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1fb230f11f
The call aa_getpeercon() can return ENOPROTOOPT error in some cases, specifically when the kernel lacks 'fine grained unix mediation'. Currently, this capability isn't available in upstream kernels, but only in patched ones (for example, the regular Ubuntu kernels). Unfortunately, the manpage lacks this info. This patch fixes this.
Fixes: https://gitlab.com/apparmor/apparmor/-/issues/366
MR: https://gitlab.com/apparmor/apparmor/-/merge_requests/1143
Approved-by: John Johansen <john@jjmx.net>
Merged-by: John Johansen <john@jjmx.net>
(cherry picked from commit b03abbd75f)
Signed-off-by: John Johansen <john.johansen@canonical.com>
146 lines
4.9 KiB
Plaintext
146 lines
4.9 KiB
Plaintext
# This publication is intellectual property of Canonical Ltd. Its contents
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# can be duplicated, either in part or in whole, provided that a copyright
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# label is visibly located on each copy.
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#
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# All information found in this book has been compiled with utmost
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# attention to detail. However, this does not guarantee complete accuracy.
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# Neither Canonical Ltd, the authors, nor the translators shall be held
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# liable for possible errors or the consequences thereof.
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#
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# Many of the software and hardware descriptions cited in this book
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# are registered trademarks. All trade names are subject to copyright
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# restrictions and may be registered trade marks. Canonical Ltd.
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# essentially adhere to the manufacturer's spelling.
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#
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# Names of products and trademarks appearing in this book (with or without
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# specific notation) are likewise subject to trademark and trade protection
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# laws and may thus fall under copyright restrictions.
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#
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=pod
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=head1 NAME
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aa_getprocattr_raw, aa_getprocattr - read and parse procattr data
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aa_getcon, aa_gettaskcon - get task confinement information
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aa_getpeercon - get the confinement of a socket's other end (peer)
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=head1 SYNOPSIS
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B<#include E<lt>sys/apparmor.hE<gt>>
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B<int aa_getprocattr_raw(pid_t tid, const char *attr, char *buf, int len, char **mode);>
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B<int aa_getprocattr(pid_t tid, const char *attr, char **label, char **mode);>
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B<int aa_gettaskcon(pid_t target, char **label, char **mode);>
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B<int aa_getcon(char **label, char **mode);>
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B<int aa_getpeercon_raw(int fd, char *buf, int *len, char **mode);>
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B<int aa_getpeercon(int fd, char **label, char **mode);>
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Link with B<-lapparmor> when compiling.
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=head1 DESCRIPTION
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The aa_getcon function gets the current AppArmor confinement context for the
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current task. The confinement context consists of a label and a mode. The label
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is usually just the name of the AppArmor profile restricting the task, but it
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may include the profile namespace or in some cases a set of profile names
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(known as a stack of profiles). The mode is a string that describes how the
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kernel is enforcing the policy defined in the profile. Profiles loaded in
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"enforce" mode will result in enforcement of the policy defined in the profile
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as well as reporting policy violation attempts. Profiles in "complain" mode
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will not enforce policy but instead report policy violation attempts.
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Some examples of possible returned *label strings are "unconfined", "/sbin/dhclient",
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and "Firefox". The string can consist of any non-NUL characters but it will be
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NUL-terminated. The *label string must be freed using free().
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The possible *mode strings are "enforce" and "complain". Additionally, *mode may
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be NULL when *label is "unconfined". B<The *mode string must not be freed>. The
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*label and *mode strings come from a single buffer allocation and are separated
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by a NUL character.
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The aa_gettaskcon function is like the aa_getcon function except it will work
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for any arbitrary task in the system.
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The aa_getpeercon function is similar to that of aa_gettaskcon except that
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it returns the confinement information for task on the other end of a socket
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connection.
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The aa_getpeercon_raw function is the backend for the aa_getpeercon function
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and does not handle buffer allocation.
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The aa_getprocattr function is the backend for the aa_getcon and aa_gettaskcon
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functions and handles the reading and parsing of the confinement data from
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different arbitrary attr files and returns the processed results in
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an allocated buffer.
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The aa_getprocattr_raw() is the backend for the aa_getprocattr function and
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does not handle buffer allocation.
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=head1 RETURN VALUE
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On success size of data placed in the buffer is returned, this includes the
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mode if present and any terminating characters. On error, -1 is returned, and
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errno(3) is set appropriately.
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=head1 ERRORS
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=over 4
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=item B<EINVAL>
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The apparmor kernel module is not loaded or the communication via the
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F</proc/*/attr/file> did not conform to protocol.
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=item B<ENOMEM>
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Insufficient kernel memory was available.
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=item B<EACCES>
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Access to the specified I<file/task> was denied.
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=item B<ENOENT>
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The specified I<file/task> does not exist or is not visible.
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=item B<ERANGE>
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The confinement data is too large to fit in the supplied buffer.
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=item B<ENOPROTOOPT>
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The kernel doesn't support the SO_PEERLABEL option in sockets. This happens
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mainly when the kernel lacks 'fine grained unix mediation' support. It also
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can happen on LSM stacking kernels where another LSM has claimed this
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interface and decides to return this error, although this is really a
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corner case.
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=back
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=head1 NOTES
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If aa_getpeercon_raw returns -1 and errno is ERANGE, the value of *len can be
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used to reallocate buf so that it is sufficiently large enough to store the
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confinement data.
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=head1 BUGS
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None known. If you find any, please report them at
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L<https://gitlab.com/apparmor/apparmor/-/issues>.
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=head1 SEE ALSO
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apparmor(7), apparmor.d(5), apparmor_parser(8), aa_change_profile(2),
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aa_splitcon(3) and L<https://wiki.apparmor.net>.
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=cut
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