/* audit.c -- Auditing support * Gateway between the kernel (e.g., selinux) and the user-space audit daemon. * System-call specific features have moved to auditsc.c * * Copyright 2003-2007 Red Hat Inc., Durham, North Carolina. * All Rights Reserved. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * * Written by Rickard E. (Rik) Faith <faith@redhat.com> * * Goals: 1) Integrate fully with Security Modules. * 2) Minimal run-time overhead: * a) Minimal when syscall auditing is disabled (audit_enable=0). * b) Small when syscall auditing is enabled and no audit record * is generated (defer as much work as possible to record * generation time): * i) context is allocated, * ii) names from getname are stored without a copy, and * iii) inode information stored from path_lookup. * 3) Ability to disable syscall auditing at boot time (audit=0). * 4) Usable by other parts of the kernel (if audit_log* is called, * then a syscall record will be generated automatically for the * current syscall). * 5) Netlink interface to user-space. * 6) Support low-overhead kernel-based filtering to minimize the * information that must be passed to user-space. * * Example user-space utilities: http://people.redhat.com/sgrubb/audit/ */ #include <linux/init.h>#include <asm/types.h>#include <linux/atomic.h>#include <linux/mm.h>#include <linux/export.h>#include <linux/slab.h>#include <linux/err.h>#include <linux/kthread.h> #include <linux/audit.h> #include <net/sock.h>#include <net/netlink.h>#include <linux/skbuff.h>#ifdef CONFIG_SECURITY#include <linux/security.h>#endif#include <linux/netlink.h>#include <linux/freezer.h>#include <linux/tty.h>#include <linux/pid_namespace.h> #include "audit.h" /* No auditing will take place until audit_initialized == AUDIT_INITIALIZED. * (Initialization happens after skb_init is called.) */#define AUDIT_DISABLED -1#define AUDIT_UNINITIALIZED 0#define AUDIT_INITIALIZED 1static int audit_initialized; #define AUDIT_OFF 0#define AUDIT_ON 1#define AUDIT_LOCKED 2int audit_enabled;int audit_ever_enabled; EXPORT_SYMBOL_GPL(audit_enabled); /* Default state when kernel boots without any parameters. */static int audit_default; /* If auditing cannot proceed, audit_failure selects what happens. */static int audit_failure = AUDIT_FAIL_PRINTK; /* * If audit records are to be written to the netlink socket, audit_pid * contains the pid of the auditd process and audit_nlk_portid contains * the portid to use to send netlink messages to that process. */int audit_pid;static int audit_nlk_portid; /* If audit_rate_limit is non-zero, limit the rate of sending audit records * to that number per second. This prevents DoS attacks, but results in * audit records being dropped. */static int audit_rate_limit; /* Number of outstanding audit_buffers allowed. */static int audit_backlog_limit = 64;static int audit_backlog_wait_time = 60 * HZ;static int audit_backlog_wait_overflow = 0; /* The identity of the user shutting down the audit system. */kuid_t audit_sig_uid = INVALID_UID;pid_t audit_sig_pid = -1;u32 audit_sig_sid = 0; /* Records can be lost in several ways: 0) [suppressed in audit_alloc] 1) out of memory in audit_log_start [kmalloc of struct audit_buffer] 2) out of memory in audit_log_move [alloc_skb] 3) suppressed due to audit_rate_limit 4) suppressed due to audit_backlog_limit*/static atomic_t audit_lost = ATOMIC_INIT(0); /* The netlink socket. */static struct sock *audit_sock; /* Hash for inode-based rules */struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS]; /* The audit_freelist is a list of pre-allocated audit buffers (if more * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of * being placed on the freelist). */static DEFINE_SPINLOCK(audit_freelist_lock);static int audit_freelist_count;static LIST_HEAD(audit_freelist); static struct sk_buff_head audit_skb_queue;/* queue of skbs to send to auditd when/if it comes back */static struct sk_buff_head audit_skb_hold_queue;static struct task_struct *kauditd_task;static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait);static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait); /* Serialize requests from userspace. */DEFINE_MUTEX(audit_cmd_mutex); /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting * audit records. Since printk uses a 1024 byte buffer, this buffer * should be at least that large. */#define AUDIT_BUFSIZ 1024 /* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the * audit_freelist. Doing so eliminates many kmalloc/kfree calls. */#define AUDIT_MAXFREE (2*NR_CPUS) /* 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 list_head list; struct sk_buff *skb; /* formatted skb ready to send */ struct audit_context *ctx; /* NULL or associated context */ gfp_t gfp_mask;}; struct audit_reply { int pid; struct sk_buff *skb;}; static void audit_set_pid(struct audit_buffer *ab, pid_t pid){ if (ab) { struct nlmsghdr *nlh = nlmsg_hdr(ab->skb); nlh->nlmsg_pid = pid; }} void audit_panic(const char *message){ switch (audit_failure) { case AUDIT_FAIL_SILENT: break; case AUDIT_FAIL_PRINTK: if (printk_ratelimit()) printk(KERN_ERR "audit: %s\n", message); break; case AUDIT_FAIL_PANIC: /* test audit_pid since printk is always losey, why bother? */ if (audit_pid) panic("audit: %s\n", message); break; }} static inline int audit_rate_check(void){ static unsigned long last_check = 0; static int messages = 0; static DEFINE_SPINLOCK(lock); unsigned long flags; unsigned long now; unsigned long elapsed; int retval = 0; if (!audit_rate_limit) return 1; spin_lock_irqsave(&lock, flags); if (++messages < audit_rate_limit) { retval = 1; } else { now = jiffies; elapsed = now - last_check; if (elapsed > HZ) { last_check = now; messages = 0; retval = 1; } } spin_unlock_irqrestore(&lock, flags); return retval;} /** * audit_log_lost - conditionally log lost audit message event * @message: the message stating reason for lost audit message * * Emit at least 1 message per second, even if audit_rate_check is * throttling. * Always increment the lost messages counter.*/void audit_log_lost(const char *message){ static unsigned long last_msg = 0; static DEFINE_SPINLOCK(lock); unsigned long flags; unsigned long now; int print; atomic_inc(&audit_lost); print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit); if (!print) { spin_lock_irqsave(&lock, flags); now = jiffies; if (now - last_msg > HZ) { print = 1; last_msg = now; } spin_unlock_irqrestore(&lock, flags); } if (print) { if (printk_ratelimit()) printk(KERN_WARNING "audit: audit_lost=%d audit_rate_limit=%d " "audit_backlog_limit=%d\n", atomic_read(&audit_lost), audit_rate_limit, audit_backlog_limit); audit_panic(message); }} static int audit_log_config_change(char *function_name, int new, int old, kuid_t loginuid, u32 sessionid, u32 sid, int allow_changes){ struct audit_buffer *ab; int rc = 0; ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE); if (unlikely(!ab)) return rc; audit_log_format(ab, "%s=%d old=%d auid=%u ses=%u", function_name, new, old, from_kuid(&init_user_ns, loginuid), sessionid); if (sid) { char *ctx = NULL; u32 len; rc = security_secid_to_secctx(sid, &ctx, &len); if (rc) { audit_log_format(ab, " sid=%u", sid); allow_changes = 0; /* Something weird, deny