Their is no reason for the parse to stitch 2 dfas together this way.
In the future there will be better ways to do this using unconpressed
dfas.
Dropping this also allows for some simplification, in other parts of
the code.
Drop the dead/unused code
Signed-off-by: John Johansen <john.johansen@canonical.com>
When the find fails but the insertion also fails, we leak the new node
that we generated. Delete the new node in this case to avoid leaking
memory.
Signed-off-by: Ryan Lee <ryan.lee@canonical.com>
Moving apply_and_clear_deny() before the first minimization pass, which
was necessary to propperly support building accept information for
older none extended permission dfas, allows us to also get rid of doing a
second minimization pass if we want to force clearing explicit deny
info from extended permission tables.
Signed-off-by: John Johansen <john.johansen@canonical.com>
switch permission bits to use perm32_t type. This is just annotating
the code as it is no different than uint32_t at this time.
We do not convert the accept values as they may be mapped permission
bits or they may be and index value.
Signed-off-by: John Johansen <john.johansen@canonical.com>
v1 of permstable32 has some broken verification checks. By using two
copies of a merged dfa and an xtable the same size of the permstable
we can work around the issue.
Signed-off-by: John Johansen <john.johansen@canonical.com>
If extended permissions are supported use them. We need to build a
permission table and set the accept state of the chfa up as an index
into the table.
For now map the front end permission layout into the old format and
then convert that to the perms table just as the kernel does.
Signed-off-by: John Johansen <john.johansen@canonical.com>
In preparation for more flags (not all of the backend dfa based),
rework the optimization and dump flag handling which has been exclusively
around the dfa up to this point.
- split dfa control and dump flags into separate fields. This gives more
room for new flags in the existing DFA set
- rename DFA_DUMP, and DFA_CONTROL to CONTROL_DFA and DUMP_DFA as
this will provide more uniform naming for none dfa flags
- group dump and control flags into a structure so they can be passed
together.
Signed-off-by: John Johansen <john.johansen@canonical.com>
v8 network permissions extend into the range used by exec mapping
so it is important to not blindly do execmapping on both the
file dfa and policydb dfa any more.
Track what type of dfa and its permissions we are building so
we can properly apply exec mapping only when building the
file dfa.
MR: https://gitlab.com/apparmor/apparmor/-/merge_requests/521
Signed-off-by: John Johansen <john.johansen@canonical.com>
The current encoding makes every xattr optional and uses this to
propogate the permission from the tail to the individual rule match
points.
This however is wrong. Instead change the encoding so that an xattr
(unless optional) is required to be matched before allowing moving
onto the next xattr match.
The permission is carried on the end on each rule portion file match,
xattr 1, xattr 2, ...
Signed-off-by: John Johansen <john.johansen@canonical.com>
xattrs can contain NULL characters in their values which means we can
not user regular NULL transitions to separate values. To fix this
use out of band transition instead.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Currently the NULL character is used as an out of band transition
for string/path elements. This works for them as the NULL character
is not valid for this data. However this does not work for binary
data that can contain a NULL character.
So far we have only dealt with fixed length fields of binary data
making the NULL separator either unnecessary.
However binary data like in the xattr match and mount data field are
variable length and can contain NULL characters. To deal with this
add the ability to specify out of band transitions, that can only
be triggered by code not input data.
The out of band transition can be used to separate variable length
data fields just as the NULL transition has been used to separate
variable length strings.
In the compressed hfa out of band transitions are expressed as a
negative offset from the states base. This leaves us room to expand
the character match range in the future if desired and on average
makes the range between the out of band transition and the input
transitions smaller than would be had if the out of band transition
had been stored after the valid input transitions.
Out of band transitions in the dfa will not break old kernels
that don't know about them, but they won't be able to trigger
the out of band transition match. So they should not be used unless
the kernel indicates that it supports them.
It should be noted that this patch only adds support for a single
out of band transition. If multiple out of band transitions are
required. It is trivial to extend.
- Add a tag indicating support in the kernel
- add a oob max range field to the dfa header so the kernel knows
what the max range that needs verifying is.
- extend oob generation fns to generate oob based on value instead
of a fixed -1.
Signed-off-by: John Johansen <john.johansen@canonical.com>
The length of a xmatch is used to prioritize multiple profiles that
match the same path, with the intent that the more specific match wins.
Currently, the length of a xmatch is computed by the position of the
first regex character.
While trying to work around issues with no_new_privs by combining
profiles, we noticed that the xmatch length computation doesn't work as
expected for multiple regexs. Consider the following two profiles:
profile all /** { }
profile bins /{,usr/,usr/local/}bin/** { }
xmatch_len is currently computed as "1" for both profiles, even though
"bins" is clearly more specific.
When determining the length of a regex, compute the smallest possible
match and use that for xmatch priority instead of the position of the
first regex character.
Currently rules are added to the expression tree in order, and then
tree simplification and factoring is done. This forces simplification
to "search" through the tree to find rules with the same permissions
during right factoring, which dependent on ordering of factoring may
not be able to group all rules of the same permissions.
Instead of having tree factoring do the work to regroup rules with the
same permissions, pregroup them as part of the expr tree construction.
And only build the full tree when the dfa is constructed.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Steve Beattie <steve@nxnw.org>
This cleans things up a bit and fixes a bug where not all rules are
getting properly counted so that the addition of policy_mediation
rules fails to generate the policy dfa in some cases.
Because the policy dfa is being generated correctly now we need to
fix some tests to use the new -M flag to specify the expected features
set of the test.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Steve Beattie <steve@nxnw.org>
Acked-by: Seth Arnold <seth.arnold@canonical.com>
This patch addresses a bunch of the compiler string conversion warnings
that were introduced with the C++-ification patch.
Signed-off-by: Steve Beattie <steve@nxnw.org>
Acked-by: Tyler Hicks <tyhicks@canonical.com>
Split hfa into hfa and compressed_hfa files. The hfa portion focuses on
creating an manipulating hfas, while compressed_hfa is used for creating
compressed hfas that can be used/reused at run time with much less memory
usage than the full blown hfa.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-By: Steve Beattie <sbeattie@ubuntu.com>
Split out the aare_rule bits that encapsulate the convertion of apparmor
rules into the final compressed dfa.
This patch will not compile because of the it needs hfa to export an interface
but hfa is going to be split so just delay until hfa and transtable are
split and they can each export their own interface.
Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-By: Steve Beattie <sbeattie@ubuntu.com>
