.\" $NetBSD: puffs_cred.3,v 1.3.12.1 2009/02/24 03:45:56 snj Exp $ .\" .\" Copyright (c) 2007 Antti Kantee. All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .Dd October 18, 2007 .Dt PUFFS_CRED 3 .Os .Sh NAME .Nm puffs_cred .Nd puffs credential and access control routines .Sh LIBRARY .Lb libpuffs .Sh SYNOPSIS .In puffs.h .Ft int .Fn puffs_cred_getuid "const struct puffs_cred *pcr" "uid_t *uid .Ft int .Fn puffs_cred_getgid "const struct puffs_cred *pcr" "gid_t *gid" .Ft int .Fo puffs_cred_getgroups .Fa "const struct puffs_cred *pcr" "gid_t *gids" "short *ngids" .Fc .Pp .Ft bool .Fn puffs_cred_isuid "const struct puffs_cred *pcr" "uid_t uid" .Ft bool .Fn puffs_cred_hasgroup "const struct puffs_cred *pcr" "gid_t gid" .Ft bool .Fn puffs_cred_iskernel "const struct puffs_cred *pcr" .Ft bool .Fn puffs_cred_isfs "const struct puffs_cred *pcr" .Ft bool .Fn puffs_cred_isjuggernaut "const struct puffs_cred *pcr" .Pp .Ft int .Fo puffs_access .Fa "enum vtype type" "mode_t file_mode" "uid_t owner" "gid_t group" .Fa "mode_t access_mode" "const struct puffs_cred *pcr" .Fc .Ft int .Fo puffs_access_chown .Fa "uid_t owner" "gid_t group" "uid_t newowner" "gid_t newgroup" .Fa "const struct puffs_cred *pcr" .Fc .Ft int .Fo puffs_access_chmod .Fa "uid_t owner" "gid_t group" "enum vtype type" "mode_t newmode" .Fa "const struct puffs_cred *pcr" .Fc .Ft int .Fo puffs_access_times .Fa "uid_t owner" "gid_t group" "mode_t file_mode" "int va_utimes_null" .Fa "const struct puffs_cred *pcr" .Fc .Sh DESCRIPTION These functions can be used to check operation credentials and perform access control. The structure .Vt struct puffs_cred can contain two types of credentials: ones belonging to users and ones belonging to the kernel. The latter is further divided into generic kernel credentials and file system credentials. The general rule is that these should be treated as more powerful than superuser credentials, but the file system is free to treat them as it sees fit. .Ss Credentials The .Fn puffs_cred_get family of functions fetch the uid or gid(s) from the given credential cookie. They return 0 for success or \-1 for an error and set .Va errno . An error happens when the credentials represent kernel or file system credentials and do not contain an uid or gid(s). .Pp For .Fn puffs_cred_getgroups , the argument .Fa gids should point to an array with room for .Fa *ngids elements. .Pp The .Fn puffs_cred_is family of functions return 1 if the truth value of the function for .Fa pcr is true and 0 if it is false. The function .Fn puffs_cred_isjuggernaut is true if .Fa pcr describes superuser, kernel or file system credentials. .Ss Access Control To help the programmers task of emulating normal kernel file system access control semantics, several helper functions are provided to check if access is allowed. They return 0 if access should be permitted or an errno value to indicate that access should be denied with the returned value. .Pp .Fn puffs_access is equivalent to the kernel .Fn vaccess function. The arguments specify current information of the file to be tested with the exception of .Fa access_mode , which is a combination of .Dv PUFFS_VREAD , .Dv PUFFS_VWRITE and .Dv PUFFS_VEXEC indicating the desired file access mode. .Pp The rest of the functions provide UFS semantics for operations. .Fn puffs_access_chown checks if it is permissible to chown a file with the current uid and gid to the new uid and gid with the credentials of .Fa pcr . .Pp .Fn puffs_access_chmod checks against permission to chmod a file of type .Fa type to the mode .Fa newmode . .Pp Finally, .Fn puffs_access_times checks if it is allowable to update the timestamps of a file. The argument .Fa va_utimes_null signals if the flags .Dv VA_UTIMES_NULL was set in .Fa va_vaflags of .Va struct vattr . If coming from a path where this information is unavailable, passing 0 as this argument restricts the permission of modification to the owner and superuser. Otherwise the function checks for write permissions to the node and returns success if the caller has write permissions. .Sh SEE ALSO .Xr puffs 3 , .Xr vnode 9