From 8fdb3eb2725040a81e8a600cf6edd3ff4d93c81f Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Christian=20G=C3=B6ttsche?= Date: Thu, 9 Dec 2021 17:49:15 +0100 Subject: [PATCH] libsepol: validate MLS levels MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Validate the level map of the policy to ensure no level refers to a non existent category. READ of size 8 at 0x602000000c58 thread T0 #0 0x568d2c in cats_ebitmap_len ./libsepol/src/kernel_to_conf.c:1003:14 #1 0x568d2c in cats_ebitmap_to_str ./libsepol/src/kernel_to_conf.c:1038:19 #2 0x55e371 in write_level_rules_to_conf ./libsepol/src/kernel_to_conf.c:1106:11 #3 0x55e371 in write_mls_rules_to_conf ./libsepol/src/kernel_to_conf.c:1140:7 #4 0x55adb1 in sepol_kernel_policydb_to_conf ./libsepol/src/kernel_to_conf.c:3103:7 #5 0x55a34f in LLVMFuzzerTestOneInput ./libsepol/fuzz/binpolicy-fuzzer.c:38:9 #6 0x45aed3 in fuzzer::Fuzzer::ExecuteCallback(unsigned char const*, unsigned long) fuzzer.o #7 0x446a12 in fuzzer::RunOneTest(fuzzer::Fuzzer*, char const*, unsigned long) fuzzer.o #8 0x44c93b in fuzzer::FuzzerDriver(int*, char***, int (*)(unsigned char const*, unsigned long)) fuzzer.o #9 0x475dd2 in main (./out/binpolicy-fuzzer+0x475dd2) #10 0x7f741d0d67ec in __libc_start_main csu/../csu/libc-start.c:332:16 #11 0x423689 in _start (./out/binpolicy-fuzzer+0x423689) Signed-off-by: Christian Göttsche --- libsepol/src/policydb_validate.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/libsepol/src/policydb_validate.c b/libsepol/src/policydb_validate.c index d4dfab5cd1..03ab4445a8 100644 --- a/libsepol/src/policydb_validate.c +++ b/libsepol/src/policydb_validate.c @@ -319,6 +319,27 @@ static int validate_mls_semantic_range(mls_semantic_range_t *range, validate_t * return -1; } +static int validate_mls_level(mls_level_t *level, validate_t *sens, validate_t *cats) +{ + if (validate_value(level->sens, sens)) + goto bad; + if (validate_ebitmap(&level->cat, cats)) + goto bad; + + return 0; + + bad: + return -1; +} + +static int validate_level_datum(__attribute__ ((unused)) hashtab_key_t k, hashtab_datum_t d, void *args) +{ + level_datum_t *level = d; + validate_t *flavors = args; + + return validate_mls_level(level->level, &flavors[SYM_LEVELS], &flavors[SYM_CATS]); +} + static int validate_user_datum(sepol_handle_t *handle, user_datum_t *user, validate_t flavors[]) { if (validate_value(user->s.value, &flavors[SYM_USERS])) @@ -399,6 +420,9 @@ static int validate_datum_array_entries(sepol_handle_t *handle, policydb_t *p, v if (hashtab_map(p->p_users.table, validate_user_datum_wrapper, &margs)) goto bad; + if (p->mls && hashtab_map(p->p_levels.table, validate_level_datum, flavors)) + goto bad; + return 0; bad: