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fs: port vfs{g,u}id helpers to mnt_idmap
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Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8ae ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Signed-off-by: Christian Brauner (Microsoft) <[email protected]>
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@brauner
brauner committed Jan 19, 2023
1 parent c14329d commit 4d7ca40
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Showing 14 changed files with 87 additions and 117 deletions.
5 changes: 2 additions & 3 deletions fs/attr.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -379,7 +379,6 @@ EXPORT_SYMBOL(may_setattr);
int notify_change(struct mnt_idmap *idmap, struct dentry *dentry,
struct iattr *attr, struct inode **delegated_inode)
{
struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
struct inode *inode = dentry->d_inode;
umode_t mode = inode->i_mode;
int error;
Expand Down Expand Up @@ -453,11 +452,11 @@ int notify_change(struct mnt_idmap *idmap, struct dentry *dentry,
* namespace of the superblock.
*/
if (ia_valid & ATTR_UID &&
!vfsuid_has_fsmapping(mnt_userns, inode->i_sb->s_user_ns,
!vfsuid_has_fsmapping(idmap, inode->i_sb->s_user_ns,
attr->ia_vfsuid))
return -EOVERFLOW;
if (ia_valid & ATTR_GID &&
!vfsgid_has_fsmapping(mnt_userns, inode->i_sb->s_user_ns,
!vfsgid_has_fsmapping(idmap, inode->i_sb->s_user_ns,
attr->ia_vfsgid))
return -EOVERFLOW;

Expand Down
5 changes: 2 additions & 3 deletions fs/fat/file.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -480,7 +480,6 @@ static int fat_allow_set_time(struct mnt_idmap *idmap,
int fat_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
struct iattr *attr)
{
struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);
struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb);
struct inode *inode = d_inode(dentry);
unsigned int ia_valid;
Expand Down Expand Up @@ -519,10 +518,10 @@ int fat_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
}

if (((attr->ia_valid & ATTR_UID) &&
(!uid_eq(from_vfsuid(mnt_userns, i_user_ns(inode), attr->ia_vfsuid),
(!uid_eq(from_vfsuid(idmap, i_user_ns(inode), attr->ia_vfsuid),
sbi->options.fs_uid))) ||
((attr->ia_valid & ATTR_GID) &&
(!gid_eq(from_vfsgid(mnt_userns, i_user_ns(inode), attr->ia_vfsgid),
(!gid_eq(from_vfsgid(idmap, i_user_ns(inode), attr->ia_vfsgid),
sbi->options.fs_gid))) ||
((attr->ia_valid & ATTR_MODE) &&
(attr->ia_mode & ~FAT_VALID_MODE)))
Expand Down
9 changes: 2 additions & 7 deletions fs/ksmbd/smb2pdu.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2513,7 +2513,6 @@ int smb2_open(struct ksmbd_work *work)
struct ksmbd_file *fp = NULL;
struct file *filp = NULL;
struct mnt_idmap *idmap = NULL;
struct user_namespace *user_ns = NULL;
struct kstat stat;
struct create_context *context;
struct lease_ctx_info *lc = NULL;
Expand Down Expand Up @@ -2767,7 +2766,6 @@ int smb2_open(struct ksmbd_work *work)
} else {
file_present = true;
idmap = mnt_idmap(path.mnt);
user_ns = mnt_idmap_owner(idmap);
}
if (stream_name) {
if (req->CreateOptions & FILE_DIRECTORY_FILE_LE) {
Expand Down Expand Up @@ -2867,7 +2865,6 @@ int smb2_open(struct ksmbd_work *work)

created = true;
idmap = mnt_idmap(path.mnt);
user_ns = mnt_idmap_owner(idmap);
if (ea_buf) {
if (le32_to_cpu(ea_buf->ccontext.DataLength) <
sizeof(struct smb2_ea_info)) {
Expand Down Expand Up @@ -2999,7 +2996,7 @@ int smb2_open(struct ksmbd_work *work)
if (!pntsd)
goto err_out;

rc = build_sec_desc(user_ns,
rc = build_sec_desc(idmap,
pntsd, NULL, 0,
OWNER_SECINFO |
GROUP_SECINFO |
Expand Down Expand Up @@ -5128,7 +5125,6 @@ static int smb2_get_info_sec(struct ksmbd_work *work,
{
struct ksmbd_file *fp;
struct mnt_idmap *idmap;
struct user_namespace *user_ns;
struct smb_ntsd *pntsd = (struct smb_ntsd *)rsp->Buffer, *ppntsd = NULL;
struct smb_fattr fattr = {{0}};
struct inode *inode;
Expand Down Expand Up @@ -5176,7 +5172,6 @@ static int smb2_get_info_sec(struct ksmbd_work *work,
return -ENOENT;

idmap = file_mnt_idmap(fp->filp);
user_ns = mnt_idmap_owner(idmap);
inode = file_inode(fp->filp);
ksmbd_acls_fattr(&fattr, idmap, inode);