request */ } else { audit_log_format(ab, " subj=%s", ctx); security_release_secctx(ctx, len); } } audit_log_format(ab, " res=%d", allow_changes); audit_log_end(ab); return rc;} static int audit_do_config_change(char *function_name, int *to_change, int new, kuid_t loginuid, u32 sessionid, u32 sid){ int allow_changes, rc = 0, old = *to_change; /* check if we are locked */ if (audit_enabled == AUDIT_LOCKED) allow_changes = 0; else allow_changes = 1; if (audit_enabled != AUDIT_OFF) { rc = audit_log_config_change(function_name, new, old, loginuid, sessionid, sid, allow_changes); if (rc) allow_changes = 0; } /* If we are allowed, make the change */ if (allow_changes == 1) *to_change = new; /* Not allowed, update reason */ else if (rc == 0) rc = -EPERM; return rc;} static int audit_set_rate_limit(int limit, kuid_t loginuid, u32 sessionid, u32 sid){ return audit_do_config_change("audit_rate_limit", &audit_rate_limit, limit, loginuid, sessionid, sid);} static int audit_set_backlog_limit(int limit, kuid_t loginuid, u32 sessionid, u32 sid){ return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, limit, loginuid, sessionid, sid);} static int audit_set_enabled(int state, kuid_t loginuid, u32 sessionid, u32 sid){ int rc; if (state < AUDIT_OFF || state > AUDIT_LOCKED) return -EINVAL; rc = audit_do_config_change("audit_enabled", &audit_enabled, state, loginuid, sessionid, sid); if (!rc) audit_ever_enabled |= !!state; return rc;} static int audit_set_failure(int state, kuid_t loginuid, u32 sessionid, u32 sid){ if (state != AUDIT_FAIL_SILENT && state != AUDIT_FAIL_PRINTK && state != AUDIT_FAIL_PANIC) return -EINVAL; return audit_do_config_change("audit_failure", &audit_failure, state, loginuid, sessionid, sid);} /* * Queue skbs to be sent to auditd when/if it comes back. These skbs should * already have been sent via prink/syslog and so if these messages are dropped * it is not a huge concern since we already passed the audit_log_lost() * notification and stuff. This is just nice to get audit messages during * boot before auditd is running or messages generated while auditd is stopped. * This only holds messages is audit_default is set, aka booting with audit=1 * or building your kernel that way. */static void audit_hold_skb(struct sk_buff *skb){ if (audit_default && skb_queue_len(&audit_skb_hold_queue) < audit_backlog_limit) skb_queue_tail(&audit_skb_hold_queue, skb); else kfree_skb(skb);} /* * For one reason or another this nlh isn't getting delivered to the userspace * audit daemon, just send it to printk. */static void audit_printk_skb(struct sk_buff *skb){ struct nlmsghdr *nlh = nlmsg_hdr(skb); char *data = nlmsg_data(nlh); if (nlh->nlmsg_type != AUDIT_EOE) { if (printk_ratelimit()) printk(KERN_NOTICE "type=%d %s\n", nlh->nlmsg_type, data); else audit_log_lost("printk limit exceeded\n"); } audit_hold_skb(skb);} static void kauditd_send_skb(struct sk_buff *skb){ int err; /* take a reference in case we can't send it and we want to hold it */ skb_get(skb); err = netlink_unicast(audit_sock, skb, audit_nlk_portid, 0); if (err < 0) { BUG_ON(err != -ECONNREFUSED); /* Shouldn't happen */ printk(KERN_ERR "audit: *NO* daemon at audit_pid=%d\n", audit_pid); audit_log_lost("auditd disappeared\n"); audit_pid = 0; /* we might get lucky and get this in the next auditd */ audit_hold_skb(skb); } else /* drop the extra reference if sent ok */ consume_skb(skb);} static int kauditd_thread(void *dummy){ struct sk_buff *skb; set_freezable(); while (!kthread_should_stop()) { /* * if auditd just started drain the queue of messages already * sent to syslog/printk. remember