diff mbox

[v3,2/7] kexec: add call to LSM hook in original kexec_load syscall

Message ID 1527160176-29269-3-git-send-email-zohar@linux.vnet.ibm.com (mailing list archive)
State New, archived
Headers show

Commit Message

Mimi Zohar May 24, 2018, 11:09 a.m. UTC
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.

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(+)

Comments

Eric W. Biederman May 24, 2018, 8:50 p.m. UTC | #1
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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diff mbox

Patch

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.