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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | CAVEATS | SEE ALSO | COLOPHON |
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security_compute_av(3) SELinux API documentation security_compute_av(3)
security_compute_av, security_compute_av_flags,
security_compute_create, security_compute_create_name,
security_compute_relabel, security_compute_member,
security_compute_user, security_validatetrans,
security_get_initial_context - query the SELinux policy database
in the kernel
#include <selinux/selinux.h>
int security_compute_av(const char *scon, const char *tcon,
security_class_t tclass, access_vector_t requested, struct
av_decision *avd);
int security_compute_av_raw(const char *scon, const char *tcon,
security_class_t tclass, access_vector_t requested, struct
av_decision *avd);
int security_compute_av_flags(const char *scon, const char *tcon,
security_class_t tclass, access_vector_t requested, struct
av_decision *avd);
int security_compute_av_flags_raw(const char *scon, const char
*tcon, security_class_t tclass, access_vector_t requested, struct
av_decision *avd);
int security_compute_create(const char *scon, const char *tcon,
security_class_t tclass, char **newcon);
int security_compute_create_raw(const char *scon, const char
*tcon, security_class_t tclass, char **newcon);
int security_compute_create_name(const char *scon, const char
*tcon, security_class_t tclass, const char *objname, char
**newcon);
int security_compute_create_name_raw(const char *scon, const char
*tcon, security_class_t tclass, const char *objname, char
**newcon);
int security_compute_relabel(const char *scon, const char *tcon,
security_class_t tclass, char **newcon);
int security_compute_relabel_raw(const char *scon, const char
*tcon, security_class_t tclass, char **newcon);
int security_compute_member(const char *scon, const char *tcon,
security_class_t tclass, char **newcon);
int security_compute_member_raw(const char *scon, const char
*tcon, security_class_t tclass, char **newcon);
int security_compute_user(const char *scon, const char *username,
char ***con);
int security_compute_user_raw(const char *scon, const char
*username, char ***con);
int security_validatetrans(const char *scon, const char *tcon,
security_class_t tclass, const char *newcon);
int security_validatetrans_raw(const char *scon, const char *tcon,
security_class_t tclass, const char *newcon);
int security_get_initial_context(const char *name, char **con);
int security_get_initial_context_raw(const char *name, char
**con);
int selinux_check_access(const char *scon, const char *tcon, const
char *class, const char *perm, void *auditdata);
int selinux_check_passwd_access(access_vector_t requested);
int checkPasswdAccess(access_vector_t requested);
This family of functions is used to obtain policy decisions from
the SELinux kernel security server (policy engine). In general,
direct use of security_compute_av() and its variant interfaces is
discouraged in favor of using selinux_check_access() since the
latter automatically handles the dynamic mapping of class and
permission names to their policy values, initialization and use of
the Access Vector Cache (AVC), and proper handling of per-domain
and global permissive mode and allow_unknown.
When using any of the functions that take policy integer values
for classes or permissions as inputs, use
string_to_security_class(3) and string_to_av_perm(3) to map the
class and permission names to their policy values. These values
may change across a policy reload, so they should be re-acquired
on every use or using a SELINUX_CB_POLICYLOAD callback set via
selinux_set_callback(3).
An alternative approach is to use selinux_set_mapping(3) to create
a mapping from class and permission index values used by the
application to the policy values, thereby allowing the application
to pass its own fixed constants for the classes and permissions to
these functions and internally mapping them on demand. However,
this also requires setting up a callback as above to address
policy reloads.
security_compute_av() queries whether the policy permits the
source context scon to access the target context tcon via class
tclass with the requested access vector. The decision is returned
in avd.
security_compute_av_flags() is identical to security_compute_av
but additionally sets the flags field of avd. Currently one flag
is supported: SELINUX_AVD_FLAGS_PERMISSIVE, which indicates the
decision is computed on a permissive domain.
security_compute_create() is used to compute a context to use for
labeling a new object in a particular class based on a SID pair.
security_compute_create_name() is identical to
security_compute_create() but also takes name of the new object in
creation as an argument. When TYPE_TRANSITION rule on the given
class and a SID pair has object name extension, we shall be able
to obtain a correct newcon according to the security policy. Note
that this interface is only supported on the linux 2.6.40 or
later. In the older kernel, the object name will be simply
ignored.
security_compute_relabel() is used to compute the new context to
use when relabeling an object, it is used in the pam_selinux.so
source and the newrole source to determine the correct label for
the tty at login time, but can be used for other things.
security_compute_member() is used to compute the context to use
when labeling a polyinstantiated object instance.
security_compute_user() is used to determine the set of user
contexts that can be reached from a source context. This function
is deprecated; use get_ordered_context_list(3) instead.
security_validatetrans() is used to determine if a transition from
scon to newcon using tcon as the object is valid for object class
tclass. This checks against the mlsvalidatetrans and validatetrans
constraints in the loaded policy. Returns 0 if allowed, and -1 if
an error occurred with errno set.
security_get_initial_context() is used to get the context of a
kernel initial security identifier specified by name
security_compute_av_raw(), security_compute_av_flags_raw(),
security_compute_create_raw(), security_compute_create_name_raw(),
security_compute_relabel_raw(), security_compute_member_raw(),
security_compute_user_raw() security_validatetrans_raw() and
security_get_initial_context_raw() behave identically to their
non-raw counterparts but do not perform context translation.
selinux_check_access() is used to check if the source context has
the access permission for the specified class on the target
context.
selinux_check_passwd_access() is used to check for a permission in
the passwd class. selinux_check_passwd_access() uses
getprevcon(3) for the source and target security contexts.
checkPasswdAccess() is a deprecated alias of the
selinux_check_passwd_access() function.
Returns zero on success or -1 on error.
These functions are not thread-safe, you have to protect them from
concurrent calls using exclusive locks when multiple threads are
executing.
string_to_security_class(3), string_to_av_perm(3),
selinux_set_callback(3), selinux_set_mapping(3), getprevcon(3),
get_ordered_context_list(3), selinux(8)
This page is part of the selinux (Security-Enhanced Linux user-
space libraries and tools) project. Information about the project
can be found at ⟨https://github.com/SELinuxProject/selinux/wiki⟩.
If you have a bug report for this manual page, see
⟨https://github.com/SELinuxProject/selinux/wiki/Contributing⟩.
This page was obtained from the project's upstream Git repository
⟨https://github.com/SELinuxProject/selinux⟩ on 2025-08-11. (At
that time, the date of the most recent commit that was found in
the repository was 2025-08-04.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
russell@coker.com.au 1 January 2004 security_compute_av(3)
Pages that refer to this page: avc_add_callback(3), avc_compute_create(3), avc_has_perm(3), avc_init(3), avc_open(3), get_ordered_context_list(3), selinux_set_mapping(3)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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