X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=fs%2Fexec.c;h=5d358131af7331d824b7d069a065e9576a0f6cd1;hb=43bc926fffd92024b46cafaf7350d669ba9ca884;hp=5e2380595d51000f3d5d2e4bc33153ec9de0bf1d;hpb=cee37fe97739d85991964371c1f3a745c00dd236;p=linux-2.6.git diff --git a/fs/exec.c b/fs/exec.c index 5e2380595..5d358131a 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -48,7 +48,9 @@ #include #include #include +#include #include +#include #include #include @@ -59,6 +61,9 @@ int core_uses_pid; char core_pattern[65] = "core"; +int suid_dumpable = 0; + +EXPORT_SYMBOL(suid_dumpable); /* The maximal length of core_pattern is also specified in sysctl.c */ static struct linux_binfmt *formats; @@ -124,8 +129,7 @@ asmlinkage long sys_uselib(const char __user * library) struct nameidata nd; int error; - nd.intent.open.flags = FMODE_READ; - error = __user_walk(library, LOOKUP_FOLLOW|LOOKUP_OPEN, &nd); + error = __user_path_lookup_open(library, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC); if (error) goto out; @@ -133,11 +137,11 @@ asmlinkage long sys_uselib(const char __user * library) if (!S_ISREG(nd.dentry->d_inode->i_mode)) goto exit; - error = permission(nd.dentry->d_inode, MAY_READ | MAY_EXEC, &nd); + error = vfs_permission(&nd, MAY_READ | MAY_EXEC); if (error) goto exit; - file = dentry_open(nd.dentry, nd.mnt, O_RDONLY); + file = nameidata_to_filp(&nd, O_RDONLY); error = PTR_ERR(file); if (IS_ERR(file)) goto out; @@ -165,6 +169,7 @@ asmlinkage long sys_uselib(const char __user * library) out: return error; exit: + release_open_intent(&nd); path_release(&nd); goto out; } @@ -303,44 +308,30 @@ void install_arg_page(struct vm_area_struct *vma, struct page *page, unsigned long address) { struct mm_struct *mm = vma->vm_mm; - pgd_t * pgd; - pud_t * pud; - pmd_t * pmd; pte_t * pte; + spinlock_t *ptl; if (unlikely(anon_vma_prepare(vma))) - goto out_sig; + goto out; flush_dcache_page(page); - pgd = pgd_offset(mm, address); - - spin_lock(&mm->page_table_lock); - pud = pud_alloc(mm, pgd, address); - if (!pud) - goto out; - pmd = pmd_alloc(mm, pud, address); - if (!pmd) - goto out; - pte = pte_alloc_map(mm, pmd, address); + pte = get_locked_pte(mm, address, &ptl); if (!pte) goto out; if (!pte_none(*pte)) { - pte_unmap(pte); + pte_unmap_unlock(pte, ptl); goto out; } - inc_mm_counter(mm, rss); + inc_mm_counter(mm, anon_rss); lru_cache_add_active(page); set_pte_at(mm, address, pte, pte_mkdirty(pte_mkwrite(mk_pte( page, vma->vm_page_prot)))); - page_add_anon_rmap(page, vma, address); - pte_unmap(pte); - spin_unlock(&mm->page_table_lock); + page_add_new_anon_rmap(page, vma, address); + pte_unmap_unlock(pte, ptl); /* no need for flush_tlb */ return; out: - spin_unlock(&mm->page_table_lock); -out_sig: __free_page(page); force_sig(SIGKILL, current); } @@ -419,12 +410,6 @@ int setup_arg_pages(struct linux_binprm *bprm, if (!mpnt) return -ENOMEM; - if (security_vm_enough_memory(arg_size >> PAGE_SHIFT) || - !vx_vmpages_avail(mm, arg_size >> PAGE_SHIFT)) { - kmem_cache_free(vm_area_cachep, mpnt); - return -ENOMEM; - } - memset(mpnt, 0, sizeof(*mpnt)); down_write(&mm->mmap_sem); @@ -495,8 +480,7 @@ struct file *open_exec(const char *name) int err; struct file *file; - nd.intent.open.flags = FMODE_READ; - err = path_lookup(name, LOOKUP_FOLLOW|LOOKUP_OPEN, &nd); + err = path_lookup_open(AT_FDCWD, name, LOOKUP_FOLLOW, &nd, FMODE_READ|FMODE_EXEC); file = ERR_PTR(err); if (!err) { @@ -504,12 +488,12 @@ struct file *open_exec(const char *name) file = ERR_PTR(-EACCES); if (!(nd.mnt->mnt_flags & MNT_NOEXEC) && S_ISREG(inode->i_mode)) { - int err = permission(inode, MAY_EXEC, &nd); + int err = vfs_permission(&nd, MAY_EXEC); if (!err && !(inode->i_mode & 0111)) err = -EACCES; file = ERR_PTR(err); if (!err) { - file = dentry_open(nd.dentry, nd.mnt, O_RDONLY); + file = nameidata_to_filp(&nd, O_RDONLY); if (!IS_ERR(file)) { err = deny_write_access(file); if (err) { @@ -521,6 +505,7 @@ out: return file; } } + release_open_intent(&nd); path_release(&nd); } goto out; @@ -579,7 +564,7 @@ static int exec_mmap(struct mm_struct *mm) arch_pick_mmap_layout(mm); if (old_mm) { up_read(&old_mm->mmap_sem); - if (active_mm != old_mm) BUG(); + BUG_ON(active_mm != old_mm); mmput(old_mm); return 0; } @@ -593,11 +578,12 @@ static int exec_mmap(struct mm_struct *mm) * disturbing other processes. (Other processes might share the signal * table via the CLONE_SIGHAND option to clone().) */ -static inline int de_thread(struct task_struct *tsk) +static int de_thread(struct task_struct *tsk) { struct signal_struct *sig = tsk->signal; struct sighand_struct *newsighand, *oldsighand = tsk->sighand; spinlock_t *lock = &oldsighand->siglock; + struct task_struct *leader = NULL; int count; /* @@ -633,15 +619,37 @@ static inline int de_thread(struct task_struct *tsk) kmem_cache_free(sighand_cachep, newsighand); return -EAGAIN; } + + /* + * child_reaper ignores SIGKILL, change it now. + * Reparenting needs write_lock on tasklist_lock, + * so it is safe to do it under read_lock. + */ + if (unlikely(current->group_leader == child_reaper)) + child_reaper = current; + zap_other_threads(current); read_unlock(&tasklist_lock); /* * Account for the thread group leader hanging around: */ - count = 2; - if (thread_group_leader(current)) - count = 1; + count = 1; + if (!thread_group_leader(current)) { + count = 2; + /* + * The SIGALRM timer survives the exec, but needs to point + * at us as the new group leader now. We have a race with + * a timer firing now getting the old leader, so we need to + * synchronize with any firing (by calling del_timer_sync) + * before we can safely let the old group leader die. + */ + sig->tsk = current; + spin_unlock_irq(lock); + if (hrtimer_cancel(&sig->real_timer)) + hrtimer_restart(&sig->real_timer); + spin_lock_irq(lock); + } while (atomic_read(&sig->count) > count) { sig->group_exit_task = current; sig->notify_count = count; @@ -652,7 +660,6 @@ static inline int de_thread(struct task_struct *tsk) } sig->group_exit_task = NULL; sig->notify_count = 0; - sig->real_timer.data = (unsigned long)current; spin_unlock_irq(lock); /* @@ -661,89 +668,87 @@ static inline int de_thread(struct task_struct *tsk) * and to assume its PID: */ if (!thread_group_leader(current)) { - struct task_struct *leader = current->group_leader, *parent; struct dentry *proc_dentry1, *proc_dentry2; - unsigned long exit_state, ptrace; /* * Wait for the thread group leader to be a zombie. * It should already be zombie at this point, most * of the time. */ + leader = current->group_leader; while (leader->exit_state != EXIT_ZOMBIE) yield(); + /* + * The only record we have of the real-time age of a + * process, regardless of execs it's done, is start_time. + * All the past CPU time is accumulated in signal_struct + * from sister threads now dead. But in this non-leader + * exec, nothing survives from the original leader thread, + * whose birth marks the true age of this process now. + * When we take on its identity by switching to its PID, we + * also take its birthdate (always earlier than our own). + */ + current->start_time = leader->start_time; + spin_lock(&leader->proc_lock); spin_lock(¤t->proc_lock); proc_dentry1 = proc_pid_unhash(current); proc_dentry2 = proc_pid_unhash(leader); write_lock_irq(&tasklist_lock); - if (leader->tgid != current->tgid) - BUG(); - if (current->pid == current->tgid) - BUG(); + BUG_ON(leader->tgid != current->tgid); + BUG_ON(current->pid == current->tgid); /* * An exec() starts a new thread group with the * TGID of the previous thread group. Rehash the * two threads with a switched PID, and release * the former thread group leader: */ - ptrace = leader->ptrace; - parent = leader->parent; - if (unlikely(ptrace) && unlikely(parent == current)) { - /* - * Joker was ptracing his own group leader, - * and now he wants to be his own parent! - * We can't have that. - */ - ptrace = 0; - } - - ptrace_unlink(current); - ptrace_unlink(leader); - remove_parent(current); - remove_parent(leader); - switch_exec_pids(leader, current); + /* Become a process group leader with the old leader's pid. + * Note: The old leader also uses thispid until release_task + * is called. Odd but simple and correct. + */ + detach_pid(current, PIDTYPE_PID); + current->pid = leader->pid; + attach_pid(current, PIDTYPE_PID, current->pid); + attach_pid(current, PIDTYPE_PGID, current->signal->pgrp); + attach_pid(current, PIDTYPE_SID, current->signal->session); + list_add_tail_rcu(¤t->tasks, &init_task.tasks); - current->parent = current->real_parent = leader->real_parent; - leader->parent = leader->real_parent = child_reaper; current->group_leader = current; - leader->group_leader = leader; + leader->group_leader = current; - add_parent(current, current->parent); - add_parent(leader, leader->parent); - if (ptrace) { - current->ptrace = ptrace; - __ptrace_link(current, parent); - } + /* Reduce leader to a thread */ + detach_pid(leader, PIDTYPE_PGID); + detach_pid(leader, PIDTYPE_SID); + list_del_init(&leader->tasks); - list_del(¤t->tasks); - list_add_tail(¤t->tasks, &init_task.tasks); current->exit_signal = SIGCHLD; - exit_state = leader->exit_state; + + BUG_ON(leader->exit_state != EXIT_ZOMBIE); + leader->exit_state = EXIT_DEAD; write_unlock_irq(&tasklist_lock); spin_unlock(&leader->proc_lock); spin_unlock(¤t->proc_lock); proc_pid_flush(proc_dentry1); proc_pid_flush(proc_dentry2); - - if (exit_state != EXIT_ZOMBIE) - BUG(); - release_task(leader); } /* - * Now there are really no other threads at all, - * so it's safe to stop telling them to kill themselves. + * There may be one thread left which is just exiting, + * but it's safe to stop telling the group to kill themselves. */ sig->flags = 0; no_thread_group: - BUG_ON(atomic_read(&sig->count) != 1); exit_itimers(sig); + if (leader) + release_task(leader); + + BUG_ON(atomic_read(&sig->count) != 1); if (atomic_read(&oldsighand->count) == 1) { /* @@ -756,7 +761,6 @@ no_thread_group: /* * Move our state over to newsighand and switch it in. */ - spin_lock_init(&newsighand->siglock); atomic_set(&newsighand->count, 1); memcpy(newsighand->action, oldsighand->action, sizeof(newsighand->action)); @@ -765,7 +769,7 @@ no_thread_group: spin_lock(&oldsighand->siglock); spin_lock(&newsighand->siglock); - current->sighand = newsighand; + rcu_assign_pointer(current->sighand, newsighand); recalc_sigpending(); spin_unlock(&newsighand->siglock); @@ -776,10 +780,7 @@ no_thread_group: kmem_cache_free(sighand_cachep, oldsighand); } - if (!thread_group_empty(current)) - BUG(); - if (!thread_group_leader(current)) - BUG(); + BUG_ON(!thread_group_leader(current)); return 0; } @@ -788,9 +789,10 @@ no_thread_group: * so that a new one can be started */ -static inline void flush_old_files(struct files_struct * files) +static void flush_old_files(struct files_struct * files) { long j = -1; + struct fdtable *fdt; spin_lock(&files->file_lock); for (;;) { @@ -798,12 +800,13 @@ static inline void flush_old_files(struct files_struct * files) j++; i = j * __NFDBITS; - if (i >= files->max_fds || i >= files->max_fdset) + fdt = files_fdtable(files); + if (i >= fdt->max_fds || i >= fdt->max_fdset) break; - set = files->close_on_exec->fds_bits[j]; + set = fdt->close_on_exec->fds_bits[j]; if (!set) continue; - files->close_on_exec->fds_bits[j] = 0; + fdt->close_on_exec->fds_bits[j] = 0; spin_unlock(&files->file_lock); for ( ; set ; i++,set >>= 1) { if (set & 1) { @@ -872,6 +875,9 @@ int flush_old_exec(struct linux_binprm * bprm) if (current->euid == current->uid && current->egid == current->gid) current->mm->dumpable = 1; + else + current->mm->dumpable = suid_dumpable; + name = bprm->filename; /* Copies the binary name from after last slash */ @@ -888,11 +894,17 @@ int flush_old_exec(struct linux_binprm * bprm) current->flags &= ~PF_RANDOMIZE; flush_thread(); + /* Set the new mm task size. We have to do that late because it may + * depend on TIF_32BIT which is only updated in flush_thread() on + * some architectures like powerpc + */ + current->mm->task_size = TASK_SIZE; + if (bprm->e_uid != current->euid || bprm->e_gid != current->egid || - permission(bprm->file->f_dentry->d_inode,MAY_READ, NULL) || + file_permission(bprm->file, MAY_READ) || (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) { suid_keys(current); - current->mm->dumpable = 0; + current->mm->dumpable = suid_dumpable; } /* An exec changes our domain. We are no longer part of the thread @@ -967,7 +979,7 @@ int prepare_binprm(struct linux_binprm *bprm) EXPORT_SYMBOL(prepare_binprm); -static inline int unsafe_exec(struct task_struct *p) +static int unsafe_exec(struct task_struct *p) { int unsafe = 0; if (p->ptrace & PT_PTRACED) { @@ -1094,6 +1106,7 @@ int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs) fput(bprm->file); bprm->file = NULL; current->did_exec = 1; + proc_exec_connector(current); return retval; } read_lock(&binfmt_lock); @@ -1139,10 +1152,9 @@ int do_execve(char * filename, int i; retval = -ENOMEM; - bprm = kmalloc(sizeof(*bprm), GFP_KERNEL); + bprm = kzalloc(sizeof(*bprm), GFP_KERNEL); if (!bprm) goto out_ret; - memset(bprm, 0, sizeof(*bprm)); file = open_exec(filename); retval = PTR_ERR(file); @@ -1201,7 +1213,6 @@ int do_execve(char * filename, /* execve success */ security_bprm_free(bprm); acct_update_integrals(current); - update_mem_hiwater(current); kfree(bprm); return retval; } @@ -1329,7 +1340,7 @@ static void format_corename(char *corename, const char *pattern, long signr) case 'h': down_read(&uts_sem); rc = snprintf(out_ptr, out_end - out_ptr, - "%s", system_utsname.nodename); + "%s", vx_new_uts(nodename)); up_read(&uts_sem); if (rc > out_end - out_ptr) goto out; @@ -1406,7 +1417,7 @@ static void zap_threads (struct mm_struct *mm) do_each_thread(g,p) { if (mm == p->mm && p != tsk && p->ptrace && p->parent->mm == mm) { - __ptrace_unlink(p); + __ptrace_detach(p, 0); } } while_each_thread(g,p); write_unlock_irq(&tasklist_lock); @@ -1416,19 +1427,16 @@ static void zap_threads (struct mm_struct *mm) static void coredump_wait(struct mm_struct *mm) { DECLARE_COMPLETION(startup_done); + int core_waiters; - mm->core_waiters++; /* let other threads block */ mm->core_startup_done = &startup_done; - /* give other threads a chance to run: */ - yield(); - zap_threads(mm); - if (--mm->core_waiters) { - up_write(&mm->mmap_sem); + core_waiters = mm->core_waiters; + up_write(&mm->mmap_sem); + + if (core_waiters) wait_for_completion(&startup_done); - } else - up_write(&mm->mmap_sem); BUG_ON(mm->core_waiters); } @@ -1440,28 +1448,52 @@ int do_coredump(long signr, int exit_code, struct pt_regs * regs) struct inode * inode; struct file * file; int retval = 0; + int fsuid = current->fsuid; + int flag = 0; binfmt = current->binfmt; if (!binfmt || !binfmt->core_dump) goto fail; + if (current->tux_exit) + current->tux_exit(); down_write(&mm->mmap_sem); if (!mm->dumpable) { up_write(&mm->mmap_sem); goto fail; } + + /* + * We cannot trust fsuid as being the "true" uid of the + * process nor do we know its entire history. We only know it + * was tainted so we dump it as root in mode 2. + */ + if (mm->dumpable == 2) { /* Setuid core dump mode */ + flag = O_EXCL; /* Stop rewrite attacks */ + current->fsuid = 0; /* Dump root private */ + } mm->dumpable = 0; - init_completion(&mm->core_done); + + retval = -EAGAIN; spin_lock_irq(¤t->sighand->siglock); - current->signal->flags = SIGNAL_GROUP_EXIT; - current->signal->group_exit_code = exit_code; + if (!(current->signal->flags & SIGNAL_GROUP_EXIT)) { + current->signal->flags = SIGNAL_GROUP_EXIT; + current->signal->group_exit_code = exit_code; + current->signal->group_stop_count = 0; + retval = 0; + } spin_unlock_irq(¤t->sighand->siglock); + if (retval) { + up_write(&mm->mmap_sem); + goto fail; + } + + init_completion(&mm->core_done); coredump_wait(mm); /* * Clear any false indication of pending signals that might * be seen by the filesystem code called to write the core file. */ - current->signal->group_stop_count = 0; clear_thread_flag(TIF_SIGPENDING); if (current->signal->rlim[RLIMIT_CORE].rlim_cur < binfmt->min_coredump) @@ -1474,7 +1506,7 @@ int do_coredump(long signr, int exit_code, struct pt_regs * regs) lock_kernel(); format_corename(corename, core_pattern, signr); unlock_kernel(); - file = filp_open(corename, O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE, 0600); + file = filp_open(corename, O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag, 0600); if (IS_ERR(file)) goto fail_unlock; inode = file->f_dentry->d_inode; @@ -1489,7 +1521,7 @@ int do_coredump(long signr, int exit_code, struct pt_regs * regs) goto close_fail; if (!file->f_op->write) goto close_fail; - if (do_truncate(file->f_dentry, 0) != 0) + if (do_truncate(file->f_dentry, 0, 0, file) != 0) goto close_fail; retval = binfmt->core_dump(signr, regs, file); @@ -1499,6 +1531,7 @@ int do_coredump(long signr, int exit_code, struct pt_regs * regs) close_fail: filp_close(file, NULL); fail_unlock: + current->fsuid = fsuid; complete_all(&mm->core_done); fail: return retval;