grub2/0337-fs-ntfs-Fix-an-OOB-read-when-parsing-directory-entri.patch

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From 7e5f031a6a6a3decc2360a7b0c71abbe598e7354 Mon Sep 17 00:00:00 2001
From: Maxim Suhanov <dfirblog@gmail.com>
Date: Mon, 28 Aug 2023 16:33:17 +0300
Subject: [PATCH 3/6] fs/ntfs: Fix an OOB read when parsing directory entries
from resident and non-resident index attributes
This fix introduces checks to ensure that index entries are never read
beyond the corresponding directory index.
The lack of this check is a minor issue, likely not exploitable in any way.
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 | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/grub-core/fs/ntfs.c b/grub-core/fs/ntfs.c
index a68e173d8285..2d78b96e19fb 100644
--- a/grub-core/fs/ntfs.c
+++ b/grub-core/fs/ntfs.c
@@ -599,7 +599,7 @@ get_utf8 (grub_uint8_t *in, grub_size_t len)
}
static int
-list_file (struct grub_ntfs_file *diro, grub_uint8_t *pos,
+list_file (struct grub_ntfs_file *diro, grub_uint8_t *pos, grub_uint8_t *end_pos,
grub_fshelp_iterate_dir_hook_t hook, void *hook_data)
{
grub_uint8_t *np;
@@ -610,6 +610,9 @@ list_file (struct grub_ntfs_file *diro, grub_uint8_t *pos,
grub_uint8_t namespace;
char *ustr;
+ if ((pos >= end_pos) || (end_pos - pos < 0x52))
+ break;
+
if (pos[0xC] & 2) /* end signature */
break;
@@ -617,6 +620,9 @@ list_file (struct grub_ntfs_file *diro, grub_uint8_t *pos,
ns = *(np++);
namespace = *(np++);
+ if (2 * ns > end_pos - pos - 0x52)
+ break;
+
/*
* Ignore files in DOS namespace, as they will reappear as Win32
* names.
@@ -806,7 +812,9 @@ grub_ntfs_iterate_dir (grub_fshelp_node_t dir,
}
cur_pos += 0x10; /* Skip index root */
- ret = list_file (mft, cur_pos + u16at (cur_pos, 0), hook, hook_data);
+ ret = list_file (mft, cur_pos + u16at (cur_pos, 0),
+ at->mft->buf + (at->mft->data->mft_size << GRUB_NTFS_BLK_SHR),
+ hook, hook_data);
if (ret)
goto done;
@@ -893,6 +901,7 @@ grub_ntfs_iterate_dir (grub_fshelp_node_t dir,
(const grub_uint8_t *) "INDX")))
goto done;
ret = list_file (mft, &indx[0x18 + u16at (indx, 0x18)],
+ indx + (mft->data->idx_size << GRUB_NTFS_BLK_SHR),
hook, hook_data);
if (ret)
goto done;
--
2.43.0