Why am I getting "error:1409F07F:SSL routines:SSL3_WRITE_PENDING: bad write retry" error while attempting an SSL_write?

Question

Am I getting the following error when attempting an SSL_write:

error:1409F07F:SSL routines:SSL3_WRITE_PENDING: bad write retry

Slaw

Hey you can separate you question from your answer, so you can accept your own answer if you think it's correct. Thanks for your tip – Bebel

Thanx for the idea, I did as you suggested, 10x! – Slaw

Answer 1

The reason is pretty simple: when SSL_Write returns with SSL_ERROR_WANT_WRITE or SSL_ERROR_WANT_READ, you have to repeat the call to SSL_write with the EXACT same parameters again, after the condition is satisfied (read/write available on the socket).

Calling it with different parameters, will yield the 1409F07F bad write retry error.

For example, when SSL_write(ssl, ptr, size) with ptr = 0xABCDEFGH, size = 4096 fails with SSL_ERROR_WANT_READ or SSL_ERROR_WANT_WRITE, when retrying the SSL_write call, the parameters ptr and size should be same. It is not equivalent if ptr is another pointer pointing to a copy of the same contents as in the original call.

However this default behavior of SSL_write can be changed by setting SSL_MODE_ENABLE_PARTIAL_WRITE and/or SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER.

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Thanks for @ShriramV for the clarifying comments, integrated to the answer

Slaw

Can you please ellbaorate 10x – Misnomer

@dragonsupercool For instance if you first SSL_write with target buffer X offset Y and size Z, you must re-call with the same values for all parameters, as the write operation will attempt to resume from where it left off (or something like that, this is where my knowledge ends ;p) – Slaw

@Amit -- this makes no sense. Are you saying that if you call SSL_write with 500 bytes of data and it returns 100 (saying it sent only 100 bytes), with an error code of SSL_ERROR_WANT_READ, you have to re-call it with the already sent 100 bytes as well as the remaining 400 bytes? – Jori

@ChrisDodd as odd as this sounds, yes. otherwise you will be getting the aforementioned error. You are welcome to test this and post your findings. – Slaw

While retrying SSL_write, the parameters should be exactly be same - literally. For example when SSL_write(ssl, ptr, size) with ptr = 0xABCDEFGH, size = 4096 fails with SSL_ERROR_WANT_READ or SSL_ERROR_WANT_WRITE, when retrying the SSL_write call, the parameters ptr and size should be same. It is not equivalent if ptr is another pointer pointing to a copy of the same contents as in the original call. However this default behavior of SSL_write can be changed by setting SSL_MODE_ENABLE_PARTIAL_WRITE and/or SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER. – Cenozoic

I got the same error of :SSL routines:SSL3_WRITE_PENDING: bad write retry. I try to send out push notification to around 15k users. I noticed that it will break around every multiple of hundreds, but before that error pops up the error of SSL: Broken pipe will show up first. I solved the problem whenever broken pipe error shows up via reconnecting the connection again. Then continue sending. It works. Just keep doing this until you send too all users. – Banda

in my case I need to initialisation again SSL connection, so it might be on every method call you will need to setup SSL connection in laravel in my case – Philemon

@ShriramV - Upvoted. Your comment about those two flags should really be part of the answer. – Expressway