Some NTFS volumes failed to mount because sparse data runs were not handled correctly during runlist unpacking. The code performed arithmetic on the special SPARSE_LCN64 marker, leading to invalid LCN values and mount errors.

Add an explicit check for the case described above, marking the run as sparse without applying arithmetic.

Fixes: 736fc7bf5f68 ("fs: ntfs3: Fix integer overflow in run_unpack()") Cc: stable@vger.kernel.org Signed-off-by: Konstantin Komarov almaz.alexandrovich@paragon-software.com --- fs/ntfs3/run.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/fs/ntfs3/run.c b/fs/ntfs3/run.c index 88550085f745..5df55e4adbb1 100644 --- a/fs/ntfs3/run.c +++ b/fs/ntfs3/run.c @@ -984,8 +984,12 @@ int run_unpack(struct runs_tree *run, struct ntfs_sb_info *sbi, CLST ino, if (!dlcn) return -EINVAL;

- if (check_add_overflow(prev_lcn, dlcn, &lcn)) + /* Check special combination: 0 + SPARSE_LCN64. */ + if (!prev_lcn && dlcn == SPARSE_LCN64) { + lcn = SPARSE_LCN64; + } else if (check_add_overflow(prev_lcn, dlcn, &lcn)) { return -EINVAL; + } prev_lcn = lcn; } else { /* The size of 'dlcn' can't be > 8. */