| /* |
| * linux/fs/exec.c |
| * |
| * Copyright (C) 1991, 1992 Linus Torvalds |
| */ |
| |
| /* |
| * #!-checking implemented by tytso. |
| */ |
| /* |
| * Demand-loading implemented 01.12.91 - no need to read anything but |
| * the header into memory. The inode of the executable is put into |
| * "current->executable", and page faults do the actual loading. Clean. |
| * |
| * Once more I can proudly say that linux stood up to being changed: it |
| * was less than 2 hours work to get demand-loading completely implemented. |
| * |
| * Demand loading changed July 1993 by Eric Youngdale. Use mmap instead, |
| * current->executable is only used by the procfs. This allows a dispatch |
| * table to check for several different types of binary formats. We keep |
| * trying until we recognize the file or we run out of supported binary |
| * formats. |
| */ |
| |
| #include <linux/slab.h> |
| #include <linux/file.h> |
| #include <linux/fdtable.h> |
| #include <linux/mm.h> |
| #include <linux/stat.h> |
| #include <linux/fcntl.h> |
| #include <linux/swap.h> |
| #include <linux/string.h> |
| #include <linux/init.h> |
| #include <linux/pagemap.h> |
| #include <linux/perf_event.h> |
| #include <linux/highmem.h> |
| #include <linux/spinlock.h> |
| #include <linux/key.h> |
| #include <linux/personality.h> |
| #include <linux/binfmts.h> |
| #include <linux/utsname.h> |
| #include <linux/pid_namespace.h> |
| #include <linux/module.h> |
| #include <linux/namei.h> |
| #include <linux/mount.h> |
| #include <linux/security.h> |
| #include <linux/syscalls.h> |
| #include <linux/tsacct_kern.h> |
| #include <linux/cn_proc.h> |
| #include <linux/audit.h> |
| #include <linux/tracehook.h> |
| #include <linux/kmod.h> |
| #include <linux/fsnotify.h> |
| #include <linux/fs_struct.h> |
| #include <linux/pipe_fs_i.h> |
| #include <linux/oom.h> |
| #include <linux/compat.h> |
| |
| #include <asm/uaccess.h> |
| #include <asm/mmu_context.h> |
| #include <asm/tlb.h> |
| #include <asm/exec.h> |
| |
| #include <trace/events/task.h> |
| #include "internal.h" |
| |
| #include <trace/events/sched.h> |
| |
| int core_uses_pid; |
| char core_pattern[CORENAME_MAX_SIZE] = "core"; |
| unsigned int core_pipe_limit; |
| int suid_dumpable = 0; |
| |
| struct core_name { |
| char *corename; |
| int used, size; |
| }; |
| static atomic_t call_count = ATOMIC_INIT(1); |
| |
| /* The maximal length of core_pattern is also specified in sysctl.c */ |
| |
| static LIST_HEAD(formats); |
| static DEFINE_RWLOCK(binfmt_lock); |
| |
| void __register_binfmt(struct linux_binfmt * fmt, int insert) |
| { |
| BUG_ON(!fmt); |
| write_lock(&binfmt_lock); |
| insert ? list_add(&fmt->lh, &formats) : |
| list_add_tail(&fmt->lh, &formats); |
| write_unlock(&binfmt_lock); |
| } |
| |
| EXPORT_SYMBOL(__register_binfmt); |
| |
| void unregister_binfmt(struct linux_binfmt * fmt) |
| { |
| write_lock(&binfmt_lock); |
| list_del(&fmt->lh); |
| write_unlock(&binfmt_lock); |
| } |
| |
| EXPORT_SYMBOL(unregister_binfmt); |
| |
| static inline void put_binfmt(struct linux_binfmt * fmt) |
| { |
| module_put(fmt->module); |
| } |
| |
| /* |
| * Note that a shared library must be both readable and executable due to |
| * security reasons. |
| * |
| * Also note that we take the address to load from from the file itself. |
| */ |
| SYSCALL_DEFINE1(uselib, const char __user *, library) |
| { |
| struct file *file; |
| char *tmp = getname(library); |
