[PATCH v6 2/6] ocfs2: Switch to security_inode_init_security()
From: Roberto Sassu <hidden>
Date: 2022-11-23 15:48:56
Also in:
linux-integrity, lkml, ocfs2-devel, selinux
Subsystem:
filesystems (vfs and infrastructure), oracle cluster filesystem 2 (ocfs2), the rest · Maintainers:
Alexander Viro, Christian Brauner, Mark Fasheh, Joel Becker, Joseph Qi, Linus Torvalds
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, 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> --- 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);
--
2.25.1