(UndefinedFunctionError) function :crypto.hmac/3 is undefined or private in OTP 24

Questions / Help
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1

Hello,

I have upgraded to OTP 24 and the application gives me below error.

2023-05-08T09:39:40.016516261Z ** (UndefinedFunctionError) function :crypto.hmac/3 is undefined or private
2023-05-08T09:39:40.016521861Z     (crypto 5.0.6.3) :crypto.hmac(:sha256, <<215, 151, 119, 26, 127, 8, 146, 85, 15, 210, 233, 150, 234, 49, 71, 114, 253, 119, 149, 8, 92, 166, 200, 71, 173, 68, 192, 10, 124, 239, 15, 252, 84, 185, 202, 48, 189, 229, 78, 102, 229, 58, 112, 117, 209, 144, 87, 238, 33, 56, ...>>, 'PUT\n\n\n40976\n\napplication/octet-stream\n\n\n\n\n\n\nx-ms-blob-type:BlockBlob\nx-ms-date:Mon, 08 May 2023 09:39:40 GMT\nx-ms-version:2014-02-14\n/test001/uploads/test/docs/test_create/6318/lfp.4d2bffda-5cd1-4d9a-b71a-8d7cd293c197.19f2a673-1f3a-4e06-9257-749b3c09a2b9.original.pdf')
2023-05-08T09:39:40.016528661Z     (erlazure 0.2) /app/deps/erlazure/src/erlazure.erl:756: :erlazure.get_shared_key/7
2023-05-08T09:39:40.016532861Z     (erlazure 0.2) /app/deps/erlazure/src/erlazure.erl:717: :erlazure.execute_request/2
2023-05-08T09:39:40.016537061Z     (erlazure 0.2) /app/deps/erlazure/src/erlazure.erl:530: :erlazure.handle_call/3
2023-05-08T09:39:40.016541161Z     (stdlib 3.17.2.2) gen_server.erl:721: :gen_server.try_handle_call/4
2023-05-08T09:39:40.016544962Z     (stdlib 3.17.2.2) gen_server.erl:750: :gen_server.handle_msg/6
2023-05-08T09:39:40.016548962Z     (stdlib 3.17.2.2) proc_lib.erl:226: :proc_lib.init_p_do_apply/3
2023-05-08T09:39:40.016567662Z Last message (from #PID<0.5946.0>): {:put_blob, 'uploads', 'test/docs/test_create/6318/lfp.4d2bffda-5cd1-4d9a-b71a-8d7cd293c197.19f2a673-1f3a-4e06-9257-749b3c09a2b9.original.pdf', :block_blob, <<37, 80, 68, 70, 45, 49, 46, 52, 10, 49, 32, 48, 32, 111, 98, 106, 10, 60, 60, 10, 47, 84, 105, 116, 108, 101, 32, 40, 254, 255, 0, 76, 0, 101, 0, 116, 0, 116, 0, 101, 0, 114, 0, 32, 0, ...>>, []}

Please help to resolve this issue.

2
1 Like
3

currently I am using :plug_crypto, “1.2.5”, but I feel the issue is with erlazure and the errors comes while uploading files into azure storage.

1 Like
4

A fix for this was merged a while back, but I’m not sure if it was packaged into a release:

2 Likes
5

Thank you for quick response, could you please guide me how can I check and confirm the same and the next step to proceed further.

6

I think you need to update plug crypto. from this it looks like you are using otp >24. OTP has updated hmac funtion.

7

I am using OTP 24, and plug_crypto : “1.2.5” i.e. the latest version.

8

Until a version of :erlazure is released with the fixes, you should be able to add git: "https://github.com/dkataskin/erlazure.git" to the :erlazure dependency in your mix.exs to use the code directly from there.

9

I tried with this change, but it doesn’t work and gives same errors.

10

I encountered the same error when upgrading and old project from OTP22/Elixir 1.9.4 to OTP24/Elixir 1.14.
If I read the documentation correctly the solution is to now use :crypto.mac functions, as the :crypto.hmac/3 is no longer present in OTP24.

https://www.erlang.org/docs/22/man/crypto.html#hmac-3

In my case I replaced my :crypto.hmac/3 call with :crypto.mac/3
https://www.erlang.org/docs/24/man/crypto.html#mac-3

11

Either that means:

  • the updated dependency hasn’t been installed. Make sure you’ve done mix deps.get after changing it. What does your mix.lock file show now?

  • or there’s another bug that wasn’t fixed by the changes to erlazure in the “fix crypto deprecations” PR

12

How I resolved this issue was as follow:

OTP 24 using i think openssl 3.0, hmac has been removed since we move to openssl 3.0.

To use an older Erlang version with ASDF, OpenSSL 1.1.1 is required, but it’s not available by default as OpenSSL 3.0 is used. If there are issues building Erlang 24 ,use the provided Linux script with the specified Elixir version with open ssl 1.1.1

        cd /usr/local/src/
        sudo git clone https://github.com/openssl/openssl.git -b OpenSSL_1_1_1-stable openssl-1.1.1m
        cd openssl-1.1.1m
        sudo ./config - prefix=/usr/local/ssl - openssldir=/usr/local/ssl shared zlib
        sudo make
        sudo make test
        sudo make install_sw
        export KERL_CONFIGURE_OPTIONS="-with-ssl=/usr/local/ssl"
        asdf install erlang 24``

If the issue persists, completely move to otp 25 and openssl 3.0 by default on all linux > 20.04

13

I don’t think this has something to do with openssl 3, it is just a deprecated interface that was removed from OTP-24. Actually if you compile OTP-24 or OTP-25 with openssl 3 you get a warning that it is not fully supported yet.