| int error = PTR_ERR(tmp); |
| static const struct open_flags uselib_flags = { |
| .open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC, |
| .acc_mode = MAY_READ | MAY_EXEC | MAY_OPEN, |
| .intent = LOOKUP_OPEN |
| }; |
| |
| if (IS_ERR(tmp)) |
| goto out; |
| |
| file = do_filp_open(AT_FDCWD, tmp, &uselib_flags, LOOKUP_FOLLOW); |
| putname(tmp); |
| error = PTR_ERR(file); |
| if (IS_ERR(file)) |
| goto out; |
| |
| error = -EINVAL; |
| if (!S_ISREG(file->f_path.dentry->d_inode->i_mode)) |
| goto exit; |
| |
| error = -EACCES; |
| if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) |
| goto exit; |
| |
| fsnotify_open(file); |
| |
| error = -ENOEXEC; |
| if(file->f_op) { |
| struct linux_binfmt * fmt; |
| |
| read_lock(&binfmt_lock); |
| list_for_each_entry(fmt, &formats, lh) { |
| if (!fmt->load_shlib) |
| continue; |
| if (!try_module_get(fmt->module)) |
| continue; |
| read_unlock(&binfmt_lock); |
| error = fmt->load_shlib(file); |
| read_lock(&binfmt_lock); |
| put_binfmt(fmt); |
| if (error != -ENOEXEC) |
| break; |
| } |
| read_unlock(&binfmt_lock); |
| } |
| exit: |
| fput(file); |
| out: |
| return error; |
| } |
| |
| #ifdef CONFIG_MMU |
| /* |
| * The nascent bprm->mm is not visible until exec_mmap() but it can |
| * use a lot of memory, account these pages in current->mm temporary |
| * for oom_badness()->get_mm_rss(). Once exec succeeds or fails, we |
| * change the counter back via acct_arg_size(0). |
| */ |
| static void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) |
| { |
| struct mm_struct *mm = current->mm; |
| long diff = (long)(pages - bprm->vma_pages); |
| |
| if (!mm || !diff) |
| return; |
| |
| bprm->vma_pages = pages; |
| add_mm_counter(mm, MM_ANONPAGES, diff); |
| } |
| |
| static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, |
| int write) |
| { |
| struct page *page; |
| int ret; |
| |
| #ifdef CONFIG_STACK_GROWSUP |
| if (write) { |
| ret = expand_downwards(bprm->vma, pos); |
| if (ret < 0) |
| return NULL; |
| } |
| #endif |
| ret = get_user_pages(current, bprm->mm, pos, |
| 1, write, 1, &page, NULL); |
| if (ret <= 0) |
| return NULL; |
| |
| if (write) { |
| unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start; |
| struct rlimit *rlim; |
| |
| acct_arg_size(bprm, size / PAGE_SIZE); |
| |
| /* |
| * We've historically supported up to 32 pages (ARG_MAX) |
| * of argument strings even with small stacks |
| */ |
| if (size <= ARG_MAX) |
| return page; |
| |
| /* |
| * Limit to 1/4-th the stack size for the argv+env strings. |
| * This ensures that: |
| * - the remaining binfmt code will not run out of stack space, |
| * - the program will have a reasonable amount of stack left |
| * to work from. |
| */ |
| rlim = current->signal->rlim; |
| if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur) / 4) { |
| put_page(page); |
| return NULL; |
| } |
| } |
| |
| return page; |
| } |
| |
| static void put_arg_page(struct page *page) |
| { |
| put_page(page); |
| } |
| |
| static void free_arg_page(struct linux_binprm *bprm, int i) |
| { |
| } |
| |
| static void free_arg_pages(struct linux_binprm *bprm) |
| { |
| } |
| |
| static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, |
| struct page *page) |
| { |
| flush_cache_page(bprm->vma, pos, page_to_pfn(page)); |
| } |
| |
| static int __bprm_mm_init(struct linux_binprm *bprm) |
| { |
| int err; |
| struct vm_area_struct *vma = NULL; |
