Expression simplification can get into an infinite loop due to eps
pairs hiding behind and alternation that can't be caught by
normalize_eps() (which exists in the first place to stop a similar
loop).
The loop in question happens in AltNode::normalize when a subtree has
the following structure.
1. elseif (child[dir]->is_type(ALT_NODE)) rotate_node too
alt
/\
/ \
/ \
eps alt
/\
/ \
/ \
alt eps
/\
/ \
/ \
eps eps
2. if (normalize_eps(dir)) results in
alt
/\
/ \
/ \
alt eps
/\
/ \
/ \
alt eps
/\
/ \
/ \
eps eps
3. elseif (child[dir]->is_type(ALT_NODE)) rotate_node too
alt
/\
/ \
/ \
alt alt
/\ /\
/ \ / \
/ \ / \
eps eps eps eps
4. elseif (child[dir]->is_type(ALT_NODE)) rotate_node too
alt
/\
/ \
/ \
eps alt
/\
/ \
/ \
eps alt
/\
/ \
/ \
eps eps
5. if (normalize_eps(dir)) results in
alt
/\
/ \
/ \
alt eps
/\
/ \
/ \
eps alt
/\
/ \
/ \
eps eps
6. elseif (child[dir]->is_type(ALT_NODE)) rotate_node too
alt
/\
/ \
/ \
eps alt
/\
/ \
/ \
alt eps
/\
/ \
/ \
eps eps
back to beginning of cycle
Fix this by detecting the creation of an eps_pair in rotate_node(),
that pair can be immediately eliminated by simplifying the tree in that
step.
In the above cycle the pair creation is caught at step 3 resulting
in
3. elseif (child[dir]->is_type(ALT_NODE)) rotate_node too
alt
/\
/ \
/ \
alt eps
/\
/ \
/ \
eps eps
4. elseif (child[dir]->is_type(ALT_NODE)) rotate_node too
alt
/\
/ \
/ \
eps alt
/\
/ \
/ \
eps eps
which gets reduced to
alt
/\
/ \
/ \
eps eps
breaking the normalization loop. The degenerate alt node will be caught
in turn when its parent is dealt with.
This needs to be backported to all releases
Closes: https://gitlab.com/apparmor/apparmor/-/issues/398
Fixes: 846cee506 ("Split out parsing and expression trees from regexp.y")
Reported-by: Christian Boltz <apparmor@cboltz.de>
Signed-off-by: John Johansen <john.johansen@canonical.com>
Closes#398
MR: https://gitlab.com/apparmor/apparmor/-/merge_requests/1252
Approved-by: Georgia Garcia <georgia.garcia@canonical.com>
Merged-by: John Johansen <john@jjmx.net>
Expression simplification can get into an infinite loop due to eps
pairs hiding behind and alternation that can't be caught by
normalize_eps() (which exists in the first place to stop a similar
loop).
The loop in question happens in AltNode::normalize when a subtree has
the following structure.
1. elseif (child[dir]->is_type(ALT_NODE)) rotate_node too
alt
/\
/ \
/ \
eps alt
/\
/ \
/ \
alt eps
/\
/ \
/ \
eps eps
2. if (normalize_eps(dir)) results in
alt
/\
/ \
/ \
alt eps
/\
/ \
/ \
alt eps
/\
/ \
/ \
eps eps
3. elseif (child[dir]->is_type(ALT_NODE)) rotate_node too
alt
/\
/ \
/ \
alt alt
/\ /\
/ \ / \
/ \ / \
eps eps eps eps
4. elseif (child[dir]->is_type(ALT_NODE)) rotate_node too
alt
/\
/ \
/ \
eps alt
/\
/ \
/ \
eps alt
/\
/ \
/ \
eps eps
5. if (normalize_eps(dir)) results in
alt
/\
/ \
/ \
alt eps
/\
/ \
/ \
eps alt
/\
/ \
/ \
eps eps
6. elseif (child[dir]->is_type(ALT_NODE)) rotate_node too
alt
/\
/ \
/ \
eps alt
/\
/ \
/ \
alt eps
/\
/ \
/ \
eps eps
back to beginning of cycle
Fix this by detecting the creation of an eps_pair in rotate_node(),
that pair can be immediately eliminated by simplifying the tree in that
step.
In the above cycle the pair creation is caught at step 3 resulting
in
3. elseif (child[dir]->is_type(ALT_NODE)) rotate_node too
alt
/\
/ \
/ \
alt eps
/\
/ \
/ \
eps eps
4. elseif (child[dir]->is_type(ALT_NODE)) rotate_node too
alt
/\
/ \
/ \
eps alt
/\
/ \
/ \
eps eps
whch gets reduces to
alt
/\
/ \
/ \
eps eps
breaking the normalization loop. The degenerate alt node will be caught
in turn when its parent is dealt with.