Expand All @@ -5188,7 +5183,7 @@ static int smb2_get_info_sec(struct ksmbd_work *work,

/* Check if sd buffer size exceeds response buffer size */
if (smb2_resp_buf_len(work, 8) > ppntsd_size)
rc = build_sec_desc(user_ns, pntsd, ppntsd, ppntsd_size,
rc = build_sec_desc(idmap, pntsd, ppntsd, ppntsd_size,
addition_info, &secdesclen, &fattr);
posix_acl_release(fattr.cf_acls);
posix_acl_release(fattr.cf_dacls);
Expand Down
50 changes: 24 additions & 26 deletions fs/ksmbd/smbacl.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -254,7 +254,7 @@ void id_to_sid(unsigned int cid, uint sidtype, struct smb_sid *ssid)
ssid->num_subauth++;
}

static int sid_to_id(struct user_namespace *user_ns,
static int sid_to_id(struct mnt_idmap *idmap,
struct smb_sid *psid, uint sidtype,
struct smb_fattr *fattr)
{
Expand All @@ -276,7 +276,7 @@ static int sid_to_id(struct user_namespace *user_ns,

id = le32_to_cpu(psid->sub_auth[psid->num_subauth - 1]);
uid = KUIDT_INIT(id);
uid = from_vfsuid(user_ns, &init_user_ns, VFSUIDT_INIT(uid));
uid = from_vfsuid(idmap, &init_user_ns, VFSUIDT_INIT(uid));
if (uid_valid(uid)) {
fattr->cf_uid = uid;
rc = 0;
Expand All @@ -287,7 +287,7 @@ static int sid_to_id(struct user_namespace *user_ns,

id = le32_to_cpu(psid->sub_auth[psid->num_subauth - 1]);
gid = KGIDT_INIT(id);
gid = from_vfsgid(user_ns, &init_user_ns, VFSGIDT_INIT(gid));
gid = from_vfsgid(idmap, &init_user_ns, VFSGIDT_INIT(gid));
if (gid_valid(gid)) {
fattr->cf_gid = gid;
rc = 0;
Expand Down Expand Up @@ -362,7 +362,7 @@ void free_acl_state(struct posix_acl_state *state)
kfree(state->groups);
}

static void parse_dacl(struct user_namespace *user_ns,
static void parse_dacl(struct mnt_idmap *idmap,
struct smb_acl *pdacl, char *end_of_acl,
struct smb_sid *pownersid, struct smb_sid *pgrpsid,
struct smb_fattr *fattr)
Expand Down Expand Up @@ -489,7 +489,7 @@ static void parse_dacl(struct user_namespace *user_ns,
acl_mode = access_flags_to_mode(fattr, ppace[i]->access_req,
ppace[i]->type);
temp_fattr.cf_uid = INVALID_UID;
ret = sid_to_id(user_ns, &ppace[i]->sid, SIDOWNER, &temp_fattr);
ret = sid_to_id(idmap, &ppace[i]->sid, SIDOWNER, &temp_fattr);
if (ret || uid_eq(temp_fattr.cf_uid, INVALID_UID)) {
pr_err("%s: Error %d mapping Owner SID to uid\n",
__func__, ret);
Expand Down Expand Up @@ -575,7 +575,7 @@ static void parse_dacl(struct user_namespace *user_ns,
free_acl_state(&default_acl_state);
}

static void set_posix_acl_entries_dacl(struct user_namespace *user_ns,
static void set_posix_acl_entries_dacl(struct mnt_idmap *idmap,
struct smb_ace *pndace,
struct smb_fattr *fattr, u32 *num_aces,
u16 *size, u32 nt_aces_num)
Expand All @@ -600,14 +600,14 @@ static void set_posix_acl_entries_dacl(struct user_namespace *user_ns,
uid_t uid;
unsigned int sid_type = SIDOWNER;

uid = posix_acl_uid_translate(user_ns, pace);
uid = posix_acl_uid_translate(idmap, pace);
if (!uid)
sid_type = SIDUNIX_USER;
id_to_sid(uid, sid_type, sid);
} else if (pace->e_tag == ACL_GROUP) {
gid_t gid;

gid = posix_acl_gid_translate(user_ns, pace);
gid = posix_acl_gid_translate(idmap, pace);
id_to_sid(gid, SIDUNIX_GROUP, sid);
} else if (pace->e_tag == ACL_OTHER && !nt_aces_num) {
smb_copy_sid(sid, &sid_everyone);
Expand Down Expand Up @@ -666,12 +666,12 @@ static void set_posix_acl_entries_dacl(struct user_namespace *user_ns,
if (pace->e_tag == ACL_USER) {
uid_t uid;

