From e2f8fbfb8d09c06decde162090fac3ee220aa280 Mon Sep 17 00:00:00 2001 From: Steve French Date: Fri, 19 Jul 2019 06:30:07 +0000 Subject: cifs: get mode bits from special sid on stat When mounting with "modefromsid" retrieve mode bits from special SID (S-1-5-88-3) on stat. Subsequent patch will fix setattr (chmod) to save mode bits in S-1-5-88-3- Note that when an ACE matching S-1-5-88-3 is not found, we default the mode to an approximation based on the owner, group and everyone permissions (as with the "cifsacl" mount option). See See e.g. https://docs.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2008-R2-and-2008/hh509017(v=ws.10) Signed-off-by: Steve French --- fs/cifs/cifsacl.c | 37 ++++++++++++++++++++++++++----------- 1 file changed, 26 insertions(+), 11 deletions(-) (limited to 'fs/cifs/cifsacl.c') diff --git a/fs/cifs/cifsacl.c b/fs/cifs/cifsacl.c index 1d377b7f2860..7fe4509e6c03 100644 --- a/fs/cifs/cifsacl.c +++ b/fs/cifs/cifsacl.c @@ -701,10 +701,9 @@ static void dump_ace(struct cifs_ace *pace, char *end_of_acl) } #endif - static void parse_dacl(struct cifs_acl *pdacl, char *end_of_acl, struct cifs_sid *pownersid, struct cifs_sid *pgrpsid, - struct cifs_fattr *fattr) + struct cifs_fattr *fattr, bool mode_from_special_sid) { int i; int num_aces = 0; @@ -757,22 +756,34 @@ static void parse_dacl(struct cifs_acl *pdacl, char *end_of_acl, #ifdef CONFIG_CIFS_DEBUG2 dump_ace(ppace[i], end_of_acl); #endif - if (compare_sids(&(ppace[i]->sid), pownersid) == 0) + if (mode_from_special_sid && + (compare_sids(&(ppace[i]->sid), + &sid_unix_NFS_mode) == 0)) { + /* + * Full permissions are: + * 07777 = S_ISUID | S_ISGID | S_ISVTX | + * S_IRWXU | S_IRWXG | S_IRWXO + */ + fattr->cf_mode &= ~07777; + fattr->cf_mode |= + le32_to_cpu(ppace[i]->sid.sub_auth[2]); + break; + } else if (compare_sids(&(ppace[i]->sid), pownersid) == 0) access_flags_to_mode(ppace[i]->access_req, ppace[i]->type, &fattr->cf_mode, &user_mask); - if (compare_sids(&(ppace[i]->sid), pgrpsid) == 0) + else if (compare_sids(&(ppace[i]->sid), pgrpsid) == 0) access_flags_to_mode(ppace[i]->access_req, ppace[i]->type, &fattr->cf_mode, &group_mask); - if (compare_sids(&(ppace[i]->sid), &sid_everyone) == 0) + else if (compare_sids(&(ppace[i]->sid), &sid_everyone) == 0) access_flags_to_mode(ppace[i]->access_req, ppace[i]->type, &fattr->cf_mode, &other_mask); - if (compare_sids(&(ppace[i]->sid), &sid_authusers) == 0) + else if (compare_sids(&(ppace[i]->sid), &sid_authusers) == 0) access_flags_to_mode(ppace[i]->access_req, ppace[i]->type, &fattr->cf_mode, @@ -851,7 +862,8 @@ static int parse_sid(struct cifs_sid *psid, char *end_of_acl) /* Convert CIFS ACL to POSIX form */ static int parse_sec_desc(struct cifs_sb_info *cifs_sb, - struct cifs_ntsd *pntsd, int acl_len, struct cifs_fattr *fattr) + struct cifs_ntsd *pntsd, int acl_len, struct cifs_fattr *fattr, + bool get_mode_from_special_sid) { int rc = 0; struct cifs_sid *owner_sid_ptr, *group_sid_ptr; @@ -900,7 +912,7 @@ static int parse_sec_desc(struct cifs_sb_info *cifs_sb, if (dacloffset) parse_dacl(dacl_ptr, end_of_acl, owner_sid_ptr, - group_sid_ptr, fattr); + group_sid_ptr, fattr, get_mode_from_special_sid); else cifs_dbg(FYI, "no ACL\n"); /* BB grant all or default perms? */ @@ -1128,8 +1140,8 @@ out: /* Translate the CIFS ACL (similar to NTFS ACL) for a file into mode bits */ int cifs_acl_to_fattr(struct cifs_sb_info *cifs_sb, struct cifs_fattr *fattr, - struct inode *inode, const char *path, - const struct cifs_fid *pfid) + struct inode *inode, bool mode_from_special_sid, + const char *path, const struct cifs_fid *pfid) { struct cifs_ntsd *pntsd = NULL; u32 acllen = 0; @@ -1156,8 +1168,11 @@ cifs_acl_to_fattr(struct cifs_sb_info *cifs_sb, struct cifs_fattr *fattr, if (IS_ERR(pntsd)) { rc = PTR_ERR(pntsd); cifs_dbg(VFS, "%s: error %d getting sec desc\n", __func__, rc); + } else if (mode_from_special_sid) { + rc = parse_sec_desc(cifs_sb, pntsd, acllen, fattr, true); } else { - rc = parse_sec_desc(cifs_sb, pntsd, acllen, fattr); + /* get approximated mode from ACL */ + rc = parse_sec_desc(cifs_sb, pntsd, acllen, fattr, false); kfree(pntsd); if (rc) cifs_dbg(VFS, "parse sec desc failed rc = %d\n", rc); -- cgit v1.2.3