loss here is ok. we already * called audit_log_lost() if it didn't go out normally. so the * race between the skb_dequeue and the next check for audit_pid * doesn't matter. * * if you ever find kauditd to be too slow we can get a perf win * by doing our own locking and keeping better track if there * are messages in this queue. I don't see the need now, but * in 5 years when I want to play with this again I'll see this * note and still have no friggin idea what i'm thinking today. */ if (audit_default && audit_pid) { skb = skb_dequeue(&audit_skb_hold_queue); if (unlikely(skb)) { while (skb && audit_pid) { kauditd_send_skb(skb); skb = skb_dequeue(&audit_skb_hold_queue); } } } skb = skb_dequeue(&audit_skb_queue); wake_up(&audit_backlog_wait); if (skb) { if (audit_pid) kauditd_send_skb(skb); else audit_printk_skb(skb); } else { DECLARE_WAITQUEUE(wait, current); set_current_state(TASK_INTERRUPTIBLE); add_wait_queue(&kauditd_wait, &wait); if (!skb_queue_len(&audit_skb_queue)) { try_to_freeze(); schedule(); } __set_current_state(TASK_RUNNING); remove_wait_queue(&kauditd_wait, &wait); } } return 0;} int audit_send_list(void *_dest){ struct audit_netlink_list *dest = _dest; int pid = dest->pid; struct sk_buff *skb; /* wait for parent to finish and send an ACK */ mutex_lock(&audit_cmd_mutex); mutex_unlock(&audit_cmd_mutex); while ((skb = __skb_dequeue(&dest->q)) != NULL) netlink_unicast(audit_sock, skb, pid, 0); kfree(dest); return 0;} struct sk_buff *audit_make_reply(int pid, int seq, int type, int done, int multi, const void *payload, int size){ struct sk_buff *skb; struct nlmsghdr *nlh; void *data; int flags = multi ? NLM_F_MULTI : 0; int t = done ? NLMSG_DONE : type; skb = nlmsg_new(size, GFP_KERNEL);Lines 1–500 of 1555. Load more
/* audit.c -- Auditing support * Gateway between the kernel (e.g., selinux) and the user-space audit daemon. * System-call specific features have moved to auditsc.c * * Copyright 2003-2007 Red Hat Inc., Durham, North Carolina. * All Rights Reserved. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * * Written by Rickard E. (Rik) Faith <faith@redhat.com> * * Goals: 1) Integrate fully with Security Modules. * 2) Minimal run-time overhead: * a) Minimal when syscall auditing is disabled (audit_enable=0). * b) Small when syscall auditing is enabled and no audit record * is generated (defer as much work as possible to record * generation time): * i) context is allocated, * ii) names from getname are stored without a copy, and * iii) inode information stored from path_lookup. * 3) Ability to disable syscall auditing at boot time (audit=0). * 4) Usable by other parts of the kernel (if audit_log* is called, * then a syscall record will be generated automatically for the * current syscall). * 5) Netlink interface to user-space. * 6) Support low-overhead kernel-based filtering to minimize the * information that must be passed to user-space. * * Example user-space utilities: http://people.redhat.com/sgrubb/audit/ */ #include <linux/init.h> #include <asm/types.h> #include <linux/atomic.h> #include <linux/mm.h> #include <linux/export.h> #include <linux/slab.h> #include <linux/err.h> #include <linux/kthread.h> #include <linux/audit.h> #include <net/sock.h> #include <net/netlink.h> #include <linux/skbuff.h> #ifdef CONFIG_SECURITY #include <linux/security.h> #endif #include <linux/netlink.h> #include <linux/freezer.h> #include <linux/tty.h> #include <linux/pid_namespace.h> #include "audit.h" /* No auditing will take place until audit_initialized == AUDIT_INITIALIZED. * (Initialization happens after skb_init is called.) */ #define AUDIT_DISABLED -1 #define AUDIT_UNINITIALIZED 0 #define AUDIT_INITIALIZED 1 static int audit_initialized; #define AUDIT_OFF 0 #define AUDIT_ON 1 #define AUDIT_LOCKED 2 int audit_enabled; int audit_ever_enabled; EXPORT_SYMBOL_GPL(audit_enabled); /* Default state when kernel boots without any parameters. */ static int audit_default; /* If auditing cannot proceed, audit_failure selects what happens. */ static int audit_failure = AUDIT_FAIL_PRINTK; /* * If audit records are to be written to the netlink socket, audit_pid * contains the pid of the auditd process and audit_nlk_portid contains * the portid to use to send netlink messages to that process. */ int audit_pid; static int audit_nlk_portid; /* If audit_rate_limit is non-zero, limit the rate of sending audit records * to that number per second. This prevents DoS attacks, but results in * audit records being dropped. */ static int audit_rate_limit; /* Number of outstanding audit_buffers allowed. */ static int audit_backlog_limit = 64; static int audit_backlog_wait_time = 60 * HZ; static int audit_backlog_wait_overflow = 0; /* The identity of the user shutting down the audit system. */ kuid_t audit_sig_uid = INVALID_UID; pid_t audit_sig_pid = -1; u32 audit_sig_sid = 0; /* Records can be lost in several ways: 0) [suppressed in audit_alloc] 1) out of memory in audit_log_start [kmalloc of struct audit_buffer] 2) out of memory in audit_log_move [alloc_skb] 3) suppressed due to audit_rate_limit 4) suppressed due to audit_backlog_limit */ static atomic_t audit_lost = ATOMIC_INIT(0); /* The netlink socket. */ static struct sock *audit_sock; /* Hash for inode-based rules */ struct list_head audit_inode_hash[AUDIT_INODE_BUCKETS]; /* The audit_freelist is a list of pre-allocated audit buffers (if more * than AUDIT_MAXFREE are in use, the audit buffer is freed instead of * being placed on the freelist). */ static DEFINE_SPINLOCK(audit_freelist_lock); static int audit_freelist_count; static LIST_HEAD(audit_freelist); static struct sk_buff_head audit_skb_queue; /* queue of skbs to send to auditd when/if it comes back */ static struct sk_buff_head audit_skb_hold_queue; static struct task_struct *kauditd_task; static DECLARE_WAIT_QUEUE_HEAD(kauditd_wait); static DECLARE_WAIT_QUEUE_HEAD(audit_backlog_wait); /* Serialize requests from userspace. */ DEFINE_MUTEX(audit_cmd_mutex); /* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting * audit records. Since printk uses a 1024 byte buffer, this buffer * should be at least that large. */ #define AUDIT_BUFSIZ 1024 /* AUDIT_MAXFREE is the number of empty audit_buffers we keep on the * audit_freelist. Doing so eliminates many kmalloc/kfree calls. */ #define AUDIT_MAXFREE (2*NR_CPUS) /* 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 list_head list; struct sk_buff *skb; /* formatted skb ready to send */ struct audit_context *ctx; /* NULL or associated context */ gfp_t gfp_mask; }; struct audit_reply { int pid; struct sk_buff *skb; }; static void audit_set_pid(struct audit_buffer *ab, pid_t pid) { if (ab) { struct nlmsghdr *nlh = nlmsg_hdr(ab->skb); nlh->nlmsg_pid = pid; } } void audit_panic(const char *message) { switch (audit_failure) { case AUDIT_FAIL_SILENT: break; case AUDIT_FAIL_PRINTK: if (printk_ratelimit()) printk(KERN_ERR "audit: %s\n", message); break; case AUDIT_FAIL_PANIC: /* test audit_pid since printk is always losey, why bother? */ if (audit_pid) panic("audit: %s\n", message); break; } } static inline int audit_rate_check(void) { static unsigned long last_check = 0; static int messages = 0; static DEFINE_SPINLOCK(lock); unsigned