6.1-stable review patch. If anyone has any objections, please let me know.
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From: Darrick J. Wong djwong@kernel.org
[ Upstream commit 24a4e1cb322e2bf0f3a1afd1978b610a23aa8f36 ]
[ 6.1: resolved conflicts in xfs_inode.c and xfs_symlink.c due to 6.1 not having switched to idmap yet ]
I noticed that callers of xfs_qm_vop_dqalloc use the following code to compute the anticipated uid of the new file:
mapped_fsuid(idmap, &init_user_ns);
whereas the VFS uses a slightly different computation for actually assigning i_uid:
mapped_fsuid(idmap, i_user_ns(inode));
Technically, these are not the same things. According to Christian Brauner, the only time that inode->i_sb->s_user_ns != &init_user_ns is when the filesystem was mounted in a new mount namespace by an unpriviledged user. XFS does not allow this, which is why we've never seen bug reports about quotas being incorrect or the uid checks in xfs_qm_vop_create_dqattach tripping debug assertions.
However, this /is/ a logic bomb, so let's make the code consistent.
Link: https://lore.kernel.org/linux-fsdevel/20240617-weitblick-gefertigt-4a41f3711... Fixes: c14329d39f2d ("fs: port fs{g,u}id helpers to mnt_idmap") Signed-off-by: Darrick J. Wong djwong@kernel.org Reviewed-by: Christoph Hellwig hch@lst.de Signed-off-by: Catherine Hoang catherine.hoang@oracle.com Acked-by: Darrick J. Wong djwong@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Leah Rumancik leah.rumancik@gmail.com Acked-by: "Darrick J. Wong" djwong@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- fs/xfs/xfs_inode.c | 16 ++++++++++------ fs/xfs/xfs_symlink.c | 8 +++++--- 2 files changed, 15 insertions(+), 9 deletions(-)
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c index b26d26d29273d..88d0a088fa862 100644 --- a/fs/xfs/xfs_inode.c +++ b/fs/xfs/xfs_inode.c @@ -983,10 +983,12 @@ xfs_create( prid = xfs_get_initial_prid(dp);
/* - * Make sure that we have allocated dquot(s) on disk. + * Make sure that we have allocated dquot(s) on disk. The uid/gid + * computation code must match what the VFS uses to assign i_[ug]id. + * INHERIT adjusts the gid computation for setgid/grpid systems. */ - error = xfs_qm_vop_dqalloc(dp, mapped_fsuid(mnt_userns, &init_user_ns), - mapped_fsgid(mnt_userns, &init_user_ns), prid, + error = xfs_qm_vop_dqalloc(dp, mapped_fsuid(mnt_userns, i_user_ns(VFS_I(dp))), + mapped_fsgid(mnt_userns, i_user_ns(VFS_I(dp))), prid, XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT, &udqp, &gdqp, &pdqp); if (error) @@ -1132,10 +1134,12 @@ xfs_create_tmpfile( prid = xfs_get_initial_prid(dp);
/* - * Make sure that we have allocated dquot(s) on disk. + * Make sure that we have allocated dquot(s) on disk. The uid/gid + * computation code must match what the VFS uses to assign i_[ug]id. + * INHERIT adjusts the gid computation for setgid/grpid systems. */ - error = xfs_qm_vop_dqalloc(dp, mapped_fsuid(mnt_userns, &init_user_ns), - mapped_fsgid(mnt_userns, &init_user_ns), prid, + error = xfs_qm_vop_dqalloc(dp, mapped_fsuid(mnt_userns, i_user_ns(VFS_I(dp))), + mapped_fsgid(mnt_userns, i_user_ns(VFS_I(dp))), prid, XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT, &udqp, &gdqp, &pdqp); if (error) diff --git a/fs/xfs/xfs_symlink.c b/fs/xfs/xfs_symlink.c index 8389f3ef88ef2..78bd02a98aa53 100644 --- a/fs/xfs/xfs_symlink.c +++ b/fs/xfs/xfs_symlink.c @@ -191,10 +191,12 @@ xfs_symlink( prid = xfs_get_initial_prid(dp);
/* - * Make sure that we have allocated dquot(s) on disk. + * Make sure that we have allocated dquot(s) on disk. The uid/gid + * computation code must match what the VFS uses to assign i_[ug]id. + * INHERIT adjusts the gid computation for setgid/grpid systems. */ - error = xfs_qm_vop_dqalloc(dp, mapped_fsuid(mnt_userns, &init_user_ns), - mapped_fsgid(mnt_userns, &init_user_ns), prid, + error = xfs_qm_vop_dqalloc(dp, mapped_fsuid(mnt_userns, i_user_ns(VFS_I(dp))), + mapped_fsgid(mnt_userns, i_user_ns(VFS_I(dp))), prid, XFS_QMOPT_QUOTALL | XFS_QMOPT_INHERIT, &udqp, &gdqp, &pdqp); if (error)