/* * Copyright (c) 1999-2005 Apple Computer, Inc. * Copyright (c) 2006 Robert N. M. Watson * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of * its contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * * $FreeBSD: head/sys/security/audit/audit.c 155558 2006-02-11 23:53:00Z rwatson $ */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * The AUDIT_EXCESSIVELY_VERBOSE define enables a number of * gratuitously noisy printf's to the console. Due to the * volume, it should be left off unless you want your system * to churn a lot whenever the audit record flow gets high. */ //#define AUDIT_EXCESSIVELY_VERBOSE #ifdef AUDIT_EXCESSIVELY_VERBOSE #define AUDIT_PRINTF(x) printf x #else #define AUDIT_PRINTF(X) #endif static uma_zone_t audit_record_zone; static MALLOC_DEFINE(M_AUDITPROC, "audit_proc", "Audit process storage"); MALLOC_DEFINE(M_AUDITDATA, "audit_data", "Audit data storage"); MALLOC_DEFINE(M_AUDITPATH, "audit_path", "Audit path storage"); MALLOC_DEFINE(M_AUDITTEXT, "audit_text", "Audit text storage"); /* * Audit control settings that are set/read by system calls and are * hence non-static. */ /* * Define the audit control flags. */ int audit_enabled; int audit_suspended; /* * Flags controlling behavior in low storage situations. * Should we panic if a write fails? Should we fail stop * if we're out of disk space? */ int audit_panic_on_write_fail; int audit_fail_stop; /* * Are we currently "failing stop" due to out of disk space? */ static int audit_in_failure; /* * Global audit statistiscs. */ struct audit_fstat audit_fstat; /* * Preselection mask for non-attributable events. */ struct au_mask audit_nae_mask; /* * Mutex to protect global variables shared between various threads and * processes. */ static struct mtx audit_mtx; /* * Queue of audit records ready for delivery to disk. We insert new * records at the tail, and remove records from the head. Also, * a count of the number of records used for checking queue depth. * In addition, a counter of records that we have allocated but are * not yet in the queue, which is needed to estimate the total * size of the combined set of records outstanding in the system. */ static TAILQ_HEAD(, kaudit_record) audit_q; static int audit_q_len; static int audit_pre_q_len; /* * Audit queue control settings (minimum free, low/high water marks, etc.) */ struct au_qctrl audit_qctrl; /* * Condition variable to signal to the worker that it has work to do: * either new records are in the queue, or a log replacement is taking * place. */ static struct cv audit_cv; /* * Worker thread that will schedule disk I/O, etc. */ static struct proc *audit_thread; /* * When an audit log is rotated, the actual rotation must be performed * by the audit worker thread, as it may have outstanding writes on the * current audit log. audit_replacement_vp holds the vnode replacing * the current vnode. We can't let more than one replacement occur * at a time, so if more than one thread requests a replacement, only * one can have the replacement "in progress" at any given moment. If * a thread tries to replace the audit vnode and discovers a replacement * is already in progress (i.e., audit_replacement_flag != 0), then it * will sleep on audit_replacement_cv waiting its turn to perform a * replacement. When a replacement is completed, this cv is signalled * by the worker thread so a waiting thread can start another replacement. * We also store a credential to perform audit log write operations with. * * The current credential and vnode are thread-local to