long flags; unsigned long now; unsigned long elapsed; int retval = 0; if (!audit_rate_limit) return 1; spin_lock_irqsave(&lock, flags); if (++messages < audit_rate_limit) { retval = 1; } else { now = jiffies; elapsed = now - last_check; if (elapsed > HZ) { last_check = now; messages = 0; retval = 1; } } spin_unlock_irqrestore(&lock, flags); return retval; } /** * audit_log_lost - conditionally log lost audit message event * @message: the message stating reason for lost audit message * * Emit at least 1 message per second, even if audit_rate_check is * throttling. * Always increment the lost messages counter. */ void audit_log_lost(const char *message) { static unsigned long last_msg = 0; static DEFINE_SPINLOCK(lock); unsigned long flags; unsigned long now; int print; atomic_inc(&audit_lost); print = (audit_failure == AUDIT_FAIL_PANIC || !audit_rate_limit); if (!print) { spin_lock_irqsave(&lock, flags); now = jiffies; if (now - last_msg > HZ) { print = 1; last_msg = now; } spin_unlock_irqrestore(&lock, flags); } if (print) { if (printk_ratelimit()) printk(KERN_WARNING "audit: audit_lost=%d audit_rate_limit=%d " "audit_backlog_limit=%d\n", atomic_read(&audit_lost), audit_rate_limit, audit_backlog_limit); audit_panic(message); } } static int audit_log_config_change(char *function_name, int new, int old, kuid_t loginuid, u32 sessionid, u32 sid, int allow_changes) { struct audit_buffer *ab; int rc = 0; ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONFIG_CHANGE); if (unlikely(!ab)) return rc; audit_log_format(ab, "%s=%d old=%d auid=%u ses=%u", function_name, new, old, from_kuid(&init_user_ns, loginuid), sessionid); if (sid) { char *ctx = NULL; u32 len; rc = security_secid_to_secctx(sid, &ctx, &len); if (rc) { audit_log_format(ab, " sid=%u", sid); allow_changes = 0; /* Something weird, deny request */ } else { audit_log_format(ab, " subj=%s", ctx); security_release_secctx(ctx, len); } } audit_log_format(ab, " res=%d", allow_changes); audit_log_end(ab); return rc; } static int audit_do_config_change(char *function_name, int *to_change, int new, kuid_t loginuid, u32 sessionid, u32 sid) { int allow_changes, rc = 0, old = *to_change; /* check if we are locked */ if (audit_enabled == AUDIT_LOCKED) allow_changes = 0; else allow_changes = 1; if (audit_enabled != AUDIT_OFF) { rc = audit_log_config_change(function_name, new, old, loginuid, sessionid, sid, allow_changes); if (rc) allow_changes = 0; } /* If we are allowed, make the change */ if (allow_changes == 1) *to_change = new; /* Not allowed, update reason */ else if (rc == 0) rc = -EPERM; return rc; } static int audit_set_rate_limit(int limit, kuid_t loginuid, u32 sessionid, u32 sid) { return audit_do_config_change("audit_rate_limit", &audit_rate_limit, limit, loginuid, sessionid, sid); } static int audit_set_backlog_limit(int limit, kuid_t loginuid, u32 sessionid, u32 sid) { return audit_do_config_change("audit_backlog_limit", &audit_backlog_limit, limit, loginuid, sessionid, sid); } static int audit_set_enabled(int state, kuid_t loginuid, u32 sessionid, u32 sid) { int rc; if (state < AUDIT_OFF || state > AUDIT_LOCKED) return -EINVAL; rc = audit_do_config_change("audit_enabled", &audit_enabled, state, loginuid, sessionid, sid); if (!rc) audit_ever_enabled |= !!state; return rc; } static int audit_set_failure(int state, kuid_t loginuid, u32 sessionid, u32 sid) { if (state != AUDIT_FAIL_SILENT && state != AUDIT_FAIL_PRINTK && state != AUDIT_FAIL_PANIC) return -EINVAL; return audit_do_config_change("audit_failure", &audit_failure, state, loginuid, sessionid, sid); } /* * Queue skbs