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authorBen Hutchings <ben@decadent.org.uk>2016-04-28 09:24:05 +0930
committerRusty Russell <rusty@rustcorp.com.au>2016-07-27 12:38:00 +0930
commitb8612e517c3c9809e1200b72c474dbfd969e5a83 (patch)
tree9cd8dfbfc47b74e99d85fc73e9e5f0a0b2fbd099
parentbca014caaa6130e57f69b5bf527967aa8ee70fdd (diff)
Documentation/module-signing.txt: Note need for version info if reusing a key
Signing a module should only make it trusted by the specific kernel it was built for, not anything else. If a module signing key is used for multiple ABI-incompatible kernels, the modules need to include enough version information to distinguish them. Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Cc: stable@vger.kernel.org Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
-rw-r--r--Documentation/module-signing.txt6
1 files changed, 6 insertions, 0 deletions
diff --git a/Documentation/module-signing.txt b/Documentation/module-signing.txt
index 696d5caf4fd8..f0e3361db20c 100644
--- a/Documentation/module-signing.txt
+++ b/Documentation/module-signing.txt
@@ -271,3 +271,9 @@ Since the private key is used to sign modules, viruses and malware could use
the private key to sign modules and compromise the operating system. The
private key must be either destroyed or moved to a secure location and not kept
in the root node of the kernel source tree.
+
+If you use the same private key to sign modules for multiple kernel
+configurations, you must ensure that the module version information is
+sufficient to prevent loading a module into a different kernel. Either
+set CONFIG_MODVERSIONS=y or ensure that each configuration has a different
+kernel release string by changing EXTRAVERSION or CONFIG_LOCALVERSION.