/* * linux/kernel/acct.c * * BSD Process Accounting for Linux * * Author: Marco van Wieringen * * Some code based on ideas and code from: * Thomas K. Dyas * * This file implements BSD-style process accounting. Whenever any * process exits, an accounting record of type "struct acct" is * written to the file specified with the acct() system call. It is * up to user-level programs to do useful things with the accounting * log. The kernel just provides the raw accounting information. * * (C) Copyright 1995 - 1997 Marco van Wieringen - ELM Consultancy B.V. * * Plugged two leaks. 1) It didn't return acct_file into the free_filps if * the file happened to be read-only. 2) If the accounting was suspended * due to the lack of space it happily allowed to reopen it and completely * lost the old acct_file. 3/10/98, Al Viro. * * Now we silently close acct_file on attempt to reopen. Cleaned sys_acct(). * XTerms and EMACS are manifestations of pure evil. 21/10/98, AV. * * Fixed a nasty interaction with with sys_umount(). If the accointing * was suspeneded we failed to stop it on umount(). Messy. * Another one: remount to readonly didn't stop accounting. * Question: what should we do if we have CAP_SYS_ADMIN but not * CAP_SYS_PACCT? Current code does the following: umount returns -EBUSY * unless we are messing with the root. In that case we are getting a * real mess with do_remount_sb(). 9/11/98, AV. * * Fixed a bunch of races (and pair of leaks). Probably not the best way, * but this one obviously doesn't introduce deadlocks. Later. BTW, found * one race (and leak) in BSD implementation. * OK, that's better. ANOTHER race and leak in BSD variant. There always * is one more bug... 10/11/98, AV. * * Oh, fsck... Oopsable SMP race in do_process_acct() - we must hold * ->mmap_sem to walk the vma list of current->mm. Nasty, since it leaks * a struct file opened for write. Fixed. 2/6/2000, AV. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* sector_div */ #include #include /* * These constants control the amount of freespace that suspend and * resume the process accounting system, and the time delay between * each check. * Turned into sysctl-controllable parameters. AV, 12/11/98 */ int acct_parm[3] = {4, 2, 30}; #define RESUME (acct_parm[0]) /* >foo% free space - resume */ #define SUSPEND (acct_parm[1]) /* needcheck)) goto out; /* May block */ if (vfs_statfs(&acct->file->f_path, &sbuf)) goto out; if (acct->active) { u64 suspend = sbuf.f_blocks * SUSPEND; do_div(suspend, 100); if (sbuf.f_bavail <= suspend) { acct->active = 0; pr_info("Process accounting paused\n"); } } else { u64 resume = sbuf.f_blocks * RESUME; do_div(resume, 100); if (sbuf.f_bavail >= resume) { acct->active = 1; pr_info("Process accounting resumed\n"); } } acct->needcheck = jiffies + ACCT_TIMEOUT*HZ; out: return acct->active; } static void acct_put(struct bsd_acct_struct *p) { if (atomic_long_dec_and_test(&p->count)) kfree_rcu(p, rcu); } static inline struct bsd_acct_struct *to_acct(struct fs_pin *p) { return p ? container_of(p, struct bsd_acct_struct, pin) : NULL; } static struct bsd_acct_struct *acct_get(struct pid_namespace *ns) { struct bsd_acct_struct *res; again: smp_rmb(); rcu_read_lock(); res = to_acct(ACCESS_ONCE(ns->bacct)); if (!res) { rcu_read_unlock(); return NULL; } if (!atomic_long_inc_not_zero(&res->count)) { rcu_read_unlock(); cpu_relax(); goto again; } rcu_read_unlock(); mutex_lock(&res->lock); if (res != to_acct(ACCESS_ONCE(ns->bacct))) { mutex_unlock(&res->lock); acct_put(res); goto again; } return res; } static void acct_pin_kill(struct fs_pin *pin) { struct bsd_acct_struct *acct = to_acct(pin); mutex_lock(&acct->lock); do_acct_process(acct); schedule_work(&acct->work); wait_for_completion(&acct->done); cmpxchg(&acct->ns->bacct, pin, NULL); mutex_unlock(&acct->lock); pin_remove(pin); acct_put(acct); } static void close_work(struct work_struct *work) { struct bsd_acct_struct *acct = container_of(work, struct bsd_acct_struct, work); struct file *file = acct->file; if (file->f_op->flush) file->f_op->flush(file, NULL); __fput_sync(file); complete(&acct->done); } static int acct_on(struct filename *pathname) { struct file *file; struct vfsmount *mnt, *internal; struct pid_namespace *ns = task_active_pid_ns(current); struct bsd_acct_struct *acct; struct fs_pin *old; int err; acct = kzalloc(sizeof(struct bsd_acct_struct), GFP_KERNEL); if (!acct) return -ENOMEM; /* Difference from BSD - they don't do O_APPEND */ file = file_open_name(pathname, O_WRONLY|O_APPEND|O_LARGEFILE, 0); if (IS_ERR(file)) { kfree(acct); return PTR_ERR(file); } if (!S_ISREG(file_inode(file)->i_mode)) { kfree(acct); filp_close(file, NULL); return -EACCES; } if (!(file->f_mode & FMODE_CAN_WRITE)) { kfree(acct); filp_close(file, NULL); return -EIO; } internal = mnt_clone_internal(&file->f_path); if (IS_ERR(internal)) { kfree(acct); filp_close(file, NULL); return PTR_ERR(internal); } err = mnt_want_write(internal); if (err) { mntput(internal); kfree(acct); filp_close(file, NULL); return err; } mnt = file->f_path.mnt; file->f_path.mnt = internal; atomic_long_set(&acct->count, 1); init_fs_pin(&acct->pin, acct_pin_kill); acct->file = file; acct->needcheck = jiffies; acct->ns = ns; mutex_init(&acct->lock); INIT_WORK(&acct->work, close_work); init_completion(&acct->done); mutex_lock_nested(&acct->lock, 1); /* nobody has seen it yet */ pin_insert(&acct->pin, mnt); rcu_read_lock(); old = xchg(&ns->bacct, &acct->pin); mutex_unlock(&acct->lock); pin_kill(old); mnt_drop_write(mnt); mntput(mnt); return 0; } static DEFINE_MUTEX(acct_on_mutex); /** * sys_acct - enable/disable process accounting * @name: file name for accounting records or NULL to shutdown accounting * * Returns 0 for success or negative errno values for failure. * * sys_acct() is the only system call needed to implement process * accounting. It takes the name of the file where accounting records * should be written. If the filename is NULL, accounting will be * shutdown. */ SYSCALL_DEFINE1(acct, const char __user *, name) { int error = 0; if (!capable(CAP_SYS_PACCT)) return -EPERM; if (name) { struct filename *tmp = getname(name); if (IS_ERR(tmp)) return PTR_ERR(tmp); mutex_lock(&acct_on_mutex); error = acct_on(tmp); mutex_unlock(&acct_on_mutex); putname(tmp); } else { rcu_read_lock(); pin_kill(task_active_pid_ns(current)->bacct); } return error; } void acct_exit_ns(struct pid_namespace *ns) { rcu_read_lock(); pin_kill(ns->bacct); } /* * encode an unsigned long into a comp_t * * This routine has been adopted from the encode_comp_t() function in * the kern_acct.c file of the FreeBSD operating system. The encoding * is a 13-bit fraction with a 3-bit (base 8) exponent. */ #define MANTSIZE 13 /* 13 bit mantissa. */ #define EXPSIZE 3 /* Base 8 (3 bit) exponent. */ #define MAXFRACT ((1 << MANTSIZE) - 1) /* Maximum fractional value. */ static comp_t encode_comp_t(unsigned long value) { int exp, rnd; exp = rnd = 0; while (value > MAXFRACT) { rnd = value & (1 << (EXPSIZE - 1)); /* Round up? */ value >>= EXPSIZE; /* Base 8 exponent == 3 bit shift. */ exp++; } /* * If we need to round up, do it (and handle overflow correctly). */ if (rnd && (++value > MAXFRACT)) { value >>= EXPSIZE; exp++; } /* * Clean it up and polish it off. */ exp <<= MANTSIZE; /* Shift the exponent into place */ exp += value; /* and add on the mantissa. */ return exp; } #if ACCT_VERSION == 1 || ACCT_VERSION == 2 /* * encode an u64 into a comp2_t (24 bits) * * Format: 5 bit base 2 exponent, 20 bits mantissa. * The leading bit of the mantissa is not stored, but implied for * non-zero exponents. * Largest encodable value is 50 bits. */ #define MANTSIZE2 20 /* 20 bit mantissa. */ #define EXPSIZE2 5 /* 5 bit base 2 exponent. */ #define MAXFRACT2 ((1ul << MANTSIZE2) - 1) /* Maximum fractional value. */ #define MAXEXP2 ((1 << EXPSIZE2) - 1) /* Maximum exponent. */ static comp2_t encode_comp2_t(u64 value) { int exp, rnd; exp = (value > (MAXFRACT2>>1)); rnd = 0; while (value > MAXFRACT2) { rnd = value & 1; value >>= 1; exp++; } /* * If we need to round up, do it (and handle overflow correctly). */ if (rnd && (++value > MAXFRACT2)) { value >>= 1; exp++; } if (exp > MAXEXP2) { /* Overflow. Return largest representable number instead. */ return (1ul << (MANTSIZE2+EXPSIZE2-1)) - 1; } else { return (value & (MAXFRACT2>>1)) | (exp << (MANTSIZE2-1)); } } #endif #if ACCT_VERSION == 3 /* * encode an u64 into a 32 bit IEEE float */ static u32 encode_float(u64 value) { unsigned exp = 190; unsigned u; if (value == 0) return 0; while ((s64)value > 0) { value <<= 1; exp--; } u = (u32)(value >> 40) & 0x7fffffu; return u | (exp << 23); } #endif /* * Write an accounting entry for an exiting process * * The acct_process() call is the workhorse of the process * accounting system. The struct acct is built here and then written * into the accounting file. This function should only be called from * do_exit() or when switching to a different output file. */ static void fill_ac(acct_t *ac) { struct pacct_struct *pacct = ¤t->signal->pacct; u64 elapsed, run_time; struct tty_struct *tty; /* * Fill the accounting struct with the needed info as recorded * by the different kernel functions. */ memset(ac, 0, sizeof(acct_t)); ac->ac_version = ACCT_VERSION | ACCT_BYTEORDER; strlcpy(ac->ac_comm, current->comm, sizeof(ac->ac_comm)); /* calculate run_time in nsec*/ run_time = ktime_get_ns(); run_time -= current->group_leader->start_time; /* convert nsec -> AHZ */ elapsed = nsec_to_AHZ(run_time); #if ACCT_VERSION == 3 ac->ac_etime = encode_float(elapsed); #else ac->ac_etime = encode_comp_t(elapsed < (unsigned long) -1l ? (unsigned long) elapsed : (unsigned long) -1l); #endif #if ACCT_VERSION == 1 || ACCT_VERSION == 2 { /* new enlarged etime field */ comp2_t etime = encode_comp2_t(elapsed); ac->ac_etime_hi = etime >> 16; ac->ac_etime_lo = (u16) etime; } #endif do_div(elapsed, AHZ); ac->ac_btime = get_seconds() - elapsed; #if ACCT_VERSION==2 ac->ac_ahz = AHZ; #endif spin_lock_irq(¤t->sighand->siglock); tty = current->signal->tty; /* Safe as we hold the siglock */ ac->ac_tty = tty ? old_encode_dev(tty_devnum(tty)) : 0; ac->ac_utime = encode_comp_t(jiffies_to_AHZ(cputime_to_jiffies(pacct->ac_utime))); ac->ac_stime = encode_comp_t(jiffies_to_AHZ(cputime_to_jiffies(pacct->ac_stime))); ac->ac_flag = pacct->ac_flag; ac->ac_mem = encode_comp_t(pacct->ac_mem); ac->ac_minflt = encode_comp_t(pacct->ac_minflt); ac->ac_majflt = encode_comp_t(pacct->ac_majflt); ac->ac_exitcode = pacct->ac_exitcode; spin_unlock_irq(¤t->sighand->siglock); } /* * do_acct_process does all actual work. Caller holds the reference to file. */ static void do_acct_process(struct bsd_acct_struct *acct) { acct_t ac; unsigned long flim; const struct cred *orig_cred; struct file *file = acct->file; /* * Accounting records are not subject to resource limits. */ flim = current->signal->rlim[RLIMIT_FSIZE].rlim_cur; current->signal->rlim[RLIMIT_FSIZE].rlim_cur = RLIM_INFINITY; /* Perform file operations on behalf of whoever enabled accounting */ orig_cred = override_creds(file->f_cred); /* * First check to see if there is enough free_space to continue * the process accounting system. */ if (!check_free_space(acct)) goto out; fill_ac(&ac); /* we really need to bite the bullet and change layout */ ac.ac_uid = from_kuid_munged(file->f_cred->user_ns, orig_cred->uid); ac.ac_gid = from_kgid_munged(file->f_cred->user_ns, orig_cred->gid); #if ACCT_VERSION == 1 || ACCT_VERSION == 2 /* backward-compatible 16 bit fields */ ac.ac_uid16 = ac.ac_uid; ac.ac_gid16 = ac.ac_gid; #endif #if ACCT_VERSION == 3 { struct pid_namespace *ns = acct->ns; ac.ac_pid = task_tgid_nr_ns(current, ns); rcu_read_lock(); ac.ac_ppid = task_tgid_nr_ns(rcu_dereference(current->real_parent), ns); rcu_read_unlock(); } #endif /* * Get freeze protection. If the fs is frozen, just skip the write * as we could deadlock the system otherwise. */ if (file_start_write_trylock(file)) { /* it's been opened O_APPEND, so position is irrelevant */ loff_t pos = 0; __kernel_write(file, (char *)&ac, sizeof(acct_t), &pos); file_end_write(file); } out: current->signal->rlim[RLIMIT_FSIZE].rlim_cur = flim; revert_creds(orig_cred); } /** * acct_collect - collect accounting information into pacct_struct * @exitcode: task exit code * @group_dead: not 0, if this thread is the last one in the process. */ void acct_collect(long exitcode, int group_dead) { struct pacct_struct *pacct = ¤t->signal->pacct; cputime_t utime, stime; unsigned long vsize = 0; if (group_dead && current->mm) { struct vm_area_struct *vma; down_read(¤t->mm->mmap_sem); vma = current->mm->mmap; while (vma) { vsize += vma->vm_end - vma->vm_start; vma = vma->vm_next; } up_read(¤t->mm->mmap_sem); } spin_lock_irq(¤t->sighand->siglock); if (group_dead) pacct->ac_mem = vsize / 1024; if (thread_group_leader(current)) { pacct->ac_exitcode = exitcode; if (current->flags & PF_FORKNOEXEC) pacct->ac_flag |= AFORK; } if (current->flags & PF_SUPERPRIV) pacct->ac_flag |= ASU; if (current->flags & PF_DUMPCORE) pacct->ac_flag |= ACORE; if (current->flags & PF_SIGNALED) pacct->ac_flag |= AXSIG; task_cputime(current, &utime, &stime); pacct->ac_utime += utime; pacct->ac_stime += stime; pacct->ac_minflt += current->min_flt; pacct->ac_majflt += current->maj_flt; spin_unlock_irq(¤t->sighand->siglock); } static void slow_acct_process(struct pid_namespace *ns) { for ( ; ns; ns = ns->parent) { struct bsd_acct_struct *acct = acct_get(ns); if (acct) { do_acct_process(acct); mutex_unlock(&acct->lock); acct_put(acct); } } } /** * acct_process * * handles process accounting for an exiting task */ void acct_process(void) { struct pid_namespace *ns; /* * This loop is safe lockless, since current is still * alive and holds its namespace, which in turn holds * its parent. */ for (ns = task_active_pid_ns(current); ns != NULL; ns = ns->parent) { if (ns->bacct) break; } if (unlikely(ns)) slow_acct_process(ns); } ove&id=2851940ffee313e0ff12540a8e11a8c54dea9c65'>netfilter: allow logging from non-init namespacesMichal Kubeček1-0/+3 Commit 69b34fb996b2 ("netfilter: xt_LOG: add net namespace support for xt_LOG") disabled logging packets using the LOG target from non-init namespaces. The motivation was to prevent containers from flooding kernel log of the host. The plan was to keep it that way until syslog namespace implementation allows containers to log in a safe way. However, the work on syslog namespace seems to have hit a dead end somewhere in 2013 and there are users who want to use xt_LOG in all network namespaces. This patch allows to do so by setting /proc/sys/net/netfilter/nf_log_all_netns to a nonzero value. This sysctl is only accessible from init_net so that one cannot switch the behaviour from inside a container. Signed-off-by: Michal Kubecek <mkubecek@suse.cz> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> 2017-02-02ipvs: free ip_vs_dest structs when refcnt=0David Windsor1-1/+1 Currently, the ip_vs_dest cache frees ip_vs_dest objects when their reference count becomes < 0. Aside from not being semantically sound, this is problematic for the new type refcount_t, which will be introduced shortly in a separate patch. refcount_t is the new kernel type for holding reference counts, and provides overflow protection and a constrained interface relative to atomic_t (the type currently being used for kernel reference counts). Per Julian Anastasov: "The problem is that dest_trash currently holds deleted dests (unlinked from RCU lists) with refcnt=0." Changing dest_trash to hold dest with refcnt=1 will allow us to free ip_vs_dest structs when their refcnt=0, in ip_vs_dest_put_and_free(). Signed-off-by: David Windsor <dwindsor@gmail.com> Signed-off-by: Julian Anastasov <ja@ssi.bg> Signed-off-by: Simon Horman <horms@verge.net.au> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> 2017-02-02netfilter: merge ctinfo into nfct pointer storage areaFlorian Westphal1-5/+6 After this change conntrack operations (lookup, creation, matching from ruleset) only access one instead of two sk_buff cache lines. This works for normal conntracks because those are allocated from a slab that guarantees hw cacheline or 8byte alignment (whatever is larger) so the 3 bits needed for ctinfo won't overlap with nf_conn addresses. Template allocation now does manual address alignment (see previous change) on arches that don't have sufficent kmalloc min alignment. Some spots intentionally use skb->_nfct instead of skb_nfct() helpers, this is to avoid undoing the skb_nfct() use when we remove untracked conntrack object in the future. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> 2017-02-02netfilter: guarantee 8 byte minalign for template addressesFlorian Westphal1-0/+2 The next change will merge skb->nfct pointer and skb->nfctinfo status bits into single skb->_nfct (unsigned long) area. For this to work nf_conn addresses must always be aligned at least on an 8 byte boundary since we will need the lower 3bits to store nfctinfo. Conntrack templates are allocated via kmalloc. kbuild test robot reported BUILD_BUG_ON failed: NFCT_INFOMASK >= ARCH_KMALLOC_MINALIGN on v1 of this patchset, so not all platforms meet this requirement. Do manual alignment if needed, the alignment offset is stored in the nf_conn entry protocol area. This works because templates are not handed off to L4 protocol trackers. Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> 2017-02-02netfilter: add and use nf_ct_set helperFlorian Westphal2-2/+9 Add a helper to assign a nf_conn entry and the ctinfo bits to an sk_buff. This avoids changing code in followup patch that merges skb->nfct and skb->nfctinfo into skb->_nfct. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> 2017-02-02skbuff: add and use skb_nfct helperFlorian Westphal1-1/+1 Followup patch renames skb->nfct and changes its type so add a helper to avoid intrusive rename change later. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> 2017-02-02netfilter: reduce direct skb->nfct usageFlorian Westphal1-3/+6 Next patch makes direct skb->nfct access illegal, reduce noise in next patch by using accessors we already have. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> 2017-02-02netfilter: conntrack: no need to pass ctinfo to error handlerFlorian Westphal1-1/+1 It is never accessed for reading and the only places that write to it are the icmp(6) handlers, which also set skb->nfct (and skb->nfctinfo). The conntrack core specifically checks for attached skb->nfct after ->error() invocation and returns early in this case. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>