| struct mm_struct *mm = bprm->mm; |
| |
| bprm->vma = vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); |
| if (!vma) |
| return -ENOMEM; |
| |
| down_write(&mm->mmap_sem); |
| vma->vm_mm = mm; |
| |
| /* |
| * Place the stack at the largest stack address the architecture |
| * supports. Later, we'll move this to an appropriate place. We don't |
| * use STACK_TOP because that can depend on attributes which aren't |
| * configured yet. |
| */ |
| BUILD_BUG_ON(VM_STACK_FLAGS & VM_STACK_INCOMPLETE_SETUP); |
| vma->vm_end = STACK_TOP_MAX; |
| vma->vm_start = vma->vm_end - PAGE_SIZE; |
| vma->vm_flags = VM_STACK_FLAGS | VM_STACK_INCOMPLETE_SETUP; |
| 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; |
| |
| mm->stack_vm = mm->total_vm = 1; |
| up_write(&mm->mmap_sem); |
| bprm->p = vma->vm_end - sizeof(void *); |
| return 0; |
| err: |
| up_write(&mm->mmap_sem); |
| bprm->vma = NULL; |
| kmem_cache_free(vm_area_cachep, vma); |
| return err; |
| } |
| |
| static bool valid_arg_len(struct linux_binprm *bprm, long len) |
| { |
| return len <= MAX_ARG_STRLEN; |
| } |
| |
| #else |
| |
| static inline void acct_arg_size(struct linux_binprm *bprm, unsigned long pages) |
| { |
| } |
| |
| static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos, |
| int write) |
| { |
| struct page *page; |
| |
| page = bprm->page[pos / PAGE_SIZE]; |
| if (!page && write) { |
| page = alloc_page(GFP_HIGHUSER|__GFP_ZERO); |
| if (!page) |
| return NULL; |
| bprm->page[pos / PAGE_SIZE] = page; |
| } |
| |
| return page; |
| } |
| |
| static void put_arg_page(struct page *page) |
| { |
| } |
| |
| static void free_arg_page(struct linux_binprm *bprm, int i) |
| { |
| if (bprm->page[i]) { |
| __free_page(bprm->page[i]); |
| bprm->page[i] = NULL; |
| } |
| } |
| |
| static void free_arg_pages(struct linux_binprm *bprm) |
| { |
| int i; |
| |
| for (i = 0; i < MAX_ARG_PAGES; i++) |
| free_arg_page(bprm, i); |
| } |
| |
| static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos, |
| struct page *page) |
| { |
| } |
| |
| static int __bprm_mm_init(struct linux_binprm *bprm) |
| { |
| bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *); |
| return 0; |
| } |
| |
| static bool valid_arg_len(struct linux_binprm *bprm, long len) |
| { |
| return len <= bprm->p; |
| } |
| |
| #endif /* CONFIG_MMU */ |
| |
| /* |
| * Create a new mm_struct and populate it with a temporary stack |
| * vm_area_struct. We don't have enough context at this point to set the stack |
| * flags, permissions, and offset, so we use temporary values. We'll update |
| * them later in setup_arg_pages(). |
| */ |
| int bprm_mm_init(struct linux_binprm *bprm) |
| { |
| int err; |
| struct mm_struct *mm = NULL; |
| |
| bprm->mm = mm = mm_alloc(); |
| err = -ENOMEM; |
| if (!mm) |
| goto err; |
| |
| err = init_new_context(current, mm); |
| if (err) |
| goto err; |
| |
| err = __bprm_mm_init(bprm); |
| if (err) |
| goto err; |
| |
| return 0; |
| |
| err: |
| if (mm) { |
| bprm->mm = NULL; |
| mmdrop(mm); |
| } |
| |
| return err; |
| } |
| |
| struct user_arg_ptr { |
| #ifdef CONFIG_COMPAT |
| bool is_compat; |
| #endif |
| union { |
| const char __user *const __user *native; |
| #ifdef CONFIG_COMPAT |
| compat_uptr_t __user *compat; |
| #endif |
| } ptr; |
| }; |
| |
| static const char __user *get_user_arg_ptr(struct user_arg_ptr argv, int nr) |
| { |
| const char __user *native; |
| |
| #ifdef CONFIG_COMPAT |
