X-Git-Url: http://ftp.safe.ca/?p=safe%2Fjmp%2Flinux-2.6;a=blobdiff_plain;f=fs%2Fexec.c;h=e6e94c626c2cbebb7699597271a953b65e611e6e;hp=8efbdc606a1e9be84eff1dc72872a7f49d8545db;hb=4434ade8c9334a3ab975d8993de456f06841899e;hpb=61be228a06dc6e8662f30e89eda3c12083c1f379 diff --git a/fs/exec.c b/fs/exec.c index 8efbdc6..e6e94c6 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -46,7 +46,6 @@ #include #include #include -#include #include #include #include @@ -196,7 +195,7 @@ static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, * to work from. */ rlim = current->signal->rlim; - if (size > rlim[RLIMIT_STACK].rlim_cur / 4) { + if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur) / 4) { put_page(page); return NULL; } @@ -247,6 +246,7 @@ static int __bprm_mm_init(struct linux_binprm *bprm) vma->vm_start = vma->vm_end - PAGE_SIZE; vma->vm_flags = VM_STACK_FLAGS; vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); + INIT_LIST_HEAD(&vma->anon_vma_chain); err = insert_vm_struct(mm, vma); if (err) goto err; @@ -517,7 +517,8 @@ static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift) /* * cover the whole range: [new_start, old_end) */ - vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL); + if (vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL)) + return -ENOMEM; /* * move the page tables downwards, on failure we rely on @@ -548,15 +549,13 @@ static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift) tlb_finish_mmu(tlb, new_end, old_end); /* - * shrink the vma to just the new range. + * Shrink the vma to just the new range. Always succeeds. */ vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL); return 0; } -#define EXTRA_STACK_VM_PAGES 20 /* random */ - /* * Finalizes the stack vm_area_struct. The flags and permissions are updated, * the stack is optionally relocated, and some extra space is added. @@ -572,10 +571,13 @@ int setup_arg_pages(struct linux_binprm *bprm, struct vm_area_struct *prev = NULL; unsigned long vm_flags; unsigned long stack_base; + unsigned long stack_size; + unsigned long stack_expand; + unsigned long rlim_stack; #ifdef CONFIG_STACK_GROWSUP /* Limit stack size to 1GB */ - stack_base = current->signal->rlim[RLIMIT_STACK].rlim_max; + stack_base = rlimit_max(RLIMIT_STACK); if (stack_base > (1 << 30)) stack_base = 1 << 30; @@ -624,16 +626,27 @@ int setup_arg_pages(struct linux_binprm *bprm, /* Move stack pages down in memory. */ if (stack_shift) { ret = shift_arg_pages(vma, stack_shift); - if (ret) { - up_write(&mm->mmap_sem); - return ret; - } + if (ret) + goto out_unlock; } + stack_expand = 131072UL; /* randomly 32*4k (or 2*64k) pages */ + stack_size = vma->vm_end - vma->vm_start; + /* + * Align this down to a page boundary as expand_stack + * will align it up. + */ + rlim_stack = rlimit(RLIMIT_STACK) & PAGE_MASK; #ifdef CONFIG_STACK_GROWSUP - stack_base = vma->vm_end + EXTRA_STACK_VM_PAGES * PAGE_SIZE; + if (stack_size + stack_expand > rlim_stack) + stack_base = vma->vm_start + rlim_stack; + else + stack_base = vma->vm_end + stack_expand; #else - stack_base = vma->vm_start - EXTRA_STACK_VM_PAGES * PAGE_SIZE; + if (stack_size + stack_expand > rlim_stack) + stack_base = vma->vm_end - rlim_stack; + else + stack_base = vma->vm_start - stack_expand; #endif ret = expand_stack(vma, stack_base); if (ret) @@ -641,7 +654,7 @@ int setup_arg_pages(struct linux_binprm *bprm, out_unlock: up_write(&mm->mmap_sem); - return 0; + return ret; } EXPORT_SYMBOL(setup_arg_pages); @@ -705,6 +718,7 @@ static int exec_mmap(struct mm_struct *mm) /* Notify parent that we're no longer interested in the old VM */ tsk = current; old_mm = current->mm; + sync_mm_rss(tsk, old_mm); mm_release(tsk, old_mm); if (old_mm) { @@ -829,7 +843,9 @@ static int de_thread(struct task_struct *tsk) attach_pid(tsk, PIDTYPE_PID, task_pid(leader)); transfer_pid(leader, tsk, PIDTYPE_PGID); transfer_pid(leader, tsk, PIDTYPE_SID); + list_replace_rcu(&leader->tasks, &tsk->tasks); + list_replace_init(&leader->sibling, &tsk->sibling); tsk->group_leader = tsk; leader->group_leader = tsk; @@ -926,6 +942,15 @@ char *get_task_comm(char *buf, struct task_struct *tsk) void set_task_comm(struct task_struct *tsk, char *buf) { task_lock(tsk); + + /* + * Threads may access current->comm without holding + * the task lock, so write the string carefully. + * Readers