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* CVE-2023-0614 Not-secret but access controlled LDAP attributes can be discovered (bug 15270)
BUG: https://bugzilla.samba.org/show_bug.cgi?id=15270
Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Joseph Sutton <josephsutton@catalyst.net.nz>
[abartlet@samba.org Adapted to LDB 2.5 series in Samba 4.16]
Redaction may be expensive if we end up needing to fetch a security
descriptor to verify rights to an attribute. Checking the search scope
is probably cheaper, so do that first.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=15270
Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
This makes it less likely that we forget to handle a case.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=15270
Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Add a hook, acl_redact_msg_for_filter(), in the aclread module, that
marks inaccessible any message elements used by an LDAP search filter
that the user has no right to access. Make the various ldb_match_*()
functions check whether message elements are accessible, and refuse to
match any that are not. Remaining message elements, not mentioned in the
search filter, are checked in aclread_callback(), and any inaccessible
elements are removed at this point.
Certain attributes, namely objectClass, distinguishedName, name, and
objectGUID, are always present, and hence the presence of said
attributes is always allowed to be checked in a search filter. This
corresponds with the behaviour of Windows.
Further, we unconditionally allow the attributes isDeleted and
isRecycled in a check for presence or equality. Windows is not known to
make this special exception, but it seems mostly harmless, and should
mitigate the performance impact on searches made by the show_deleted
module.
As a result of all these changes, our behaviour regarding confidential
attributes happens to match Windows more closely. For the test in
confidential_attr.py, we can now model our attribute handling with
DC_MODE_RETURN_ALL, which corresponds to the behaviour exhibited by
Windows.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=15270
Pair-Programmed-With: Andrew Bartlett <abartlet@samba.org>
Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz>
Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
[abartlet@samba.org adapted due to Samba 4.17 and lower
not having the patches for CVE-2020-25720 and 4.16 and lower
not having the patches for CVE-2022-32743 ]
Change all uses of ldb_kv_filter_attrs() to use
ldb_filter_attrs_in_place() instead. This function does less work than
its predecessor, and no longer requires the allocation of a second ldb
message. Some of the work is able to be split out into separate
functions that each accomplish a single task, with a purpose to make the
code clearer.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=15270
Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
ldb_filter_attrs() previously did too much. Now its replacement,
ldb_filter_attrs_in_place(), only does the actual filtering, while
taking ownership of each element's values is handled in a separate
function, ldb_msg_elements_take_ownership().
Also, ldb_filter_attrs_in_place() no longer adds the distinguishedName
to the message if it is missing. That is handled in another function,
ldb_msg_add_distinguished_name().
As we're now modifying the original message rather than copying it into
a new one, we no longer need the filtered_msg parameter.
We adapt a test, based on ldb_filter_attrs_test, to exercise the new
function.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=15270
Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
At present this function is an exact duplicate of ldb_filter_attrs(),
but in the next commit we shall modify it to work in place, without the
need for the allocation of a second message.
The test is a near duplicate of the existing test for
ldb_filter_attrs().
BUG: https://bugzilla.samba.org/show_bug.cgi?id=15270
Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Many places in Samba depend upon various components of an ldb message
being talloc allocated, and hence able to be used as talloc contexts.
The elements and values of an unpacked ldb message point to unowned data
inside the memory-mapped database, and this function ensures that such
messages have talloc ownership of said elements and values.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=15270
Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Add ldb_filter_attrs_test to the list of tests so that it actually gets
run.
Remove a duplicate ldb_msg_test that was accidentally added in commit
5ca90e758a.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=15270
Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
If the value of an ldb message element is not zero-terminated, calling
ldb_msg_find_attr_as_string() will cause the function to read off the
end of the buffer in an attempt to verify that the value is
zero-terminated. This can cause unexpected behaviour and make the test
randomly fail.
To avoid this, we must have a terminating null byte that is *not*
counted as part of the length, and so we must calculate the length with
strlen() rather than sizeof.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=15270
Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
The value can be quite large, the allocation will take much
longer than the actual match and is repeated per candidate
record.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=15331
BUG: https://bugzilla.samba.org/show_bug.cgi?id=15270
Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Joseph Sutton <josephsutton@catalyst.net.nz>
(cherry picked from commit cad96f59a0)
[abartlet@samba.org Included in the security release as this
makes the new large_ldap.py timeout test more reliable]
This aims to minimise usage of the error-prone pattern of searching for
a just-added message element in order to make modifications to it (and
potentially finding the wrong element).
BUG: https://bugzilla.samba.org/show_bug.cgi?id=15009
Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz>
Currently, there are many places where we use ldb_msg_add_empty() to add
an empty element to a message, and then call ldb_msg_add_value() or
similar to add values to that element. However, this performs an
unnecessary search of the message's elements to locate the new element.
