James Carter 9af9169241 libsepol/cil: Improve checking for bad inheritance patterns ... commits 37863b0b14 (libsepol/cil: Improve degenerate inheritance check) and 74d00a8dec (libsepol/cil: Detect degenerate inheritance and exit with an error) attempted to detect and exit with an error when compiling policies that have degenerate inheritances. These policies result in the exponential growth of memory usage while copying the blocks that are inherited. There were two problems with the previous attempts to detect this bad inheritance problem. The first is that the quick check using cil_possible_degenerate_inheritance() did not detect all patterns of degenerate inheritance. The second problem is that the detection of inheritance loops during the CIL_PASS_BLKIN_LINK pass did not detect all inheritance loops which made it possible for the full degenerate inheritance checking done with cil_check_for_degenerate_inheritance() to have a stack overflow when encountering the inheritance loops. Both the degenerate and loop inheritance checks need to be done at the same time and done after the CIL_PASS_BLKIN_LINK pass. Otherwise, if loops are being detected first, then a degenerate policy can cause the consumption of all system memory and if degenerate policy is being detected first, then an inheritance loop can cause a stack overflow. With the new approach, the quick check is eliminated and the full check is always done after the CIL_PASS_BLKIN_LINK pass. Because of this the "inheritance_check" field in struct cil_resolve_args is not needed and removed and the functions cil_print_recursive_blockinherit(), cil_check_recursive_blockinherit(), and cil_possible_degenerate_inheritance() have been deleted. The function cil_count_potential() is renamed cil_check_inheritances() and has checks for both degenerate inheritance and inheritance loops. The inheritance checking is improved and uses an approach similar to commit c28525a26f (libsepol/cil: Properly check for loops in sets). As has been the case with these degenerate inheritance patches, these issues were discovered by the secilc-fuzzer. Signed-off-by: James Carter <jwcart2@gmail.com>		2021-07-07 12:29:15 -04:00
..
include/cil	libsepol/cil: Provide option to allow qualified names in declarations	2021-07-03 16:00:26 +02:00
src	libsepol/cil: Improve checking for bad inheritance patterns	2021-07-07 12:29:15 -04:00
test	libsepol: Move secilc out of libsepol	2015-03-31 12:31:38 -04:00
.gitignore	Merge commit '76ba6eaa7333483a8cc0c73a7880f7acf99c2656'	2015-02-18 09:25:20 -05:00