| if (unlikely(argv.is_compat)) { |
| compat_uptr_t compat; |
| |
| if (get_user(compat, argv.ptr.compat + nr)) |
| return ERR_PTR(-EFAULT); |
| |
| return compat_ptr(compat); |
| } |
| #endif |
| |
| if (get_user(native, argv.ptr.native + nr)) |
| return ERR_PTR(-EFAULT); |
| |
| return native; |
| } |
| |
| /* |
| * count() counts the number of strings in array ARGV. |
| */ |
| static int count(struct user_arg_ptr argv, int max) |
| { |
| int i = 0; |
| |
| if (argv.ptr.native != NULL) { |
| for (;;) { |
| const char __user *p = get_user_arg_ptr(argv, i); |
| |
| if (!p) |
| break; |
| |
| if (IS_ERR(p)) |
| return -EFAULT; |
| |
| if (i++ >= max) |
| return -E2BIG; |
| |
| if (fatal_signal_pending(current)) |
| return -ERESTARTNOHAND; |
| cond_resched(); |
| } |
| } |
| return i; |
| } |
| |
| /* |
| * 'copy_strings()' copies argument/environment strings from the old |
| * processes's memory to the new process's stack. The call to get_user_pages() |
| * ensures the destination page is created and not swapped out. |
| */ |
| static int copy_strings(int argc, struct user_arg_ptr argv, |
| struct linux_binprm *bprm) |
| { |
| struct page *kmapped_page = NULL; |
| char *kaddr = NULL; |
| unsigned long kpos = 0; |
| int ret; |
| |
| while (argc-- > 0) { |
| const char __user *str; |
| int len; |
| unsigned long pos; |
| |
| ret = -EFAULT; |
| str = get_user_arg_ptr(argv, argc); |
| if (IS_ERR(str)) |
| goto out; |
| |
| len = strnlen_user(str, MAX_ARG_STRLEN); |
| if (!len) |
| goto out; |
| |
| ret = -E2BIG; |
| if (!valid_arg_len(bprm, len)) |
| goto out; |
| |
| /* We're going to work our way backwords. */ |
| pos = bprm->p; |
| str += len; |
| bprm->p -= len; |
| |
| while (len > 0) { |
| int offset, bytes_to_copy; |
| |
| if (fatal_signal_pending(current)) { |
| ret = -ERESTARTNOHAND; |
| goto out; |
| } |
| cond_resched(); |
| |
| offset = pos % PAGE_SIZE; |
| if (offset == 0) |
| offset = PAGE_SIZE; |
| |
| bytes_to_copy = offset; |
| if (bytes_to_copy > len) |
| bytes_to_copy = len; |
| |
| offset -= bytes_to_copy; |
| pos -= bytes_to_copy; |
| str -= bytes_to_copy; |
| len -= bytes_to_copy; |
| |
| if (!kmapped_page || kpos != (pos & PAGE_MASK)) { |
| struct page *page; |
| |
| page = get_arg_page(bprm, pos, 1); |
| if (!page) { |
| ret = -E2BIG; |
| goto out; |
| } |
| |
| if (kmapped_page) { |
| flush_kernel_dcache_page(kmapped_page); |
| kunmap(kmapped_page); |
| put_arg_page(kmapped_page); |
| } |
| kmapped_page = page; |
| kaddr = kmap(kmapped_page); |
| kpos = pos & PAGE_MASK; |
| flush_arg_page(bprm, kpos, kmapped_page); |
| } |
| if (copy_from_user(kaddr+offset, str, bytes_to_copy)) { |
| ret = -EFAULT; |
| goto out; |
| } |
| } |
| } |
| ret = 0; |
| out: |
| if (kmapped_page) { |
| flush_kernel_dcache_page(kmapped_page); |
| kunmap(kmapped_page); |
| put_arg_page(kmapped_page); |
| } |
| return ret; |
| } |
| |
| /* |
| * Like copy_strings, but get argv and its values from kernel memory. |
| */ |
| int copy_strings_kernel(int argc, const char *const *__argv, |
| struct linux_binprm *bprm) |
| { |
| int r; |
| mm_segment_t oldfs = get_fs(); |
| struct user_arg_ptr argv = { |
| .ptr.native = (const char __user *const __user *)__argv, |
| }; |
| |
| set_fs(KERNEL_DS); |
| r = copy_strings(argc, argv, bprm); |
| set_fs(oldfs); |
| |
| return r; |
| } |
| EXPORT_SYMBOL(copy_strings_kernel); |
| |
| #ifdef CONFIG_MMU |
| |
| /* |
