From: Coiby Xu <coxu@redhat.com>
To: kexec@lists.infradead.org
Cc: "Ondrej Kozina" <okozina@redhat.com>,
"Milan Broz" <gmazyland@gmail.com>,
"Thomas Staudt" <tstaudt@de.ibm.com>,
"Daniel P . Berrangé" <berrange@redhat.com>,
"Kairui Song" <ryncsn@gmail.com>,
dm-devel@redhat.com, "Jan Pazdziora" <jpazdziora@redhat.com>,
"Pingfan Liu" <kernelfans@gmail.com>,
"Baoquan He" <bhe@redhat.com>, "Dave Young" <dyoung@redhat.com>,
linux-kernel@vger.kernel.org, x86@kernel.org,
"Dave Hansen" <dave.hansen@intel.com>,
"Vitaly Kuznetsov" <vkuznets@redhat.com>,
"Eric Biederman" <ebiederm@xmission.com>
Subject: [PATCH v3 1/7] kexec_file: allow to place kexec_buf randomly
Date: Thu, 25 Apr 2024 18:04:25 +0800 [thread overview]
Message-ID: <20240425100434.198925-2-coxu@redhat.com> (raw)
In-Reply-To: <20240425100434.198925-1-coxu@redhat.com>
Currently, kexec_buf is placed in order which means for the same
machine, the info in the kexec_buf is always located at the same
position each time the machine is booted. This may cause a risk for
sensitive information like LUKS volume key. Now struct kexec_buf has a
new field random which indicates it's supposed to be placed in a random
position.
Suggested-by: Jan Pazdziora <jpazdziora@redhat.com>
Signed-off-by: Coiby Xu <coxu@redhat.com>
---
include/linux/kexec.h | 2 ++
kernel/kexec_file.c | 15 +++++++++++++++
2 files changed, 17 insertions(+)
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 060835bb82d5..fc1e20d565d5 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -171,6 +171,7 @@ int kexec_image_post_load_cleanup_default(struct kimage *image);
* @buf_min: The buffer can't be placed below this address.
* @buf_max: The buffer can't be placed above this address.
* @top_down: Allocate from top of memory.
+ * @random: Place the buffer at a random position.
*/
struct kexec_buf {
struct kimage *image;
@@ -182,6 +183,7 @@ struct kexec_buf {
unsigned long buf_min;
unsigned long buf_max;
bool top_down;
+ bool random;
};
int kexec_load_purgatory(struct kimage *image, struct kexec_buf *kbuf);
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 2d1db05fbf04..e0630fe30d43 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -25,6 +25,7 @@
#include <linux/elfcore.h>
#include <linux/kernel.h>
#include <linux/kernel_read_file.h>
+#include <linux/prandom.h>
#include <linux/syscalls.h>
#include <linux/vmalloc.h>
#include "kexec_internal.h"
@@ -432,6 +433,16 @@ SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd,
return ret;
}
+static unsigned long kexec_random_start(unsigned long start, unsigned long end)
+{
+ unsigned long temp_start;
+ unsigned short i;
+
+ get_random_bytes(&i, sizeof(unsigned short));
+ temp_start = start + (end - start) / USHRT_MAX * i;
+ return temp_start;
+}
+
static int locate_mem_hole_top_down(unsigned long start, unsigned long end,
struct kexec_buf *kbuf)
{
@@ -440,6 +451,8 @@ static int locate_mem_hole_top_down(unsigned long start, unsigned long end,
temp_end = min(end, kbuf->buf_max);
temp_start = temp_end - kbuf->memsz + 1;
+ if (kbuf->random)
+ temp_start = kexec_random_start(temp_start, temp_end);
do {
/* align down start */
@@ -477,6 +490,8 @@ static int locate_mem_hole_bottom_up(unsigned long start, unsigned long end,
unsigned long temp_start, temp_end;
temp_start = max(start, kbuf->buf_min);
+ if (kbuf->random)
+ temp_start = kexec_random_start(temp_start, end);
do {
temp_start = ALIGN(temp_start, kbuf->buf_align);
--
2.44.0
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
next prev parent reply other threads:[~2024-04-25 10:04 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-25 10:04 [PATCH v3 0/7] Support kdump with LUKS encryption by reusing LUKS volume keys Coiby Xu
2024-04-25 10:04 ` Coiby Xu [this message]
2024-05-20 6:16 ` [PATCH v3 1/7] kexec_file: allow to place kexec_buf randomly Baoquan He
2024-05-21 1:58 ` Coiby Xu
2024-05-21 3:13 ` Baoquan He
2024-05-24 7:22 ` Coiby Xu
2024-04-25 10:04 ` [PATCH v3 2/7] crash_dump: make dm crypt keys persist for the kdump kernel Coiby Xu
2024-04-26 13:10 ` kernel test robot
2024-05-21 3:20 ` Baoquan He
2024-05-23 5:34 ` Coiby Xu
2024-04-25 10:04 ` [PATCH v3 3/7] crash_dump: store dm keys in kdump reserved memory Coiby Xu
2024-04-25 10:04 ` [PATCH v3 4/7] crash_dump: reuse saved dm crypt keys for CPU/memory hot-plugging Coiby Xu
2024-05-21 3:48 ` Baoquan He
2024-05-24 7:40 ` Coiby Xu
2024-04-25 10:04 ` [PATCH v3 5/7] crash_dump: retrieve dm crypt keys in kdump kernel Coiby Xu
2024-04-25 10:04 ` [PATCH v3 6/7] x86/crash: pass dm crypt keys to " Coiby Xu
2024-04-25 10:04 ` [PATCH v3 7/7] x86/crash: make the page that stores the dm crypt keys inaccessible Coiby Xu
2024-05-20 6:18 ` [PATCH v3 0/7] Support kdump with LUKS encryption by reusing LUKS volume keys Baoquan He
2024-05-21 1:43 ` Coiby Xu
2024-05-21 3:19 ` Baoquan He
2024-05-30 9:33 ` Dave Young
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20240425100434.198925-2-coxu@redhat.com \
--to=coxu@redhat.com \
--cc=berrange@redhat.com \
--cc=bhe@redhat.com \
--cc=dave.hansen@intel.com \
--cc=dm-devel@redhat.com \
--cc=dyoung@redhat.com \
--cc=ebiederm@xmission.com \
--cc=gmazyland@gmail.com \
--cc=jpazdziora@redhat.com \
--cc=kernelfans@gmail.com \
--cc=kexec@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=okozina@redhat.com \
--cc=ryncsn@gmail.com \
--cc=tstaudt@de.ibm.com \
--cc=vkuznets@redhat.com \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).