From: Dmitry Vyukov dvyukov@google.com
[ Upstream commit 04e57a2d952bbd34bc45744e72be3eecdc344294 ]
If tomoyo is used in a testing/fuzzing environment in learning mode, for lots of domains the quota will be exceeded and stay exceeded for prolonged periods of time. In such cases it's pointless (and slow) to walk the whole acl list again and again just to rediscover that the quota is exceeded. We already have the TOMOYO_DIF_QUOTA_WARNED flag that notes the overflow condition. Check it early to avoid the slowdown.
[penguin-kernel] This patch causes a user visible change that the learning mode will not be automatically resumed after the quota is increased. To resume the learning mode, administrator will need to explicitly clear TOMOYO_DIF_QUOTA_WARNED flag after increasing the quota. But I think that this change is generally preferable, for administrator likely wants to optimize the acl list for that domain before increasing the quota, or that domain likely hits the quota again. Therefore, don't try to care to clear TOMOYO_DIF_QUOTA_WARNED flag automatically when the quota for that domain changed.
Signed-off-by: Dmitry Vyukov dvyukov@google.com Signed-off-by: Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp Signed-off-by: Sasha Levin sashal@kernel.org --- security/tomoyo/util.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/security/tomoyo/util.c b/security/tomoyo/util.c index eba0b3395851e..861fc6f4ebfb7 100644 --- a/security/tomoyo/util.c +++ b/security/tomoyo/util.c @@ -1029,6 +1029,8 @@ bool tomoyo_domain_quota_is_ok(struct tomoyo_request_info *r) return false; if (!domain) return true; + if (READ_ONCE(domain->flags[TOMOYO_DIF_QUOTA_WARNED])) + return false; list_for_each_entry_rcu(ptr, &domain->acl_info_list, list, srcu_read_lock_held(&tomoyo_ss)) { u16 perm; @@ -1074,14 +1076,12 @@ bool tomoyo_domain_quota_is_ok(struct tomoyo_request_info *r) if (count < tomoyo_profile(domain->ns, domain->profile)-> pref[TOMOYO_PREF_MAX_LEARNING_ENTRY]) return true; - if (!domain->flags[TOMOYO_DIF_QUOTA_WARNED]) { - domain->flags[TOMOYO_DIF_QUOTA_WARNED] = true; - /* r->granted = false; */ - tomoyo_write_log(r, "%s", tomoyo_dif[TOMOYO_DIF_QUOTA_WARNED]); + WRITE_ONCE(domain->flags[TOMOYO_DIF_QUOTA_WARNED], true); + /* r->granted = false; */ + tomoyo_write_log(r, "%s", tomoyo_dif[TOMOYO_DIF_QUOTA_WARNED]); #ifndef CONFIG_SECURITY_TOMOYO_INSECURE_BUILTIN_SETTING - pr_warn("WARNING: Domain '%s' has too many ACLs to hold. Stopped learning mode.\n", - domain->domainname->name); + pr_warn("WARNING: Domain '%s' has too many ACLs to hold. Stopped learning mode.\n", + domain->domainname->name); #endif - } return false; }