Mimi Zohar
2023-Feb-17 21:30 UTC
[Ocfs2-devel] [PATCH v7 2/6] ocfs2: Switch to security_inode_init_security()
On Fri, 2023-02-17 at 14:51 -0500, Mimi Zohar wrote:> On Thu, 2022-12-01 at 11:41 +0100, Roberto Sassu wrote: > > From: Roberto Sassu <roberto.sassu at 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, 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 at huawei.com> > > Reviewed-by: Casey Schaufler <casey at schaufler-ca.com> > > My previous review missed a couple of concerns. > > > --- > > 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; > > - } > > Although security_inode_init_security() does not return -EOPNOTSUPP, > ocfs2_init_security_get() could. Refer to commit 8154da3d2114 ("ocfs2: > Add incompatible flag for extended attribute"). It was added as a > temporary solution back in 2008, so it is highly unlikely that it is > still needed. > > > + mlog_errno(status); > > + goto leave; > > Without the -EOPNOTSUPP test, ocfs2_mknod() would not create the inode; > and similarly ocfs2_symlink(), below, would not create the symlink. It > would be safer not to remove the -EOPNOTSUPP test. > > > } > > > > /* 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); > > The "if (unlikely(IS_PRIVATE(inode))" test exists in both > security_old_inode_init_security() and security_inode_init_security(), > but return different values. In the former case, it returns > -EOPNOTSUPP. In the latter case, it returns 0. The question is > whether or not we need to be concerned about private inodes on ocfs2. > If private inodes on ocfs2 are possible, then ocsf2_mknod() or > ocfs2_symlink() would fail to create the inode or symlink.Correction, previously when returning -EOPNOTSUPP for private inodes, xattrs would not be wrriten. By returning 0 without setting si->enable to 0, xattrs will be written.> > > + /* > > + * 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); >-- thanks, Mimi
Roberto Sassu
2023-Feb-20 09:27 UTC
[Ocfs2-devel] [PATCH v7 2/6] ocfs2: Switch to security_inode_init_security()
On Fri, 2023-02-17 at 16:30 -0500, Mimi Zohar wrote:> On Fri, 2023-02-17 at 14:51 -0500, Mimi Zohar wrote: > > On Thu, 2022-12-01 at 11:41 +0100, Roberto Sassu wrote: > > > From: Roberto Sassu <roberto.sassu at 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, 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 at huawei.com> > > > Reviewed-by: Casey Schaufler <casey at schaufler-ca.com> > > > > My previous review missed a couple of concerns. > > > > > --- > > > 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; > > > - } > > > > Although security_inode_init_security() does not return -EOPNOTSUPP, > > ocfs2_init_security_get() could. Refer to commit 8154da3d2114 ("ocfs2: > > Add incompatible flag for extended attribute"). It was added as a > > temporary solution back in 2008, so it is highly unlikely that it is > > still needed. > > > > > + mlog_errno(status); > > > + goto leave; > > > > Without the -EOPNOTSUPP test, ocfs2_mknod() would not create the inode; > > and similarly ocfs2_symlink(), below, would not create the symlink. It > > would be safer not to remove the -EOPNOTSUPP test. > > > > > } > > > > > > /* 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); > > > > The "if (unlikely(IS_PRIVATE(inode))" test exists in both > > security_old_inode_init_security() and security_inode_init_security(), > > but return different values. In the former case, it returns > > -EOPNOTSUPP. In the latter case, it returns 0. The question is > > whether or not we need to be concerned about private inodes on ocfs2. > > If private inodes on ocfs2 are possible, then ocsf2_mknod() or > > ocfs2_symlink() would fail to create the inode or symlink. > > Correction, previously when returning -EOPNOTSUPP for private inodes, > xattrs would not be wrriten. By returning 0 without setting si->enable > to 0, xattrs will be written.Ok, but if there is a private inode, we would be setting si->enable to zero. Should be ok, I guess. Thanks Roberto> > > + /* > > > + * 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);