diff --git a/fs/ntfs3/fslog.c b/fs/ntfs3/fslog.c index 10dbe9922bf1..acfa18b84401 100644 --- a/fs/ntfs3/fslog.c +++ b/fs/ntfs3/fslog.c @@ -2791,13 +2791,14 @@ static inline bool check_file_record(const struct MFT_REC *rec, u16 fn = le16_to_cpu(rec->rhdr.fix_num); u16 ao = le16_to_cpu(rec->attr_off); u32 rs = sbi->record_size; + u32 used = le32_to_cpu(rec->used); /* Check the file record header for consistency. */ if (rec->rhdr.sign != NTFS_FILE_SIGNATURE || fo > (SECTOR_SIZE - ((rs >> SECTOR_SHIFT) + 1) * sizeof(short)) || (fn - 1) * SECTOR_SIZE != rs || ao < MFTRECORD_FIXUP_OFFSET_1 || ao > sbi->record_size - SIZEOF_RESIDENT || !is_rec_inuse(rec) || - le32_to_cpu(rec->total) != rs) { + le32_to_cpu(rec->total) != rs || used > rs || used < ao) { return false; } @@ -2809,6 +2810,15 @@ static inline bool check_file_record(const struct MFT_REC *rec, return false; } + /* + * The do_action() handlers compute memmove lengths as + * "rec->used - ", which underflows when + * rec->used is smaller than the attribute walk reached. At this + * point attr is the ATTR_END marker; rec->used must cover it. + */ + if (used < PtrOffset(rec, attr) + sizeof(attr->type)) + return false; + return true; }