This needs to be backported to all releases
Closes: https://gitlab.com/apparmor/apparmor/-/issues/398
Fixes: 846cee506 ("Split out parsing and expression trees from regexp.y")
Reported-by: Christian Boltz <apparmor@cboltz.de>
Signed-off-by: John Johansen <john.johansen@canonical.com>
technically a # leading a value in an assignment expression is allowed,
however people are also using it to a comment at the end of a line.
ie.
```
@{var1}=value1 # comment about this value or for a given system
```
this unsurprisingly leads to odd/unexpected behavior when the variable
is used.
```
allow rw /@{var1},
```
expands into
```
allow rw /{value1,#,comment,about,this,value,or,for,a,given,system},
```
change a leading # of a value in an assignment expression to a comment.
If the # is really supposed to lead the value, require it to be escaped
or in quotes.
ie.
```
@{var1}=value1 \#not_a_comment
```
Note: this could potentially break som policy if the # was used as the
leading character for a value in an assignment expression, but
is worth it to avoid the confusion.
Signed-off-by: John Johansen <john.johansen@canonical.com>
MR: https://gitlab.com/apparmor/apparmor/-/merge_requests/1255
Approved-by: Georgia Garcia <georgia.garcia@canonical.com>
Merged-by: John Johansen <john@jjmx.net>
technically a # leading a value in an assignment expression is allowed,
however people are also using it to a comment at the end of a line.
ie.
@{var1}=value1 # comment about this value or for a given system
this unsurprisingly leads to odd/unexpected behavior when the variable
is used.
allow rw /@{var1},
expands into
allow rw /{value1,#,comment,about,this,value,or,for,a,given,system},
change a leading # as value in an assignment expression to a comment.
If the # is really supposed to lead the value, require it to be escaped
or in quotes.
ie.
@{var1}=value1 \#not_a_comment
Note: this could potentially break som policy if the # was used as the
leading character for a value in an assignment expression, but
is worth it to avoid the confusion.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Add a flag that allows setting the error code AppArmor will send when
an operation is denied. This should not be used normally.
Signed-off-by: Georgia Garcia <georgia.garcia@canonical.com>
This updates the man page for the recent inet mediation patch.
This is an extension of MR 1202, it adds a patch that changes the anonymous ip address anon to be ip address none which is a better fit.
This patch adds documentation of the recent network changes which extended all network rules to support access permissions, and added address and port matching for inet and inet6 families.
Signed-off-by: Georgia Garcia <georgia.garcia@canonical.com>
MR: https://gitlab.com/apparmor/apparmor/-/merge_requests/1213
Approved-by: John Johansen <john@jjmx.net>
Merged-by: John Johansen <john@jjmx.net>
inet mediation allows specifying rules for sockets that don't have
a known address, whether because it is unbound or because the
kernel doesn't make the address available.
The current code uses the word anon for anonymous, but that has
proven to be unclear. Switch from using anon to none, to emphasize
that this is a case where there just isn't an address to use as
part of mediation.
Signed-off-by: John Johansen <john.johansen@canonical.com>
When a family is specified in the network rules, we have to make sure
the conditionals match the family. A netlink rule should not be able
to specify ip and port for local and remote (peer) sockets, for example.
When type or protocol is specified in network rules along with inet
conditionals, we should only generate rules for the families that
support those conditionals.
Signed-off-by: Georgia Garcia <georgia.garcia@canonical.com>
The abstraction lxc/start-container shipped by the liblxc-common
package uses the following mount rule which was not allowed by our
regexes:
mount options=(rw, make-slave) -> **,
mount options=(rw, make-rslave) -> **,
Since in AppArmor regex ** includes '/' but * by itself doesn't, I'm
adding explicit support for **.
Signed-off-by: Georgia Garcia <georgia.garcia@canonical.com>
Add support for a default_allow mode that facillitates writing profiles
in that allow everything by default. This is not normally recomended
but fascilitates creating basic profiles while working to transition
policy away from unconfined.
This mode is being added specifically to replace the use of the
unconfined flag in these transitional profiles as the use of unconfined
in policy is confusing and does not reflect the semantics of what is
being done.
Generally the goal for policy should be to remove all default_allow
profiles once the policy is fully developed.
Note: this patch only adds parsing of default_allow mode. Currently
it sets the unconfined flag to achieve default allow but this
prevents deny rules from being applied. Once dominance is fixed a
subsequent patch will transition default_allow away from using
the unconfined flag.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Extend the policy syntax to have a rule that allows specifying all
permissions for all rule types.
allow all,
This is useful for making blacklist based policy, but can also be
useful when combined with other rule prefixes, eg. to add audit
to all rules.
audit access all,
Signed-off-by: John Johansen <john.johansen@canonical.com>
Add a flag that allows setting the signal used to kill the process.
This should not be normally used but can be very useful when
debugging applications, interaction with apparmor.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Add support for specifying the path prefix used when attach disconnected
is specified. The kernel supports prepending a different value than
/ when a path is disconnected. Expose through a profile flag.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Add support for the prompt profile flag. That allows policy to do an upcall to userspace if supported by the kernel and if a userspace daemon is available.