audit_worker. */ static struct cv audit_replacement_cv; static int audit_replacement_flag; static struct vnode *audit_replacement_vp; static struct ucred *audit_replacement_cred; /* * Condition variable to signal to the worker that it has work to do: * either new records are in the queue, or a log replacement is taking * place. */ static struct cv audit_commit_cv; /* * Condition variable for auditing threads wait on when in fail-stop mode. * Threads wait on this CV forever (and ever), never seeing the light of * day again. */ static struct cv audit_fail_cv; /* * Flags related to Kernel->user-space communication. */ static int audit_file_rotate_wait; /* * Construct an audit record for the passed thread. */ static int audit_record_ctor(void *mem, int size, void *arg, int flags) { struct kaudit_record *ar; struct thread *td; KASSERT(sizeof(*ar) == size, ("audit_record_ctor: wrong size")); td = arg; ar = mem; bzero(ar, sizeof(*ar)); ar->k_ar.ar_magic = AUDIT_RECORD_MAGIC; nanotime(&ar->k_ar.ar_starttime); /* * Export the subject credential. * * XXXAUDIT: td_ucred access is OK without proc lock, but some other * fields here may require the proc lock. */ cru2x(td->td_ucred, &ar->k_ar.ar_subj_cred); ar->k_ar.ar_subj_ruid = td->td_ucred->cr_ruid; ar->k_ar.ar_subj_rgid = td->td_ucred->cr_rgid; ar->k_ar.ar_subj_egid = td->td_ucred->cr_groups[0]; ar->k_ar.ar_subj_auid = td->td_proc->p_au->ai_auid; ar->k_ar.ar_subj_asid = td->td_proc->p_au->ai_asid; ar->k_ar.ar_subj_pid = td->td_proc->p_pid; ar->k_ar.ar_subj_amask = td->td_proc->p_au->ai_mask; ar->k_ar.ar_subj_term = td->td_proc->p_au->ai_termid; bcopy(td->td_proc->p_comm, ar->k_ar.ar_subj_comm, MAXCOMLEN); return (0); } static void audit_record_dtor(void *mem, int size, void *arg) { struct kaudit_record *ar; KASSERT(sizeof(*ar) == size, ("audit_record_dtor: wrong size")); ar = mem; if (ar->k_ar.ar_arg_upath1 != NULL) free(ar->k_ar.ar_arg_upath1, M_AUDITPATH); if (ar->k_ar.ar_arg_upath2 != NULL) free(ar->k_ar.ar_arg_upath2, M_AUDITPATH); if (ar->k_ar.ar_arg_text != NULL) free(ar->k_ar.ar_arg_text, M_AUDITTEXT); if (ar->k_udata != NULL) free(ar->k_udata, M_AUDITDATA); } /* * XXXAUDIT: Should adjust comments below to make it clear that we get to * this point only if we believe we have storage, so not having space here * is a violation of invariants derived from administrative procedures. * I.e., someone else has written to the audit partition, leaving less space * than we accounted for. */ static int audit_record_write(struct vnode *vp, struct kaudit_record *ar, struct ucred *cred, struct thread *td) { int ret; long temp; struct au_record *bsm; struct vattr vattr; struct statfs *mnt_stat = &vp->v_mount->mnt_stat; int vfslocked; vfslocked = VFS_LOCK_GIANT(vp->v_mount); /* * First, gather statistics on the audit log file and file system * so that we know how we're doing on space. In both cases, * if we're unable to perform the operation, we drop the record * and return. However, this is arguably an assertion failure. * XXX Need a FreeBSD equivalent. */ ret = VFS_STATFS(vp->v_mount, mnt_stat, td); if (ret) goto out; vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); ret = VOP_GETATTR(vp, &vattr, cred, td); VOP_UNLOCK(vp, 0, td); if (ret) goto out; /* update the global stats struct */ audit_fstat.af_currsz = vattr.va_size; /* * XXX Need to decide what to do if the trigger to the audit daemon * fails. */ /* * If we fall below minimum free blocks (hard limit), tell the audit * daemon to force a rotation off of the file system. We also stop * writing, which