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| -rw-r--r-- | source3/smbd/posix_acls.c | 618 |
1 files changed, 618 insertions, 0 deletions
diff --git a/source3/smbd/posix_acls.c b/source3/smbd/posix_acls.c new file mode 100644 index 0000000000..b463ec2479 --- /dev/null +++ b/source3/smbd/posix_acls.c @@ -0,0 +1,618 @@ +#ifdef HAVE_POSIX_ACLS +#define OLD_NTDOMAIN 1 +/* + Unix SMB/Netbios implementation. + Version 1.9. + SMB NT Security Descriptor / Unix permission conversion. + Copyright (C) Jeremy Allison 1994-2000 + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. +*/ + +#include "includes.h" + +/**************************************************************************** + Function to create owner and group SIDs from a SMB_STRUCT_STAT. +****************************************************************************/ + +static void create_file_sids(SMB_STRUCT_STAT *psbuf, DOM_SID *powner_sid, DOM_SID *pgroup_sid) +{ + uid_to_sid( powner_sid, psbuf->st_uid ); + gid_to_sid( pgroup_sid, psbuf->st_gid ); +} + +/**************************************************************************** + Map unix perms to NT. +****************************************************************************/ + +static SEC_ACCESS map_unix_perms( int *pacl_type, mode_t perm, int r_mask, int w_mask, int x_mask, BOOL is_directory) +{ + SEC_ACCESS sa; + uint32 nt_mask = 0; + + *pacl_type = SEC_ACE_TYPE_ACCESS_ALLOWED; + + if((perm & (r_mask|w_mask|x_mask)) == (r_mask|w_mask|x_mask)) { + nt_mask = UNIX_ACCESS_RWX; + } else if((perm & (r_mask|w_mask|x_mask)) == 0) { + nt_mask = UNIX_ACCESS_NONE; + } else { + nt_mask |= (perm & r_mask) ? UNIX_ACCESS_R : 0; + if(is_directory) + nt_mask |= (perm & w_mask) ? UNIX_ACCESS_W : 0; + else + nt_mask |= (perm & w_mask) ? UNIX_ACCESS_W : 0; + nt_mask |= (perm & x_mask) ? UNIX_ACCESS_X : 0; + } + init_sec_access(&sa,nt_mask); + return sa; +} + +/**************************************************************************** + Validate a SID. +****************************************************************************/ + +static BOOL validate_unix_sid( DOM_SID *psid, uint32 *prid, DOM_SID *sd_sid) +{ + extern DOM_SID global_sam_sid; + DOM_SID sid; + + if(!sd_sid) { + DEBUG(5,("validate_unix_sid: sid missing.\n")); + return False; + } + + sid_copy(psid, sd_sid); + sid_copy(&sid, sd_sid); + + if(!sid_split_rid(&sid, prid)) { + DEBUG(5,("validate_unix_sid: cannot get RID from sid.\n")); + return False; + } + + if(!sid_equal( &sid, &global_sam_sid)) { + DEBUG(5,("validate_unix_sid: sid is not ours.\n")); + return False; + } + + return True; +} + +/**************************************************************************** + Map NT perms to UNIX. +****************************************************************************/ + +#define FILE_SPECIFIC_READ_BITS (FILE_READ_DATA|FILE_READ_EA|FILE_READ_ATTRIBUTES) +#define FILE_SPECIFIC_WRITE_BITS (FILE_WRITE_DATA|FILE_APPEND_DATA|FILE_WRITE_EA|FILE_WRITE_ATTRIBUTES) +#define FILE_SPECIFIC_EXECUTE_BITS (FILE_EXECUTE) + +static mode_t map_nt_perms( SEC_ACCESS sec_access, int type) +{ + mode_t mode = 0; + + switch(type) { + case S_IRUSR: + if(sec_access.mask & GENERIC_ALL_ACCESS) + mode = S_IRUSR|S_IWUSR|S_IXUSR; + else { + mode |= (sec_access.mask & (GENERIC_READ_ACCESS|FILE_SPECIFIC_READ_BITS)) ? S_IRUSR : 0; + mode |= (sec_access.mask & (GENERIC_WRITE_ACCESS|FILE_SPECIFIC_WRITE_BITS)) ? S_IWUSR : 0; + mode |= (sec_access.mask & (GENERIC_EXECUTE_ACCESS|FILE_SPECIFIC_EXECUTE_BITS)) ? S_IXUSR : 0; + } + break; + case S_IRGRP: + if(sec_access.mask & GENERIC_ALL_ACCESS) + mode = S_IRGRP|S_IWGRP|S_IXGRP; + else { + mode |= (sec_access.mask & (GENERIC_READ_ACCESS|FILE_SPECIFIC_READ_BITS)) ? S_IRGRP : 0; + mode |= (sec_access.mask & (GENERIC_WRITE_ACCESS|FILE_SPECIFIC_WRITE_BITS)) ? S_IWGRP : 0; + mode |= (sec_access.mask & (GENERIC_EXECUTE_ACCESS|FILE_SPECIFIC_EXECUTE_BITS)) ? S_IXGRP : 0; + } + break; + case S_IROTH: + if(sec_access.mask & GENERIC_ALL_ACCESS) + mode = S_IROTH|S_IWOTH|S_IXOTH; + else { + mode |= (sec_access.mask & (GENERIC_READ_ACCESS|FILE_SPECIFIC_READ_BITS)) ? S_IROTH : 0; + mode |= (sec_access.mask & (GENERIC_WRITE_ACCESS|FILE_SPECIFIC_WRITE_BITS)) ? S_IWOTH : 0; + mode |= (sec_access.mask & (GENERIC_EXECUTE_ACCESS|FILE_SPECIFIC_EXECUTE_BITS)) ? S_IXOTH : 0; + } + break; + } + + return mode; +} + +/**************************************************************************** + Unpack a SEC_DESC into a owner, group and set of UNIX permissions. +****************************************************************************/ + +static BOOL unpack_nt_permissions(SMB_STRUCT_STAT *psbuf, uid_t *puser, gid_t *pgrp, mode_t *pmode, + uint32 security_info_sent, SEC_DESC *psd, BOOL is_directory) +{ + extern DOM_SID global_sid_World; + DOM_SID owner_sid; + DOM_SID grp_sid; + DOM_SID file_owner_sid; + DOM_SID file_grp_sid; + uint32 owner_rid; + uint32 grp_rid; + SEC_ACL *dacl = psd->dacl; + BOOL all_aces_are_inherit_only = (is_directory ? True : False); + int i; + enum SID_NAME_USE sid_type; + + *pmode = 0; + *puser = (uid_t)-1; + *pgrp = (gid_t)-1; + + if(security_info_sent == 0) { + DEBUG(0,("unpack_nt_permissions: no security info sent !\n")); + return False; + } + + /* + * Windows 2000 sends the owner and group SIDs as the logged in + * user, not the connected user. But it still sends the file + * owner SIDs on an ACL set. So we need to check for the file + * owner and group SIDs as well as the owner SIDs. JRA. + */ + + create_file_sids(psbuf, &file_owner_sid, &file_grp_sid); + + /* + * Validate the owner and group SID's. + */ + + memset(&owner_sid, '\0', sizeof(owner_sid)); + memset(&grp_sid, '\0', sizeof(grp_sid)); + + DEBUG(5,("unpack_nt_permissions: validating owner_sid.\n")); + + /* + * Don't immediately fail if the owner sid cannot be validated. + * This may be a group chown only set. + */ + + if (security_info_sent & OWNER_SECURITY_INFORMATION) { + if (!sid_to_uid( &owner_sid, puser, &sid_type)) + DEBUG(3,("unpack_nt_permissions: unable to validate owner sid.\n")); + } + + /* + * Don't immediately fail if the group sid cannot be validated. + * This may be an owner chown only set. + */ + + if (security_info_sent & GROUP_SECURITY_INFORMATION) { + if (!sid_to_gid( &grp_sid, pgrp, &sid_type)) + DEBUG(3,("unpack_nt_permissions: unable to validate group sid.\n")); + } + + /* + * If no DACL then this is a chown only security descriptor. + */ + + if(!(security_info_sent & DACL_SECURITY_INFORMATION) || !dacl) { + *pmode = 0; + return True; + } + + /* + * Now go through the DACL and ensure that + * any owner/group sids match. + */ + + for(i = 0; i < dacl->num_aces; i++) { + DOM_SID ace_sid; + SEC_ACE *psa = &dacl->ace[i]; + + if((psa->type != SEC_ACE_TYPE_ACCESS_ALLOWED) && + (psa->type != SEC_ACE_TYPE_ACCESS_DENIED)) { + DEBUG(3,("unpack_nt_permissions: unable to set anything but an ALLOW or DENY ACE.\n")); + return False; + } + + /* + * Ignore or remove bits we don't care about on a directory ACE. + */ + + if(is_directory) { + if(psa->flags & SEC_ACE_FLAG_INHERIT_ONLY) { + DEBUG(3,("unpack_nt_permissions: ignoring inherit only ACE.