diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/acct.c | 456 | ||||
| -rw-r--r-- | kernel/fork.c | 2 | ||||
| -rw-r--r-- | kernel/module.c | 14 | ||||
| -rw-r--r-- | kernel/seccomp.c | 10 |
4 files changed, 213 insertions, 269 deletions
diff --git a/kernel/acct.c b/kernel/acct.c index 51793520566f..b4c667d22e79 100644 --- a/kernel/acct.c +++ b/kernel/acct.c @@ -59,6 +59,7 @@ #include <asm/div64.h> #include <linux/blkdev.h> /* sector_div */ #include <linux/pid_namespace.h> +#include <linux/fs_pin.h> /* * These constants control the amount of freespace that suspend and @@ -75,172 +76,190 @@ int acct_parm[3] = {4, 2, 30}; /* * External references and all of the globals. */ -static void do_acct_process(struct bsd_acct_struct *acct, - struct pid_namespace *ns, struct file *); +static void do_acct_process(struct bsd_acct_struct *acct); -/* - * This structure is used so that all the data protected by lock - * can be placed in the same cache line as the lock. This primes - * the cache line to have the data after getting the lock. - */ struct bsd_acct_struct { + struct fs_pin pin; + struct mutex lock; int active; unsigned long needcheck; struct file *file; struct pid_namespace *ns; - struct list_head list; + struct work_struct work; + struct completion done; }; -static DEFINE_SPINLOCK(acct_lock); -static LIST_HEAD(acct_list); - /* * Check the amount of free space and suspend/resume accordingly. */ -static int check_free_space(struct bsd_acct_struct *acct, struct file *file) +static int check_free_space(struct bsd_acct_struct *acct) { struct kstatfs sbuf; - int res; - int act; - u64 resume; - u64 suspend; - - spin_lock(&acct_lock); - res = acct->active; - if (!file || time_is_before_jiffies(acct->needcheck)) + + if (time_is_before_jiffies(acct->needcheck)) goto out; - spin_unlock(&acct_lock); /* May block */ - if (vfs_statfs(&file->f_path, &sbuf)) - return res; - suspend = sbuf.f_blocks * SUSPEND; - resume = sbuf.f_blocks * RESUME; - - do_div(suspend, 100); - do_div(resume, 100); - - if (sbuf.f_bavail <= suspend) - act = -1; - else if (sbuf.f_bavail >= resume) - act = 1; - else - act = 0; - - /* - * If some joker switched acct->file under us we'ld better be - * silent and _not_ touch anything. - */ - spin_lock(&acct_lock); - if (file != acct->file) { - if (act) - res = act > 0; + if (vfs_statfs(&acct->file->f_path, &sbuf)) goto out; - } if (acct->active) { - if (act < 0) { + 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 { - if (act > 0) { + 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; - res = acct->active; out: - spin_unlock(&acct_lock); + return acct->active; +} + +static struct bsd_acct_struct *acct_get(struct pid_namespace *ns) +{ + struct bsd_acct_struct *res; +again: + smp_rmb(); + rcu_read_lock(); + res = ACCESS_ONCE(ns->bacct); + if (!res) { + rcu_read_unlock(); + return NULL; + } + if (!atomic_long_inc_not_zero(&res->pin.count)) { + rcu_read_unlock(); + cpu_relax(); + goto again; + } + rcu_read_unlock(); + mutex_lock(&res->lock); + if (!res->ns) { + mutex_unlock(&res->lock); + pin_put(&res->pin); + goto again; + } return res; } -/* - * Close the old accounting file (if currently open) and then replace - * it with file (if non-NULL). - * - * NOTE: acct_lock MUST be held on entry and exit. - */ -static void acct_file_reopen(struct bsd_acct_struct *acct, struct file *file, - struct pid_namespace *ns) +static void close_work(struct work_struct *work) { - struct file *old_acct = NULL; - struct pid_namespace *old_ns = NULL; - - if (acct->file) { - old_acct = acct->file; - old_ns = acct->ns; - acct->active = 0; - acct->file = NULL; + 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 void acct_kill(struct bsd_acct_struct *acct, + struct bsd_acct_struct *new) +{ + if (acct) { + struct pid_namespace *ns = acct->ns; + do_acct_process(acct); + INIT_WORK(&acct->work, close_work); + init_completion(&acct->done); + schedule_work(&acct->work); + wait_for_completion(&acct->done); + pin_remove(&acct->pin); + ns->bacct = new; acct->ns = NULL; - list_del(&acct->list); - } - if (file) { - acct->file = file; - acct->ns = ns; - acct->needcheck = jiffies + ACCT_TIMEOUT*HZ; - acct->active = 1; - list_add(&acct->list, &acct_list); + atomic_long_dec(&acct->pin.count); + mutex_unlock(&acct->lock); + pin_put(&acct->pin); } - if (old_acct) { - mnt_unpin(old_acct->f_path.mnt); - spin_unlock(&acct_lock); - do_acct_process(acct, old_ns, old_acct); - filp_close(old_acct, NULL); - spin_lock(&acct_lock); +} + +static void acct_pin_kill(struct fs_pin *pin) +{ + struct bsd_acct_struct *acct; + acct = container_of(pin, struct bsd_acct_struct, pin); + mutex_lock(&acct->lock); + if (!acct->ns) { + mutex_unlock(&acct->lock); + pin_put(pin); + acct = NULL; } + acct_kill(acct, NULL); } static int acct_on(struct filename *pathname) { struct file *file; - struct vfsmount *mnt; - struct pid_namespace *ns; - struct bsd_acct_struct *acct = NULL; + struct vfsmount *mnt, *internal; + struct pid_namespace *ns = task_active_pid_ns(current); + struct bsd_acct_struct *acct, *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)) + 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_op->write) { + kfree(acct); filp_close(file, NULL); return -EIO; } - - ns = task_active_pid_ns(current); - if (ns->bacct == NULL) { - acct = kzalloc(sizeof(struct bsd_acct_struct), GFP_KERNEL); - if (acct == NULL) { - filp_close(file, NULL); - return -ENOMEM; - } + internal = mnt_clone_internal(&file->f_path); + if (IS_ERR(internal)) { + kfree(acct); + filp_close(file, NULL); + return PTR_ERR(internal); } - - spin_lock(&acct_lock); - if (ns->bacct == NULL) { - ns->bacct = acct; - acct = NULL; + err = mnt_want_write(internal); + if (err) { + mntput(internal); + kfree(acct); + filp_close(file, NULL); + return err; } - mnt = file->f_path.mnt; - mnt_pin(mnt); - acct_file_reopen(ns->bacct, file, ns); - spin_unlock(&acct_lock); - - mntput(mnt); /* it's pinned, now give up active reference */ - kfree(acct); - + file->f_path.mnt = internal; + + atomic_long_set(&acct->pin.count, 1); + acct->pin.kill = acct_pin_kill; + acct->file = file; + acct->needcheck = jiffies; + acct->ns = ns; + mutex_init(&acct->lock); + mutex_lock_nested(&acct->lock, 1); /* nobody has seen it yet */ + pin_insert(&acct->pin, mnt); + + old = acct_get(ns); + if (old) + acct_kill(old, acct); + else + ns->bacct = acct; + mutex_unlock(&acct->lock); + 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 @@ -264,78 +283,20 @@ SYSCALL_DEFINE1(acct, const char __user *, 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 { - struct bsd_acct_struct *acct; - - acct = task_active_pid_ns(current)->bacct; - if (acct == NULL) - return 0; - - spin_lock(&acct_lock); - acct_file_reopen(acct, NULL, NULL); - spin_unlock(&acct_lock); + acct_kill(acct_get(task_active_pid_ns(current)), NULL); } return error; } -/** - * acct_auto_close - turn off a filesystem's accounting if it is on - * @m: vfsmount being shut down - * - * If the accounting is turned on for a file in the subtree pointed to - * to by m, turn accounting off. Done when m is about to die. - */ -void acct_auto_close_mnt(struct vfsmount *m) -{ - struct bsd_acct_struct *acct; - - spin_lock(&acct_lock); -restart: - list_for_each_entry(acct, &acct_list, list) - if (acct->file && acct->file->f_path.mnt == m) { - acct_file_reopen(acct, NULL, NULL); - goto restart; - } - spin_unlock(&acct_lock); -} - -/** - * acct_auto_close - turn off a filesystem's accounting if it is on - * @sb: super block for the filesystem - * - * If the accounting is turned on for a file in the filesystem pointed - * to by sb, turn accounting off. - */ -void acct_auto_close(struct super_block *sb) -{ - struct bsd_acct_struct *acct; - - spin_lock(&acct_lock); -restart: - list_for_each_entry(acct, &acct_list, list) - if (acct->file && acct->file->f_path.dentry->d_sb == sb) { - acct_file_reopen(acct, NULL, NULL); - goto restart; - } - spin_unlock(&acct_lock); -} - void acct_exit_ns(struct pid_namespace *ns) { - struct bsd_acct_struct *acct = ns->bacct; - - if (acct == NULL) - return; - - spin_lock(&acct_lock); - if (acct->file != NULL) - acct_file_reopen(acct, NULL, NULL); - spin_unlock(&acct_lock); - - kfree(acct); + acct_kill(acct_get(ns), NULL); } /* @@ -450,38 +411,20 @@ static u32 encode_float(u64 value) * do_exit() or when switching to a different output file. */ -/* - * do_acct_process does all actual work. Caller holds the reference to file. - */ -static void do_acct_process(struct bsd_acct_struct *acct, - struct pid_namespace *ns, struct file *file) +static void fill_ac(acct_t *ac) { struct pacct_struct *pacct = ¤t->signal->pacct; - acct_t ac; - mm_segment_t fs; - unsigned long flim; u64 elapsed, run_time; struct tty_struct *tty; - const struct cred *orig_cred; - - /* 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, file)) - goto out; /* * Fill the accounting struct with the needed info as recorded * by the different kernel functions. */ - memset(&ac, 0, sizeof(acct_t)); + memset(ac, 0, sizeof(acct_t)); - ac.ac_version = ACCT_VERSION | ACCT_BYTEORDER; - strlcpy(ac.ac_comm, current->comm, sizeof(ac.ac_comm)); + 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(); @@ -489,9 +432,9 @@ static void do_acct_process(struct bsd_acct_struct *acct, /* convert nsec -> AHZ */ elapsed = nsec_to_AHZ(run_time); #if ACCT_VERSION == 3 - ac.ac_etime = encode_float(elapsed); + ac->ac_etime = encode_float(elapsed); #else - ac.ac_etime = encode_comp_t(elapsed < (unsigned long) -1l ? + ac->ac_etime = encode_comp_t(elapsed < (unsigned long) -1l ? (unsigned long) elapsed : (unsigned long) -1l); #endif #if ACCT_VERSION == 1 || ACCT_VERSION == 2 @@ -499,18 +442,58 @@ static void do_acct_process(struct bsd_acct_struct *acct, /* new enlarged etime field */ comp2_t etime = encode_comp2_t(elapsed); - ac.ac_etime_hi = etime >> 16; - ac.ac_etime_lo = (u16) etime; + ac->ac_etime_hi = etime >> 16; + ac->ac_etime_lo = (u16) etime; } #endif do_div(elapsed, AHZ); - ac.ac_btime = get_seconds() - elapsed; + 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 pid_namespace *ns = acct->ns; + 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 == 2 - ac.ac_ahz = AHZ; -#endif #if ACCT_VERSION == 1 || ACCT_VERSION == 2 /* backward-compatible 16 bit fields */ ac.ac_uid16 = ac.ac_uid; @@ -522,45 +505,18 @@ static void do_acct_process(struct bsd_acct_struct *acct, ac.ac_ppid = task_tgid_nr_ns(rcu_dereference(current->real_parent), ns); rcu_read_unlock(); #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); - ac.ac_io = encode_comp_t(0 /* current->io_usage */); /* %% */ - ac.ac_rw = encode_comp_t(ac.ac_io / 1024); - ac.ac_swaps = encode_comp_t(0); - /* * 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)) - goto out; - /* - * Kernel segment override to datasegment and write it - * to the accounting file. - */ - fs = get_fs(); - set_fs(KERNEL_DS); - /* - * 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; - file->f_op->write(file, (char *)&ac, - sizeof(acct_t), &file->f_pos); - current->signal->rlim[RLIMIT_FSIZE].rlim_cur = flim; - set_fs(fs); - file_end_write(file); + 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); } @@ -609,34 +565,20 @@ void acct_collect(long exitcode, int group_dead) spin_unlock_irq(¤t->sighand->siglock); } -static void acct_process_in_ns(struct pid_namespace *ns) +static void slow_acct_process(struct pid_namespace *ns) { - struct file *file = NULL; - struct bsd_acct_struct *acct; - - acct = ns->bacct; - /* - * accelerate the common fastpath: - */ - if (!acct || !acct->file) - return; - - spin_lock(&acct_lock); - file = acct->file; - if (unlikely(!file)) { - spin_unlock(&acct_lock); - return; + for ( ; ns; ns = ns->parent) { + struct bsd_acct_struct *acct = acct_get(ns); + if (acct) { + do_acct_process(acct); + mutex_unlock(&acct->lock); + pin_put(&acct->pin); + } } - get_file(file); - spin_unlock(&acct_lock); - - do_acct_process(acct, ns, file); - fput(file); } /** - * acct_process - now just a wrapper around acct_process_in_ns, - * which in turn is a wrapper around do_acct_process. + * acct_process * * handles process accounting for an exiting task */ @@ -649,6 +591,10 @@ void acct_process(void) * alive and holds its namespace, which in turn holds * its parent. */ - for (ns = task_active_pid_ns(current); ns != NULL; ns = ns->parent) - acct_process_in_ns(ns); + for (ns = task_active_pid_ns(current); ns != NULL; ns = ns->parent) { + if (ns->bacct) + break; + } + if (unlikely(ns)) + slow_acct_process(ns); } diff --git a/kernel/fork.c b/kernel/fork.c index 1380d8ace334..0cf9cdb6e491 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1105,7 +1105,7 @@ static void copy_seccomp(struct task_struct *p) * needed because this new task is not yet running and cannot * be racing exec. */ - BUG_ON(!spin_is_locked(¤t->sighand->siglock)); + assert_spin_locked(¤t->sighand->siglock); /* Ref-count the new filter user, and assign it. */ get_seccomp_filter(current); diff --git a/kernel/module.c b/kernel/module.c index ae79ce615cb9..6f69463f0066 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -3381,6 +3381,8 @@ static inline int within(unsigned long addr, void *start, unsigned long size) */ static inline int is_arm_mapping_symbol(const char *str) { + if (str[0] == '.' && str[1] == 'L') + return true; return str[0] == '$' && strchr("atd", str[1]) && (str[2] == '\0' || str[2] == '.'); } @@ -3444,8 +3446,7 @@ const char *module_address_lookup(unsigned long addr, list_for_each_entry_rcu(mod, &modules, list) { if (mod->state == MODULE_STATE_UNFORMED) continue; - if (within_module_init(addr, mod) || - within_module_core(addr, mod)) { + if (within_module(addr, mod)) { if (modname) *modname = mod->name; ret = get_ksymbol(mod, addr, size, offset); @@ -3469,8 +3470,7 @@ int lookup_module_symbol_name(unsigned long addr, char *symname) list_for_each_entry_rcu(mod, &modules, list) { if (mod->state == MODULE_STATE_UNFORMED) continue; - if (within_module_init(addr, mod) || - within_module_core(addr, mod)) { + if (within_module(addr, mod)) { const char *sym; sym = get_ksymbol(mod, addr, NULL, NULL); @@ -3495,8 +3495,7 @@ int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size, list_for_each_entry_rcu(mod, &modules, list) { if (mod->state == MODULE_STATE_UNFORMED) continue; - if (within_module_init(addr, mod) || - within_module_core(addr, mod)) { + if (within_module(addr, mod)) { const char *sym; sym = get_ksymbol(mod, addr, size, offset); @@ -3760,8 +3759,7 @@ struct module *__module_address(unsigned long addr) list_for_each_entry_rcu(mod, &modules, list) { if (mod->state == MODULE_STATE_UNFORMED) continue; - if (within_module_core(addr, mod) - || within_module_init(addr, mod)) + if (within_module(addr, mod)) return mod; } return NULL; diff --git a/kernel/seccomp.c b/kernel/seccomp.c index 25b0043f4755..44eb005c6695 100644 --- a/kernel/seccomp.c +++ b/kernel/seccomp.c @@ -203,7 +203,7 @@ static u32 seccomp_run_filters(int syscall) static inline bool seccomp_may_assign_mode(unsigned long seccomp_mode) { - BUG_ON(!spin_is_locked(¤t->sighand->siglock)); + assert_spin_locked(¤t->sighand->siglock); if (current->seccomp.mode && current->seccomp.mode != seccomp_mode) return false; @@ -214,7 +214,7 @@ static inline bool seccomp_may_assign_mode(unsigned long seccomp_mode) static inline void seccomp_assign_mode(struct task_struct *task, unsigned long seccomp_mode) { - BUG_ON(!spin_is_locked(&task->sighand->siglock)); + assert_spin_locked(&task->sighand->siglock); task->seccomp.mode = seccomp_mode; /* @@ -253,7 +253,7 @@ static inline pid_t seccomp_can_sync_threads(void) struct task_struct *thread, *caller; BUG_ON(!mutex_is_locked(¤t->signal->cred_guard_mutex)); - BUG_ON(!spin_is_locked(¤t->sighand->siglock)); + assert_spin_locked(¤t->sighand->siglock); /* Validate all threads being eligible for synchronization. */ caller = current; @@ -294,7 +294,7 @@ static inline void seccomp_sync_threads(void) struct task_struct *thread, *caller; BUG_ON(!mutex_is_locked(¤t->signal->cred_guard_mutex)); - BUG_ON(!spin_is_locked(¤t->sighand->siglock)); + assert_spin_locked(¤t->sighand->siglock); /* Synchronize all threads. */ caller = current; @@ -464,7 +464,7 @@ static long seccomp_attach_filter(unsigned int flags, unsigned long total_insns; struct seccomp_filter *walker; - BUG_ON(!spin_is_locked(¤t->sighand->siglock)); + assert_spin_locked(¤t->sighand->siglock); /* Validate resulting filter length. */ total_insns = filter->prog->len; |