Signed-off-by: John Johansen <john.johansen@canonical.com>
MR: https://gitlab.com/apparmor/apparmor/-/merge_requests/1062
Approved-by: John Johansen <john@jjmx.net>
Merged-by: John Johansen <john@jjmx.net>
Do this to simplify test identification, and also support the different
invocation mechanisms of unittest, like running individual tests.
MR: https://gitlab.com/apparmor/apparmor/-/merge_requests/1070
Signed-off-by: Steve Beattie <steve.beattie@canonical.com>
Approved-by: John Johansen <john@jjmx.net>
Add tests for passing the parser a file that doesn't exist, a symlink
to a file that doesn't exist, and a directory that contains that
latter. Also include tests for different levels of -j passed as an
argument. These tests are based on the fixing commit 1259319508
("parser: Fix parser failing to handle errors when setting up work")
MR: https://gitlab.com/apparmor/apparmor/-/merge_requests/1070
Signed-off-by: Steve Beattie <steve.beattie@canonical.com>
Approved-by: John Johansen <john@jjmx.net>
Allowing access to a debug flag can greatly improve policy debugging.
This is different than the debug mode of old, that was removed. It only
will trigger additional messages to the kernel ring buffer, not
the audit log, and it does not change mediation.
Signed-off-by: John Johansen <john.johansen@canonical.com>
MR: https://gitlab.com/apparmor/apparmor/-/merge_requests/1048
made it so rules like
mount slave /snap/bin/** -> /**,
mount /snap/bin/** -> /**,
would get passed into change_mount_type rule generation when they
shouldn't have been. This would result in two different errors.
1. If kernel mount flags were present on the rule. The error would
be caught causing an error to be returned, causing profile compilation
to fail.
2. If the rule did not contain explicit flags then rule would generate
change_mount_type permissions based on souly the mount point. And
the implied set of flags. However this is incorrect as it should
not generate change_mount permissions for this type of rule. Not
only does it ignore the source/device type condition but it
generates permissions that were never intended.
When used in combination with a deny prefix this overly broad
rule can result in almost all mount rules being denied, as the
denial takes priority over the allow mount rules.
Fixes: https://bugs.launchpad.net/apparmor/+bug/2023814
Fixes: https://bugzilla.opensuse.org/show_bug.cgi?id=1211989
Fixes: 9d3f8c6cc ("parser: fix parsing of source as mount point for propagation type flags")
Fixes: MR: https://gitlab.com/apparmor/apparmor/-/merge_requests/1048
MR: https://gitlab.com/apparmor/apparmor/-/merge_requests/1054
Signed-off-by: John Johansen <john.johansen@canonical.com>
(cherry picked from commit 86d193e183)
Signed-off-by: John Johansen <john.johansen@canonical.com>
Before 300889c3a, mount rules would compile policy when using source
as mount point for rules that contain propagation type flags, such as
unbindable, runbindable, private, rprivate, slave, rslave, shared, and
rshared. Even though it compiled, the rule generated would not work as
expected.
This commit fixes both issues. It allows the usage of source as mount
point for the specified flags, albeit with a deprecation warning, and
it correctly generates the mount rule.
The policy fails to load when both source and mount point are
specified, keeping the original behavior (reference
parser/tst/simple_tests/mount/bad_opt_10.sd for example).
Fixes: https://bugs.launchpad.net/bugs/1648245
Fixes: https://bugs.launchpad.net/bugs/2023025
Signed-off-by: Georgia Garcia <georgia.garcia@canonical.com>
These tests contains incompatible mount options and broken
after ("parser: add conflicting flags check for options= conditionals")
Signed-off-by: Alexander Mikhalitsyn <aleksandr.mikhalitsyn@canonical.com>
Acked-by: John Johansen <john.johansen@canonical.com>
I've seen this test fail because "apparmor_parser -N" returned the expected
lines, but in a different order than what's expected (dirtest.out).
To fix this, sort both the expected and actual output.
Per the discussion in #243, this MR removes Python 2 compatibility. Namely, this merge request:
- removes code behind `sys` and `platform` interpreter version checks
- removes `unicode` vs. `str` handling
- removes unnecessary `__future__` imports
- removes unnecessary `object` inheritance
- removes unnecessary `super()` arguments
- uncomments commented-out code with "uncomment when python3 only" notes or some variant of that message
Regarding the `unicode` vs. `str` handling, it's arguably more Pythonic to check `isinstance(x, str)` as opposed to `type(x) is str`, but I didn't want to alter code behavior.
A change needs to be made to the `INCOMPLETE_COVERAGE` setting in `utils/test/Makefile` to get the pipeline to pass. I didn't get anywhere tweaking the setting myself, so someone else with more AppArmor experience will have to make that change.
MR: https://gitlab.com/apparmor/apparmor/-/merge_requests/894
Approved-by: Christian Boltz <apparmor@cboltz.de>
Merged-by: Christian Boltz <apparmor@cboltz.de>
