91 lines
2.2 KiB
Groff
91 lines
2.2 KiB
Groff
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.\" Hey Emacs! This file is -*- nroff -*- source.
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.\"
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.\" Author: Eamon Walsh (ewalsh@epoch.ncsc.mil) 2004
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.TH "avc_context_to_sid" "3" "27 May 2004" "" "SE Linux API documentation"
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.SH "NAME"
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avc_context_to_sid, avc_sid_to_context, sidput, sidget \- obtain and manipulate security ID's.
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.SH "SYNOPSIS"
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.B #include <selinux/selinux.h>
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.br
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.B #include <selinux/avc.h>
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.sp
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.BI "int avc_context_to_sid(security_context_t " ctx ", security_id_t *" sid ");"
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.sp
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.BI "int avc_sid_to_context(security_id_t " sid ", security_context_t *" ctx ");"
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.sp
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.BI "int sidget(security_id_t " sid ");"
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.sp
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.BI "int sidput(security_id_t " sid ");"
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.SH "DESCRIPTION"
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Security ID's (SID's) are reference-counted, opaque representations of security contexts.
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.B avc_context_to_sid
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returns a SID for the given
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.I context
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in the memory referenced by
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.IR sid ,
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incrementing its reference count by 1.
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.B avc_sid_to_context
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returns a copy of the context represented by
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.I sid
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in the memory referenced by
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.IR ctx .
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The user must free the copy with
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.BR freecon (3).
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.B sidget
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increments the reference count of
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.I sid
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by 1.
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.B sidput
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decrements the reference count of
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.I sid
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by 1. If the count ever reaches zero, the SID becomes
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invalid and must not be used any further.
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.SH "RETURN VALUE"
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.B sidget
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and
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.B sidput
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return the new reference count. A return value of zero indicates
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an invalid SID.
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.B avc_context_to_sid
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and
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.B avc_sid_to_context
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return zero on success. On error, \-1 is returned and
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.I errno
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is set appropriately.
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.SH "ERRORS"
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.TP
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.B EINVAL
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The provided
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.I sid
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has a zero reference count and is invalid.
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.TP
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.B ENOMEM
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An attempt to allocate memory failed.
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.SH "NOTES"
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The expected usage pattern for these functions is that
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.B avc_context_to_sid
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will be called once to obtain a SID for a newly created object,
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.B sidget
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will be called on a SID when its object is duplicated, and
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.B sidput
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will be called on a SID when its object is destroyed. Proper reference counting is necessary to ensure that SID's and associated cache entries are reclaimed from memory when no longer needed.
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.SH "AUTHOR"
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Eamon Walsh <ewalsh@epoch.ncsc.mil>
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.SH "SEE ALSO"
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.BR avc_init (3),
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.BR avc_has_perm (3),
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.BR avc_cache_stats (3),
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.BR avc_add_callback (3),
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.BR getcon (3),
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.BR freecon (3)
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