uid = posix_acl_uid_translate(user_ns, pace);
uid = posix_acl_uid_translate(idmap, pace);
id_to_sid(uid, SIDCREATOR_OWNER, sid);
} else if (pace->e_tag == ACL_GROUP) {
gid_t gid;

gid = posix_acl_gid_translate(user_ns, pace);
gid = posix_acl_gid_translate(idmap, pace);
id_to_sid(gid, SIDCREATOR_GROUP, sid);
} else {
kfree(sid);
Expand All @@ -689,7 +689,7 @@ static void set_posix_acl_entries_dacl(struct user_namespace *user_ns,
}
}

static void set_ntacl_dacl(struct user_namespace *user_ns,
static void set_ntacl_dacl(struct mnt_idmap *idmap,
struct smb_acl *pndacl,
struct smb_acl *nt_dacl,
unsigned int aces_size,
Expand Down Expand Up @@ -723,13 +723,13 @@ static void set_ntacl_dacl(struct user_namespace *user_ns,
}
}

set_posix_acl_entries_dacl(user_ns, pndace, fattr,
set_posix_acl_entries_dacl(idmap, pndace, fattr,
&num_aces, &size, nt_num_aces);
pndacl->num_aces = cpu_to_le32(num_aces);
pndacl->size = cpu_to_le16(le16_to_cpu(pndacl->size) + size);
}

static void set_mode_dacl(struct user_namespace *user_ns,
static void set_mode_dacl(struct mnt_idmap *idmap,
struct smb_acl *pndacl, struct smb_fattr *fattr)
{
struct smb_ace *pace, *pndace;
Expand All @@ -741,7 +741,7 @@ static void set_mode_dacl(struct user_namespace *user_ns,
pace = pndace = (struct smb_ace *)((char *)pndacl + sizeof(struct smb_acl));

if (fattr->cf_acls) {
set_posix_acl_entries_dacl(user_ns, pndace, fattr,
set_posix_acl_entries_dacl(idmap, pndace, fattr,
&num_aces, &size, num_aces);
goto out;
}
Expand Down Expand Up @@ -808,7 +808,7 @@ static int parse_sid(struct smb_sid *psid, char *end_of_acl)
}

/* Convert CIFS ACL to POSIX form */
int parse_sec_desc(struct user_namespace *user_ns, struct smb_ntsd *pntsd,
int parse_sec_desc(struct mnt_idmap *idmap, struct smb_ntsd *pntsd,
int acl_len, struct smb_fattr *fattr)
{
int rc = 0;
Expand Down Expand Up @@ -851,7 +851,7 @@ int parse_sec_desc(struct user_namespace *user_ns, struct smb_ntsd *pntsd,
return rc;
}

rc = sid_to_id(user_ns, owner_sid_ptr, SIDOWNER, fattr);
rc = sid_to_id(idmap, owner_sid_ptr, SIDOWNER, fattr);
if (rc) {
pr_err("%s: Error %d mapping Owner SID to uid\n",
__func__, rc);
Expand All @@ -866,7 +866,7 @@ int parse_sec_desc(struct user_namespace *user_ns, struct smb_ntsd *pntsd,
__func__, rc);
return rc;
}
rc = sid_to_id(user_ns, group_sid_ptr, SIDUNIX_GROUP, fattr);
rc = sid_to_id(idmap, group_sid_ptr, SIDUNIX_GROUP, fattr);
if (rc) {
pr_err("%s: Error %d mapping Group SID to gid\n",
__func__, rc);
Expand All @@ -881,15 +881,15 @@ int parse_sec_desc(struct user_namespace *user_ns, struct smb_ntsd *pntsd,
pntsd->type |= cpu_to_le16(DACL_PROTECTED);

if (dacloffset) {
parse_dacl(user_ns, dacl_ptr, end_of_acl,
parse_dacl(idmap, dacl_ptr, end_of_acl,
owner_sid_ptr, group_sid_ptr, fattr);
}

return 0;
}

/* Convert permission bits from mode to equivalent CIFS ACL */
int build_sec_desc(struct user_namespace *user_ns,
int build_sec_desc(struct mnt_idmap *idmap,
struct smb_ntsd *pntsd, struct smb_ntsd *ppntsd,
int ppntsd_size, int addition_info, __u32 *secdesclen,
struct smb_fattr *fattr)
Expand Down Expand Up @@ -950,7 +950,7 @@ int build_sec_desc(struct user_namespace *user_ns,
dacl_ptr->num_aces = 0;

if (!ppntsd) {
set_mode_dacl(user_ns, dacl_ptr, fattr);
set_mode_dacl(idmap, dacl_ptr, fattr);
} else {
struct smb_acl *ppdacl_ptr;
unsigned int dacl_offset = le32_to_cpu(ppntsd->dacloffset);
Expand All @@ -966,7 +966,7 @@ int build_sec_desc(struct user_namespace *user_ns,
ppdacl_size < sizeof(struct smb_acl))
goto out;

