STATX_ATTR_CHANGE_MONOTONIC is kernel-internal. cp_statx() strips it from stx_attributes but copies attributes_mask verbatim, so it leaks to userland on filesystems that advertise it (nfs, ceph), e.g. stx_attributes_mask = 0x8000000000303000 on NFS. Add a new mask constant and apply it to both fields. Fixes: a1175d6b1bda ("vfs: plumb i_version handling into struct kstat") Reviewed-by: Jan Kara Signed-off-by: Jeff Layton --- Changes in v2: - Add new STATX_ATTR_INTERNAL_MASK constant - Keep lines below 80 columns - Link to v1: https://lore.kernel.org/r/20261029-statx-v1-1-9600cdb896b3@kernel.org --- fs/stat.c | 6 +++--- include/linux/stat.h | 3 +++ 2 files changed, 6 insertions(+), 3 deletions(-) diff --git a/fs/stat.c b/fs/stat.c index a2e63c6c45b7..34d786c1de3e 100644 --- a/fs/stat.c +++ b/fs/stat.c @@ -710,8 +710,7 @@ cp_statx(const struct kstat *stat, struct statx __user *buffer) /* STATX_CHANGE_COOKIE is kernel-only for now */ tmp.stx_mask = stat->result_mask & ~STATX_CHANGE_COOKIE; tmp.stx_blksize = stat->blksize; - /* STATX_ATTR_CHANGE_MONOTONIC is kernel-only for now */ - tmp.stx_attributes = stat->attributes & ~STATX_ATTR_CHANGE_MONOTONIC; + tmp.stx_attributes = stat->attributes & ~STATX_ATTR_INTERNAL_MASK; tmp.stx_nlink = stat->nlink; tmp.stx_uid = from_kuid_munged(current_user_ns(), stat->uid); tmp.stx_gid = from_kgid_munged(current_user_ns(), stat->gid); @@ -719,7 +718,8 @@ cp_statx(const struct kstat *stat, struct statx __user *buffer) tmp.stx_ino = stat->ino; tmp.stx_size = stat->size; tmp.stx_blocks = stat->blocks; - tmp.stx_attributes_mask = stat->attributes_mask; + tmp.stx_attributes_mask = stat->attributes_mask & + ~STATX_ATTR_INTERNAL_MASK; tmp.stx_atime.tv_sec = stat->atime.tv_sec; tmp.stx_atime.tv_nsec = stat->atime.tv_nsec; tmp.stx_btime.tv_sec = stat->btime.tv_sec; diff --git a/include/linux/stat.h b/include/linux/stat.h index 9c5709132862..4f0a4af7a067 100644 --- a/include/linux/stat.h +++ b/include/linux/stat.h @@ -69,4 +69,7 @@ struct kstat { /* file attribute values */ #define STATX_ATTR_CHANGE_MONOTONIC 0x8000000000000000ULL /* version monotonically increases */ +/* mask of STATX_ATTR_* bits that is private to the kernel */ +#define STATX_ATTR_INTERNAL_MASK (STATX_ATTR_CHANGE_MONOTONIC) + #endif --- base-commit: c339f4010dea8b0d754f84ace70cd1b089878ef8 change-id: 20261029-statx-3f1d8cd8d877 Best regards, -- Jeff Layton