are:
  unsafe_convert(::Type{Ptr{UInt8}}, ::String) at pointer.jl:27
  unsafe_convert(::Type{Ptr{Int8}}, ::String) at pointer.jl:28
  unsafe_convert{T}(::Type{Ptr{Void}}, ::Base.RefValue{T}) at refpointer.jl:49
  ...
 in macro expansion at /Users/josh/.julia/v0.5/MbedTLS/src/error.jl:3 [inlined]
 in parse_key!(::MbedTLS.PKContext, ::Array{UInt8,1}, ::Nullable{Union{}}) at /Users/josh/.julia/v0.5/MbedTLS/src/pk.jl:46
 in parse_key!(::MbedTLS.PKContext, ::Array{UInt8,1}) at /Users/josh/.julia/v0.5/MbedTLS/src/pk.jl:38

Working

This does work if I make these changes in pk.jl:

function parse_key!(ctx::PKContext, key, maybe_pw::Nullable = Nullable())
    key_bs = convert(Vector{UInt8}, key)  # was String(key)
    if isnull(maybe_pw)
        pw = C_NULL
        pw_size = 0
    else
        pw = convert(Vector{UInt8}, get(maybe_pw))  # was String(get(maybe_pw))
        pw_size = sizeof(pw)  # Might be off-by-one
    end
    @err_check ccall((:mbedtls_pk_parse_key, MBED_TLS), Cint,
        (Ptr{Void}, Ptr{Void}, Csize_t, Ptr{Void}, Csize_t),
        ctx.data, key_bs, sizeof(key_bs)+1, pw, pw_size)
end

[joshbode]

This works, too, by changing Ptr{Void} to Ptr{Cuchar} which may make more sense:

function parse_key!(ctx::PKContext, key, maybe_pw::Nullable = Nullable())
    key_bs = String(key)
    if isnull(maybe_pw)
        pw = C_NULL
        pw_size = 0
    else
        pw = String(get(maybe_pw))
        pw_size = sizeof(pw)  # Might be off-by-one
    end
    @err_check ccall((:mbedtls_pk_parse_key, MBED_TLS), Cint,
        (Ptr{Void}, Ptr{Cuchar}, Csize_t, Ptr{Cuchar}, Csize_t),
        ctx.data, key_bs, sizeof(key_bs)+1, pw, pw_size)
end

[malmaud]

Fixed in #72