From: Miklos Szeredi mszeredi@redhat.com
stable inclusion from linux-4.19.177 commit f1cb5984909ce2737caa205b63509c59141bcf49
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[ Upstream commit 554677b97257b0b69378bd74e521edb7e94769ff ]
The vfs_getxattr() in ovl_xattr_set() is used to check whether an xattr exist on a lower layer file that is to be removed. If the xattr does not exist, then no need to copy up the file.
This call of vfs_getxattr() wasn't wrapped in credential override, and this is probably okay. But for consitency wrap this instance as well.
Reported-by: "Eric W. Biederman" ebiederm@xmission.com Signed-off-by: Miklos Szeredi mszeredi@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com Signed-off-by: Cheng Jian cj.chengjian@huawei.com --- fs/overlayfs/inode.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index 252a3c6b4744..d1e9d926150b 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -329,7 +329,9 @@ int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name, goto out;
if (!value && !upperdentry) { + old_cred = ovl_override_creds(dentry->d_sb); err = vfs_getxattr(realdentry, name, NULL, 0); + revert_creds(old_cred); if (err < 0) goto out_drop_write; }