/* audit.c -- Auditing support -*- linux-c -*- * Gateway between the kernel (e.g., selinux) and the user-space audit daemon. * System-call specific features have moved to auditsc.c * * Copyright 2003-2004 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 SELinux. * 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/faith/audit/ */ #include <linux/init.h>#include <asm/atomic.h>#include <asm/types.h>#include <linux/mm.h>#include <linux/module.h> #include <linux/audit.h> #include <net/sock.h>#include <linux/skbuff.h>#include <linux/netlink.h> /* No auditing will take place until audit_initialized != 0. * (Initialization happens after skb_init is called.) */static int audit_initialized; /* No syscall auditing will take place unless audit_enabled != 0. */int 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 (non-zero) pid. */static int audit_pid; /* If audit_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 atomic_t audit_backlog = ATOMIC_INIT(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; /* There are two lists of audit buffers. The txlist contains audit * buffers that cannot be sent immediately to the netlink device because * we are in an irq context (these are sent later in a tasklet). * * The second list 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_txlist_lock);static DEFINE_SPINLOCK(audit_freelist_lock);static int audit_freelist_count = 0;static LIST_HEAD(audit_txlist);static LIST_HEAD(audit_freelist); /* There are three lists of rules -- one to search at task creation * time, one to search at syscall entry time, and another to search at * syscall exit time. */static LIST_HEAD(audit_tsklist);static LIST_HEAD(audit_entlist);static LIST_HEAD(audit_extlist); /* The netlink socket is only to be read by 1 CPU, which lets us assume * that list additions and deletions never happen simultaneiously in * auditsc.c */static DECLARE_MUTEX(audit_netlink_sem); /* 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_head sklist; /* formatted skbs ready to send */ struct audit_context *ctx; /* NULL or associated context */ int len; /* used area of tmp */ char tmp[AUDIT_BUFSIZ]; /* Pointer to header and contents */ struct nlmsghdr *nlh; int total; int type; int pid; int count; /* Times requeued */}; void audit_set_type(struct audit_buffer *ab, int type){ ab->type = type;} struct audit_entry { struct list_head list; struct audit_rule rule;}; static void audit_panic(const char *message){ switch (audit_failure) { case AUDIT_FAIL_SILENT: break; case AUDIT_FAIL_PRINTK: printk(KERN_ERR "audit: %s\n", message); break; case AUDIT_FAIL_PANIC: 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;} /* Emit at least 1 message per second, even if audit_rate_check is * throttling. */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) { printk(KERN_WARNING "audit: audit_lost=%d audit_backlog=%d" " audit_rate_limit=%d audit_backlog_limit=%d\n", atomic_read(&audit_lost), atomic_read(&audit_backlog), audit_rate_limit, audit_backlog_limit); audit_panic(message); } } int audit_set_rate_limit(int limit){ int old = audit_rate_limit; audit_rate_limit = limit; audit_log(current->audit_context, "audit_rate_limit=%d old=%d", audit_rate_limit, old); return old;} int audit_set_backlog_limit(int limit){ int old = audit_backlog_limit; audit_backlog_limit = limit; audit_log(current->audit_context, "audit_backlog_limit=%d old=%d", audit_backlog_limit, old); return old;} int audit_set_enabled(int state){ int old = audit_enabled; if (state != 0 && state != 1) return -EINVAL; audit_enabled = state; audit_log(current->audit_context, "audit_enabled=%d old=%d", audit_enabled, old); return old;} int audit_set_failure(int state){ int old = audit_failure; if (state != AUDIT_FAIL_SILENT && state != AUDIT_FAIL_PRINTK && state != AUDIT_FAIL_PANIC) return -EINVAL; audit_failure = state; audit_log(current->audit_context, "audit_failure=%d old=%d", audit_failure, old); return old;} #ifdef CONFIG_NETvoid audit_send_reply(int pid, int seq, int type, int done, int multi, void *payload, int size){ struct sk_buff *skb; struct nlmsghdr *nlh; int len = NLMSG_SPACE(size); void *data; int flags = multi ? NLM_F_MULTI : 0; int t = done ? NLMSG_DONE : type; skb = alloc_skb(len, GFP_KERNEL); if (!skb) goto nlmsg_failure; nlh = NLMSG_PUT(skb, pid, seq, t, len - sizeof(*nlh)); nlh->nlmsg_flags = flags; data = NLMSG_DATA(nlh); memcpy(data, payload, size); netlink_unicast(audit_sock, skb, pid, MSG_DONTWAIT); return; nlmsg_failure: /* Used by NLMSG_PUT */ if (skb) kfree_skb(skb);} /* * Check for appropriate CAP_AUDIT_ capabilities on incoming audit * control messages. */static int audit_netlink_ok(kernel_cap_t eff_cap, u16 msg_type){ int err = 0; switch (msg_type) { case AUDIT_GET: case AUDIT_LIST: case AUDIT_SET: case AUDIT_ADD: case AUDIT_DEL: if (!cap_raised(eff_cap, CAP_AUDIT_CONTROL)) err = -EPERM; break; case AUDIT_USER: if (!cap_raised(eff_cap, CAP_AUDIT_WRITE)) err = -EPERM; break; default: /* bad msg */ err = -EINVAL; } return err;} static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh){ u32 uid, pid, seq; void *data; struct audit_status *status_get, status_set; int err; struct audit_buffer *ab; u16 msg_type = nlh->nlmsg_type; err = audit_netlink_ok(NETLINK_CB(skb).eff_cap, msg_type); if (err) return err; pid = NETLINK_CREDS(skb)->pid; uid = NETLINK_CREDS(skb)->uid; seq = nlh->nlmsg_seq; data = NLMSG_DATA(nlh); switch (msg_type) { case AUDIT_GET: status_set.enabled = audit_enabled; status_set.failure = audit_failure; status_set.pid = audit_pid; status_set.rate_limit = audit_rate_limit; status_set.backlog_limit = audit_backlog_limit; status_set.lost = atomic_read(&audit_lost); status_set.backlog = atomic_read(&audit_backlog); audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_GET, 0, 0, &status_set, sizeof(status_set)); break; case AUDIT_SET: if (nlh->nlmsg_len < sizeof(struct audit_status)) return -EINVAL; status_get = (struct audit_status *)data; if (status_get->mask & AUDIT_STATUS_ENABLED) { err = audit_set_enabled(status_get->enabled); if (err < 0) return err; } if (status_get->mask & AUDIT_STATUS_FAILURE) { err = audit_set_failure(status_get->failure); if (err < 0) return err; } if (status_get->mask & AUDIT_STATUS_PID) { int old = audit_pid; audit_pid = status_get->pid; audit_log(current->audit_context, "audit_pid=%d old=%d", audit_pid, old); } if (status_get->mask & AUDIT_STATUS_RATE_LIMIT) audit_set_rate_limit(status_get->rate_limit); if (status_get->mask & AUDIT_STATUS_BACKLOG_LIMIT) audit_set_backlog_limit(status_get->backlog_limit); break; case AUDIT_USER: ab = audit_log_start(NULL); if (!ab) break; /* audit_panic has been called */ audit_log_format(ab, "user pid=%d uid=%d length=%d msg='%.1024s'", pid, uid, (int)(nlh->nlmsg_len - ((char *)data - (char *)nlh)), (char *)data); ab->type = AUDIT_USER; ab->pid = pid; audit_log_end(ab); break; case AUDIT_ADD: case AUDIT_DEL: if (nlh->nlmsg_len < sizeof(struct audit_rule)) return -EINVAL; /* fallthrough */ case AUDIT_LIST:#ifdef CONFIG_AUDITSYSCALL err = audit_receive_filter(nlh->nlmsg_type, NETLINK_CB(skb).pid, uid, seq, data);#else err = -EOPNOTSUPP;#endif break; default: err = -EINVAL; break; } return err < 0 ? err : 0;} /* Get message from skb (based on rtnetlink_rcv_skb). Each message is * processed by audit_receive_msg. Malformed skbs with wrong length are * discarded silently. */static int audit_receive_skb(struct sk_buff *skb){ int err; struct nlmsghdr *nlh; u32 rlen; while (skb->len >= NLMSG_SPACE(0)) { nlh = (struct nlmsghdr *)skb->data; if (nlh->nlmsg_len < sizeof(*nlh) || skb->len < nlh->nlmsg_len) return 0; rlen = NLMSG_ALIGN(nlh->nlmsg_len); if (rlen > skb->len) rlen = skb->len; if ((err = audit_receive_msg(skb, nlh))) { netlink_ack(skb, nlh, err); } else if (nlh->nlmsg_flags & NLM_F_ACK) netlink_ack(skb, nlh, 0); skb_pull(skb, rlen); } return 0;} /* Receive messages from netlink socket. */static void audit_receive(struct sock *sk, int length){ struct sk_buff *skb; if (down_trylock(&audit_netlink_sem)) return; /* FIXME: this must not cause starvation */ while ((skb = skb_dequeue(&sk->sk_receive_queue))) { if (audit_receive_skb(skb) && skb->len) skb_queue_head(&sk->sk_receive_queue, skb); else kfree_skb(skb); } up(&audit_netlink_sem);} /* Move data from tmp buffer into an skb. This is an extra copy, and * that is unfortunate. However, the copy will only occur when a record * is being written to user space, which is already a high-overhead * operation. (Elimination of the copy is possible, for example, by * writing directly into a pre-allocated skb, at the cost of wasting * memory. */static void audit_log_move(struct audit_buffer *ab){ struct sk_buff *skb; char *start; int extra = ab->nlh ? 0 : NLMSG_SPACE(0); /* possible resubmission */ if (ab->len == 0) return; skb = skb_peek(&ab->sklist); if (!skb || skb_tailroom(skb) <= ab->len + extra) { skb = alloc_skb(2 * ab->len + extra, GFP_ATOMIC); if (!skb) { ab->len = 0; /* Lose information in ab->tmp */ audit_log_lost("out of memory in audit_log_move"); return; } __skb_queue_tail(&ab->sklist, skb); if (!ab->nlh) ab->nlh = (struct nlmsghdr *)skb_put(skb, NLMSG_SPACE(0)); } start = skb_put(skb, ab->len); memcpy(start, ab->tmp, ab->len); ab->len = 0;} Lines 1–500 of 836. Load more
/* audit.c -- Auditing support -*- linux-c -*- * Gateway between the kernel (e.g., selinux) and the user-space audit daemon. * System-call specific features have moved to auditsc.c * * Copyright 2003-2004 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 SELinux. * 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/faith/audit/ */ #include <linux/init.h> #include <asm/atomic.h> #include <asm/types.h> #include <linux/mm.h> #include <linux/module.h> #include <linux/audit.h> #include <net/sock.h> #include <linux/skbuff.h> #include <linux/netlink.h> /* No auditing will take place until audit_initialized != 0. * (Initialization happens after skb_init is called.) */ static int audit_initialized; /* No syscall auditing will take place unless audit_enabled != 0. */ int 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 (non-zero) pid. */ static int audit_pid; /* If audit_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 atomic_t audit_backlog = ATOMIC_INIT(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; /* There are two lists of audit buffers. The txlist contains audit * buffers that cannot be sent immediately to the netlink device because * we are in an irq context (these are sent later in a tasklet). * * The second list 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_txlist_lock); static DEFINE_SPINLOCK(audit_freelist_lock); static int audit_freelist_count = 0; static LIST_HEAD(audit_txlist); static LIST_HEAD(audit_freelist); /* There are three lists of rules -- one to search at task creation * time, one to search at syscall entry time, and another to search at * syscall exit time. */ static LIST_HEAD(audit_tsklist); static LIST_HEAD(audit_entlist); static LIST_HEAD(audit_extlist); /* The netlink socket is only to be read by 1 CPU, which lets us assume * that list additions and deletions never happen simultaneiously