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When running a web server like Apache, it’s not uncommon to encounter SSL Library errors. One such error is the “SSL Library Error: error:0200100D:system library:fopen:Permission denied” error, which can occur when the web server cannot access a required SSL certificate file due to insufficient permissions.

This error can be particularly frustrating because it’s often unclear what’s causing it. However, you can take a few steps to troubleshoot and resolve the issue.

Step 1: Check File Ownership and Permissions

The first step is to verify that the ownership and permissions of the SSL certificate file are correct. In this case, the error message mentions explicitly the “certificate.key” file, so that’s the file we’ll focus on.

First, check the ownership of the file by running the following command:

ls -l /home/user/certs/certificate.key

This should output a line that looks something like this:

-rw-r----- 1 user user 1675 Mar 16 10:34 /home/user/certs/certificate.key

The key things to look for here are the username and group that owns the file (in this case, “user” in both cases) and the file permissions (in this case, “rw-r—–“).

If the ownership and permissions are correct, move on to the next step. If not, you must adjust them using the “chown” and “chmod” commands. For example, to change the ownership of the file to the “apache” user and group, you could run:

sudo chown apache:apache /home/user/certs/certificate.key

And to give the file read permissions for everyone, you could run:

sudo chmod a+r /home/user/certs/certificate.key

Step 2: Check SELinux Context

If the file ownership and permissions are correct, the next step is to check the SELinux context of the file. SELinux is a security module that’s often enabled on Linux systems, and it can prevent Apache (or other web servers) from accessing files that don’t have the proper context.

To check the SELinux context of the file, run the following command:

ls -Z /home/necs/user/certificate.key

This should output a line that looks something like this:

-rw-r-----. user user unconfined_u:object_r:httpd_config_t:s0 /home/user/certs/certificate.key

The critical part here is the “httpd_config_t” context, which tells SELinux that the Apache web server can access this file. If the context is incorrect or missing, you must adjust it using the “chcon” command. For example, to set the correct context for the “certificate.key” file, you could run:

sudo chcon system_u:object_r:httpd_config_t:s0 /home/user/certs/certificate.key

This will allow Apache to access the contents of the file that is located at that location. Another option that is not recommended, is to disable SELinux for your server entirely.

Step 3: Check AppArmor Profile

If you’re still getting the “Permission denied” error after verifying the file ownership, permissions, and SELinux context, the next step is to check the AppArmor profile for Apache. AppArmor is another security module often used on Ubuntu systems, and it can prevent Apache from accessing files outside its designated directories.

To verify that AppArmor is currently running, run the following command:

sudo aa-status

This is the output on an Ubuntu server:

apparmor module is loaded.
41 profiles are loaded.
41 profiles are in enforce mode.
   /snap/snapd/16292/usr/lib/snapd/snap-confine
   /snap/snapd/16292/usr/lib/snapd/snap-confine//mount-namespace-capture-helper
   /snap/snapd/17029/usr/lib/snapd/snap-confine
   /snap/snapd/17029/usr/lib/snapd/snap-confine//mount-namespace-capture-helper
   /snap/snapd/17336/usr/lib/snapd/snap-confine
   /snap/snapd/17336/usr/lib/snapd/snap-confine//mount-namespace-capture-helper
   /snap/snapd/17576/usr/lib/snapd/snap-confine
   /snap/snapd/17576/usr/lib/snapd/snap-confine//mount-namespace-capture-helper
   /snap/snapd/17883/usr/lib/snapd/snap-confine
   /snap/snapd/17883/usr/lib/snapd/snap-confine//mount-namespace-capture-helper
   /snap/snapd/17950/usr/lib/snapd/snap-confine
   /snap/snapd/17950/usr/lib/snapd/snap-confine//mount-namespace-capture-helper
   /snap/snapd/18357/usr/lib/snapd/snap-confine
   /snap/snapd/18357/usr/lib/snapd/snap-confine//mount-namespace-capture-helper
   /usr/bin/man
   /usr/lib/NetworkManager/nm-dhcp-client.action
   /usr/lib/NetworkManager/nm-dhcp-helper
   /usr/lib/connman/scripts/dhclient-script
   /usr/lib/snapd/snap-confine
   /usr/lib/snapd/snap-confine//mount-namespace-capture-helper
   /usr/sbin/tcpdump
   /{,usr/}sbin/dhclient
   docker-default
   lsb_release
   man_filter
   man_groff
   nvidia_modprobe
   nvidia_modprobe//kmod
   snap-update-ns.lxd
   snap.lxd.activate
   snap.lxd.benchmark
   snap.lxd.buginfo
   snap.lxd.check-kernel
   snap.lxd.daemon
   snap.lxd.hook.configure
   snap.lxd.hook.install
   snap.lxd.hook.remove
   snap.lxd.lxc
   snap.lxd.lxc-to-lxd
   snap.lxd.lxd
   snap.lxd.migrate
0 profiles are in complain mode.
64 processes have profiles defined.
64 processes are in enforce mode.

To check the AppArmor profile for Apache, run the following command:

sudo aa-status | grep httpd

This should output a line that looks something like this:

httpd

If the output shows that Apache is running with an AppArmor profile, you’ll need to check that profile to ensure it’s not blocking access to the SSL certificate file. To do this, open the AppArmor profile for editing with the following command:

sudo nano /etc/apparmor.d/usr.sbin.apache2

Then look for a section that starts with the following line:

# Allow access to SSL certificate and key files

This section should include lines that look something like this:

/home/user/certs/* r,
/home/user/certs/** rwk,

If these lines are missing or incorrect, you must add or modify them accordingly. Once you’ve made the necessary changes, save the file and restart Apache with the following command:

sudo systemctl restart apache2

Step 4: Check Filesystem Permissions

If none of the above steps have resolved the issue, there may be a problem with the filesystem. This could be due to various issues, such as a corrupt filesystem or a problem with the underlying storage device.

You can use the “fsck” command to check for filesystem errors. For example, to check the filesystem on the root partition, you could run:

sudo fsck /dev/sda1

If any errors are found, the “fsck” command will attempt to fix them automatically. However, if the errors are severe, you may need to repair the filesystem manually or restore from backup.

Conclusion

In summary, the “SSL Library Error: error:0200100D:system library:fopen:Permission denied” error in Apache can be caused by various issues related to file permissions, SELinux context, AppArmor profile, or filesystem errors. By following the troubleshooting steps outlined in this article, you should be able to identify and resolve the underlying issue, and get your web server up and running again. These four steps are the most common ones that I have found to resolve this sort of error. Good luck.

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