\n")); + continue; + } + + /* + * At least one of the ACE entries wasn't inherit only. + * Flag this so we know the returned mode is valid. + */ + + all_aces_are_inherit_only = False; + } + + /* + * Windows 2000 sets these flags even on *file* ACE's. This is wrong + * but we can ignore them for now. Revisit this when we go to POSIX + * ACLs on directories. + */ + + psa->flags &= ~(SEC_ACE_FLAG_OBJECT_INHERIT|SEC_ACE_FLAG_CONTAINER_INHERIT); + + if(psa->flags != 0) { + DEBUG(1,("unpack_nt_permissions: unable to set ACE flags (%x).\n", + (unsigned int)psa->flags)); + return False; + } + + /* + * The security mask may be UNIX_ACCESS_NONE which should map into + * no permissions (we overload the WRITE_OWNER bit for this) or it + * should be one of the ALL/EXECUTE/READ/WRITE bits. Arrange for this + * to be so. Any other bits override the UNIX_ACCESS_NONE bit. + */ + + psa->info.mask &= (GENERIC_ALL_ACCESS|GENERIC_EXECUTE_ACCESS|GENERIC_WRITE_ACCESS| + GENERIC_READ_ACCESS|UNIX_ACCESS_NONE|FILE_ALL_ATTRIBUTES); + + if(psa->info.mask != UNIX_ACCESS_NONE) + psa->info.mask &= ~UNIX_ACCESS_NONE; + + sid_copy(&ace_sid, &psa->sid); + + if(sid_equal(&ace_sid, &file_owner_sid)) { + /* + * Map the desired permissions into owner perms. + */ + + if(psa->type == SEC_ACE_TYPE_ACCESS_ALLOWED) + *pmode |= map_nt_perms( psa->info, S_IRUSR); + else + *pmode &= ~(map_nt_perms( psa->info, S_IRUSR)); + + } else if( sid_equal(&ace_sid, &file_grp_sid)) { + /* + * Map the desired permissions into group perms. + */ + + if(psa->type == SEC_ACE_TYPE_ACCESS_ALLOWED) + *pmode |= map_nt_perms( psa->info, S_IRGRP); + else + *pmode &= ~(map_nt_perms( psa->info, S_IRGRP)); + + } else if( sid_equal(&ace_sid, &global_sid_World)) { + /* + * Map the desired permissions into other perms. + */ + + if(psa->type == SEC_ACE_TYPE_ACCESS_ALLOWED) + *pmode |= map_nt_perms( psa->info, S_IROTH); + else + *pmode &= ~(map_nt_perms( psa->info, S_IROTH)); + + } else { + DEBUG(0,("unpack_nt_permissions: unknown SID used in ACL.\n")); + return False; + } + } + + if (is_directory && all_aces_are_inherit_only) { + /* + * Windows 2000 is doing one of these weird 'inherit acl' + * traverses to conserve NTFS ACL resources. Just pretend + * there was no DACL sent. JRA. + */ + + DEBUG(10,("unpack_nt_permissions: Win2k inherit acl traverse. Ignoring DACL.\n")); + free_sec_acl(&psd->dacl); + } + + return True; +} + +/**************************************************************************** + Go through the ACL entries one by one, count them and extract the permset + of the mask entry as we scan the acl. +****************************************************************************/ + +size_t get_num_posix_entries(acl_t posix_acl, acl_permset_t *posix_mask) +{ + size_t num_entries; + acl_entry_t entry; + int entry_id = ACL_FIRST_ENTRY; + + *posix_mask = (ACL_READ|ACL_WRITE|ACL_EXECUTE); + + for( num_entries = 0; acl_get_entry(posix_acl, entry_id, &entry) != -1; num_entries++) { + acl_tag_t tagtype; + acl_permset_t permset; + + entry_id = ACL_NEXT_ENTRY; + if (acl_get_tag_type(entry, &tagtype) == -1) + continue; + + if (tagtype == ACL_MASK) + if (acl_get_permset(entry, &permset) == 0) + *posix_mask = permset; + } + + return num_entries; +} + +/**************************************************************************** + Reply to query a security descriptor from an fsp. If it succeeds it allocates + the