| * During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX. Once |
| * the binfmt code determines where the new stack should reside, we shift it to |
| * its final location. The process proceeds as follows: |
| * |
| * 1) Use shift to calculate the new vma endpoints. |
| * 2) Extend vma to cover both the old and new ranges. This ensures the |
| * arguments passed to subsequent functions are consistent. |
| * 3) Move vma's page tables to the new range. |
| * 4) Free up any cleared pgd range. |
| * 5) Shrink the vma to cover only the new range. |
| */ |
| static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift) |
| { |
| struct mm_struct *mm = vma->vm_mm; |
| unsigned long old_start = vma->vm_start; |
| unsigned long old_end = vma->vm_end; |
| unsigned long length = old_end - old_start; |
| unsigned long new_start = old_start - shift; |
| unsigned long new_end = old_end - shift; |
| struct mmu_gather tlb; |
| |
| BUG_ON(new_start > new_end); |
| |
| /* |
| * ensure there are no vmas between where we want to go |
| * and where we are |
| */ |
| if (vma != find_vma(mm, new_start)) |
| return -EFAULT; |
| |
| /* |
| * cover the whole range: [new_start, old_end) |
| */ |
| if (vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL)) |
| return -ENOMEM; |
| |
| /* |
| * move the page tables downwards, on failure we rely on |
| * process cleanup to remove whatever mess we made. |
| */ |
| if (length != move_page_tables(vma, old_start, |
| vma, new_start, length)) |
| return -ENOMEM; |
| |
| lru_add_drain(); |
| tlb_gather_mmu(&tlb, mm, 0); |
| if (new_end > old_start) { |
| /* |
| * when the old and new regions overlap clear from new_end. |
| */ |
| free_pgd_range(&tlb, new_end, old_end, new_end, |
| vma->vm_next ? vma->vm_next->vm_start : 0); |
| } else { |
| /* |
| * otherwise, clean from old_start; this is done to not touch |
| * the address space in [new_end, old_start) some architectures |
| * have constraints on va-space that make this illegal (IA64) - |
| * for the others its just a little faster. |
| */ |
| free_pgd_range(&tlb, old_start, old_end, new_end, |
| vma->vm_next ? vma->vm_next->vm_start : 0); |
| } |
| tlb_finish_mmu(&tlb, new_end, old_end); |
| |
| /* |
| * Shrink the vma to just the new range. Always succeeds. |
| */ |
| vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL); |
| |
| return 0; |
| } |
| |
| /* |
| * Finalizes the stack vm_area_struct. The flags and permissions are updated, |
| * the stack is optionally relocated, and some extra space is added. |
| */ |
| int setup_arg_pages(struct linux_binprm *bprm, |
| unsigned long stack_top, |
| int executable_stack) |
| { |
| unsigned long ret; |
| unsigned long stack_shift; |
| struct mm_struct *mm = current->mm; |
| struct vm_area_struct *vma = bprm->vma; |
| 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 = rlimit_max(RLIMIT_STACK); |
| if (stack_base > (1 << 30)) |
| stack_base = 1 << 30; |
| |
| /* Make sure we didn't let the argument array grow too large. */ |
| if (vma->vm_end - vma->vm_start > stack_base) |
| return -ENOMEM; |
| |
| stack_base = PAGE_ALIGN(stack_top - stack_base); |
| |
| stack_shift = vma->vm_start - stack_base; |
| mm->arg_start = bprm->p - stack_shift; |
| bprm->p = vma->vm_end - stack_shift; |
| #else |
| stack_top = arch_align_stack(stack_top); |
| stack_top = PAGE_ALIGN(stack_top); |
| |
| if (unlikely(stack_top < mmap_min_addr) || |
| unlikely(vma->vm_end - vma->vm_start >= stack_top - mmap_min_addr)) |
