|
 |
63f1a98 |
From d7e857c8a02ae15a940faacc6e8b688cc590c4d7 Mon Sep 17 00:00:00 2001
|
|
|
63f1a98 |
From: Sebastian Krahmer <krahmer@suse.com>
|
|
|
63f1a98 |
Date: Tue, 28 Nov 2017 17:24:38 +0800
|
|
|
31cddd6 |
Subject: [PATCH] AUDIT-0: http boot tracker bug
|
|
|
63f1a98 |
|
|
|
63f1a98 |
Fixing a memory leak in case of error, and a integer overflow, leading to a
|
|
|
63f1a98 |
heap overflow due to overly large chunk sizes.
|
|
|
63f1a98 |
|
|
|
63f1a98 |
We need to check against some maximum value, otherwise values like 0xffffffff
|
|
|
63f1a98 |
will eventually lead in the allocation functions to small sized buffers, since
|
|
|
63f1a98 |
the len is rounded up to the next reasonable alignment. The following memcpy
|
|
|
63f1a98 |
will then smash the heap, leading to RCE.
|
|
|
63f1a98 |
|
|
|
63f1a98 |
This is no big issue for pure http boot, since its going to execute an
|
|
|
63f1a98 |
untrusted kernel anyway, but it will break trusted boot scenarios, where only
|
|
|
63f1a98 |
signed code is allowed to be executed.
|
|
|
63f1a98 |
|
|
|
63f1a98 |
Signed-off-by: Michael Chang <mchang@suse.com>
|
|
|
63f1a98 |
---
|
|
|
63f1a98 |
grub-core/net/efi/net.c | 4 +++-
|
|
|
63f1a98 |
grub-core/net/http.c | 5 ++++-
|
|
|
63f1a98 |
2 files changed, 7 insertions(+), 2 deletions(-)
|
|
|
63f1a98 |
|
|
|
63f1a98 |
diff --git a/grub-core/net/efi/net.c b/grub-core/net/efi/net.c
|
|
|
63f1a98 |
index 9e0078ac1c6..2bf15447fd5 100644
|
|
|
63f1a98 |
--- a/grub-core/net/efi/net.c
|
|
|
63f1a98 |
+++ b/grub-core/net/efi/net.c
|
|
|
63f1a98 |
@@ -645,8 +645,10 @@ grub_efihttp_chunk_read (grub_file_t file, char *buf,
|
|
|
63f1a98 |
|
|
|
63f1a98 |
rd = efi_net_interface (read, file, chunk, sz);
|
|
|
63f1a98 |
|
|
|
63f1a98 |
- if (rd <= 0)
|
|
|
63f1a98 |
+ if (rd <= 0) {
|
|
|
63f1a98 |
+ grub_free (chunk);
|
|
|
63f1a98 |
return rd;
|
|
|
63f1a98 |
+ }
|
|
|
63f1a98 |
|
|
|
63f1a98 |
if (buf)
|
|
|
63f1a98 |
{
|
|
|
63f1a98 |
diff --git a/grub-core/net/http.c b/grub-core/net/http.c
|
|
|
63f1a98 |
index f182d7b871d..5004ecfee42 100644
|
|
|
63f1a98 |
--- a/grub-core/net/http.c
|
|
|
63f1a98 |
+++ b/grub-core/net/http.c
|
|
|
63f1a98 |
@@ -31,7 +31,8 @@ GRUB_MOD_LICENSE ("GPLv3+");
|
|
|
63f1a98 |
|
|
|
63f1a98 |
enum
|
|
|
63f1a98 |
{
|
|
|
63f1a98 |
- HTTP_PORT = 80
|
|
|
63f1a98 |
+ HTTP_PORT = 80,
|
|
|
63f1a98 |
+ HTTP_MAX_CHUNK_SIZE = 0x80000000
|
|
|
63f1a98 |
};
|
|
|
63f1a98 |
|
|
|
63f1a98 |
|
|
|
63f1a98 |
@@ -78,6 +79,8 @@ parse_line (grub_file_t file, http_data_t data, char *ptr, grub_size_t len)
|
|
|
63f1a98 |
if (data->in_chunk_len == 2)
|
|
|
63f1a98 |
{
|
|
|
63f1a98 |
data->chunk_rem = grub_strtoul (ptr, 0, 16);
|
|
|
63f1a98 |
+ if (data->chunk_rem > HTTP_MAX_CHUNK_SIZE)
|
|
|
63f1a98 |
+ return GRUB_ERR_NET_PACKET_TOO_BIG;
|
|
|
63f1a98 |
grub_errno = GRUB_ERR_NONE;
|
|
|
63f1a98 |
if (data->chunk_rem == 0)
|
|
|
63f1a98 |
{
|