I have not looked into that, but seems like a good idea. Would this be
done via a well-known extended attributes as well ?
On Thu, Jan 9, 2020 at 2:10 PM Steve French <smfrench@xxxxxxxxx> wrote:
>
> One loosely related question ...
>
> Your patch adds the ability to set creation time (birth time) which
> can be useful for backup/restore cases, but doesn't address the other
> hole in Linux (the inability to restore a files ctime).
>
> In Linux the ability to set timestamps seems quite limited (utimes
> only allows setting mtime and atime).
>
> Since setting all 4 timestamps is allowed over SMB3 (and all older
> dialects as well), should we extend this to allow setting ctime not
> just creation time over SMB3/CIFS mounts?
>
> On Thu, Dec 19, 2019 at 10:53 AM Boris Protopopov
> <boris.v.protopopov@xxxxxxxxx> wrote:
> >
> > Add extended attribute "system.cifs_ntsd" (and alias "system.smb3_ntsd")
> > to allow for setting owner and DACL in the security descriptor. This is in
> > addition to the existing "system.cifs_acl" and "system.smb3_acl" attributes
> > that allow for setting DACL only. Add support for setting creation time and
> > dos attributes using set_file_info() calls to complement the existing
> > support for getting these attributes via query_path_info() calls.
> >
> > Signed-off-by: Boris Protopopov <bprotopopov@xxxxxxxxxxx>
> > ---
> > fs/cifs/xattr.c | 128 +++++++++++++++++++++++++++++++++++++++++++++++++++-----
> > 1 file changed, 117 insertions(+), 11 deletions(-)
> >
> > diff --git a/fs/cifs/xattr.c b/fs/cifs/xattr.c
> > index 9076150758d8..c41856e6fa22 100644
> > --- a/fs/cifs/xattr.c
> > +++ b/fs/cifs/xattr.c
> > @@ -32,7 +32,8 @@
> > #include "cifs_unicode.h"
> >
> > #define MAX_EA_VALUE_SIZE CIFSMaxBufSize
> > -#define CIFS_XATTR_CIFS_ACL "system.cifs_acl"
> > +#define CIFS_XATTR_CIFS_ACL "system.cifs_acl" /* DACL only */
> > +#define CIFS_XATTR_CIFS_NTSD "system.cifs_ntsd" /* owner plus DACL */
> > #define CIFS_XATTR_ATTRIB "cifs.dosattrib" /* full name: user.cifs.dosattrib */
> > #define CIFS_XATTR_CREATETIME "cifs.creationtime" /* user.cifs.creationtime */
> > /*
> > @@ -40,12 +41,62 @@
> > * confusing users and using the 20+ year old term 'cifs' when it is no longer
> > * secure, replaced by SMB2 (then even more highly secure SMB3) many years ago
> > */
> > -#define SMB3_XATTR_CIFS_ACL "system.smb3_acl"
> > +#define SMB3_XATTR_CIFS_ACL "system.smb3_acl" /* DACL only */
> > +#define SMB3_XATTR_CIFS_NTSD "system.smb3_ntsd" /* owner plus DACL */
> > #define SMB3_XATTR_ATTRIB "smb3.dosattrib" /* full name: user.smb3.dosattrib */
> > #define SMB3_XATTR_CREATETIME "smb3.creationtime" /* user.smb3.creationtime */
> > /* BB need to add server (Samba e.g) support for security and trusted prefix */
> >
> > -enum { XATTR_USER, XATTR_CIFS_ACL, XATTR_ACL_ACCESS, XATTR_ACL_DEFAULT };
> > +enum { XATTR_USER, XATTR_CIFS_ACL, XATTR_ACL_ACCESS, XATTR_ACL_DEFAULT,
> > + XATTR_CIFS_NTSD };
> > +
> > +static int cifs_attrib_set(unsigned int xid, struct cifs_tcon *pTcon,
> > + struct inode *inode, char *full_path,
> > + const void *value, size_t size)
> > +{
> > + ssize_t rc = -EOPNOTSUPP;
> > + __u32 *pattrib = (__u32 *)value;
> > + __u32 attrib;
> > + FILE_BASIC_INFO info_buf;
> > +
> > + if ((value == NULL) || (size != sizeof(__u32)))
> > + return -ERANGE;
> > +
> > + memset(&info_buf, 0, sizeof(info_buf));
> > + info_buf.Attributes = attrib = cpu_to_le32(*pattrib);
> > +
> > + if (pTcon->ses->server->ops->set_file_info)
> > + rc = pTcon->ses->server->ops->set_file_info(inode, full_path,
> > + &info_buf, xid);
> > + if (rc == 0)
> > + CIFS_I(inode)->cifsAttrs = attrib;
> > +
> > + return rc;
> > +}
> > +
> > +static int cifs_creation_time_set(unsigned int xid, struct cifs_tcon *pTcon,
> > + struct inode *inode, char *full_path,
> > + const void *value, size_t size)
> > +{
> > + ssize_t rc = -EOPNOTSUPP;
> > + __u64 *pcreation_time = (__u64 *)value;
> > + __u64 creation_time;
> > + FILE_BASIC_INFO info_buf;
> > +
> > + if ((value == NULL) || (size != sizeof(__u64)))
> > + return -ERANGE;
> > +
> > + memset(&info_buf, 0, sizeof(info_buf));
> > + info_buf.CreationTime = creation_time = cpu_to_le64(*pcreation_time);
> > +
> > + if (pTcon->ses->server->ops->set_file_info)
> > + rc = pTcon->ses->server->ops->set_file_info(inode, full_path,