without a lock may see incomplete new + * names but are safe from non-terminating string reads. + */ + memset(tsk->comm, 0, TASK_COMM_LEN); + wmb(); strlcpy(tsk->comm, buf, sizeof(tsk->comm)); task_unlock(tsk); perf_event_comm(tsk); @@ -933,9 +958,7 @@ void set_task_comm(struct task_struct *tsk, char *buf) int flush_old_exec(struct linux_binprm * bprm) { - char * name; - int i, ch, retval; - char tcomm[sizeof(current->comm)]; + int retval; /* * Make sure we have a private signal table and that @@ -956,6 +979,25 @@ int flush_old_exec(struct linux_binprm * bprm) bprm->mm = NULL; /* We're using it now */ + current->flags &= ~PF_RANDOMIZE; + flush_thread(); + current->personality &= ~bprm->per_clear; + + return 0; + +out: + return retval; +} +EXPORT_SYMBOL(flush_old_exec); + +void setup_new_exec(struct linux_binprm * bprm) +{ + int i, ch; + char * name; + char tcomm[sizeof(current->comm)]; + + arch_pick_mmap_layout(current->mm); + /* This is the point of no return */ current->sas_ss_sp = current->sas_ss_size = 0; @@ -977,9 +1019,6 @@ int flush_old_exec(struct linux_binprm * bprm) tcomm[i] = '\0'; set_task_comm(current, tcomm); - 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 @@ -995,8 +1034,6 @@ int flush_old_exec(struct linux_binprm * bprm) set_dumpable(current->mm, suid_dumpable); } - current->personality &= ~bprm->per_clear; - /* * Flush performance counters when crossing a * security domain: @@ -1011,14 +1048,8 @@ int flush_old_exec(struct linux_binprm * bprm) flush_signal_handlers(current, 0); flush_old_files(current->files); - - return 0; - -out: - return retval; } - -EXPORT_SYMBOL(flush_old_exec); +EXPORT_SYMBOL(setup_new_exec); /* * Prepare credentials and lock ->cred_guard_mutex. @@ -1211,9 +1242,6 @@ int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs) retval = security_bprm_check(bprm); if (retval) return retval; - retval = ima_bprm_check(bprm); - if (retval) - return retval; /* kernel module loader fixup */ /* so we don't try to load run modprobe in kernel space. */ @@ -1359,8 +1387,6 @@ int do_execve(char * filename, if (retval < 0) goto out; - current->stack_start = current->mm->start_stack; - /* execve succeeded */ current->fs->in_exec = 0; current->in_execve = 0; @@ -1395,18 +1421,16 @@ out_ret: return retval; } -int set_binfmt(struct linux_binfmt *new) +void set_binfmt(struct linux_binfmt *new) { - struct linux_binfmt *old = current->binfmt; + struct mm_struct *mm = current->mm; - if (new) { - if (!try_module_get(new->module)) - return -1; - } - current->binfmt = new; - if (old) - module_put(old->module); - return 0; + if (mm->binfmt) + module_put(mm->binfmt->module); + + mm->binfmt = new; + if (new) + __module_get(new->module); } EXPORT_SYMBOL(set_binfmt); @@ -1507,7 +1531,7 @@ static int format_corename(char *corename, long signr) /* core limit size */ case 'c': rc = snprintf(out_ptr, out_end - out_ptr, - "%lu", current->signal->rlim[RLIMIT_CORE].rlim_cur); + "%lu", rlimit(RLIMIT_CORE)); if (rc > out_end - out_ptr) goto out; out_ptr += rc; @@ -1535,12 +1559,13 @@ out: return ispipe; } -static int zap_process(struct task_struct *start) +static int zap_process(struct task_struct *start, int exit_code) { struct task_struct *t; int nr = 0; start->signal->flags = SIGNAL_GROUP_EXIT; + start->signal->group_exit_code = exit_code; start->signal->group_stop_count = 0; t = start; @@ -1565,8 +1590,7 @@ static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm, spin_lock_irq(&tsk->sighand->siglock); if (!signal_group_exit(tsk->signal)) { mm->core_state = core_state; - tsk->signal->group_exit_code = exit_code; - nr = zap_process(tsk); + nr = zap_process(tsk, exit_code); } spin_unlock_irq(&tsk->sighand->siglock); if (unlikely(nr < 0)) @@ -1615,7 +1639,7 @@ static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm, if (p->mm) { if (unlikely(p->mm == mm)) { lock_task_sighand(p, &flags); - nr += zap_process(p); + nr += zap_process(p, exit_code); unlock_task_sighand(p, &flags); } break; @@ -1722,14 +1746,19 @@ void set_dumpable(struct mm_struct *mm, int value) } } -int get_dumpable(struct mm_struct *mm) +static int __get_dumpable(unsigned long mm_flags) { int ret; - ret = mm->flags & 0x3; + ret = mm_flags & MMF_DUMPABLE_MASK; return (ret >= 2) ? 