From 7859e7ea69da340b1c39d5a09ce7a2642c7d6a13 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 14 Dec 2021 14:42:57 +0800 Subject: [PATCH] xfs: fix up non-directory creation in SGID directories mainline inclusion from mainline-v5.11-rc4 commit 01ea173e103edd5ec41acec65b9261b87e123fc2 category: bugfix bugzilla: 185881 CVE: CVE-2021-4037 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=01ea173e103edd5ec41acec65b9261b87e123fc2 ------------------------------------------------- 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 conflicts: fs/xfs/xfs_inode.c Signed-off-by: Guo Xuenan Reviewed-by: Zhang Yi Reviewed-by: Xiu Jianfeng Signed-off-by: Yang Yingliang --- 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 a5566ec89f90..6ef2bda5860e 100644 --- a/fs/xfs/xfs_inode.c +++ b/fs/xfs/xfs_inode.c @@ -756,6 +756,7 @@ xfs_ialloc( xfs_buf_t **ialloc_context, xfs_inode_t **ipp) { + struct inode *dir = pip ? VFS_I(pip) : NULL; struct xfs_mount *mp = tp->t_mountp; xfs_ino_t ino; xfs_inode_t *ip; @@ -810,18 +811,17 @@ xfs_ialloc( if (ip->i_d.di_version == 1) ip->i_d.di_version = 2; - inode->i_mode = mode; set_nlink(inode, nlink); - inode->i_uid = current_fsuid(); inode->i_rdev = rdev; xfs_set_projid(ip, 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); } /* -- GitLab