[PATCH v2 2/3] ntfs: fix MFT bitmap scan 2^32 boundary check

[DaeMyung Kang <charsyam@gmail.com>]

NTFS MFT record numbers are limited to the 32-bit range, and
ntfs_mft_record_layout() rejects mft_no >= 2^32.  The free-MFT-record
bitmap scan in ntfs_mft_bitmap_find_and_alloc_free_rec_nolock() also
guards against this overflow but uses a strict greater than comparison,
allowing record number 2^32 itself through this earlier check.

Every other 2^32 boundary check in fs/ntfs/mft.c uses '>=', so the
strict greater than here is both a real off-by-one and an internal
inconsistency.  A model with ll == 2^32 confirms the current check
accepts the value while the corrected check rejects it.

Use '>=' so the boundary matches the layout-time rejection and the
surrounding bitmap-scan checks.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: DaeMyung Kang <charsyam@gmail.com>
---
 fs/ntfs/mft.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ntfs/mft.c b/fs/ntfs/mft.c
index 827b99f4597a..b056c9bbdf5f 100644
--- a/fs/ntfs/mft.c
+++ b/fs/ntfs/mft.c
@@ -1045,7 +1045,7 @@ static s64 ntfs_mft_bitmap_find_and_alloc_free_rec_nolock(struct ntfs_volume *vo
 				b = ffz((unsigned long)*byte);
 				if (b < 8 && b >= (bit & 7)) {
 					ll = data_pos + (bit & ~7ull) + b;
-					if (unlikely(ll > (1ll << 32))) {
+					if (unlikely(ll >= (1ll << 32))) {
 						folio_unlock(folio);
 						kunmap_local(buf);
 						folio_put(folio);
-- 
2.43.0