diff mbox series

[5.10,CANDIDATE,10/11] xfs: fix up non-directory creation in SGID directories

Message ID 20220617100641.1653164-11-amir73il@gmail.com (mailing list archive)
State New, archived
Headers show
Series xfs stable candidate patches for 5.10.y (v5.15+) | expand

Commit Message

Amir Goldstein June 17, 2022, 10:06 a.m. UTC 
From: Christoph Hellwig <hch@lst.de>

commit 01ea173e103edd5ec41acec65b9261b87e123fc2 upstream.

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 <christian.brauner@ubuntu.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
 fs/xfs/xfs_inode.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)
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Patch

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 1ae669d12301..ae86fbdc1bab 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -802,6 +802,7 @@  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;
@@ -847,18 +848,17 @@  xfs_ialloc(
 		return error;
 	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);
 	}
 
 	/*