space for the return elements and returns the size needed to return the + security descriptor. This should be the only external function needed for + the UNIX style get ACL. +****************************************************************************/ + +size_t get_nt_acl(files_struct *fsp, SEC_DESC **ppdesc) +{ + extern DOM_SID global_sid_World; + SMB_STRUCT_STAT sbuf; + SEC_ACE ace_list[6]; + DOM_SID owner_sid; + DOM_SID group_sid; + size_t sd_size; + SEC_ACL *psa = NULL; + SEC_ACCESS owner_access; + int owner_acl_type; + SEC_ACCESS group_access; + int grp_acl_type; + SEC_ACCESS other_access; + int other_acl_type; + int num_acls = 0; + acl_t posix_acl; + + *ppdesc = NULL; + + if(fsp->is_directory || fsp->fd == -1) { + if(dos_stat(fsp->fsp_name, &sbuf) != 0) { + return 0; + } + /* + * Get the ACL from the path. + */ + + if ((posix_acl = acl_get_file( dos_to_unix(fsp->fsp_name, False), ACL_TYPE_ACCESS)) == NULL) + return 0; + + } else { + if(fsp->conn->vfs_ops.fstat(fsp->fd,&sbuf) != 0) { + return 0; + } + /* + * Get the ACL from the fd. + */ + if ((posix_acl = acl_get_fd( fsp->fd)) == NULL) + return 0; + } + + /* + * Get the owner, group and world SIDs. + */ + + create_file_sids(&sbuf, &owner_sid, &group_sid); + + /* + * Count the number of entries in the ACL and return + * the mask. + */ + + num_posix_entries = get_num_posix_entries(posix_acl, &posix_mask); + + /* + * Create the generic 3 element UNIX acl. + */ + + owner_access = map_unix_perms(&owner_acl_type, sbuf.st_mode, + S_IRUSR, S_IWUSR, S_IXUSR, fsp->is_directory); + group_access = map_unix_perms(&grp_acl_type, sbuf.st_mode, + S_IRGRP, S_IWGRP, S_IXGRP, fsp->is_directory); + other_access = map_unix_perms(&other_acl_type, sbuf.st_mode, + S_IROTH, S_IWOTH, S_IXOTH, fsp->is_directory); + + if(owner_access.mask) + init_sec_ace(&ace_list[num_acls++], &owner_sid, owner_acl_type, owner_access, 0); + + if(group_access.mask) + init_sec_ace(&ace_list[num_acls++], &group_sid, grp_acl_type, group_access, 0); + + if(other_access.mask) + init_sec_ace(&ace_list[num_acls++], &global_sid_World, other_acl_type, other_access, 0); + + if(fsp->is_directory) { + /* + * For directory ACLs we also add in the inherited permissions + * ACE entries. These are the permissions a file would get when + * being created in the directory. + */ + mode_t mode = unix_mode( fsp->conn, FILE_ATTRIBUTE_ARCHIVE, fsp->fsp_name); + + owner_access = map_unix_perms(&owner_acl_type, mode, + S_IRUSR, S_IWUSR, S_IXUSR, fsp->is_directory); + group_access = map_unix_perms(&grp_acl_type, mode, + S_IRGRP, S_IWGRP, S_IXGRP, fsp->is_directory); + other_access = map_unix_perms(&other_acl_type, mode, + S_IROTH, S_IWOTH, S_IXOTH, fsp->is_directory); + + if(owner_access.mask) + init_sec_ace(&ace_list[num_acls++], &owner_sid, owner_acl_type, + owner_access, SEC_ACE_FLAG_OBJECT_INHERIT|SEC_ACE_FLAG_INHERIT_ONLY); + + if(group_access.mask) + init_sec_ace(&ace_list[num_acls++], &group_sid, grp_acl_type, + group_access, SEC_ACE_FLAG_OBJECT_INHERIT|SEC_ACE_FLAG_INHERIT_ONLY); + + if(other_access.mask) + init_sec_ace(&ace_list[num_acls++], &global_sid_World, other_acl_type, + other_access, SEC_ACE_FLAG_OBJECT_INHERIT|SEC_ACE_FLAG_INHERIT_ONLY); + } + + if(num_acls) { + if((psa = make_sec_acl( ACL_REVISION, num_acls, ace_list)) == NULL) { + DEBUG(0,("get_nt_acl: Unable to malloc space for acl.\n")); + return 0; + } + } + + *ppdesc = make_standard_sec_desc( &owner_sid, &group_sid, psa, &sd_size); + + if(!*ppdesc) { + DEBUG(0,("get_nt_acl: Unable to malloc space for security descriptor.