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fs/smb/client: implement chmod() for SMB3 POSIX Extensions

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The NT ACL format for an SMB3 POSIX Extensions chmod() is a single ACE with the
magic S-1-5-88-3-mode SID:

  NT Security Descriptor
      Revision: 1
      Type: 0x8004, Self Relative, DACL Present
      Offset to owner SID: 56
      Offset to group SID: 124
      Offset to SACL: 0
      Offset to DACL: 20
      Owner: S-1-5-21-3177838999-3893657415-1037673384-1000
      Group: S-1-22-2-1000
      NT User (DACL) ACL
          Revision: NT4 (2)
          Size: 36
          Num ACEs: 1
          NT ACE: S-1-5-88-3-438, flags 0x00, Access Allowed, mask 0x00000000
              Type: Access Allowed
              NT ACE Flags: 0x00
              Size: 28
              Access required: 0x00000000
              SID: S-1-5-88-3-438

Owner and Group should be NULL, but the server is not required to fail the
request if they are present.

Signed-off-by: Ralph Boehme <slow@samba.org>
Cc: stable@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Ralph Boehme 2024-11-14 11:05:13 +01:00 committed by Steve French
parent 128630e1db
commit d413eabff1
4 changed files with 37 additions and 23 deletions
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50
fs/smb/client/cifsacl.c
View File

@ -885,12 +885,17 @@ unsigned int setup_authusers_ACE(struct smb_ace *pntace)
* Fill in the special SID based on the mode. See
* https://technet.microsoft.com/en-us/library/hh509017(v=ws.10).aspx
*/
unsigned int setup_special_mode_ACE(struct smb_ace *pntace, __u64 nmode)
unsigned int setup_special_mode_ACE(struct smb_ace *pntace,
bool posix,
__u64 nmode)
{
int i;
unsigned int ace_size = 28;
pntace->type = ACCESS_DENIED_ACE_TYPE;
if (posix)
pntace->type = ACCESS_ALLOWED_ACE_TYPE;
else
pntace->type = ACCESS_DENIED_ACE_TYPE;
pntace->flags = 0x0;
pntace->access_req = 0;
pntace->sid.num_subauth = 3;
@ -933,7 +938,8 @@ static void populate_new_aces(char *nacl_base,
struct smb_sid *pownersid,
struct smb_sid *pgrpsid,
__u64 *pnmode, u32 *pnum_aces, u16 *pnsize,
bool modefromsid)
bool modefromsid,
bool posix)
{
__u64 nmode;
u32 num_aces = 0;
@ -950,13 +956,15 @@ static void populate_new_aces(char *nacl_base,
num_aces = *pnum_aces;
nsize = *pnsize;
if (modefromsid) {
if (modefromsid || posix) {
pnntace = (struct smb_ace *) (nacl_base + nsize);
nsize += setup_special_mode_ACE(pnntace, nmode);
num_aces++;
pnntace = (struct smb_ace *) (nacl_base + nsize);
nsize += setup_authusers_ACE(pnntace);
nsize += setup_special_mode_ACE(pnntace, posix, nmode);
num_aces++;
if (modefromsid) {
pnntace = (struct smb_ace *) (nacl_base + nsize);
nsize += setup_authusers_ACE(pnntace);
num_aces++;
}
goto set_size;
}
@ -1076,7 +1084,7 @@ static __u16 replace_sids_and_copy_aces(struct smb_acl *pdacl, struct smb_acl *p
static int set_chmod_dacl(struct smb_acl *pdacl, struct smb_acl *pndacl,
struct smb_sid *pownersid, struct smb_sid *pgrpsid,
__u64 *pnmode, bool mode_from_sid)
__u64 *pnmode, bool mode_from_sid, bool posix)
{
int i;
u16 size = 0;
@ -1094,11 +1102,11 @@ static int set_chmod_dacl(struct smb_acl *pdacl, struct smb_acl *pndacl,
nsize = sizeof(struct smb_acl);
/* If pdacl is NULL, we don't have a src. Simply populate new ACL. */
if (!pdacl) {
if (!pdacl || posix) {
populate_new_aces(nacl_base,
pownersid, pgrpsid,
pnmode, &num_aces, &nsize,
mode_from_sid);
mode_from_sid, posix);
goto finalize_dacl;
}
@ -1115,7 +1123,7 @@ static int set_chmod_dacl(struct smb_acl *pdacl, struct smb_acl *pndacl,
populate_new_aces(nacl_base,
pownersid, pgrpsid,
pnmode, &num_aces, &nsize,
mode_from_sid);
mode_from_sid, posix);
new_aces_set = true;
}
@ -1144,7 +1152,7 @@ static int set_chmod_dacl(struct smb_acl *pdacl, struct smb_acl *pndacl,
populate_new_aces(nacl_base,
pownersid, pgrpsid,
pnmode, &num_aces, &nsize,
mode_from_sid);
mode_from_sid, posix);
new_aces_set = true;
}
@ -1251,7 +1259,7 @@ static int parse_sec_desc(struct cifs_sb_info *cifs_sb,
/* Convert permission bits from mode to equivalent CIFS ACL */
static int build_sec_desc(struct smb_ntsd *pntsd, struct smb_ntsd *pnntsd,
__u32 secdesclen, __u32 *pnsecdesclen, __u64 *pnmode, kuid_t uid, kgid_t gid,
bool mode_from_sid, bool id_from_sid, int *aclflag)
bool mode_from_sid, bool id_from_sid, bool posix, int *aclflag)
{
int rc = 0;
__u32 dacloffset;
@ -1288,7 +1296,7 @@ static int build_sec_desc(struct smb_ntsd *pntsd, struct smb_ntsd *pnntsd,
ndacl_ptr->num_aces = cpu_to_le32(0);
rc = set_chmod_dacl(dacl_ptr, ndacl_ptr, owner_sid_ptr, group_sid_ptr,
pnmode, mode_from_sid);
pnmode, mode_from_sid, posix);
sidsoffset = ndacloffset + le16_to_cpu(ndacl_ptr->size);
/* copy the non-dacl portion of secdesc */
@ -1587,6 +1595,7 @@ id_mode_to_cifs_acl(struct inode *inode, const char *path, __u64 *pnmode,
struct tcon_link *tlink = cifs_sb_tlink(cifs_sb);
struct smb_version_operations *ops;
bool mode_from_sid, id_from_sid;
bool posix = tlink_tcon(tlink)->posix_extensions;
const u32 info = 0;
if (IS_ERR(tlink))
@ -1622,12 +1631,13 @@ id_mode_to_cifs_acl(struct inode *inode, const char *path, __u64 *pnmode,
id_from_sid = false;
/* Potentially, five new ACEs can be added to the ACL for U,G,O mapping */
nsecdesclen = secdesclen;
if (pnmode && *pnmode != NO_CHANGE_64) { /* chmod */
if (mode_from_sid)
nsecdesclen += 2 * sizeof(struct smb_ace);
if (posix)
nsecdesclen = 1 * sizeof(struct smb_ace);
else if (mode_from_sid)
nsecdesclen = secdesclen + (2 * sizeof(struct smb_ace));
else /* cifsacl */
nsecdesclen += 5 * sizeof(struct smb_ace);
nsecdesclen = secdesclen + (5 * sizeof(struct smb_ace));
} else { /* chown */
/* When ownership changes, changes new owner sid length could be different */
nsecdesclen = sizeof(struct smb_ntsd) + (sizeof(struct smb_sid) * 2);
@ -1657,7 +1667,7 @@ id_mode_to_cifs_acl(struct inode *inode, const char *path, __u64 *pnmode,
}
rc = build_sec_desc(pntsd, pnntsd, secdesclen, &nsecdesclen, pnmode, uid, gid,
mode_from_sid, id_from_sid, &aclflag);
mode_from_sid, id_from_sid, posix, &aclflag);
cifs_dbg(NOISY, "build_sec_desc rc: %d\n", rc);

