Summary of login.conf support changes:
o Incorporated BSDI code and enhancements, better logging for error
checking (which has been shown to be a problem, and is therefore
justified, imho); also some minor things we were missing, including
better quad_t math, which checks for under/overflows.
o setusercontext() now allows user resource limit overrides, but
does this AFTER dropping root privs, to restrict the user to
droping hard limits and set soft limits within the kernel's
allowed user limits.
o umask() only set once, and only if requested.
o add _secure_path(), and use in login.conf to guard against
symlinks etc. and non-root owned or non-user owned files being
used. Derived from BSDI contributed code.
o revamped authentication code to BSDI's latest api, which
includes deleting authenticate() and adding auth_check()
and a few other functions. This is still marked as depecated
in BSDI, but is included for completeness. No other source
in the tree uses this anyway, so it is now bracketed with
#ifdef LOGIN_CAP_AUTH which is by default not defined. Only
auth_checknologin() and auth_cat() are actually used in
module login_auth.c.
o AUTH_NONE definition removed (collided with other includes
in the tree). [bde]
o BSDI's login_getclass() now accepts a char *classname
parameter rather than struct passwd *pwd. We now do likewise,
but added login_getpwclass() for (sort of) backwards
compatiblity, namely because we handle root as a special
case for the default class. This will require quite a few
changes elsewhere in the source tree.
o We no longer pretend to support rlim_t as a long type.
o Revised code formatting to be more bsd-ish style.
1997-05-10 18:55:38 +00:00
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.\" Copyright (c) 1997 David Nugent <davidn@blaze.net.au>
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, is permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice immediately at the beginning of the file, without modification,
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.\" this list of conditions, and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. This work was done expressly for inclusion into FreeBSD. Other use
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.\" is permitted provided this notation is included.
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.\" 4. Absolutely no warranty of function or purpose is made by the author
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.\" David Nugent.
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.\" 5. Modifications may be freely made to this file providing the above
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.\" conditions are met.
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.\"
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1997-05-15 06:06:32 +00:00
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.\" $Id: _secure_path.3,v 1.1 1997/05/10 18:55:37 davidn Exp $
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Summary of login.conf support changes:
o Incorporated BSDI code and enhancements, better logging for error
checking (which has been shown to be a problem, and is therefore
justified, imho); also some minor things we were missing, including
better quad_t math, which checks for under/overflows.
o setusercontext() now allows user resource limit overrides, but
does this AFTER dropping root privs, to restrict the user to
droping hard limits and set soft limits within the kernel's
allowed user limits.
o umask() only set once, and only if requested.
o add _secure_path(), and use in login.conf to guard against
symlinks etc. and non-root owned or non-user owned files being
used. Derived from BSDI contributed code.
o revamped authentication code to BSDI's latest api, which
includes deleting authenticate() and adding auth_check()
and a few other functions. This is still marked as depecated
in BSDI, but is included for completeness. No other source
in the tree uses this anyway, so it is now bracketed with
#ifdef LOGIN_CAP_AUTH which is by default not defined. Only
auth_checknologin() and auth_cat() are actually used in
module login_auth.c.
o AUTH_NONE definition removed (collided with other includes
in the tree). [bde]
o BSDI's login_getclass() now accepts a char *classname
parameter rather than struct passwd *pwd. We now do likewise,
but added login_getpwclass() for (sort of) backwards
compatiblity, namely because we handle root as a special
case for the default class. This will require quite a few
changes elsewhere in the source tree.
o We no longer pretend to support rlim_t as a long type.
o Revised code formatting to be more bsd-ish style.
1997-05-10 18:55:38 +00:00
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.\"
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.Dd May 2, 1997
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.Os FreeBSD
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.Dt _SECURE_PATH 3
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.Sh NAME
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.Nm _secure_path
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.Nd determine if a file appears to be secure
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.Sh SYNOPSIS
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.Fd #include <sys/types.h>
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.Fd #include <libutil.h>
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.Ft int
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.Fn _secure_path "const char *path" "uid_t uid" "gid_t gid"
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.Pp
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.Sh DESCRIPTION
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This function does some basic security checking on a given path.
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It is intended to be used by processes running with root privileges
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in order to decide whether or not to trust the contents of a given
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file.
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It uses a method often used to detect system compromise.
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.Pp
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A file is considered 'secure' if it meets the following conditions:
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.Bl -enum
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.It
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The file exists, and is a regular file (not a symlink, device
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special or named pipe, etc.),
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.It
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Is not world writable.
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.It
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1997-05-15 06:06:32 +00:00
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Is owned by the given uid or uid 0, if uid is not -1,
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Summary of login.conf support changes:
o Incorporated BSDI code and enhancements, better logging for error
checking (which has been shown to be a problem, and is therefore
justified, imho); also some minor things we were missing, including
better quad_t math, which checks for under/overflows.
o setusercontext() now allows user resource limit overrides, but
does this AFTER dropping root privs, to restrict the user to
droping hard limits and set soft limits within the kernel's
allowed user limits.
o umask() only set once, and only if requested.
o add _secure_path(), and use in login.conf to guard against
symlinks etc. and non-root owned or non-user owned files being
used. Derived from BSDI contributed code.
o revamped authentication code to BSDI's latest api, which
includes deleting authenticate() and adding auth_check()
and a few other functions. This is still marked as depecated
in BSDI, but is included for completeness. No other source
in the tree uses this anyway, so it is now bracketed with
#ifdef LOGIN_CAP_AUTH which is by default not defined. Only
auth_checknologin() and auth_cat() are actually used in
module login_auth.c.
o AUTH_NONE definition removed (collided with other includes
in the tree). [bde]
o BSDI's login_getclass() now accepts a char *classname
parameter rather than struct passwd *pwd. We now do likewise,
but added login_getpwclass() for (sort of) backwards
compatiblity, namely because we handle root as a special
case for the default class. This will require quite a few
changes elsewhere in the source tree.
o We no longer pretend to support rlim_t as a long type.
o Revised code formatting to be more bsd-ish style.
1997-05-10 18:55:38 +00:00
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.It
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Is not group wriable or it has group ownership by the given
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gid, if gid is not -1.
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.El
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.Sh RETURN VALUES
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This function returns zero if the file exists and may be
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considered secure, -2 if the file does not exist, and
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-1 otherwise to indicate a security failure.
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.Xr syslog 3 ,
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is used to log any failure of this function, including the
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reason, at LOG_ERR priority.
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.Sh BUGS
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The checks carried out are rudamentary and no attempt is made
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to eliminate race conditions between use of this function and
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access to the file referenced.
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.Sh SEE ALSO
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.Xr lstat 3 ,
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.Xr syslog 3 .
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.Sh HISTORY
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Code from which this function was derived was contributed to the
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FreeBSD project by Berkeley Software Design, Inc.
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