| From foo@baz Mon Apr 9 17:09:24 CEST 2018 |
| From: Miklos Szeredi <mszeredi@redhat.com> |
| Date: Mon, 29 May 2017 15:15:27 +0200 |
| Subject: ovl: filter trusted xattr for non-admin |
| |
| From: Miklos Szeredi <mszeredi@redhat.com> |
| |
| |
| [ Upstream commit a082c6f680da298cf075886ff032f32ccb7c5e1a ] |
| |
| Filesystems filter out extended attributes in the "trusted." domain for |
| unprivlieged callers. |
| |
| Overlay calls underlying filesystem's method with elevated privs, so need |
| to do the filtering in overlayfs too. |
| |
| Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> |
| Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| fs/overlayfs/inode.c | 12 +++++++++++- |
| 1 file changed, 11 insertions(+), 1 deletion(-) |
| |
| --- a/fs/overlayfs/inode.c |
| +++ b/fs/overlayfs/inode.c |
| @@ -227,6 +227,16 @@ int ovl_xattr_get(struct dentry *dentry, |
| return res; |
| } |
| |
| +static bool ovl_can_list(const char *s) |
| +{ |
| + /* List all non-trusted xatts */ |
| + if (strncmp(s, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) != 0) |
| + return true; |
| + |
| + /* Never list trusted.overlay, list other trusted for superuser only */ |
| + return !ovl_is_private_xattr(s) && capable(CAP_SYS_ADMIN); |
| +} |
| + |
| ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size) |
| { |
| struct dentry *realdentry = ovl_dentry_real(dentry); |
| @@ -250,7 +260,7 @@ ssize_t ovl_listxattr(struct dentry *den |
| return -EIO; |
| |
| len -= slen; |
| - if (ovl_is_private_xattr(s)) { |
| + if (!ovl_can_list(s)) { |
| res -= slen; |
| memmove(s, s + slen, len); |
| } else { |
