Why openssl ignore -days for expiration date for self signed certificate?

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I have a bash script that generates a self-signed certificate and works perfectly fine:

#! /bin/bash

# Generate self signed root CA cert
openssl req -nodes -x509 -days 358000 -newkey rsa:2048 -keyout ca.key -out ca.crt -subj "/C=IR/ST=TEH/L=Torento/O=CTO/OU=root/CN=es.example.com/emailAddress=info@example.com"

# Generate server cert to be signed
openssl req -nodes -newkey rsa:2048 -days 358000 -keyout server.key -out server.csr -subj "/C=IR/ST=TEH/L=Torento/O=CTO/OU=server/CN=es.example.com/emailAddress=info@example.com"

# Sign the server cert
openssl x509 -req -in server.csr -CA ca.crt -CAkey ca.key -CAcreateserial -out server.crt

# Create server PEM file
cat server.key server.crt > server.pem


# Generate client cert to be signed
openssl req -nodes -newkey rsa:2048 -days 358000 -keyout client.key -out client.csr -subj "/C=IR/ST=TEH/L=Torento/O=CTO/OU=client/CN=es.example.com/emailAddress=info@example.com"

# Sign the client cert
openssl x509 -req -in client.csr -CA ca.crt -CAkey ca.key -CAserial ca.srl -out client.crt

# Create client PEM file
cat client.key client.crt > client.pem

When I check the expiration time of the generated client.pem, it shows expiration time at 10th of Aug.:

$ openssl x509 -enddate -noout -in client.pem
notAfter=Aug 10 12:32:07 2018 GMT

What is the problem with expiration date?

Answer

The validity is set with openssl x509 and not with openssl req.
It you put the -days option with x509 command, it will work.

You get the 30/08 because there isn’t a -days option that override the default certificate validity of 30 days, as mentioned in x509 the man page:

-days arg
specifies the number of days to make a certificate valid for. The default is 30 days.

Side note, generating certificate with 358000 days (980 years!) validity is too long if you want reasonable security.

Attribution
Source : Link , Question Author : Alireza , Answer Author : oliv

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