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    SubjectRe: [PATCH v3 2/7] kexec: add call to LSM hook in original kexec_load syscall
    Mimi Zohar <zohar@linux.vnet.ibm.com> writes:

    > In order for LSMs and IMA-appraisal to differentiate between the
    > original and new syscalls, both the original and new syscalls must call
    > an LSM hook. This patch adds a call to security_kernel_read_data() in
    > the original kexec syscall.

    Until the lsm hook mess gets cleaned up.

    Nacked-by: "Eric W. Biederman" <ebiederm@xmission.com>

    >
    > Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
    > Cc: Eric Biederman <ebiederm@xmission.com>
    > Cc: Luis R. Rodriguez <mcgrof@kernel.org>
    > Cc: Kees Cook <keescook@chromium.org>
    > Cc: David Howells <dhowells@redhat.com>
    > ---
    > kernel/kexec.c | 8 ++++++++
    > 1 file changed, 8 insertions(+)
    >
    > diff --git a/kernel/kexec.c b/kernel/kexec.c
    > index aed8fb2564b3..061ada41c18c 100644
    > --- a/kernel/kexec.c
    > +++ b/kernel/kexec.c
    > @@ -11,6 +11,7 @@
    > #include <linux/capability.h>
    > #include <linux/mm.h>
    > #include <linux/file.h>
    > +#include <linux/security.h>
    > #include <linux/kexec.h>
    > #include <linux/mutex.h>
    > #include <linux/list.h>
    > @@ -195,10 +196,17 @@ static int do_kexec_load(unsigned long entry, unsigned long nr_segments,
    > static inline int kexec_load_check(unsigned long nr_segments,
    > unsigned long flags)
    > {
    > + int result;
    > +
    > /* We only trust the superuser with rebooting the system. */
    > if (!capable(CAP_SYS_BOOT) || kexec_load_disabled)
    > return -EPERM;
    >
    > + /* Permit LSMs and IMA to fail the kexec */
    > + result = security_kernel_read_data(NULL, READING_KEXEC_IMAGE);
    > + if (result < 0)
    > + return result;
    > +
    > /*
    > * Verify we have a legal set of flags
    > * This leaves us room for future extensions.

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