From: Maxim Suhanov Date: Mon, 28 Aug 2023 16:33:17 +0300 Subject: 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 Signed-off-by: Maxim Suhanov Reviewed-by: Daniel Kiper --- 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 a68e173..2d78b96 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;