From 01ea173e103edd5ec41acec65b9261b87e123fc2 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 22 Jan 2021 16:48:18 -0800 Subject: [PATCH] xfs: fix up non-directory creation in SGID directories XFS always inherits the SGID bit if it is set on the parent inode, while the generic inode_init_owner does not do this in a few cases where it can create a possible security problem, see commit 0fa3ecd87848 ("Fix up non-directory creation in SGID directories") for details. Switch XFS to use the generic helper for the normal path to fix this, just keeping the simple field inheritance open coded for the case of the non-sgid case with the bsdgrpid mount option. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: Christian Brauner Signed-off-by: Christoph Hellwig Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong --- fs/xfs/xfs_inode.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c index 8ebd9c64aa481..e2a1db4cee431 100644 --- a/fs/xfs/xfs_inode.c +++ b/fs/xfs/xfs_inode.c @@ -775,6 +775,7 @@ xfs_init_new_inode( prid_t prid, struct xfs_inode **ipp) { + struct inode *dir = pip ? VFS_I(pip) : NULL; struct xfs_mount *mp = tp->t_mountp; struct xfs_inode *ip; unsigned int flags; @@ -804,18 +805,17 @@ xfs_init_new_inode( ASSERT(ip != NULL); inode = VFS_I(ip); - inode->i_mode = mode; set_nlink(inode, nlink); - inode->i_uid = current_fsuid(); inode->i_rdev = rdev; ip->i_d.di_projid = prid; - if (pip && XFS_INHERIT_GID(pip)) { - inode->i_gid = VFS_I(pip)->i_gid; - if ((VFS_I(pip)->i_mode & S_ISGID) && S_ISDIR(mode)) - inode->i_mode |= S_ISGID; + if (dir && !(dir->i_mode & S_ISGID) && + (mp->m_flags & XFS_MOUNT_GRPID)) { + inode->i_uid = current_fsuid(); + inode->i_gid = dir->i_gid; + inode->i_mode = mode; } else { - inode->i_gid = current_fsgid(); + inode_init_owner(inode, dir, mode); } /* -- 2.39.5