fs/ntfs3: Fix shift-out-of-bounds in ntfs_fill_super

Reported-by: syzbot+478c1bf0e6bf4a8f3a04@syzkaller.appspotmail.com
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>

Author: aalexandrovich

fs/ntfs3/ntfs_fs.h

@@ -42,9 +42,11 @@ enum utf16_endian;
 #define MINUS_ONE_T			((size_t)(-1))
 /* Biggest MFT / smallest cluster */
 #define MAXIMUM_BYTES_PER_MFT		4096
+#define MAXIMUM_SHIFT_BYTES_PER_MFT	12
 #define NTFS_BLOCKS_PER_MFT_RECORD	(MAXIMUM_BYTES_PER_MFT / 512)
 
 #define MAXIMUM_BYTES_PER_INDEX		4096
+#define MAXIMUM_SHIFT_BYTES_PER_INDEX	12
 #define NTFS_BLOCKS_PER_INODE		(MAXIMUM_BYTES_PER_INDEX / 512)
 
 /* NTFS specific error code when fixup failed. */

fs/ntfs3/super.c

@@ -899,9 +899,17 @@ static int ntfs_init_from_boot(struct super_block *sb, u32 sector_size,
 		goto out;
 	}
 
-	sbi->record_size = record_size =
-		boot->record_size < 0 ? 1 << (-boot->record_size) :
-					(u32)boot->record_size << cluster_bits;
+	if (boot->record_size >= 0) {
+		record_size = (u32)boot->record_size << cluster_bits;
+	} else if (-boot->record_size <= MAXIMUM_SHIFT_BYTES_PER_MFT) {
+		record_size = 1u << (-boot->record_size);
+	} else {
+		ntfs_err(sb, "%s: invalid record size %d.", hint,
+			 boot->record_size);
+		goto out;
+	}
+
+	sbi->record_size = record_size;
 	sbi->record_bits = blksize_bits(record_size);
 	sbi->attr_size_tr = (5 * record_size >> 4); // ~320 bytes
 
@@ -918,9 +926,15 @@ static int ntfs_init_from_boot(struct super_block *sb, u32 sector_size,
 		goto out;
 	}
 
-	sbi->index_size = boot->index_size < 0 ?
-				  1u << (-boot->index_size) :
-				  (u32)boot->index_size << cluster_bits;
+	if (boot->index_size >= 0) {
+		sbi->index_size = (u32)boot->index_size << cluster_bits;
+	} else if (-boot->index_size <= MAXIMUM_SHIFT_BYTES_PER_INDEX) {
+		sbi->index_size = 1u << (-boot->index_size);
+	} else {
+		ntfs_err(sb, "%s: invalid index size %d.", hint,
+			 boot->index_size);
+		goto out;
+	}
 
 	/* Check index record size. */
 	if (sbi->index_size < SECTOR_SIZE || !is_power_of_2(sbi->index_size)) {