means this audit record is probably lost. * If we fall below the minimum percent free blocks (soft limit), * then kindly suggest to the audit daemon to do something. */ if (mnt_stat->f_bfree < AUDIT_HARD_LIMIT_FREE_BLOCKS) { send_trigger(AUDIT_TRIGGER_NO_SPACE); /* Hopefully userspace did something about all the previous * triggers that were sent prior to this critical condition. * If fail-stop is set, then we're done; goodnight Gracie. */ if (audit_fail_stop) panic("Audit log space exhausted and fail-stop set."); else { audit_suspended = 1; ret = ENOSPC; goto out; } } else /* * Send a message to the audit daemon that disk space * is getting low. * * XXXAUDIT: Check math and block size calculation here. */ if (audit_qctrl.aq_minfree != 0) { temp = mnt_stat->f_blocks / (100 / audit_qctrl.aq_minfree); if (mnt_stat->f_bfree < temp) send_trigger(AUDIT_TRIGGER_LOW_SPACE); } /* Check if the current log file is full; if so, call for * a log rotate. This is not an exact comparison; we may * write some records over the limit. If that's not * acceptable, then add a fudge factor here. */ if ((audit_fstat.af_filesz != 0) && (audit_file_rotate_wait == 0) && (vattr.va_size >= audit_fstat.af_filesz)) { audit_file_rotate_wait = 1; send_trigger(AUDIT_TRIGGER_OPEN_NEW); } /* * If the estimated amount of audit data in the audit event queue * (plus records allocated but not yet queued) has reached the * amount of free space on the disk, then we need to go into an * audit fail stop state, in which we do not permit the * allocation/committing of any new audit records. We continue to * process packets but don't allow any activities that might * generate new records. In the future, we might want to detect * when space is available again and allow operation to continue, * but this behavior is sufficient to meet fail stop requirements * in CAPP. */ if (audit_fail_stop && (unsigned long) ((audit_q_len + audit_pre_q_len + 1) * MAX_AUDIT_RECORD_SIZE) / mnt_stat->f_bsize >= (unsigned long)(mnt_stat->f_bfree)) { printf( "audit_worker: free space below size of audit queue, failing stop\n"); audit_in_failure = 1; } /* * If there is a user audit record attached to the kernel record, * then write the user record. */ /* XXX Need to decide a few things here: IF the user audit * record is written, but the write of the kernel record fails, * what to do? Should the kernel record come before or after the * user record? For now, we write the user record first, and * we ignore errors. */ if (ar->k_ar_commit & AR_COMMIT_USER) { /* * Try submitting the record to any active audit pipes. */ audit_pipe_submit((void *)ar->k_udata, ar->k_ulen); /* * And to disk. */ ret = vn_rdwr(UIO_WRITE, vp, (void *)ar->k_udata, ar->k_ulen, (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, cred, NULL, NULL, td); if (ret) goto out; } /* * Convert the internal kernel record to BSM format and write it * out if everything's OK. */ if (!(ar->k_ar_commit & AR_COMMIT_KERNEL)) { ret = 0; goto out; } /* * XXXAUDIT: Should we actually allow this conversion to fail? With * sleeping memory allocation and invariants checks, perhaps not. */ ret = kaudit_to_bsm(ar, &bsm); if (ret == BSM_NOAUDIT) { ret = 0; goto out; } /* * XXX: We drop the record on BSM conversion failure, but really * this is an assertion failure. */ if (ret == BSM_FAILURE) { AUDIT_PRINTF(("BSM conversion failure\n")); ret = EINVAL; goto out; } /* * Try submitting the record to any active audit pipes. */ audit_pipe_submit((void *)bsm->data, bsm->len); /* * XXX * We should break the