[PATCH v3 2/7] kexec: add call to LSM hook in original kexec_load syscall
From: Eric W. Biederman <hidden>
Date: 2018-05-24 20:50:17
Also in:
kexec, linux-integrity, lkml
Mimi Zohar [off-list ref] 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" [off-list ref]
quoted hunk
Signed-off-by: Mimi Zohar <redacted> Cc: Eric Biederman <redacted> Cc: Luis R. Rodriguez <mcgrof@kernel.org> Cc: Kees Cook <redacted> 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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