| return -ENOMEM; |
| |
| stack_shift = vma->vm_end - stack_top; |
| |
| bprm->p -= stack_shift; |
| mm->arg_start = bprm->p; |
| #endif |
| |
| if (bprm->loader) |
| bprm->loader -= stack_shift; |
| bprm->exec -= stack_shift; |
| |
| down_write(&mm->mmap_sem); |
| vm_flags = VM_STACK_FLAGS; |
| |
| /* |
| * Adjust stack execute permissions; explicitly enable for |
| * EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone |
| * (arch default) otherwise. |
| */ |
| if (unlikely(executable_stack == EXSTACK_ENABLE_X)) |
| vm_flags |= VM_EXEC; |
| else if (executable_stack == EXSTACK_DISABLE_X) |
| vm_flags &= ~VM_EXEC; |
| vm_flags |= mm->def_flags; |
| vm_flags |= VM_STACK_INCOMPLETE_SETUP; |
| |
| ret = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end, |
| vm_flags); |
| if (ret) |
| goto out_unlock; |
| BUG_ON(prev != vma); |
| |
| /* Move stack pages down in memory. */ |
| if (stack_shift) { |
| ret = shift_arg_pages(vma, stack_shift); |
| if (ret) |
| goto out_unlock; |
| } |
| |
| /* mprotect_fixup is overkill to remove the temporary stack flags */ |
| vma->vm_flags &= ~VM_STACK_INCOMPLETE_SETUP; |
| |
| 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 |
| if (stack_size + stack_expand > rlim_stack) |
| stack_base = vma->vm_start + rlim_stack; |
| else |
| stack_base = vma->vm_end + stack_expand; |
| #else |
| if (stack_size + stack_expand > rlim_stack) |
| stack_base = vma->vm_end - rlim_stack; |
| else |
| stack_base = vma->vm_start - stack_expand; |
| #endif |
| current->mm->start_stack = bprm->p; |
| ret = expand_stack(vma, stack_base); |
| if (ret) |
| ret = -EFAULT; |
| |
| out_unlock: |
| up_write(&mm->mmap_sem); |
| return ret; |
| } |
| EXPORT_SYMBOL(setup_arg_pages); |
| |
| #endif /* CONFIG_MMU */ |
| |
| struct file *open_exec(const char *name) |
| { |
| struct file *file; |
| int err; |
| static const struct open_flags open_exec_flags = { |
| .open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC, |
| .acc_mode = MAY_EXEC | MAY_OPEN, |
| .intent = LOOKUP_OPEN |
| }; |
| |
| file = do_filp_open(AT_FDCWD, name, &open_exec_flags, LOOKUP_FOLLOW); |
| if (IS_ERR(file)) |
| goto out; |
| |
| err = -EACCES; |
| if (!S_ISREG(file->f_path.dentry->d_inode->i_mode)) |
| goto exit; |
| |
| if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) |
| goto exit; |
| |
| fsnotify_open(file); |
| |
| err = deny_write_access(file); |
| if (err) |
| goto exit; |
| |
| out: |
| return file; |
| |
| exit: |
| fput(file); |
| return ERR_PTR(err); |
| } |
| EXPORT_SYMBOL(open_exec); |
| |
| int kernel_read(struct file *file, loff_t offset, |
| char *addr, unsigned long count) |
| { |
| mm_segment_t old_fs; |
| loff_t pos = offset; |
| int result; |
| |
| old_fs = get_fs(); |
| set_fs(get_ds()); |
| /* The cast to a user pointer is valid due to the set_fs() */ |
| result = vfs_read(file, (void __user *)addr, count, &pos); |
| set_fs(old_fs); |
| return result; |
| } |
| |
| EXPORT_SYMBOL(kernel_read); |
| |
| static int exec_mmap(struct mm_struct *mm) |
| { |
| struct task_struct *tsk; |
| struct mm_struct * old_mm, *active_mm; |
| |
| /* Notify parent that we're no longer interested in the old VM */ |
| tsk = current; |
| old_mm = current->mm; |
| mm_release(tsk, old_mm); |
| |
| if (old_mm) { |
| sync_mm_rss(old_mm); |
| /* |
| * Make sure that if there is a core dump in progress |
| * for the old mm, we get out and die instead of going |
