CODEWITHSUNDEEP
pythonpipesubprocess
demonguy
demonguy

Reputation: 2017

Python Subprocess, how can I pass raw hex data to command line?

I have a command cat hash.bin | openssl pkeyutl -sign -inkey privk.pem which can get result correctly.

Now I want to do it with python subprocess, I do it like this (where hash is read from hash.bin)

cmd = ['openssl', 'pkeyutl', '-sign', '-inkey ', prvk]
p = Popen(cmd, stdin=PIPE, stdout=PIPE, stderr=STDOUT)
out = p.communicate(input=hash)[0]
print(out)

But openssl failed.

I can't use -in and -out because my code can't access to hard drive..

Upvotes: 0

Views: 628

Answers (1)

mhawke
mhawke

Reputation: 87084

The problem is caused by the stray space character following the inkey command.

Try removing the space and it should work:

cmd = ['openssl', 'pkeyutl', '-sign', '-inkey', prvk]

The reason is that Popen() is passing through the space character as part of the -inkey option's token. openssl is deciding that there is not an option named -inkey (with a space), so it exits. It is as if you were executing this from the command line:

cat hash.bin | openssl pkeyutl -sign '-inkey ' privk.pem

which fails.

Upvotes: 1

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