On Thu, 2019-04-18 at 00:51 -0300, Thiago Jung Bauermann wrote: > IMA will use the module_signature format for append signatures, so export > the relevant definitions and factor out the code which verifies that the > appended signature trailer is valid. > > Also, create a CONFIG_MODULE_SIG_FORMAT option so that IMA can select it > and be able to use mod_check_sig() without having to depend on either > CONFIG_MODULE_SIG or CONFIG_MODULES. > > Signed-off-by: Thiago Jung Bauermann <bauer...@linux.ibm.com> > Cc: Jessica Yu <j...@kernel.org>
Just a couple minor questions/comments below. Reviewed-by: Mimi Zohar <zo...@linux.ibm.com> > --- < snip > > diff --git a/init/Kconfig b/init/Kconfig > index 4592bf7997c0..a71019553ee1 100644 > --- a/init/Kconfig > +++ b/init/Kconfig > @@ -1906,7 +1906,7 @@ config MODULE_SRCVERSION_ALL > config MODULE_SIG > bool "Module signature verification" > depends on MODULES > - select SYSTEM_DATA_VERIFICATION > + select MODULE_SIG_FORMAT > help > Check modules for valid signatures upon load: the signature > is simply appended to the module. For more information see > @@ -2036,6 +2036,10 @@ config TRIM_UNUSED_KSYMS > > endif # MODULES > > +config MODULE_SIG_FORMAT > + def_bool n > + select SYSTEM_DATA_VERIFICATION Normally Kconfigs, in the same file, are defined before they are used. I'm not sure if that is required or just a convention. > config MODULES_TREE_LOOKUP > def_bool y > depends on PERF_EVENTS || TRACING > diff --git a/kernel/Makefile b/kernel/Makefile > index 6c57e78817da..d2f2488f80ab 100644 > --- a/kernel/Makefile > +++ b/kernel/Makefile > @@ -57,6 +57,7 @@ endif > obj-$(CONFIG_UID16) += uid16.o > obj-$(CONFIG_MODULES) += module.o > obj-$(CONFIG_MODULE_SIG) += module_signing.o > +obj-$(CONFIG_MODULE_SIG_FORMAT) += module_signature.o > obj-$(CONFIG_KALLSYMS) += kallsyms.o > obj-$(CONFIG_BSD_PROCESS_ACCT) += acct.o > obj-$(CONFIG_CRASH_CORE) += crash_core.o > diff --git a/kernel/module.c b/kernel/module.c > index 985caa467aef..326ddeb364dd 100644 > --- a/kernel/module.c > +++ b/kernel/module.c > @@ -19,6 +19,7 @@ > #include <linux/export.h> > #include <linux/extable.h> > #include <linux/moduleloader.h> > +#include <linux/module_signature.h> > #include <linux/trace_events.h> > #include <linux/init.h> > #include <linux/kallsyms.h> > diff --git a/kernel/module_signature.c b/kernel/module_signature.c > new file mode 100644 > index 000000000000..6d5e59f27f55 > --- /dev/null > +++ b/kernel/module_signature.c > @@ -0,0 +1,45 @@ > +// SPDX-License-Identifier: GPL-2.0+ > +/* > + * Module signature checker > + * > + * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. > + * Written by David Howells (dhowe...@redhat.com) > + */ > + > +#include <linux/errno.h> > +#include <linux/printk.h> > +#include <linux/module_signature.h> > +#include <asm/byteorder.h> > + > +/** > + * mod_check_sig - check that the given signature is sane > + * > + * @ms: Signature to check. > + * @file_len: Size of the file to which @ms is appended. "name" is missing. Mimi > + */
