|
 |
12e206 |
From 65550e3682fd27304c905e4627c3cd9f5840c260 Mon Sep 17 00:00:00 2001
|
|
|
12e206 |
From: Bandan Das <bsd@redhat.com>
|
|
|
12e206 |
Date: Thu, 26 Oct 2017 10:03:48 +0200
|
|
|
12e206 |
Subject: [PATCH] multiboot: validate multiboot header address values
|
|
|
12e206 |
|
|
|
12e206 |
RH-Author: Bandan Das <bsd@redhat.com>
|
|
|
12e206 |
Message-id: <jpgefpqw7i3.fsf@linux.bootlegged.copy>
|
|
|
12e206 |
Patchwork-id: 77443
|
|
|
12e206 |
O-Subject: [RHEL-7.5 qemu-kvm PATCH] multiboot: validate multiboot header address values
|
|
|
12e206 |
Bugzilla: 1501120
|
|
|
12e206 |
RH-Acked-by: Thomas Huth <thuth@redhat.com>
|
|
|
12e206 |
RH-Acked-by: Laurent Vivier <lvivier@redhat.com>
|
|
|
12e206 |
RH-Acked-by: Peter Xu <peterx@redhat.com>
|
|
|
12e206 |
|
|
|
12e206 |
While loading kernel via multiboot-v1 image, (flags & 0x00010000)
|
|
|
12e206 |
indicates that multiboot header contains valid addresses to load
|
|
|
12e206 |
the kernel image. These addresses are used to compute kernel
|
|
|
12e206 |
size and kernel text offset in the OS image. Validate these
|
|
|
12e206 |
address values to avoid an OOB access issue.
|
|
|
12e206 |
|
|
|
12e206 |
This is CVE-2017-14167.
|
|
|
12e206 |
|
|
|
12e206 |
Reported-by: Thomas Garnier <thgarnie@google.com>
|
|
|
12e206 |
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
|
|
|
12e206 |
Message-Id: <20170907063256.7418-1-ppandit@redhat.com>
|
|
|
12e206 |
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
|
|
|
12e206 |
(cherry picked from commit ed4f86e8b6eff8e600c69adee68c7cd34dd2cccb)
|
|
|
12e206 |
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
|
|
|
12e206 |
---
|
|
|
12e206 |
hw/i386/multiboot.c | 19 +++++++++++++++++++
|
|
|
12e206 |
1 file changed, 19 insertions(+)
|
|
|
12e206 |
|
|
|
12e206 |
diff --git a/hw/i386/multiboot.c b/hw/i386/multiboot.c
|
|
|
12e206 |
index 09211e0..7eec230 100644
|
|
|
12e206 |
--- a/hw/i386/multiboot.c
|
|
|
12e206 |
+++ b/hw/i386/multiboot.c
|
|
|
12e206 |
@@ -200,15 +200,34 @@ int load_multiboot(FWCfgState *fw_cfg,
|
|
|
12e206 |
uint32_t mh_header_addr = ldl_p(header+i+12);
|
|
|
12e206 |
uint32_t mh_load_end_addr = ldl_p(header+i+20);
|
|
|
12e206 |
uint32_t mh_bss_end_addr = ldl_p(header+i+24);
|
|
|
12e206 |
+
|
|
|
12e206 |
mh_load_addr = ldl_p(header+i+16);
|
|
|
12e206 |
+ if (mh_header_addr < mh_load_addr) {
|
|
|
12e206 |
+ fprintf(stderr, "invalid mh_load_addr address\n");
|
|
|
12e206 |
+ exit(1);
|
|
|
12e206 |
+ }
|
|
|
12e206 |
+
|
|
|
12e206 |
uint32_t mb_kernel_text_offset = i - (mh_header_addr - mh_load_addr);
|
|
|
12e206 |
uint32_t mb_load_size = 0;
|
|
|
12e206 |
mh_entry_addr = ldl_p(header+i+28);
|
|
|
12e206 |
|
|
|
12e206 |
if (mh_load_end_addr) {
|
|
|
12e206 |
+ if (mh_bss_end_addr < mh_load_addr) {
|
|
|
12e206 |
+ fprintf(stderr, "invalid mh_bss_end_addr address\n");
|
|
|
12e206 |
+ exit(1);
|
|
|
12e206 |
+ }
|
|
|
12e206 |
mb_kernel_size = mh_bss_end_addr - mh_load_addr;
|
|
|
12e206 |
+
|
|
|
12e206 |
+ if (mh_load_end_addr < mh_load_addr) {
|
|
|
12e206 |
+ fprintf(stderr, "invalid mh_load_end_addr address\n");
|
|
|
12e206 |
+ exit(1);
|
|
|
12e206 |
+ }
|
|
|
12e206 |
mb_load_size = mh_load_end_addr - mh_load_addr;
|
|
|
12e206 |
} else {
|
|
|
12e206 |
+ if (kernel_file_size < mb_kernel_text_offset) {
|
|
|
12e206 |
+ fprintf(stderr, "invalid kernel_file_size\n");
|
|
|
12e206 |
+ exit(1);
|
|
|
12e206 |
+ }
|
|
|
12e206 |
mb_kernel_size = kernel_file_size - mb_kernel_text_offset;
|
|
|
12e206 |
mb_load_size = mb_kernel_size;
|
|
|
12e206 |
}
|
|
|
12e206 |
--
|
|
|
12e206 |
1.8.3.1
|
|
|
12e206 |
|