in * auditsc.c */ static DECLARE_MUTEX(audit_netlink_sem); /* 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_head sklist; /* formatted skbs ready to send */ struct audit_context *ctx; /* NULL or associated context */ int len; /* used area of tmp */ char tmp[AUDIT_BUFSIZ]; /* Pointer to header and contents */ struct nlmsghdr *nlh; int total; int type; int pid; int count; /* Times requeued */ }; void audit_set_type(struct audit_buffer *ab, int type) { ab->type = type; } struct audit_entry { struct list_head list; struct audit_rule rule; }; static void audit_panic(const char *message) { switch (audit_failure) { case AUDIT_FAIL_SILENT: break; case AUDIT_FAIL_PRINTK: printk(KERN_ERR "audit: %s\n", message); break; case AUDIT_FAIL_PANIC: 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; } /* Emit at least 1 message per second, even if audit_rate_check is * throttling. */ 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) { printk(KERN_WARNING "audit: audit_lost=%d audit_backlog=%d" " audit_rate_limit=%d audit_backlog_limit=%d\n", atomic_read(&audit_lost), atomic_read(&audit_backlog), audit_rate_limit, audit_backlog_limit); audit_panic(message); } } int audit_set_rate_limit(int limit) { int old = audit_rate_limit; audit_rate_limit = limit; audit_log(current->audit_context, "audit_rate_limit=%d old=%d", audit_rate_limit, old); return old; } int audit_set_backlog_limit(int limit) { int old = audit_backlog_limit; audit_backlog_limit = limit; audit_log(current->audit_context, "audit_backlog_limit=%d old=%d", audit_backlog_limit, old); return old; } int audit_set_enabled(int state) { int old = audit_enabled; if (state != 0 && state != 1) return -EINVAL; audit_enabled = state; audit_log(current->audit_context, "audit_enabled=%d old=%d", audit_enabled, old); return old; } int audit_set_failure(int state) { int old = audit_failure; if (state != AUDIT_FAIL_SILENT && state != AUDIT_FAIL_PRINTK && state != AUDIT_FAIL_PANIC) return -EINVAL; audit_failure = state; audit_log(current->audit_context, "audit_failure=%d old=%d", audit_failure, old); return old; } #ifdef CONFIG_NET void audit_send_reply(int pid, int seq, int type, int done, int multi, void *payload, int size) { struct sk_buff *skb; struct nlmsghdr *nlh; int len = NLMSG_SPACE(size); void *data; int flags = multi ? NLM_F_MULTI : 0; int t = done ? NLMSG_DONE : type; skb = alloc_skb(len, GFP_KERNEL); if (!skb) goto nlmsg_failure; nlh = NLMSG_PUT(skb, pid, seq, t, len - sizeof(*nlh)); nlh->nlmsg_flags = flags; data = NLMSG_DATA(nlh); memcpy(data, payload, size); netlink_unicast(audit_sock, skb, pid, MSG_DONTWAIT); return; nlmsg_failure: /* Used by NLMSG_PUT */ if (skb) kfree_skb(skb); } /* * Check for appropriate CAP_AUDIT_ capabilities on incoming audit * control messages. */ static int audit_netlink_ok(kernel_cap_t eff_cap, u16 msg_type) { int err = 0; switch (msg_type) { case AUDIT_GET: case AUDIT_LIST: case AUDIT_SET: case AUDIT_ADD: case AUDIT_DEL: if (!cap_raised(eff_cap, CAP_AUDIT_CONTROL)) err = -EPERM; break; case AUDIT_USER: if (!cap_raised(eff_cap, CAP_AUDIT_WRITE)) err = -EPERM; break; default: /* bad msg */ err = -EINVAL; } return err; } static int audit_receive_msg(struct sk_buff *skb, struct nlmsghdr *nlh) { u32 uid, pid, seq; void *data; struct audit_status *status_get, status_set; int err; struct audit_buffer *ab; u16 msg_type = nlh->nlmsg_type; err = audit_netlink_ok(NETLINK_CB(skb).eff_cap, msg_type); if (err) return err; pid = NETLINK_CREDS(skb)->pid; uid = NETLINK_CREDS(skb)->uid; seq = nlh->nlmsg_seq; data = NLMSG_DATA(nlh); switch (msg_type) { case AUDIT_GET: status_set.enabled = audit_enabled; status_set.failure = audit_failure; status_set.pid = audit_pid; status_set.rate_limit = audit_rate_limit; status_set.backlog_limit = audit_backlog_limit; status_set.lost = atomic_read(&audit_lost); status_set.backlog = atomic_read(&audit_backlog); audit_send_reply(NETLINK_CB(skb).pid, seq, AUDIT_GET, 0, 0, &status_set, sizeof(status_set)); break; case AUDIT_SET: if (nlh->nlmsg_len < sizeof(struct audit_status)) return -EINVAL; status_get = (struct audit_status *)data; if (status_get->mask & AUDIT_STATUS_ENABLED) { err = audit_set_enabled(status_get->enabled); if (err < 0) return err; } if (status_get->mask & AUDIT_STATUS_FAILURE) { err = audit_set_failure(status_get->failure); if (err < 0) return err; } if (status_get->mask & AUDIT_STATUS_PID) { int old = audit_pid; audit_pid = status_get->pid; audit_log(current->audit_context, "audit_pid=%d old=%d", audit_pid, old); } if (status_get->mask & AUDIT_STATUS_RATE_LIMIT) audit_set_rate_limit(status_get->rate_limit); if (status_get->mask & AUDIT_STATUS_BACKLOG_LIMIT) audit_set_backlog_limit(status_get->backlog_limit); break; case AUDIT_USER: ab = audit_log_start(NULL); if (!ab) break; /* audit_panic has been called */ audit_log_format(ab, "user pid=%d uid=%d length=%d msg='%.1024s'", pid, uid, (int)(nlh->nlmsg_len - ((char *)data - (char *)nlh)), (char *)data); ab->type = AUDIT_USER; ab->pid = pid; audit_log_end(ab); break; case AUDIT_ADD: case AUDIT_DEL: if (nlh->nlmsg_len < sizeof(struct audit_rule)) return -EINVAL; /* fallthrough */ case AUDIT_LIST: #ifdef CONFIG_AUDITSYSCALL err = audit_receive_filter(nlh->nlmsg_type, NETLINK_CB(skb).pid, uid, seq, data); #else err = -EOPNOTSUPP; #endif break; default: err = -EINVAL; break; } return err < 0 ? err : 0; } /* Get message from skb (based on rtnetlink_rcv_skb). Each message is * processed by audit_receive_msg. Malformed skbs with wrong length are * discarded silently. */ static int audit_receive_skb(struct sk_buff *skb) { int err; struct nlmsghdr *nlh; u32 rlen; while (skb->len >= NLMSG_SPACE(0)) { nlh = (struct nlmsghdr *)skb->data; if (nlh->nlmsg_len < sizeof(*nlh) || skb->len < nlh->nlmsg_len) return 0; rlen = NLMSG_ALIGN(nlh->nlmsg_len); if (rlen > skb->len) rlen = skb->len; if ((err = audit_receive_msg(skb, nlh))) { netlink_ack(skb, nlh, err); } else if (nlh->nlmsg_flags & NLM_F_ACK) netlink_ack(skb, nlh, 0); skb_pull(skb, rlen); } return 0; } /* Receive messages from netlink socket. */ static void audit_receive(struct sock *sk, int length) { struct sk_buff *skb; if (down_trylock(&audit_netlink_sem)) return; /* FIXME: this must not cause starvation */ while ((skb = skb_dequeue(&sk->sk_receive_queue))) { if (audit_receive_skb(skb) && skb->len) skb_queue_head(&sk->sk_receive_queue, skb); else kfree_skb(skb); } up(&audit_netlink_sem); } /* Move data from tmp buffer into an skb. This is an extra copy, and * that is unfortunate. However, the copy will only occur when a record * is being written to user space, which is already a high-overhead * operation. (Elimination of the copy is possible, for example, by * writing directly into a pre-allocated skb, at the cost of wasting * memory. */ static void audit_log_move(struct audit_buffer *ab) { struct sk_buff *skb; char *start; int extra = ab->nlh ? 0 : NLMSG_SPACE(0); /* possible resubmission */ if (ab->len == 0) return; skb = skb_peek(&ab->sklist); if (!skb || skb_tailroom(skb) <= ab->len + extra) { skb = alloc_skb(2 * ab->len + extra, GFP_ATOMIC); if (!skb) { ab->len = 0; /* Lose information in ab->tmp */ audit_log_lost("out of memory in audit_log_move"); return; } __skb_queue_tail(&ab->sklist, skb); if (!ab->nlh) ab->nlh = (struct nlmsghdr *)skb_put(skb, NLMSG_SPACE(0)); } start = skb_put(skb, ab->len); memcpy(start, ab->tmp, ab->len); ab->len = 0; }