Re: [PATCH v32 24/28] Audit: Add framework for auxiliary records

Add a list for auxiliary record data to the audit_buffer structure. Add the audit_stamp information to the audit_buffer as there's no guarantee that there will be an audit_context containing the stamp associated with the event. At audit_log_end() time create auxiliary records (none are currently defined) as have been added to the list. Signed-off-by: Casey Schaufler <casey(a)schaufler-ca.com&gt;

--- kernel/audit.c | 84 ++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 74 insertions(+), 10 deletions(-) diff --git a/kernel/audit.c b/kernel/audit.c index f012c3786264..559fb14e0380 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -191,15 +191,25 @@ static struct audit_ctl_mutex { * should be at least that large. */ #define AUDIT_BUFSIZ 1024 +/* The audit_context_entry contains data required to create an + * auxiliary record. + */ +struct audit_context_entry { + struct list_head list; + int type; /* Audit record type */ +}; + /* The audit_buffer is used when formatting an audit record. The caller * locks briefly to get the record off the freelist or to allocate the * buffer, and locks briefly to send the buffer to the netlink layer or * to place it on a transmit queue. Multiple audit_buffers can be in * use simultaneously. */ struct audit_buffer { - struct sk_buff *skb; /* formatted skb ready to send */ - struct audit_context *ctx; /* NULL or associated context */ - gfp_t gfp_mask; + struct sk_buff *skb; /* formatted skb ready to send */ + struct audit_context *ctx; /* NULL or associated context */ + struct list_head aux_records; /* aux record data */ + struct audit_stamp stamp; /* event stamp */ + gfp_t gfp_mask; }; struct audit_reply { @@ -1765,6 +1775,7 @@ static struct audit_buffer *audit_buffer_alloc(struct audit_context *ctx, ab->ctx = ctx; ab->gfp_mask = gfp_mask; + INIT_LIST_HEAD(&ab->aux_records); return ab; @@ -1825,7 +1836,6 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, int type) { struct audit_buffer *ab; - struct audit_stamp stamp; if (audit_initialized != AUDIT_INITIALIZED) return NULL; @@ -1880,14 +1890,14 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask, return NULL; } - audit_get_stamp(ab->ctx, &stamp); + audit_get_stamp(ab->ctx, &ab->stamp); /* cancel dummy context to enable supporting records */ if (ctx) ctx->dummy = 0; audit_log_format(ab, "audit(%llu.%03lu:%u): ", - (unsigned long long)stamp.ctime.tv_sec, - stamp.ctime.tv_nsec/1000000, - stamp.serial); + (unsigned long long)ab->stamp.ctime.tv_sec, + ab->stamp.ctime.tv_nsec/1000000, + ab->stamp.serial); return ab; } @@ -2378,7 +2388,7 @@ int audit_signal_info(int sig, struct task_struct *t) } /** - * audit_log_end - end one audit record + * __audit_log_end - end one audit record * @ab: the audit_buffer * * We can not do a netlink send inside an irq context because it blocks (last @@ -2386,7 +2396,7 @@ int audit_signal_info(int sig, struct task_struct *t) * queue and a kthread is scheduled to remove them from the queue outside the * irq context. May be called in any context. */ -void audit_log_end(struct audit_buffer *ab) +void __audit_log_end(struct audit_buffer *ab) { struct sk_buff *skb; struct nlmsghdr *nlh; @@ -2408,6 +2418,60 @@ void audit_log_end(struct audit_buffer *ab) wake_up_interruptible(&kauditd_wait); } else audit_log_lost("rate limit exceeded"); +} + +/** + * audit_log_end - end one audit record + * @ab: the audit_buffer + * + * Let __audit_log_end() handle the message while the buffer housekeeping + * is done here. + * If there are other records that have been deferred for the event + * create them here. + */ +void audit_log_end(struct audit_buffer *ab) +{ + struct audit_context_entry *entry; + struct audit_context mcontext; + struct audit_context *mctx; + struct audit_buffer *mab; + struct list_head *l; + struct list_head *n; + + if (!ab) + return; + + __audit_log_end(ab); + + if (list_empty(&ab->aux_records)) { + audit_buffer_free(ab); + return; + } + + if (ab->ctx == NULL) { + mcontext.stamp = ab->stamp; + mctx = &mcontext; + } else + mctx = ab->ctx; + + list_for_each_safe(l, n, &ab->aux_records) { + entry = list_entry(l, struct audit_context_entry, list); + mab = audit_log_start(mctx, ab->gfp_mask, entry->type); + if (!mab) { + audit_panic("alloc error in audit_log_end"); + continue; + } + switch (entry->type) { + /* Don't know of any quite yet. */ + default: + audit_panic("Unknown type in audit_log_end"); + break; + } + __audit_log_end(mab); + audit_buffer_free(mab); + list_del(&entry->list); + kfree(entry); + } audit_buffer_free(ab); }