Commit Graph

3 Commits

Author SHA1 Message Date
Christian Göttsche 9e6f8ed70e libsepol: operate on const pointers during validation
The actual policy should not be modified during validation, thus use
const pointers.

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Acked-by: James Carter <jwcart2@gmail.com>
2022-08-09 09:52:37 -04:00
Christian Göttsche 938530171b libsepol: rename validate_policydb to policydb_validate
Most global functions operating on a policy database use policydb as
prefix.

Since this function is not exported there should not be any external
use.

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Acked-by: James Carter <jwcart2@gmail.com>
2022-08-09 09:52:31 -04:00
James Carter 0861c659b5 libsepol: Validate policydb values when reading binary policy
Nicolas Iooss reports that fuzzing /usr/libexec/hll/pp with the
American Fuzzy Lop revealed that inconsistent policy modules could be
created that caused NULL dereferences and other problems.

When reading in a binary modular or kernel policy, check values in the
policydb to verify consistency. When reading in the data for commons,
classes, roles, types, users, booleans, sensitivities, and categories
verify that their value is between 1 and the number of primary
identifiers (value-1 is used to index the sym_val_to_name array for
all of these and the val_to_struct array for classes, roles, users,
and types.) Next all references in policy rules are checked to ensure
that they refer to a valid value.

It is possible for the type and role struct and name arrays to have
gaps in them. For roles, there will be gaps in the case of a kernel
policy created from a policy with role attributes, but nothing in the
policy will refer to any of the gaps. For types, there will be gaps
for any kernel policy with a version from 20 to 23, but, unfortunately,
there will be references to the gaps. This is because, while attributes
exist in these policies, they only exist in the type_attr_map. For
policies with versions between 20 and 23, it must be assumed that all
of the gaps and any references to them are valid. To check for
references to gaps, bitmaps are created to map where the gaps are and
all values are verified to be within the proper range and not within a
gap.

Reported-by: Nicolas Iooss <nicolas.iooss@m4x.org>
Signed-off-by: James Carter <jwcart2@gmail.com>
2021-02-19 16:34:47 +01:00