> > + &info_buf, xid);
> > + if (rc == 0)
> > + CIFS_I(inode)->createtime = creation_time;
> > +
> > + return rc;
> > +}
> >
> > static int cifs_xattr_set(const struct xattr_handler *handler,
> > struct dentry *dentry, struct inode *inode,
> > @@ -86,6 +137,23 @@ static int cifs_xattr_set(const struct xattr_handler *handler,
> >
> > switch (handler->flags) {
> > case XATTR_USER:
> > + cifs_dbg(FYI, "%s:setting user xattr %s\n", __func__, name);
> > + if ((strcmp(name, CIFS_XATTR_ATTRIB) == 0) ||
> > + (strcmp(name, SMB3_XATTR_ATTRIB) == 0)) {
> > + rc = cifs_attrib_set(xid, pTcon, inode, full_path,
> > + value, size);
> > + if (rc == 0) /* force revalidate of the inode */
> > + CIFS_I(inode)->time = 0;
> > + break;
> > + } else if ((strcmp(name, CIFS_XATTR_CREATETIME) == 0) ||
> > + (strcmp(name, SMB3_XATTR_CREATETIME) == 0)) {
> > + rc = cifs_creation_time_set(xid, pTcon, inode,
> > + full_path, value, size);
> > + if (rc == 0) /* force revalidate of the inode */
> > + CIFS_I(inode)->time = 0;
> > + break;
> > + }
> > +
> > if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
> > goto out;
> >
> > @@ -95,7 +163,8 @@ static int cifs_xattr_set(const struct xattr_handler *handler,
> > cifs_sb->local_nls, cifs_sb);
> > break;
> >
> > - case XATTR_CIFS_ACL: {
> > + case XATTR_CIFS_ACL:
> > + case XATTR_CIFS_NTSD: {
> > struct cifs_ntsd *pacl;
> >
> > if (!value)
> > @@ -106,12 +175,25 @@ static int cifs_xattr_set(const struct xattr_handler *handler,
> > } else {
> > memcpy(pacl, value, size);
> > if (value &&
> > - pTcon->ses->server->ops->set_acl)
> > - rc = pTcon->ses->server->ops->set_acl(pacl,
> > - size, inode,
> > - full_path, CIFS_ACL_DACL);
> > - else
> > + pTcon->ses->server->ops->set_acl) {
> > + rc = 0;
> > + if (handler->flags == XATTR_CIFS_NTSD) {
> > + /* set owner and DACL */
> > + rc = pTcon->ses->server->ops->set_acl(
> > + pacl, size, inode,
> > + full_path,
> > + CIFS_ACL_OWNER);
> > + }
> > + if (rc == 0) {
> > + /* set DACL */
> > + rc = pTcon->ses->server->ops->set_acl(
> > + pacl, size, inode,
> > + full_path,
> > + CIFS_ACL_DACL);
> > + }
> > + } else {
> > rc = -EOPNOTSUPP;
> > + }
> > if (rc == 0) /* force revalidate of the inode */
> > CIFS_I(inode)->time = 0;
> > kfree(pacl);
> > @@ -179,7 +261,7 @@ static int cifs_creation_time_get(struct dentry *dentry, struct inode *inode,
> > void *value, size_t size)
> > {
> > ssize_t rc;
> > - __u64 * pcreatetime;
> > + __u64 *pcreatetime;
> >
> > rc = cifs_revalidate_dentry_attr(dentry);
> > if (rc)
> > @@ -244,7 +326,9 @@ static int cifs_xattr_get(const struct xattr_handler *handler,
> > full_path, name, value, size, cifs_sb);
> > break;
> >
> > - case XATTR_CIFS_ACL: {
> > + case XATTR_CIFS_ACL:
> > + case XATTR_CIFS_NTSD: {
> > + /* the whole ntsd is fetched regardless */
> > u32 acllen;
> > struct cifs_ntsd *pacl;
> >
> > @@ -382,6 +466,26 @@ static const struct xattr_handler smb3_acl_xattr_handler = {
> > .set = cifs_xattr_set,
> > };
> >
> > +static const struct xattr_handler cifs_cifs_ntsd_xattr_handler = {
> > + .name = CIFS_XATTR_CIFS_NTSD,
> > + .flags = XATTR_CIFS_NTSD,
> > + .get = cifs_xattr_get,
> > + .set = cifs_xattr_set,
> > +};
> > +
> > +/*
> > + * Although this is just an alias for the above, need to move away from
> > + * confusing users and using the 20 year old term 'cifs' when it is no
> > + * longer secure and was replaced by SMB2/SMB3 a long time ago, and
> > + * SMB3 and later are highly secure.
> > + */
> > +static const struct xattr_handler smb3_ntsd_xattr_handler = {
> > + .name = SMB3_XATTR_CIFS_NTSD,
> > + .flags = XATTR_CIFS_NTSD,
> > + .get = cifs_xattr_get,
> > + .set = cifs_xattr_set,
> > +};
> > +
> > static const struct xattr_handler cifs_posix_acl_access_xattr_handler = {
> > .name = XATTR_NAME_POSIX_ACL_ACCESS,
> > .flags = XATTR_ACL_ACCESS,
> > @@ -401,6 +505,8 @@ const struct xattr_handler *cifs_xattr_handlers[] = {
> > &cifs_os2_xattr_handler,
> > &cifs_cifs_acl_xattr_handler,
> > &smb3_acl_xattr_handler, /* alias for above since avoiding "cifs" */
> > + &cifs_cifs_ntsd_xattr_handler,
> > + &smb3_ntsd_xattr_handler, /* alias for above since avoiding "cifs" */
> > &cifs_posix_acl_access_xattr_handler,
> > &cifs_posix_acl_default_xattr_handler,
> > NULL
> > --
> > 2.14.5
> >
>
>
> --
> Thanks,
>
> Steve