set_ntacl_dacl(user_ns, dacl_ptr, ppdacl_ptr,
set_ntacl_dacl(idmap, dacl_ptr, ppdacl_ptr,
ntacl_size - sizeof(struct smb_acl),
nowner_sid_ptr, ngroup_sid_ptr,
fattr);
Expand Down Expand Up @@ -1191,7 +1191,6 @@ int smb_check_perm_dacl(struct ksmbd_conn *conn, const struct path *path,
__le32 *pdaccess, int uid)
{
struct mnt_idmap *idmap = mnt_idmap(path->mnt);
struct user_namespace *user_ns = mnt_idmap_owner(idmap);
struct smb_ntsd *pntsd = NULL;
struct smb_acl *pdacl;
struct posix_acl *posix_acls;
Expand Down Expand Up @@ -1297,9 +1296,9 @@ int smb_check_perm_dacl(struct ksmbd_conn *conn, const struct path *path,
pa_entry = posix_acls->a_entries;
for (i = 0; i < posix_acls->a_count; i++, pa_entry++) {
if (pa_entry->e_tag == ACL_USER)
id = posix_acl_uid_translate(user_ns, pa_entry);
id = posix_acl_uid_translate(idmap, pa_entry);
else if (pa_entry->e_tag == ACL_GROUP)
id = posix_acl_gid_translate(user_ns, pa_entry);
id = posix_acl_gid_translate(idmap, pa_entry);
else
continue;

Expand Down Expand Up @@ -1362,14 +1361,13 @@ int set_info_sec(struct ksmbd_conn *conn, struct ksmbd_tree_connect *tcon,
struct smb_fattr fattr = {{0}};
struct inode *inode = d_inode(path->dentry);
struct mnt_idmap *idmap = mnt_idmap(path->mnt);
struct user_namespace *user_ns = mnt_idmap_owner(idmap);
struct iattr newattrs;

fattr.cf_uid = INVALID_UID;
fattr.cf_gid = INVALID_GID;
fattr.cf_mode = inode->i_mode;

rc = parse_sec_desc(user_ns, pntsd, ntsd_len, &fattr);
rc = parse_sec_desc(idmap, pntsd, ntsd_len, &fattr);
if (rc)
goto out;

Expand Down
12 changes: 6 additions & 6 deletions fs/ksmbd/smbacl.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -190,9 +190,9 @@ struct posix_acl_state {
struct posix_ace_state_array *groups;
};

int parse_sec_desc(struct user_namespace *user_ns, struct smb_ntsd *pntsd,
int parse_sec_desc(struct mnt_idmap *idmap, struct smb_ntsd *pntsd,
int acl_len, struct smb_fattr *fattr);
int build_sec_desc(struct user_namespace *user_ns, struct smb_ntsd *pntsd,
int build_sec_desc(struct mnt_idmap *idmap, struct smb_ntsd *pntsd,
struct smb_ntsd *ppntsd, int ppntsd_size, int addition_info,
__u32 *secdesclen, struct smb_fattr *fattr);
int init_acl_state(struct posix_acl_state *state, int cnt);
Expand All @@ -211,25 +211,25 @@ int set_info_sec(struct ksmbd_conn *conn, struct ksmbd_tree_connect *tcon,
void id_to_sid(unsigned int cid, uint sidtype, struct smb_sid *ssid);
void ksmbd_init_domain(u32 *sub_auth);

static inline uid_t posix_acl_uid_translate(struct user_namespace *mnt_userns,
static inline uid_t posix_acl_uid_translate(struct mnt_idmap *idmap,
struct posix_acl_entry *pace)
{
vfsuid_t vfsuid;

/* If this is an idmapped mount, apply the idmapping. */
vfsuid = make_vfsuid(mnt_userns, &init_user_ns, pace->e_uid);
vfsuid = make_vfsuid(idmap, &init_user_ns, pace->e_uid);

/* Translate the kuid into a userspace id ksmbd would see. */
return from_kuid(&init_user_ns, vfsuid_into_kuid(vfsuid));
}

static inline gid_t posix_acl_gid_translate(struct user_namespace *mnt_userns,
static inline gid_t posix_acl_gid_translate(struct mnt_idmap *idmap,
struct posix_acl_entry *pace)
{
vfsgid_t vfsgid;

/* If this is an idmapped mount, apply the idmapping. */
vfsgid = make_vfsgid(mnt_userns, &init_user_ns, pace->e_gid);
vfsgid = make_vfsgid(idmap, &init_user_ns, pace->e_gid);

/* Translate the kgid into a userspace id ksmbd would see. */
return from_kgid(&init_user_ns, vfsgid_into_kgid(vfsgid));
Expand Down
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