0b91a0e913
* change wc_linuxkm_pie_reloc_tab from unsigned int[] to struct wc_linuxkm_pie_reloc_tab_ent[], with dest_segment and reloc_type members; * add enum wc_reloc_dest_segment and enum wc_reloc_type; * update GENERATE_RELOC_TAB recipe in Makefile to render the dest segment and reloc type; * add struct reloc_layout_ent, and reloc_layouts[] fully populated for x86 and ARM relocations; * refactor find_reloc_tab_offset() and wc_linuxkm_normalize_relocations() to reflect the above; linuxkm/module_hooks.c: tweak various printf format characters and arguments for compatibility with ARM32; linuxkm/linuxkm_wc_port.h: include linux/inet.h and define wc_linuxkm_inet_pton() and XINET_PTON(), unless WOLFCRYPT_ONLY.
wolfSSL linuxkm (linux kernel module)
libwolfssl supports building as a linux kernel module (libwolfssl.ko).
When loaded, wolfCrypt and wolfSSL API are made available to the rest of
the kernel, supporting cryptography and TLS in kernel space.
Performing cryptographic operations in kernel space has significant advantages over user space for high throughput network (VPN, IPsec, MACsec, TLS, etc) and filesystem (dm-crypt/LUKS, fscrypt disk encryption) IO processing, with the added benefit that keys can be kept isolated to kernel space. Additionally, when wolfCrypt-FIPS is used, this provides a simple recipe for FIPS-compliant kernels.
Supported features:
- crypto acceleration: AES-NI, AVX, etc.
- kernel crypto API registration (wolfCrypt algs appear as drivers in
/proc/crypto.). CONFIG_CRYPTO_FIPS, and crypto-manager self-tests.- FIPS-compliant patches to
drivers/char/random.c, covering kernels 5.10 to 6.15. - Supports FIPS-compliant WireGuard (https://github.com/wolfssl/wolfguard).
- TLS 1.3 and DTLS 1.3 kernel offload.
Building and Installing
Build linuxkm with:
$ ./configure --enable-linuxkm --with-linux-source=/usr/src/linux
$ make -j module
note: replace /usr/src/linux with a path to your fully configured and built
target kernel source tree.
Assuming you are targeting your native system, install with:
$ sudo make install
$ sudo modprobe libwolfssl
options
| linuxkm option | description |
|---|---|
| --enable-linuxkm-lkcapi-register | Register wolfcrypt algs with linux kernel crypto API. Options are 'all', 'none', or comma separated list of algs. |
| --enable-linuxkm-pie | Enable relocatable object build of module |
| --enable-linuxkm-benchmarks | Run crypto benchmark at module load |
Kernel Patches
The dir linuxkm/patches contains a patch to the linux kernel CRNG. The
CRNG provides the implementation for /dev/random, /dev/urandom, and
getrandom().
The patch updates these two sources
drivers/char/random.cinclude/linux/random.h
to use FIPS-compliant algorithms, instead of chacha and blake2s.
Patches are provided for several kernel versions, ranging from 5.10.x to
6.15.
patch procedure
- Ensure kernel src tree is clean before patching:
cd ~/kernelsrc/
make mrproper
- Verify patches will apply clean with a dry run check:
patch -p1 --dry-run <~/wolfssl-5.8.2/linuxkm/patches/6.12/WOLFSSL_LINUXKM_HAVE_GET_RANDOM_CALLBACKS-6v12.patch
checking file drivers/char/random.c
checking file include/linux/random.h
- Finally patch the kernel:
patch -p1 <~/wolfssl-5.8.2/linuxkm/patches/6.12/WOLFSSL_LINUXKM_HAVE_GET_RANDOM_CALLBACKS-6v12.patch
patching file drivers/char/random.c
patching file include/linux/random.h
- Build kernel.