4
fs/smb/client/cifsproto.h
View File

@ -244,7 +244,9 @@ extern int cifs_set_acl(struct mnt_idmap *idmap,
extern int set_cifs_acl(struct smb_ntsd *pntsd, __u32 len, struct inode *ino,
const char *path, int flag);
extern unsigned int setup_authusers_ACE(struct smb_ace *pace);
extern unsigned int setup_special_mode_ACE(struct smb_ace *pace, __u64 nmode);
extern unsigned int setup_special_mode_ACE(struct smb_ace *pace,
bool posix,
__u64 nmode);
extern unsigned int setup_special_user_owner_ACE(struct smb_ace *pace);
extern void dequeue_mid(struct mid_q_entry *mid, bool malformed);

4
fs/smb/client/inode.c
View File

@ -3062,6 +3062,7 @@ cifs_setattr_nounix(struct dentry *direntry, struct iattr *attrs)
int rc = -EACCES;
__u32 dosattr = 0;
__u64 mode = NO_CHANGE_64;
bool posix = cifs_sb_master_tcon(cifs_sb)->posix_extensions;
xid = get_xid();
@ -3152,7 +3153,8 @@ cifs_setattr_nounix(struct dentry *direntry, struct iattr *attrs)
mode = attrs->ia_mode;
rc = 0;
if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_CIFS_ACL) ||
(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MODE_FROM_SID)) {
(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MODE_FROM_SID) ||
posix) {
rc = id_mode_to_cifs_acl(inode, full_path, &mode,
INVALID_UID, INVALID_GID);
if (rc) {

2
fs/smb/client/smb2pdu.c
View File

@ -2683,7 +2683,7 @@ create_sd_buf(umode_t mode, bool set_owner, unsigned int *len)
ptr += sizeof(struct smb3_acl);
/* create one ACE to hold the mode embedded in reserved special SID */
acelen = setup_special_mode_ACE((struct smb_ace *)ptr, (__u64)mode);
acelen = setup_special_mode_ACE((struct smb_ace *)ptr, false, (__u64)mode);
ptr += acelen;
acl_size = acelen + sizeof(struct smb3_acl);
ace_count = 1;