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authorDavid Woodhouse <David.Woodhouse@intel.com>2015-07-20 23:16:29 +0300
committerDavid Howells <dhowells@redhat.com>2015-08-07 18:26:14 +0300
commit19e91b69d77bab16405cc284b451378e89a4110c (patch)
tree5f4d0904c0b1b98ef728bde634240ec4678fca22 /Documentation/module-signing.txt
parent6e3e281f39af78bd680b82d9762bf6c4f8f3f5f4 (diff)
downloadlinux-19e91b69d77bab16405cc284b451378e89a4110c.tar.xz
modsign: Allow external signing key to be specified
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> Signed-off-by: David Howells <dhowells@redhat.com>
Diffstat (limited to 'Documentation/module-signing.txt')
-rw-r--r--Documentation/module-signing.txt31
1 files changed, 26 insertions, 5 deletions
diff --git a/Documentation/module-signing.txt b/Documentation/module-signing.txt
index faaa6ea002f7..84597c7ea175 100644
--- a/Documentation/module-signing.txt
+++ b/Documentation/module-signing.txt
@@ -88,6 +88,22 @@ This has a number of options available:
than being a module) so that modules signed with that algorithm can have
their signatures checked without causing a dependency loop.
+ (4) "File name or PKCS#11 URI of module signing key" (CONFIG_MODULE_SIG_KEY)
+
+ Setting this option to something other than its default of
+ "signing_key.priv" will disable the autogeneration of signing keys and
+ allow the kernel modules to be signed with a key of your choosing.
+ The string provided should identify a file containing a private key
+ in PEM form, or — on systems where the OpenSSL ENGINE_pkcs11 is
+ appropriately installed — a PKCS#11 URI as defined by RFC7512.
+
+ If the PEM file containing the private key is encrypted, or if the
+ PKCS#11 token requries a PIN, this can be provided at build time by
+ means of the KBUILD_SIGN_PIN variable.
+
+ The corresponding X.509 certificate in DER form should still be placed
+ in a file named signing_key.x509 in the top-level build directory.
+
=======================
GENERATING SIGNING KEYS
@@ -100,8 +116,9 @@ it can be deleted or stored securely. The public key gets built into the
kernel so that it can be used to check the signatures as the modules are
loaded.
-Under normal conditions, the kernel build will automatically generate a new
-keypair using openssl if one does not exist in the files:
+Under normal conditions, when CONFIG_MODULE_SIG_KEY is unchanged from its
+default of "signing_key.priv", the kernel build will automatically generate
+a new keypair using openssl if one does not exist in the files:
signing_key.priv
signing_key.x509
@@ -135,8 +152,12 @@ kernel sources tree and the openssl command. The following is an example to
generate the public/private key files:
openssl req -new -nodes -utf8 -sha256 -days 36500 -batch -x509 \
- -config x509.genkey -outform DER -out signing_key.x509 \
- -keyout signing_key.priv
+ -config x509.genkey -outform PEM -out kernel_key.pem \
+ -keyout kernel_key.pem
+
+The full pathname for the resulting kernel_key.pem file can then be specified
+in the CONFIG_MODULE_SIG_KEY option, and the certificate and key therein will
+be used instead of an autogenerated keypair.
=========================
@@ -181,7 +202,7 @@ To manually sign a module, use the scripts/sign-file tool available in
the Linux kernel source tree. The script requires 4 arguments:
1. The hash algorithm (e.g., sha256)
- 2. The private key filename
+ 2. The private key filename or PKCS#11 URI
3. The public key filename
4. The kernel module to be signed