2 : ret; } +int get_dumpable(struct mm_struct *mm) +{ + return __get_dumpable(mm->flags); +} + static void wait_for_dump_helpers(struct file *file) { struct pipe_inode_info *pipe; @@ -1760,21 +1789,30 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs) struct mm_struct *mm = current->mm; struct linux_binfmt * binfmt; struct inode * inode; - struct file * file; const struct cred *old_cred; struct cred *cred; int retval = 0; int flag = 0; int ispipe = 0; - unsigned long core_limit = current->signal->rlim[RLIMIT_CORE].rlim_cur; char **helper_argv = NULL; int helper_argc = 0; int dump_count = 0; static atomic_t core_dump_count = ATOMIC_INIT(0); + struct coredump_params cprm = { + .signr = signr, + .regs = regs, + .limit = rlimit(RLIMIT_CORE), + /* + * We must use the same mm->flags while dumping core to avoid + * inconsistency of bit flags, since this flag is not protected + * by any locks. + */ + .mm_flags = mm->flags, + }; audit_core_dumps(signr); - binfmt = current->binfmt; + binfmt = mm->binfmt; if (!binfmt || !binfmt->core_dump) goto fail; @@ -1788,7 +1826,7 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs) /* * If another thread got here first, or we are not dumpable, bail out. */ - if (mm->core_state || !get_dumpable(mm)) { + if (mm->core_state || !__get_dumpable(cprm.mm_flags)) { up_write(&mm->mmap_sem); put_cred(cred); goto fail; @@ -1799,7 +1837,8 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs) * process nor do we know its entire history. We only know it * was tainted so we dump it as root in mode 2. */ - if (get_dumpable(mm) == 2) { /* Setuid core dump mode */ + if (__get_dumpable(cprm.mm_flags) == 2) { + /* Setuid core dump mode */ flag = O_EXCL; /* Stop rewrite attacks */ cred->fsuid = 0; /* Dump root private */ } @@ -1826,15 +1865,15 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs) ispipe = format_corename(corename, signr); unlock_kernel(); - if ((!ispipe) && (core_limit < binfmt->min_coredump)) + if ((!ispipe) && (cprm.limit < binfmt->min_coredump)) goto fail_unlock; if (ispipe) { - if (core_limit == 0) { + if (cprm.limit == 0) { /* * Normally core limits are irrelevant to pipes, since * we're not writing to the file system, but we use - * core_limit of 0 here as a speacial value. Any + * cprm.limit of 0 here as a speacial value. Any * non-zero limit gets set to RLIM_INFINITY below, but * a limit of 0 skips the dump. This is a consistent * way to catch recursive crashes. We can still crash @@ -1867,25 +1906,25 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs) goto fail_dropcount; } - core_limit = RLIM_INFINITY; + cprm.limit = RLIM_INFINITY; /* SIGPIPE can happen, but it's just never processed */ if (call_usermodehelper_pipe(helper_argv[0], helper_argv, NULL, - &file)) { + &cprm.file)) { printk(KERN_INFO "Core dump to %s pipe failed\n", corename); goto fail_dropcount; } } else - file = filp_open(corename, + cprm.file = filp_open(corename, O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag, 0600); - if (IS_ERR(file)) + if (IS_ERR(cprm.file)) goto fail_dropcount; - inode = file->f_path.dentry->d_inode; + inode = cprm.file->f_path.dentry->d_inode; if (inode->i_nlink > 1) goto close_fail; /* multiple links - don't dump */ - if (!ispipe && d_unhashed(file->f_path.dentry)) + if (!ispipe && d_unhashed(cprm.file->f_path.dentry)) goto close_fail; /* AK: actually i see no reason to not allow this for named pipes etc., @@ -1895,24 +1934,26 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs) /* * Dont allow local users get cute and trick others to coredump * into their pre-created files: + * Note, this is not relevant for pipes */ - if (inode->i_uid != current_fsuid()) + if (!ispipe && (inode->i_uid != current_fsuid())) goto close_fail; - if (!file->f_op) + if (!cprm.file->f_op) goto close_fail; - if (!file->f_op->write) + if (!cprm.file->f_op->write) goto close_fail; - if (!ispipe && do_truncate(file->f_path.dentry, 0, 0, file) != 0) + if (!ispipe && + do_truncate(cprm.file->f_path.dentry, 0, 0, cprm.file) != 0) goto close_fail; - retval = binfmt->core_dump(signr, regs, file, core_limit); + retval = binfmt->core_dump(&cprm); if (retval) current->signal->group_exit_code |= 0x80; close_fail: if (ispipe && core_pipe_limit) - wait_for_dump_helpers(file); - filp_close(file, NULL); + wait_for_dump_helpers(cprm.file); + filp_close(cprm.file, NULL); fail_dropcount: if (dump_count) atomic_dec(&core_dump_count);