[Cc: Alex]
On Wed, May 22, 2024 at 09:10:07PM -0400, Michael Jeanson wrote:
> Pass the idmapped mount information to the different helper
> functions. Adapt the uid/gid checks in exfat_setattr to use the
> vfsuid/vfsgid helpers.
>
> Based on the fat implementation in commit 4b7899368108
> ("fat: handle idmapped mounts") by Christian Brauner.
>
> Cc: Namjae Jeon <linkinjeon@xxxxxxxxxx>
> Cc: Sungjong Seo <sj1557.seo@xxxxxxxxxxx>
> Cc: Christian Brauner <brauner@xxxxxxxxxx>
> Cc: Seth Forshee <sforshee@xxxxxxxxxx>
> Cc: linux-fsdevel@xxxxxxxxxxxxxxx
> Signed-off-by: Michael Jeanson <mjeanson@xxxxxxxxxxxx>
> ---
Looks good to me but maybe Alex sees some issues I dont,
Reviewed-by: Christian Brauner <brauner@xxxxxxxxxx>
> fs/exfat/file.c | 22 +++++++++++++---------
> fs/exfat/super.c | 2 +-
> 2 files changed, 14 insertions(+), 10 deletions(-)
>
> diff --git a/fs/exfat/file.c b/fs/exfat/file.c
> index 9adfc38ca7da..64c31867bc76 100644
> --- a/fs/exfat/file.c
> +++ b/fs/exfat/file.c
> @@ -89,12 +89,14 @@ static int exfat_cont_expand(struct inode *inode, loff_t size)
> return -EIO;
> }
>
> -static bool exfat_allow_set_time(struct exfat_sb_info *sbi, struct inode *inode)
> +static bool exfat_allow_set_time(struct mnt_idmap *idmap,
> + struct exfat_sb_info *sbi, struct inode *inode)
> {
> mode_t allow_utime = sbi->options.allow_utime;
>
> - if (!uid_eq(current_fsuid(), inode->i_uid)) {
> - if (in_group_p(inode->i_gid))
> + if (!vfsuid_eq_kuid(i_uid_into_vfsuid(idmap, inode),
> + current_fsuid())) {
> + if (vfsgid_in_group_p(i_gid_into_vfsgid(idmap, inode)))
> allow_utime >>= 3;
> if (allow_utime & MAY_WRITE)
> return true;
> @@ -283,7 +285,7 @@ int exfat_getattr(struct mnt_idmap *idmap, const struct path *path,
> struct inode *inode = d_backing_inode(path->dentry);
> struct exfat_inode_info *ei = EXFAT_I(inode);
>
> - generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat);
> + generic_fillattr(idmap, request_mask, inode, stat);
> exfat_truncate_atime(&stat->atime);
> stat->result_mask |= STATX_BTIME;
> stat->btime.tv_sec = ei->i_crtime.tv_sec;
> @@ -311,20 +313,22 @@ int exfat_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
> /* Check for setting the inode time. */
> ia_valid = attr->ia_valid;
> if ((ia_valid & (ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)) &&
> - exfat_allow_set_time(sbi, inode)) {
> + exfat_allow_set_time(idmap, sbi, inode)) {
> attr->ia_valid &= ~(ATTR_MTIME_SET | ATTR_ATIME_SET |
> ATTR_TIMES_SET);
> }
>
> - error = setattr_prepare(&nop_mnt_idmap, dentry, attr);
> + error = setattr_prepare(idmap, dentry, attr);
> attr->ia_valid = ia_valid;
> if (error)
> goto out;
>
> if (((attr->ia_valid & ATTR_UID) &&
> - !uid_eq(attr->ia_uid, sbi->options.fs_uid)) ||
> + (!uid_eq(from_vfsuid(idmap, i_user_ns(inode), attr->ia_vfsuid),
> + sbi->options.fs_uid))) ||
> ((attr->ia_valid & ATTR_GID) &&
> - !gid_eq(attr->ia_gid, sbi->options.fs_gid)) ||
> + (!gid_eq(from_vfsgid(idmap, i_user_ns(inode), attr->ia_vfsgid),
> + sbi->options.fs_gid))) ||
> ((attr->ia_valid & ATTR_MODE) &&
> (attr->ia_mode & ~(S_IFREG | S_IFLNK | S_IFDIR | 0777)))) {
> error = -EPERM;
> @@ -343,7 +347,7 @@ int exfat_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
> if (attr->ia_valid & ATTR_SIZE)
> inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode));
>
> - setattr_copy(&nop_mnt_idmap, inode, attr);
> + setattr_copy(idmap, inode, attr);
> exfat_truncate_inode_atime(inode);
>
> if (attr->ia_valid & ATTR_SIZE) {
> diff --git a/fs/exfat/super.c b/fs/exfat/super.c
> index 3d5ea2cfad66..1f2b3b0c4923 100644
> --- a/fs/exfat/super.c
> +++ b/fs/exfat/super.c
> @@ -788,7 +788,7 @@ static struct file_system_type exfat_fs_type = {
> .init_fs_context = exfat_init_fs_context,
> .parameters = exfat_parameters,
> .kill_sb = exfat_kill_sb,
> - .fs_flags = FS_REQUIRES_DEV,
> + .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
> };
>
> static void exfat_inode_init_once(void *foo)
> --
> 2.45.1
>