| * through with the exec. We must hold mmap_sem around |
| * checking core_state and changing tsk->mm. |
| */ |
| down_read(&old_mm->mmap_sem); |
| if (unlikely(old_mm->core_state)) { |
| up_read(&old_mm->mmap_sem); |
| return -EINTR; |
| } |
| } |
| task_lock(tsk); |
| active_mm = tsk->active_mm; |
| tsk->mm = mm; |
| tsk->active_mm = mm; |
| activate_mm(active_mm, mm); |
| task_unlock(tsk); |
| arch_pick_mmap_layout(mm); |
| if (old_mm) { |
| up_read(&old_mm->mmap_sem); |
| BUG_ON(active_mm != old_mm); |
| setmax_mm_hiwater_rss(&tsk->signal->maxrss, old_mm); |
| mm_update_next_owner(old_mm); |
| mmput(old_mm); |
| return 0; |
| } |
| mmdrop(active_mm); |
| return 0; |
| } |
| |
| /* |
| * This function makes sure the current process has its own signal table, |
| * so that flush_signal_handlers can later reset the handlers without |
| * disturbing other processes. (Other processes might share the signal |
| * table via the CLONE_SIGHAND option to clone().) |
| */ |
| static int de_thread(struct task_struct *tsk) |
| { |
| struct signal_struct *sig = tsk->signal; |
| struct sighand_struct *oldsighand = tsk->sighand; |
| spinlock_t *lock = &oldsighand->siglock; |
| |
| if (thread_group_empty(tsk)) |
| goto no_thread_group; |
| |
| /* |
| * Kill all other threads in the thread group. |
| */ |
| spin_lock_irq(lock); |
| if (signal_group_exit(sig)) { |
| /* |
| * Another group action in progress, just |
| * return so that the signal is processed. |
| */ |
| spin_unlock_irq(lock); |
| return -EAGAIN; |
| } |
| |
| sig->group_exit_task = tsk; |
| sig->notify_count = zap_other_threads(tsk); |
| if (!thread_group_leader(tsk)) |
| sig->notify_count--; |
| |
| while (sig->notify_count) { |
| __set_current_state(TASK_UNINTERRUPTIBLE); |
| spin_unlock_irq(lock); |
| schedule(); |
| spin_lock_irq(lock); |
| } |
| spin_unlock_irq(lock); |
| |
| /* |
| * At this point all other threads have exited, all we have to |
| * do is to wait for the thread group leader to become inactive, |
| * and to assume its PID: |
| */ |
| if (!thread_group_leader(tsk)) { |
| struct task_struct *leader = tsk->group_leader; |
| |
| sig->notify_count = -1; /* for exit_notify() */ |
| for (;;) { |
| write_lock_irq(&tasklist_lock); |
| if (likely(leader->exit_state)) |
| break; |
| __set_current_state(TASK_UNINTERRUPTIBLE); |
| write_unlock_irq(&tasklist_lock); |
| schedule(); |
| } |
| |
| /* |
| * 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). |
| */ |
| tsk->start_time = leader->start_time; |
| |
| BUG_ON(!same_thread_group(leader, tsk)); |
| BUG_ON(has_group_leader_pid(tsk)); |
| /* |
| * 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: |
| */ |
| |
| /* Become a process group leader with the old leader's pid. |
| * The old leader becomes a thread of the this thread group. |
| * Note: The old leader also uses this pid until release_task |
| * is called. Odd but simple and correct. |
| */ |
| detach_pid(tsk, PIDTYPE_PID); |
| tsk->pid = leader->pid; |
| 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; |
| |
| tsk->exit_signal = SIGCHLD; |
| leader->exit_signal = -1; |
| |
| BUG_ON(leader->exit_state != EXIT_ZOMBIE); |
| leader->exit_state = EXIT_DEAD; |
| |
| /* |
| * We are going to release_task()->ptrace_unlink() silently, |
| * the tracer can sleep in do_wait(). EXIT_DEAD guarantees |
| * the tracer wont't block again waiting for this thread. |
