| Message ID | 20230314081720.4158676-3-roberto.sassu@huaweicloud.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | evm: Do HMAC of multiple per LSM xattrs for new inodes | expand |
On Tue, 2023-03-14 at 09:17 +0100, Roberto Sassu wrote: > From: Roberto Sassu <roberto.sassu@huawei.com> > > In preparation for removing security_old_inode_init_security(), switch to > security_inode_init_security(). > > Extend the existing ocfs2_initxattrs() to take the > ocfs2_security_xattr_info structure from fs_info, and populate the > name/value/len triple with the first xattr provided by LSMs. > > As fs_info was not used before, ocfs2_initxattrs() can now handle the case > of replicating the behavior of security_old_inode_init_security(), i.e. > just obtaining the xattr, in addition to setting all xattrs provided by > LSMs. > > Supporting multiple xattrs is not currently supported where > security_old_inode_init_security() was called (mknod, symlink), as it > requires non-trivial changes that can be done at a later time. Like for > reiserfs, even if EVM is invoked, it will not provide an xattr (if it is > not the first to set it, its xattr will be discarded; if it is the first, > it does not have xattrs to calculate the HMAC on). > > Finally, since security_inode_init_security(), unlike > security_old_inode_init_security(), returns zero instead of -EOPNOTSUPP if > no xattrs were provided by LSMs or if inodes are private, additionally > check in ocfs2_init_security_get() if the xattr name is set. > > If not, act as if security_old_inode_init_security() returned -EOPNOTSUPP, > and set si->enable to zero to notify to the functions following > ocfs2_init_security_get() that no xattrs are available. > > Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> > Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> > Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
On Tue, Mar 14, 2023 at 4:18 AM Roberto Sassu <roberto.sassu@huaweicloud.com> wrote: > > From: Roberto Sassu <roberto.sassu@huawei.com> > > In preparation for removing security_old_inode_init_security(), switch to > security_inode_init_security(). > > Extend the existing ocfs2_initxattrs() to take the > ocfs2_security_xattr_info structure from fs_info, and populate the > name/value/len triple with the first xattr provided by LSMs. > > As fs_info was not used before, ocfs2_initxattrs() can now handle the case > of replicating the behavior of security_old_inode_init_security(), i.e. > just obtaining the xattr, in addition to setting all xattrs provided by > LSMs. > > Supporting multiple xattrs is not currently supported where > security_old_inode_init_security() was called (mknod, symlink), as it > requires non-trivial changes that can be done at a later time. Like for > reiserfs, even if EVM is invoked, it will not provide an xattr (if it is > not the first to set it, its xattr will be discarded; if it is the first, > it does not have xattrs to calculate the HMAC on). > > Finally, since security_inode_init_security(), unlike > security_old_inode_init_security(), returns zero instead of -EOPNOTSUPP if > no xattrs were provided by LSMs or if inodes are private, additionally > check in ocfs2_init_security_get() if the xattr name is set. > > If not, act as if security_old_inode_init_security() returned -EOPNOTSUPP, > and set si->enable to zero to notify to the functions following > ocfs2_init_security_get() that no xattrs are available. > > Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com> > Reviewed-by: Casey Schaufler <casey@schaufler-ca.com> > Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com> > --- > fs/ocfs2/namei.c | 2 ++ > fs/ocfs2/xattr.c | 30 ++++++++++++++++++++++++++---- > 2 files changed, 28 insertions(+), 4 deletions(-) Merged into lsm/next, thanks.
diff --git a/fs/ocfs2/namei.c b/fs/ocfs2/namei.c index 9175dbc4720..17c52225b87 100644 --- a/fs/ocfs2/namei.c +++ b/fs/ocfs2/namei.c @@ -242,6 +242,7 @@ static int ocfs2_mknod(struct mnt_idmap *idmap, int want_meta = 0; int xattr_credits = 0; struct ocfs2_security_xattr_info si = { + .name = NULL, .enable = 1, }; int did_quota_inode = 0; @@ -1805,6 +1806,7 @@ static int ocfs2_symlink(struct mnt_idmap *idmap, int want_clusters = 0; int xattr_credits = 0; struct ocfs2_security_xattr_info si = { + .name = NULL, .enable = 1, }; int did_quota = 0, did_quota_inode = 0; diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c index 389308efe85..469ec45baee 100644 --- a/fs/ocfs2/xattr.c +++ b/fs/ocfs2/xattr.c @@ -7259,9 +7259,21 @@ static int ocfs2_xattr_security_set(const struct xattr_handler *handler, static int ocfs2_initxattrs(struct inode *inode, const struct xattr *xattr_array, void *fs_info) { + struct ocfs2_security_xattr_info *si = fs_info; const struct xattr *xattr; int err = 0; + if (si) { + si->value = kmemdup(xattr_array->value, xattr_array->value_len, + GFP_KERNEL); + if (!si->value) + return -ENOMEM; + + si->name = xattr_array->name; + si->value_len = xattr_array->value_len; + return 0; + } + for (xattr = xattr_array; xattr->name != NULL; xattr++) { err = ocfs2_xattr_set(inode, OCFS2_XATTR_INDEX_SECURITY, xattr->name, xattr->value, @@ -7277,13 +7289,23 @@ int ocfs2_init_security_get(struct inode *inode, const struct qstr *qstr, struct ocfs2_security_xattr_info *si) { + int ret; + /* check whether ocfs2 support feature xattr */ if (!ocfs2_supports_xattr(OCFS2_SB(dir->i_sb))) return -EOPNOTSUPP; - if (si) - return security_old_inode_init_security(inode, dir, qstr, - &si->name, &si->value, - &si->value_len); + if (si) { + ret = security_inode_init_security(inode, dir, qstr, + &ocfs2_initxattrs, si); + /* + * security_inode_init_security() does not return -EOPNOTSUPP, + * we have to check the xattr ourselves. + */ + if (!ret && !si->name) + si->enable = 0; + + return ret; + } return security_inode_init_security(inode, dir, qstr, &ocfs2_initxattrs, NULL);