write functionality away from the BSM record * generation and have the BSM generation done before this function * is called. This function will then take the BSM record as a * parameter. */ ret = (vn_rdwr(UIO_WRITE, vp, (void *)bsm->data, bsm->len, (off_t)0, UIO_SYSSPACE, IO_APPEND|IO_UNIT, cred, NULL, NULL, td)); kau_free(bsm); out: /* * When we're done processing the current record, we have to * check to see if we're in a failure mode, and if so, whether * this was the last record left to be drained. If we're done * draining, then we fsync the vnode and panic. */ if (audit_in_failure && audit_q_len == 0 && audit_pre_q_len == 0) { VOP_LOCK(vp, LK_DRAIN | LK_INTERLOCK, td); (void)VOP_FSYNC(vp, MNT_WAIT, td); VOP_UNLOCK(vp, 0, td); panic("Audit store overflow; record queue drained."); } VFS_UNLOCK_GIANT(vfslocked); return (ret); } /* * The audit_worker thread is responsible for watching the event queue, * dequeueing records, converting them to BSM format, and committing them to * disk. In order to minimize lock thrashing, records are dequeued in sets * to a thread-local work queue. In addition, the audit_work performs the * actual exchange of audit log vnode pointer, as audit_vp is a thread-local * variable. */ static void audit_worker(void *arg) { int do_replacement_signal, error; TAILQ_HEAD(, kaudit_record) ar_worklist; struct kaudit_record *ar; struct vnode *audit_vp, *old_vp; int vfslocked; struct ucred *audit_cred, *old_cred; struct thread *audit_td; AUDIT_PRINTF(("audit_worker starting\n")); /* * These are thread-local variables requiring no synchronization. */ TAILQ_INIT(&ar_worklist); audit_cred = NULL; audit_td = curthread; audit_vp = NULL; mtx_lock(&audit_mtx); while (1) { /* * First priority: replace the audit log target if requested. * Accessing the vnode here requires dropping the audit_mtx; * in case another replacement was scheduled while the mutex * was released, we loop. * * XXX It could well be we should drain existing records * first to ensure that the timestamps and ordering * are right. */ do_replacement_signal = 0; while (audit_replacement_flag != 0) { old_cred = audit_cred; old_vp = audit_vp; audit_cred = audit_replacement_cred; audit_vp = audit_replacement_vp; audit_replacement_cred = NULL; audit_replacement_vp = NULL; audit_replacement_flag = 0; audit_enabled = (audit_vp != NULL); /* * XXX: What to do about write failures here? */ if (old_vp != NULL) { AUDIT_PRINTF(("Closing old audit file\n")); mtx_unlock(&audit_mtx); vfslocked = VFS_LOCK_GIANT(old_vp->v_mount); vn_close(old_vp, AUDIT_CLOSE_FLAGS, old_cred, audit_td); VFS_UNLOCK_GIANT(vfslocked); crfree(old_cred); mtx_lock(&audit_mtx); old_cred = NULL; old_vp = NULL; AUDIT_PRINTF(("Audit file closed\n")); } if (audit_vp != NULL) { AUDIT_PRINTF(("Opening new audit file\n")); } do_replacement_signal = 1; } /* * Signal that replacement have occurred to wake up and * start any other replacements started in parallel. We can * continue about our business in the mean time. We * broadcast so that both new replacements can be inserted, * but also so that the source(s) of replacement can return * successfully. */ if (do_replacement_signal) cv_broadcast(&audit_replacement_cv); /* * Next, check to see if we have any records to drain into * the vnode. If not, go back to waiting for an event. */ if (TAILQ_EMPTY(&audit_q)) { AUDIT_PRINTF(("audit_worker waiting\n")); cv_wait(&audit_cv, &audit_mtx); AUDIT_PRINTF(("audit_worker woken up\n")); AUDIT_PRINTF(("audit_worker: new vp = %p; value of flag %d\n", audit_replacement_vp, audit_replacement_flag)); continue; } /* * If we have records, but there's no active vnode to write * to, drain the record queue. Generally, we prevent the * unnecessary allocation of records elsewhere, but we need * to allow for races between conditional allocation and * queueing. Go back to waiting when we're done. */ if (audit_vp == NULL) { while ((ar = TAILQ_FIRST(&audit_q))) { TAILQ_REMOVE(&audit_q, ar, k_q); uma_zfree(audit_record_zone, ar); audit_q_len--; /* * XXXRW: Why broadcast if we hold the * mutex and know that audit_vp is NULL? */ if (audit_q_len <= audit_qctrl.aq_lowater) cv_broadcast(&audit_commit_cv); } continue; } /* * We have both records to write and an active vnode to write * to. Dequeue a record, and start the write. Eventually, * it might make sense to dequeue several records and perform * our own clustering, if the lower layers aren't doing it * automatically enough. */ while ((ar = TAILQ_FIRST(&audit_q))) { TAILQ_REMOVE(&audit_q, ar, k_q); audit_q_len--; if (audit_q_len <= audit_qctrl.aq_lowater) cv_broadcast(&audit_commit_cv); TAILQ_INSERT_TAIL(&ar_worklist, ar, k_q); } mtx_unlock(&audit_mtx); while ((ar = TAILQ_FIRST(&ar_worklist))) { TAILQ_REMOVE(&ar_worklist, ar, k_q); if (audit_vp != NULL) { error = audit_record_write(audit_vp, ar, audit_cred, audit_td); if (error && audit_panic_on_write_fail) panic("audit_worker: write error %d\n", error); else if (error) printf("audit_worker: write error %d\n", error); } uma_zfree(audit_record_zone, ar); } mtx_lock(&audit_mtx); } } /* * Initialize the Audit subsystem: configuration state, work queue, * synchronization primitives, worker thread, and trigger device node. Also * call into the BSM assembly code to initialize it. */ static void audit_init(void) { int error; printf("Security auditing service present\n"); audit_enabled = 0; audit_suspended = 0; audit_panic_on_write_fail = 0; audit_fail_stop = 0; audit_in_failure = 0; audit_replacement_vp = NULL; audit_replacement_cred = NULL; audit_replacement_flag = 0; audit_fstat.af_filesz = 0; /* '0' means unset, unbounded */ audit_fstat.af_currsz = 0; audit_nae_mask.am_success = AU_NULL; audit_nae_mask.am_failure = AU_NULL; TAILQ_INIT(&audit_q); audit_q_len = 0; audit_pre_q_len = 0; audit_qctrl.aq_hiwater = AQ_HIWATER; audit_qctrl.aq_lowater = AQ_LOWATER; audit_qctrl.aq_bufsz = AQ_BUFSZ; audit_qctrl.aq_minfree = AU_FS_MINFREE; mtx_init(&audit_mtx, "audit_mtx", NULL, MTX_DEF); cv_init(&audit_cv, "audit_cv"); cv_init(&audit_replacement_cv, "audit_replacement_cv"); cv_init(&audit_commit_cv, "audit_commit_cv"); cv_init(&audit_fail_cv, "audit_fail_cv"); audit_record_zone = uma_zcreate("audit_record_zone", sizeof(struct kaudit_record), audit_record_ctor, audit_record_dtor, NULL, NULL, UMA_ALIGN_PTR, 0); /* Initialize the BSM audit subsystem. */ kau_init(); audit_file_rotate_wait = 0; audit_trigger_init(); /* Register shutdown handler. */ EVENTHANDLER_REGISTER(shutdown_pre_sync, audit_shutdown, NULL, SHUTDOWN_PRI_FIRST); error = kthread_create(audit_worker, NULL, &audit_thread, RFHIGHPID, 0, "audit_worker"); if (error != 0) panic("audit_init: kthread_create returned %d", error); } SYSINIT(audit_init, SI_SUB_AUDIT, SI_ORDER_FIRST, audit_init, NULL) /* * audit_rotate_vnode() is called by a user or kernel thread to configure or * de-configure auditing on a vnode. The arguments are the replacement * credential and vnode to substitute for the current credential and vnode, * if any. If either is set to NULL, both should be NULL, and this is used * to indicate that audit is being