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SubjectRe: [PATCH v7 2/6] ocfs2: Switch to security_inode_init_security()
From
Hi,

Sorry for the late reply.

I don't have much background on this thread. It seems that we have to
check EOPNOTSUPP since ocfs2_init_security_get() may return EOPNOTSUPP
if it doesn't support extended attribute feature for backward
compatibility.

Other looks good. So with above comments addressed, you can add:
Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com>

On 1/10/23 4:55 PM, Roberto Sassu wrote:
> On Thu, 2022-12-01 at 11:41 +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.
>
> Hi Mark, Joel, Joseph
>
> some time ago I sent this patch set to switch to the newer
> function security_inode_init_security(). Almost all the other parts of
> this patch set have been reviewed, and the patch set itself should be
> ready to be merged.
>
> I kindly ask if you could have a look at this patch and give your
> Reviewed-by, so that Paul could take the patch set.
>
> Thanks a lot!
>
> Roberto
>
>> 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, modify the handling of the return value from
>> ocfs2_init_security_get(). As security_inode_init_security() does not
>> return -EOPNOTSUPP, remove this case and directly handle the error if the
>> return value is not zero.
>>
>> However, the previous case of receiving -EOPNOTSUPP should be still
>> taken into account, as security_inode_init_security() could return zero
>> without setting xattrs and ocfs2 would consider it as if the xattr was set.
>>
>> Instead, if security_inode_init_security() returned zero, look at the xattr
>> if it was set, and behave accordingly, i.e. set si->enable to zero to
>> notify to the functions following ocfs2_init_security_get() that the xattr
>> is not available (same as if security_old_inode_init_security() returned
>> -EOPNOTSUPP).
>>
>> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
>> Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
>> ---
>> fs/ocfs2/namei.c | 18 ++++++------------
>> fs/ocfs2/xattr.c | 30 ++++++++++++++++++++++++++----
>> 2 files changed, 32 insertions(+), 16 deletions(-)
>>
>> diff --git a/fs/ocfs2/namei.c b/fs/ocfs2/namei.c
>> index 05f32989bad6..55fba81cd2d1 100644
>> --- a/fs/ocfs2/namei.c
>> +++ b/fs/ocfs2/namei.c
>> @@ -242,6 +242,7 @@ static int ocfs2_mknod(struct user_namespace *mnt_userns,
>> int want_meta = 0;
>> int xattr_credits = 0;
>> struct ocfs2_security_xattr_info si = {
>> + .name = NULL,
>> .enable = 1,
>> };
>> int did_quota_inode = 0;
>> @@ -315,12 +316,8 @@ static int ocfs2_mknod(struct user_namespace *mnt_userns,
>> /* get security xattr */
>> status = ocfs2_init_security_get(inode, dir, &dentry->d_name, &si);
>> if (status) {
>> - if (status == -EOPNOTSUPP)
>> - si.enable = 0;
>> - else {
>> - mlog_errno(status);
>> - goto leave;
>> - }
>> + mlog_errno(status);
>> + goto leave;
>> }
>>
>> /* calculate meta data/clusters for setting security and acl xattr */
>> @@ -1805,6 +1802,7 @@ static int ocfs2_symlink(struct user_namespace *mnt_userns,
>> 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;
>> @@ -1875,12 +1873,8 @@ static int ocfs2_symlink(struct user_namespace *mnt_userns,
>> /* get security xattr */
>> status = ocfs2_init_security_get(inode, dir, &dentry->d_name, &si);
>> if (status) {
>> - if (status == -EOPNOTSUPP)
>> - si.enable = 0;
>> - else {
>> - mlog_errno(status);
>> - goto bail;
>> - }
>> + mlog_errno(status);
>> + goto bail;
>> }
>>
>> /* calculate meta data/clusters for setting security xattr */
>> diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
>> index 95d0611c5fc7..55699c573541 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);

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