to be sent to auditd when/if it comes back. These skbs should * already have been sent via prink/syslog and so if these messages are dropped * it is not a huge concern since we already passed the audit_log_lost() * notification and stuff. This is just nice to get audit messages during * boot before auditd is running or messages generated while auditd is stopped. * This only holds messages is audit_default is set, aka booting with audit=1 * or building your kernel that way. */ static void audit_hold_skb(struct sk_buff *skb) { if (audit_default && skb_queue_len(&audit_skb_hold_queue) < audit_backlog_limit) skb_queue_tail(&audit_skb_hold_queue, skb); else kfree_skb(skb); } /* * For one reason or another this nlh isn't getting delivered to the userspace * audit daemon, just send it to printk. */ static void audit_printk_skb(struct sk_buff *skb) { struct nlmsghdr *nlh = nlmsg_hdr(skb); char *data = nlmsg_data(nlh); if (nlh->nlmsg_type != AUDIT_EOE) { if (printk_ratelimit()) printk(KERN_NOTICE "type=%d %s\n", nlh->nlmsg_type, data); else audit_log_lost("printk limit exceeded\n"); } audit_hold_skb(skb); } static void kauditd_send_skb(struct sk_buff *skb) { int err; /* take a reference in case we can't send it and we want to hold it */ skb_get(skb); err = netlink_unicast(audit_sock, skb, audit_nlk_portid, 0); if (err < 0) { BUG_ON(err != -ECONNREFUSED); /* Shouldn't happen */ printk(KERN_ERR "audit: *NO* daemon at audit_pid=%d\n", audit_pid); audit_log_lost("auditd disappeared\n"); audit_pid = 0; /* we might get lucky and get this in the next auditd */ audit_hold_skb(skb); } else /* drop the extra reference if sent ok */ consume_skb(skb); } static int kauditd_thread(void *dummy) { struct sk_buff *skb; set_freezable(); while (!kthread_should_stop()) { /* * if auditd just started drain the queue of messages already * sent to syslog/printk. remember loss here is ok. we already * called audit_log_lost() if it didn't go out normally. so the * race between the skb_dequeue and the next check for audit_pid * doesn't matter. * * if you ever find kauditd to be too slow we can get a perf win * by doing our own locking and keeping better track if there * are messages in this queue. I don't see the need now, but * in 5 years when I want to play with this again I'll see this * note and still have no friggin idea what i'm thinking today. */ if (audit_default && audit_pid) { skb = skb_dequeue(&audit_skb_hold_queue); if (unlikely(skb)) { while (skb && audit_pid) { kauditd_send_skb(skb); skb = skb_dequeue(&audit_skb_hold_queue); } } } skb = skb_dequeue(&audit_skb_queue); wake_up(&audit_backlog_wait); if (skb) { if (audit_pid) kauditd_send_skb(skb); else audit_printk_skb(skb); } else { DECLARE_WAITQUEUE(wait, current); set_current_state(TASK_INTERRUPTIBLE); add_wait_queue(&kauditd_wait, &wait); if (!skb_queue_len(&audit_skb_queue)) { try_to_freeze(); schedule(); } __set_current_state(TASK_RUNNING); remove_wait_queue(&kauditd_wait, &wait); } } return 0; } int audit_send_list(void *_dest) { struct audit_netlink_list *dest = _dest; int pid = dest->pid; struct sk_buff *skb; /* wait for parent to finish and send an ACK */ mutex_lock(&audit_cmd_mutex); mutex_unlock(&audit_cmd_mutex); while ((skb = __skb_dequeue(&dest->q)) != NULL) netlink_unicast(audit_sock, skb, pid, 0); kfree(dest); return 0; } struct sk_buff *audit_make_reply(int pid, int seq, int type, int done, int multi, const void *payload, int size) { struct sk_buff *skb; struct nlmsghdr *nlh; void *data; int flags = multi ? NLM_F_MULTI : 0; int t = done ? NLMSG_DONE : type; skb = nlmsg_new(size, GFP_KERNEL);