Compiling Linux Kernel fails looking at OpenSSL header files

Description

While compiling the Linux kernel, some error described below are met with the scripts/sign-file or scripts/extract-cert host compilation steps.

Additional information

Here are the build logs that are displayed when error occurs:

  HOSTCC  scripts/asn1_compiler
  HOSTCC  scripts/extract-cert
In file included from /usr/include/openssl/e_os2.h:13,
                 from /usr/include/openssl/bio.h:13,
                 from ../scripts/extract-cert.c:21:
/usr/include/x86_64-linux-gnu/openssl/opensslconf.h:13:10: fatal error: openssl/opensslv.h: Aucun fichier ou dossier de ce type
   13 | #include <openssl/opensslv.h>
      |          ^~~~~~~~~~~~~~~~~~~~
compilation terminated.
make[2]: *** [scripts/Makefile.host:107 : scripts/extract-cert] Erreur 1
make[1]: *** [/data/linux-at91/Makefile:1120 : scripts] Erreur 2
make: *** [../Makefile:179 : sub-make] Erreur 2

  HOSTCC  scripts/extract-cert
../scripts/extract-cert.c:21:10: fatal error: openssl/bio.h: Aucun fichier ou dossier de ce type
   21 | #include <openssl/bio.h>
      |          ^~~~~~~~~~~~~~~
compilation terminated.
make[2]: *** [scripts/Makefile.host:107 : scripts/extract-cert] Erreur 1
make[1]: *** [/data/linux-at91/Makefile:1120 : scripts] Erreur 2
make: *** [../Makefile:179 : sub-make] Erreur 2

This is due to missing OpenSSL development package which needs to be installed in on your host machine. These requirements are mentioned in a dedicated Kernel documentation page: Minimal requirements to compile the Kernel.

Solution

Depending on your host machine distribution, you should install libssl-dev or equivalent package with following commands:

For Ubuntu up to version 18.04:

$ sudo apt install libssl1.0-dev

For Ubuntu version 20.04 onward:

$ sudo apt install libssl-dev

For CentOS or old Fedora:

 sudo yum install openssl-devel

For modern Fedora:

 sudo dnf install openssl-devel

These commands will require root privileges or being in a correct sudoers group.