\n")); + sd_size = 0; + } + + free_sec_acl(&psa); + + return sd_size; +} + +/**************************************************************************** + Reply to set a security descriptor on an fsp. security_info_sent is the + description of the following NT ACL. + This should be the only external function needed for the UNIX style set ACL. +****************************************************************************/ + +BOOL set_nt_acl(files_struct *fsp, uint32 security_info_sent, SEC_DESC *psd) +{ + connection_struct *conn = fsp->conn; + uid_t user = (uid_t)-1; + gid_t grp = (gid_t)-1; + mode_t perms = 0; + SMB_STRUCT_STAT sbuf; + BOOL got_dacl = False; + + /* + * Get the current state of the file. + */ + + if(fsp->is_directory) { + if(dos_stat(fsp->fsp_name, &sbuf) != 0) + return False; + } else { + + int ret; + + if(fsp->fd == -1) + ret = conn->vfs_ops.stat(dos_to_unix(fsp->fsp_name,False), &sbuf); + else + ret = conn->vfs_ops.fstat(fsp->fd,&sbuf); + + if(ret != 0) + return False; + } + + /* + * Unpack the user/group/world id's and permissions. + */ + + if (!unpack_nt_permissions( &sbuf, &user, &grp, &perms, security_info_sent, psd, fsp->is_directory)) + return False; + + if (psd->dacl != NULL) + got_dacl = True; + + /* + * Do we need to chown ? + */ + + if((user != (uid_t)-1 || grp != (uid_t)-1) && (sbuf.st_uid != user || sbuf.st_gid != grp)) { + + DEBUG(3,("call_nt_transact_set_security_desc: chown %s. uid = %u, gid = %u.\n", + fsp->fsp_name, (unsigned int)user, (unsigned int)grp )); + + if(dos_chown( fsp->fsp_name, user, grp) == -1) { + DEBUG(3,("call_nt_transact_set_security_desc: chown %s, %u, %u failed. Error = %s.\n", + fsp->fsp_name, (unsigned int)user, (unsigned int)grp, strerror(errno) )); + return False; + } + + /* + * Recheck the current state of the file, which may have changed. + * (suid/sgid bits, for instance) + */ + + if(fsp->is_directory) { + if(dos_stat(fsp->fsp_name, &sbuf) != 0) { + return False; + } + } else { + + int ret; + + if(fsp->fd == -1) + ret = conn->vfs_ops.stat(dos_to_unix(fsp->fsp_name,False), &sbuf); + else + ret = conn->vfs_ops.fstat(fsp->fd,&sbuf); + + if(ret != 0) + return False; + } + } + + /* + * Only change security if we got a DACL. + */ + + if((security_info_sent & DACL_SECURITY_INFORMATION) && got_dacl) { + + /* + * Check to see if we need to change anything. + * Enforce limits on modified bits *only*. Don't enforce masks + * on bits not changed by the user. + */ + + if(fsp->is_directory) { + + perms &= (lp_dir_security_mask(SNUM(conn)) | sbuf.st_mode); + perms |= (lp_force_dir_security_mode(SNUM(conn)) & ( perms ^ sbuf.st_mode )); + + } else { + + perms &= (lp_security_mask(SNUM(conn)) | sbuf.st_mode); + perms |= (lp_force_security_mode(SNUM(conn)) & ( perms ^ sbuf.st_mode )); + + } + + /* + * Preserve special bits. + */ + + perms |= (sbuf.st_mode & ~0777); + + /* + * Do we need to chmod ? + */ + + if(sbuf.st_mode != perms) { + + DEBUG(3,("call_nt_transact_set_security_desc: chmod %s. perms = 0%o.\n", + fsp->fsp_name, (unsigned int)perms )); + + if(conn->vfs_ops.chmod(dos_to_unix(fsp->fsp_name, False), perms) == -1) { + DEBUG(3,("call_nt_transact_set_security_desc: chmod %s, 0%o failed. Error = %s.\n", + fsp->fsp_name, (unsigned int)perms, strerror(errno) )); + return False; + } + } + } + + return True; +} +#undef OLD_NTDOMAIN +#else /* HAVE_POSIX_ACLS */ + void dummy_posix_acls(void) {;} /* So some compilers don't complain. */ +#endif /* HAVE_POSIX_ACLS */ |