Moreover, if an element with the same attribute name already exists
earlier in the message, the values will be added to that element,
instead of to the intended newly added element.
A similar pattern exists where we add values to a message, and then call
ldb_msg_find_element() to locate that message element and sets its flags
to (e.g.) LDB_FLAG_MOD_REPLACE. This also performs an unnecessary
search, and may locate the wrong message element for setting the flags.
To avoid these problems, add functions for appending a value to a
message, so that a particular value can be added to the end of a message
in a single operation.
For ADD requests, it is important that no two message elements share the
same attribute name, otherwise things will break. (Normally,
ldb_msg_normalize() is called before processing the request to help
ensure this.) Thus, we must be careful not to append an attribute to an
ADD message, unless we are sure (e.g. through ldb_msg_find_element())
that an existing element for that attribute is not present.
These functions will be used in the next commit.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=15009
Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz>
Using the newly added ldb flag, we can now detect when a message has
been shallow-copied so that its elements share their values with the
original message elements. Then when adding values to the copied
message, we now make a copy of the shared values array first.
This should prevent a use-after-free that occurred in LDB modules when
new values were added to a shallow copy of a message by calling
talloc_realloc() on the original values array, invalidating the 'values'
pointer in the original message element. The original values pointer can
later be used in the database audit logging module which logs database
requests, and potentially cause a crash.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=15009
Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz>
When making a shallow copy of an ldb message, mark the message elements
of the copy as sharing their values with the message elements in the
original message.
This flag value will be heeded in the next commit.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=15009
Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz>
* Fix build problems
BUG: https://bugzilla.samba.org/show_bug.cgi?id=15071
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Andreas Schneider <asn@samba.org>
Autobuild-User(v4-16-test): Stefan Metzmacher <metze@samba.org>
Autobuild-Date(v4-16-test): Thu Jun 9 12:14:04 UTC 2022 on sn-devel-184
The LDB filter processing is where the time is spent in the LDB stack
but the timeout event will not get run while this is ongoing, so we
must confirm we have not yet timed out manually.
RN: Ensure that the LDB request has not timed out during filter processing
as the LDAP server MaxQueryDuration is otherwise not honoured.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=14694
Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
This avoids master having an older or identical LDB version
to Samba 4.15.x while it gains additional changes that may
not all be backported.
Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
Autobuild-User(master): Jeremy Allison <jra@samba.org>
Autobuild-Date(master): Tue Oct 5 19:57:51 UTC 2021 on sn-devel-184
Previously, containment testing using the 'in' operator was handled by
performing an equality comparison between the chosen object and each of
the message's keys in turn. This behaviour was prone to errors due to
not considering differences in case between otherwise equal elements, as
the indexing operations do.
Containment testing should now be more consistent with the indexing
operations and with the get() method of ldb.Message.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=14845
Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
These tests verify that the 'in' operator on ldb.Message is consistent
with indexing and the get() method. This means that the 'dn' element
should always be present, lookups should be case-insensitive, and use of
an invalid type should result in a TypeError.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=14845
Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Previously, a TypeError was raised and subsequently overridden by a
KeyError.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=14845
Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Make a deep copy of the message elements in msg_diff() so that if either
of the input messages are deallocated early, the result does not refer
to non-existing elements.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=14642
BUG: https://bugzilla.samba.org/show_bug.cgi?id=14836
Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
Autobuild-User(master): Jeremy Allison <jra@samba.org>
Autobuild-Date(master): Sat Sep 4 00:55:32 UTC 2021 on sn-devel-184
- Improve calculate_popt_array_length()
- Use C99 initializers for builtin_popt_options[]
- pyldb: Fix Message.items() for a message containing elements
- pyldb: Add test for Message.items()
- tests: Use ldbsearch '--scope instead of '-s'
- pyldb: fix a typo
- Change page size of guidindexpackv1.ldb
- Use a 1MiB lmdb so the test also passes on aarch64 CentOS stream
- attrib_handler casefold: simplify space dropping
- fix ldb_comparison_fold off-by-one overrun
- CVE-2020-27840: pytests: move Dn.validate test to ldb
- CVE-2020-27840 ldb_dn: avoid head corruption in ldb_dn_explode
- CVE-2021-20277 ldb/attrib_handlers casefold: stay in bounds
- CVE-2021-20277 ldb tests: ldb_match tests with extra spaces
- improve comments for ldb_module_connect_backend()
- test/ldb_tdb: correct introductory comments
- ldb.h: remove undefined async_ctx function signatures
- correct comments in attrib_handers val_to_int64
- dn tests use cmocka print functions
- ldb_match: remove redundant check
- add tests for ldb_wildcard_compare
- ldb_match: trailing chunk must match end of string
- pyldb: catch potential overflow error in py_timestring
- ldb: remove some 'if PY3's in tests
- Add missing break in switch statement
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Previously, message elements were being freed before the call to
Py_BuildValue(), resulting in an exception being raised. Additionally,
only the first element of the returned list was ever assigned to.
Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
We should use long options in tests to make clear what we are trying to
do.
Signed-off-by: Andreas Schneider <asn@samba.org>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
As this is a TDB file, the file has been backed up using tdbbackup to
get a different page size. This fixes running the repack.py test on
aarch64.
Signed-off-by: Andreas Schneider <asn@samba.org>
Reviewed-by: Gary Lockyer <gary@catalyst.net.nz>
Autobuild-User(master): Andreas Schneider <asn@cryptomilk.org>
Autobuild-Date(master): Fri Apr 23 08:26:00 UTC 2021 on sn-devel-184
As seen in CVE-2021-20277, ldb_handler_fold() has been making mistakes
when collapsing spaces down to a single space.
This patch fixes the way it handles internal spaces (CVE-2021-20277
was about leading spaces), and involves a rewrite of the parsing loop.
The bug has a detailed description of the problem.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=14656
Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Autobuild-User(master): Andrew Bartlett <abartlet@samba.org>
Autobuild-Date(master): Wed Apr 7 03:16:39 UTC 2021 on sn-devel-184
We run one character over in comparing all the bytes in two ldb_vals.
In almost all circumstances both ldb_vals would have an allocated '\0'
in the overrun position, but it is best not to rely on that.
Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Autobuild-User(master): Stefan Metzmacher <metze@samba.org>
Autobuild-Date(master): Wed Mar 24 13:11:52 UTC 2021 on sn-devel-184
We had the test in the Samba Python segfault suite because
a) the signal catching infrastructure was there, and
b) the ldb tests lack Samba's knownfail mechanism, which allowed us to
assert the failure.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=14595
Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
A DN string with lots of trailing space can cause ldb_dn_explode() to
put a zero byte in the wrong place in the heap.
When a DN string has a value represented with trailing spaces,
like this
"CN=foo ,DC=bar"
the whitespace is supposed to be ignored. We keep track of this in the
`t` pointer, which is NULL when we are not walking through trailing
spaces, and points to the first space when we are. We are walking with
the `p` pointer, writing the value to `d`, and keeping the length in
`l`.
"CN=foo ,DC= " ==> "foo "
^ ^ ^
t p d
--l---
The value is finished when we encounter a comma or the end of the
string. If `t` is not NULL at that point, we assume there are trailing
spaces and wind `d and `l` back by the correct amount. Then we switch
to expecting an attribute name (e.g. "CN"), until we get to an "=",
which puts us back into looking for a value.
Unfortunately, we forget to immediately tell `t` that we'd finished
the last value, we can end up like this:
"CN=foo ,DC= " ==> ""
^ ^ ^
t p d
l=0
where `p` is pointing to a new value that contains only spaces, while
`t` is still referring to the old value. `p` notices the value ends,
and we subtract `p - t` from `d`:
"CN=foo ,DC= " ==> ? ""
^ ^ ^
t p d
l ~= SIZE_MAX - 8
At that point `d` wants to terminate its string with a '\0', but
instead it terminates someone else's byte. This does not crash if the
number of trailing spaces is small, as `d` will point into a previous
value (a copy of "foo" in this example). Corrupting that value will
ultimately not matter, as we will soon try to allocate a buffer `l`
long, which will be greater than the available memory and the whole
operation will fail properly.
However, with more spaces, `d` will point into memory before the
beginning of the allocated buffer, with the exact offset depending on
the length of the earlier attributes and the number of spaces.
What about a longer DN with more attributes? For example,
"CN=foo ,DC= ,DC=example,DC=com" -- since `d` has moved out of
bounds, won't we continue to use it and write more DN values into
mystery memory? Fortunately not, because the aforementioned allocation
of `l` bytes must happen first, and `l` is now huge. The allocation
happens in a talloc_memdup(), which is by default restricted to
allocating 256MB.
So this allows a person who controls a string parsed by ldb_dn_explode
to corrupt heap memory by placing a single zero byte at a chosen
offset before the allocated buffer.
An LDAP bind request can send a string DN as a username. This DN is
necessarily parsed before the password is checked, so an attacker does
not need proper credentials. The attacker can easily cause a denial of
service and we cannot rule out more subtle attacks.
The immediate solution is to reset `t` to NULL when a comma is
encountered, indicating that we are no longer looking at trailing
whitespace.
Found with the help of Honggfuzz.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=14595
Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
For a string that had N spaces at the beginning, we would
try to move N bytes beyond the end of the string.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=14655
Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