disabled. The real work is done in the * audit_worker thread, but audit_rotate_vnode() waits synchronously for that * to complete. * * The vnode should be referenced and opened by the caller. The credential * should be referenced. audit_rotate_vnode() will own both references as of * this call, so the caller should not release either. * * XXXAUDIT: Review synchronize communication logic. Really, this is a * message queue of depth 1. * * XXXAUDIT: Enhance the comments below to indicate that we are basically * acquiring ownership of the communications queue, inserting our message, * and waiting for an acknowledgement. */ void audit_rotate_vnode(struct ucred *cred, struct vnode *vp) { /* * If other parallel log replacements have been requested, we wait * until they've finished before continuing. */ mtx_lock(&audit_mtx); while (audit_replacement_flag != 0) { AUDIT_PRINTF(("audit_rotate_vnode: sleeping to wait for " "flag\n")); cv_wait(&audit_replacement_cv, &audit_mtx); AUDIT_PRINTF(("audit_rotate_vnode: woken up (flag %d)\n", audit_replacement_flag)); } audit_replacement_cred = cred; audit_replacement_flag = 1; audit_replacement_vp = vp; /* * Wake up the audit worker to perform the exchange once we * release the mutex. */ cv_signal(&audit_cv); /* * Wait for the audit_worker to broadcast that a replacement has * taken place; we know that once this has happened, our vnode * has been replaced in, so we can return successfully. */ AUDIT_PRINTF(("audit_rotate_vnode: waiting for news of " "replacement\n")); cv_wait(&audit_replacement_cv, &audit_mtx); AUDIT_PRINTF(("audit_rotate_vnode: change acknowledged by " "audit_worker (flag " "now %d)\n", audit_replacement_flag)); mtx_unlock(&audit_mtx); audit_file_rotate_wait = 0; /* We can now request another rotation */ } /* * Drain the audit queue and close the log at shutdown. Note that this can * be called both from the system shutdown path and also from audit * configuration syscalls, so 'arg' and 'howto' are ignored. */ void audit_shutdown(void *arg, int howto) { audit_rotate_vnode(NULL, NULL); } /* * Return the current thread's audit record, if any. */ __inline__ struct kaudit_record * currecord(void) { return (curthread->td_ar); } /* * MPSAFE * * XXXAUDIT: There are a number of races present in the code below due to * release and re-grab of the mutex. The code should be revised to become * slightly less racy. * * XXXAUDIT: Shouldn't there be logic here to sleep waiting on available * pre_q space, suspending the system call until there is room? */ struct kaudit_record * audit_new(int event, struct thread *td) { struct kaudit_record *ar; int no_record; mtx_lock(&audit_mtx); no_record = (audit_suspended || !audit_enabled); mtx_unlock(&audit_mtx); if (no_record) return (NULL); /* * XXX: The number of outstanding uncommitted audit records is * limited to the number of concurrent threads servicing system * calls in the kernel. */ ar = uma_zalloc_arg(audit_record_zone, td, M_WAITOK); ar->k_ar.ar_event = event; mtx_lock(&audit_mtx); audit_pre_q_len++; mtx_unlock(&audit_mtx); return (ar); } /* * MPSAFE */ void audit_commit(struct kaudit_record *ar, int error, int retval) { int sorf; struct au_mask *aumask; if (ar == NULL) return; /* * Decide whether to commit the audit record by checking the * error value from the system call and using the appropriate * audit mask. * * XXXAUDIT: Synchronize access to audit_nae_mask? */ if (ar->k_ar.ar_subj_auid == AU_DEFAUDITID) aumask = &audit_nae_mask; else aumask = &ar->k_ar.ar_subj_amask; if (error) sorf = AU_PRS_FAILURE; else sorf = AU_PRS_SUCCESS; switch(ar->k_ar.ar_event) { case AUE_OPEN_RWTC: /* The open syscall always writes a AUE_OPEN_RWTC event; change * it to the proper type of event based on the flags and the * error value. */ ar->k_ar.ar_event = flags_and_error_to_openevent( ar->k_ar.ar_arg_fflags, error); break; case AUE_SYSCTL: ar->k_ar.ar_event = ctlname_to_sysctlevent( ar->k_ar.ar_arg_ctlname, ar->k_ar.ar_valid_arg); break; case AUE_AUDITON: /* Convert the auditon() command to an event */ ar->k_ar.ar_event = auditon_command_event(ar->k_ar.ar_arg_cmd); break; } if (au_preselect(ar->k_ar.ar_event, aumask, sorf) != 0) ar->k_ar_commit |= AR_COMMIT_KERNEL; /* * XXXRW: Why is this necessary? Should we ever accept a record that * we're not willing to commit? */ if ((ar->k_ar_commit & (AR_COMMIT_USER | AR_COMMIT_KERNEL)) == 0) { mtx_lock(&audit_mtx); audit_pre_q_len--; mtx_unlock(&audit_mtx); uma_zfree(audit_record_zone, ar); return; } ar->k_ar.ar_errno = error; ar->k_ar.ar_retval = retval; /* * We might want to do some system-wide post-filtering * here at some point. */ /* * Timestamp system call end. */ nanotime(&ar->k_ar.ar_endtime); mtx_lock(&audit_mtx); /* * Note: it could be that some records initiated while audit was * enabled should still be committed? */ if (audit_suspended || !audit_enabled) { audit_pre_q_len--; mtx_unlock(&audit_mtx); uma_zfree(audit_record_zone, ar); return; } /* * Constrain the number of committed audit records based on * the configurable parameter. */ while (audit_q_len >= audit_qctrl.aq_hiwater) { AUDIT_PRINTF(("audit_commit: sleeping to wait for " "audit queue to drain below high water mark\n")); cv_wait(&audit_commit_cv, &audit_mtx); AUDIT_PRINTF(("audit_commit: woke up waiting for " "audit queue draining\n")); } TAILQ_INSERT_TAIL(&audit_q, ar, k_q); audit_q_len++; audit_pre_q_len--; cv_signal(&audit_cv); mtx_unlock(&audit_mtx); } /* * audit_syscall_enter() is called on entry to each system call. It is * responsible for deciding whether or not to audit the call (preselection), * and if so, allocating a per-thread audit record. audit_new() will fill in * basic thread/credential properties. */ void audit_syscall_enter(unsigned short code, struct thread *td) { int audit_event; struct au_mask *aumask; KASSERT(td->td_ar == NULL, ("audit_syscall_enter: td->td_ar != NULL")); /* * In FreeBSD, each ABI has its own system call table, and hence * mapping of system call codes to audit events. Convert the code to * an audit event identifier using the process system call table * reference. In Darwin, there's only one, so we use the global * symbol for the system call table. * * XXXAUDIT: Should we audit that a bad system call was made, and if * so, how? */ if (code >= td->td_proc->p_sysent->sv_size) return; audit_event = td->td_proc->p_sysent->sv_table[code].sy_auevent; if (audit_event == AUE_NULL) return; /* * Check which audit mask to use; either the kernel non-attributable * event mask or the process audit mask. */ if (td->td_proc->p_au->ai_auid == AU_DEFAUDITID) aumask = &audit_nae_mask; else aumask = &td->td_proc->p_au->ai_mask; /* * Allocate an audit record, if preselection allows it, and store * in the thread for later use. */ if (au_preselect(audit_event, aumask, AU_PRS_FAILURE | AU_PRS_SUCCESS)) { /* * If we're out of space and need to suspend unprivileged * processes, do that here rather than trying to allocate * another audit record. * * XXXRW: We might wish to be able to continue here in the * future, if the system recovers. That should be possible * by