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| author | Paul Moore <paul@paul-moore.com> | 2016-11-29 22:53:26 +0100 |
|---|---|---|
| committer | Paul Moore <paul@paul-moore.com> | 2016-12-14 19:06:04 +0100 |
| commit | a09cfa470817ac086cf68418da13a2b91c2744ef (patch) | |
| tree | a701499dc5828aa54314d843917ea35a60cc436c | |
| parent | audit: handle a clean auditd shutdown with grace (diff) | |
| download | linux-a09cfa470817ac086cf68418da13a2b91c2744ef.tar.xz linux-a09cfa470817ac086cf68418da13a2b91c2744ef.zip | |
audit: don't ever sleep on a command record/message
Sleeping on a command record/message in audit_log_start() could slow
something, e.g. auditd, from doing something important, e.g. clean
shutdown, which could present problems on a heavily loaded system.
This patch allows tasks to bypass any queue restrictions if they are
logging a command record/message.
Signed-off-by: Paul Moore <paul@paul-moore.com>
| -rw-r--r-- | kernel/audit.c | 18 |
1 files changed, 13 insertions, 5 deletions
diff --git a/kernel/audit.c b/kernel/audit.c index b447a6b1fdc8..f20eee0db7e6 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -1488,11 +1488,19 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, if (unlikely(!audit_filter(type, AUDIT_FILTER_TYPE))) return NULL; - /* don't ever fail/sleep on auditd since we need auditd to drain the - * queue; also, when we are checking for auditd, compare PIDs using - * task_tgid_vnr() since auditd_pid is set in audit_receive_msg() using - * a PID anchored in the caller's namespace */ - if (!(audit_pid && audit_pid == task_tgid_vnr(current))) { + /* don't ever fail/sleep on these two conditions: + * 1. auditd generated record - since we need auditd to drain the + * queue; also, when we are checking for auditd, compare PIDs using + * task_tgid_vnr() since auditd_pid is set in audit_receive_msg() + * using a PID anchored in the caller's namespace + * 2. audit command message - record types 1000 through 1099 inclusive + * are command messages/records used to manage the kernel subsystem + * and the audit userspace, blocking on these messages could cause + * problems under load so don't do it (note: not all of these + * command types are valid as record types, but it is quicker to + * just check two ints than a series of ints in a if/switch stmt) */ + if (!((audit_pid && audit_pid == task_tgid_vnr(current)) || + (type >= 1000 && type <= 1099))) { long sleep_time = audit_backlog_wait_time; while (audit_backlog_limit && |