94 lines
3.4 KiB
Diff
94 lines
3.4 KiB
Diff
|
From 43651027d24e62a7a463254165e1e46e42aecdea Mon Sep 17 00:00:00 2001
|
||
|
|
From: Maxim Suhanov <dfirblog@gmail.com>
|
||
|
|
Date: Mon, 28 Aug 2023 16:31:57 +0300
|
||
|
|
Subject: [PATCH 1/6] fs/ntfs: Fix an OOB write when parsing the
|
||
|
|
$ATTRIBUTE_LIST attribute for the $MFT file
|
||
|
|
|
||
|
|
When parsing an extremely fragmented $MFT file, i.e., the file described
|
||
|
|
using the $ATTRIBUTE_LIST attribute, current NTFS code will reuse a buffer
|
||
|
|
containing bytes read from the underlying drive to store sector numbers,
|
||
|
|
which are consumed later to read data from these sectors into another buffer.
|
||
|
|
|
||
|
|
These sectors numbers, two 32-bit integers, are always stored at predefined
|
||
|
|
offsets, 0x10 and 0x14, relative to first byte of the selected entry within
|
||
|
|
the $ATTRIBUTE_LIST attribute. Usually, this won't cause any problem.
|
||
|
|
|
||
|
|
However, when parsing a specially-crafted file system image, this may cause
|
||
|
|
the NTFS code to write these integers beyond the buffer boundary, likely
|
||
|
|
causing the GRUB memory allocator to misbehave or fail. These integers contain
|
||
|
|
values which are controlled by on-disk structures of the NTFS file system.
|
||
|
|
|
||
|
|
Such modification and resulting misbehavior may touch a memory range not
|
||
|
|
assigned to the GRUB and owned by firmware or another EFI application/driver.
|
||
|
|
|
||
|
|
This fix introduces checks to ensure that these sector numbers are never
|
||
|
|
written beyond the boundary.
|
||
|
|
|
||
|
|
Fixes: CVE-2023-4692
|
||
|
|
|
||
|
|
Reported-by: Maxim Suhanov <dfirblog@gmail.com>
|
||
|
|
Signed-off-by: Maxim Suhanov <dfirblog@gmail.com>
|
||
|
|
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
|
||
|
|
---
|
||
|
|
grub-core/fs/ntfs.c | 18 +++++++++++++++++-
|
||
|
|
1 file changed, 17 insertions(+), 1 deletion(-)
|
||
|
|
|
||
|
|
diff --git a/grub-core/fs/ntfs.c b/grub-core/fs/ntfs.c
|
||
|
|
index bbdbe24ada83..c3c4db117bba 100644
|
||
|
|
--- a/grub-core/fs/ntfs.c
|
||
|
|
+++ b/grub-core/fs/ntfs.c
|
||
|
|
@@ -184,7 +184,7 @@ find_attr (struct grub_ntfs_attr *at, grub_uint8_t attr)
|
||
|
|
}
|
||
|
|
if (at->attr_end)
|
||
|
|
{
|
||
|
|
- grub_uint8_t *pa;
|
||
|
|
+ grub_uint8_t *pa, *pa_end;
|
||
|
|
|
||
|
|
at->emft_buf = grub_malloc (at->mft->data->mft_size << GRUB_NTFS_BLK_SHR);
|
||
|
|
if (at->emft_buf == NULL)
|
||
|
|
@@ -209,11 +209,13 @@ find_attr (struct grub_ntfs_attr *at, grub_uint8_t attr)
|
||
|
|
}
|
||
|
|
at->attr_nxt = at->edat_buf;
|
||
|
|
at->attr_end = at->edat_buf + u32at (pa, 0x30);
|
||
|
|
+ pa_end = at->edat_buf + n;
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
at->attr_nxt = at->attr_end + u16at (pa, 0x14);
|
||
|
|
at->attr_end = at->attr_end + u32at (pa, 4);
|
||
|
|
+ pa_end = at->mft->buf + (at->mft->data->mft_size << GRUB_NTFS_BLK_SHR);
|
||
|
|
}
|
||
|
|
at->flags |= GRUB_NTFS_AF_ALST;
|
||
|
|
while (at->attr_nxt < at->attr_end)
|
||
|
|
@@ -230,6 +232,13 @@ find_attr (struct grub_ntfs_attr *at, grub_uint8_t attr)
|
||
|
|
at->flags |= GRUB_NTFS_AF_GPOS;
|
||
|
|
at->attr_cur = at->attr_nxt;
|
||
|
|
pa = at->attr_cur;
|
||
|
|
+
|
||
|
|
+ if ((pa >= pa_end) || (pa_end - pa < 0x18))
|
||
|
|
+ {
|
||
|
|
+ grub_error (GRUB_ERR_BAD_FS, "can\'t parse attribute list");
|
||
|
|
+ return NULL;
|
||
|
|
+ }
|
||
|
|
+
|
||
|
|
grub_set_unaligned32 ((char *) pa + 0x10,
|
||
|
|
grub_cpu_to_le32 (at->mft->data->mft_start));
|
||
|
|
grub_set_unaligned32 ((char *) pa + 0x14,
|
||
|
|
@@ -240,6 +249,13 @@ find_attr (struct grub_ntfs_attr *at, grub_uint8_t attr)
|
||
|
|
{
|
||
|
|
if (*pa != attr)
|
||
|
|
break;
|
||
|
|
+
|
||
|
|
+ if ((pa >= pa_end) || (pa_end - pa < 0x18))
|
||
|
|
+ {
|
||
|
|
+ grub_error (GRUB_ERR_BAD_FS, "can\'t parse attribute list");
|
||
|
|
+ return NULL;
|
||
|
|
+ }
|
||
|
|
+
|
||
|
|
if (read_attr
|
||
|
|
(at, pa + 0x10,
|
||
|
|
u32at (pa, 0x10) * (at->mft->data->mft_size << GRUB_NTFS_BLK_SHR),
|
||
|
|
--
|
||
|
|
2.43.0
|
||
|
|
|