means of checking the condition in a loop around * cv_wait(). It might be desirable to reevaluate whether an * audit record is still required for this event by * re-calling au_preselect(). */ if (audit_in_failure && suser(td) != 0) { cv_wait(&audit_fail_cv, &audit_mtx); panic("audit_failing_stop: thread continued"); } td->td_ar = audit_new(audit_event, td); } else td->td_ar = NULL; } /* * audit_syscall_exit() is called from the return of every system call, or in * the event of exit1(), during the execution of exit1(). It is responsible * for committing the audit record, if any, along with return condition. */ void audit_syscall_exit(int error, struct thread *td) { int retval; /* * Commit the audit record as desired; once we pass the record * into audit_commit(), the memory is owned by the audit * subsystem. * The return value from the system call is stored on the user * thread. If there was an error, the return value is set to -1, * imitating the behavior of the cerror routine. */ if (error) retval = -1; else retval = td->td_retval[0]; audit_commit(td->td_ar, error, retval); if (td->td_ar != NULL) AUDIT_PRINTF(("audit record committed by pid %d\n", td->td_proc->p_pid)); td->td_ar = NULL; } /* * Allocate storage for a new process (init, or otherwise). */ void audit_proc_alloc(struct proc *p) { KASSERT(p->p_au == NULL, ("audit_proc_alloc: p->p_au != NULL (%d)", p->p_pid)); p->p_au = malloc(sizeof(*(p->p_au)), M_AUDITPROC, M_WAITOK); /* XXXAUDIT: Zero? Slab allocate? */ //printf("audit_proc_alloc: pid %d p_au %p\n", p->p_pid, p->p_au); } /* * Allocate storage for a new thread. */ void audit_thread_alloc(struct thread *td) { td->td_ar = NULL; } /* * Thread destruction. */ void audit_thread_free(struct thread *td) { KASSERT(td->td_ar == NULL, ("audit_thread_free: td_ar != NULL")); } /* * Initialize the audit information for the a process, presumably the first * process in the system. * XXX It is not clear what the initial values should be for audit ID, * session ID, etc. */ void audit_proc_kproc0(struct proc *p) { KASSERT(p->p_au != NULL, ("audit_proc_kproc0: p->p_au == NULL (%d)", p->p_pid)); //printf("audit_proc_kproc0: pid %d p_au %p\n", p->p_pid, p->p_au); bzero(p->p_au, sizeof(*(p)->p_au)); } void audit_proc_init(struct proc *p) { KASSERT(p->p_au != NULL, ("audit_proc_init: p->p_au == NULL (%d)", p->p_pid)); //printf("audit_proc_init: pid %d p_au %p\n", p->p_pid, p->p_au); bzero(p->p_au, sizeof(*(p)->p_au)); p->p_au->ai_auid = AU_DEFAUDITID; } /* * Copy the audit info from the parent process to the child process when * a fork takes place. */ void audit_proc_fork(struct proc *parent, struct proc *child) { PROC_LOCK_ASSERT(parent, MA_OWNED); PROC_LOCK_ASSERT(child, MA_OWNED); KASSERT(parent->p_au != NULL, ("audit_proc_fork: parent->p_au == NULL (%d)", parent->p_pid)); KASSERT(child->p_au != NULL, ("audit_proc_fork: child->p_au == NULL (%d)", child->p_pid)); //printf("audit_proc_fork: parent pid %d p_au %p\n", parent->p_pid, // parent->p_au); //printf("audit_proc_fork: child pid %d p_au %p\n", child->p_pid, // child->p_au); bcopy(parent->p_au, child->p_au, sizeof(*child->p_au)); /* * XXXAUDIT: Zero pointers to external memory, or assert they are * zero? */ } /* * Free the auditing structure for the process. */ void audit_proc_free(struct proc *p) { KASSERT(p->p_au != NULL, ("p->p_au == NULL (%d)", p->p_pid)); //printf("audit_proc_free: pid %d p_au %p\n", p->p_pid, p->p_au); /* * XXXAUDIT: Assert that external memory pointers are NULL? */ free(p->p_au, M_AUDITPROC); p->p_au = NULL; }