| */ |
| if (unlikely(leader->ptrace)) |
| __wake_up_parent(leader, leader->parent); |
| write_unlock_irq(&tasklist_lock); |
| |
| release_task(leader); |
| } |
| |
| sig->group_exit_task = NULL; |
| sig->notify_count = 0; |
| |
| no_thread_group: |
| /* we have changed execution domain */ |
| tsk->exit_signal = SIGCHLD; |
| |
| exit_itimers(sig); |
| flush_itimer_signals(); |
| |
| if (atomic_read(&oldsighand->count) != 1) { |
| struct sighand_struct *newsighand; |
| /* |
| * This ->sighand is shared with the CLONE_SIGHAND |
| * but not CLONE_THREAD task, switch to the new one. |
| */ |
| newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL); |
| if (!newsighand) |
| return -ENOMEM; |
| |
| atomic_set(&newsighand->count, 1); |
| memcpy(newsighand->action, oldsighand->action, |
| sizeof(newsighand->action)); |
| |
| write_lock_irq(&tasklist_lock); |
| spin_lock(&oldsighand->siglock); |
| rcu_assign_pointer(tsk->sighand, newsighand); |
| spin_unlock(&oldsighand->siglock); |
| write_unlock_irq(&tasklist_lock); |
| |
| __cleanup_sighand(oldsighand); |
| } |
| |
| BUG_ON(!thread_group_leader(tsk)); |
| return 0; |
| } |
| |
| char *get_task_comm(char *buf, struct task_struct *tsk) |
| { |
| /* buf must be at least sizeof(tsk->comm) in size */ |
| task_lock(tsk); |
| strncpy(buf, tsk->comm, sizeof(tsk->comm)); |
| task_unlock(tsk); |
| return buf; |
| } |
| EXPORT_SYMBOL_GPL(get_task_comm); |
| |
| /* |
| * These functions flushes out all traces of the currently running executable |
| * so that a new one can be started |
| */ |
| |
| void set_task_comm(struct task_struct *tsk, char *buf) |
| { |
| task_lock(tsk); |
| |
| trace_task_rename(tsk, buf); |
| |
| /* |
| * 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); |
| } |
| |
| static void filename_to_taskname(char *tcomm, const char *fn, unsigned int len) |
| { |
| int i, ch; |
| |
| /* Copies the binary name from after last slash */ |
| for (i = 0; (ch = *(fn++)) != '\0';) { |
| if (ch == '/') |
| i = 0; /* overwrite what we wrote */ |
| else |
| if (i < len - 1) |
| tcomm[i++] = ch; |
| } |
| tcomm[i] = '\0'; |
| } |
| |
| int flush_old_exec(struct linux_binprm * bprm) |
| { |
| int retval; |
| |
| /* |
| * Make sure we have a private signal table and that |
| * we are unassociated from the previous thread group. |
| */ |
| retval = de_thread(current); |
| if (retval) |
| goto out; |
| |
| set_mm_exe_file(bprm->mm, bprm->file); |
| |
| filename_to_taskname(bprm->tcomm, bprm->filename, sizeof(bprm->tcomm)); |
| /* |
| * Release all of the old mmap stuff |
| */ |
| acct_arg_size(bprm, 0); |
| retval = exec_mmap(bprm->mm); |
| if (retval) |
| goto out; |
| |
| bprm->mm = NULL; /* We're using it now */ |
| |
| set_fs(USER_DS); |
| current->flags &= ~(PF_RANDOMIZE | PF_FORKNOEXEC | PF_KTHREAD); |
| flush_thread(); |
| current->personality &= ~bprm->per_clear; |
| |
| return 0; |
| |
| out: |
| return retval; |
| } |
| EXPORT_SYMBOL(flush_old_exec); |
| |
| void would_dump(struct linux_binprm *bprm, struct file *file) |
| { |
| if (inode_permission(file->f_path.dentry->d_inode, MAY_READ) < 0) |
| bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP; |
| } |
| EXPORT_SYMBOL(would_dump); |
| |
| void setup_new_exec(struct linux_binprm * bprm) |
| { |
| arch_pick_mmap_layout(current->mm); |
| |
| /* This is the point of no return */ |
| current->sas_ss_sp = current->sas_ss_size = 0; |
| |
| if (uid_eq(current_euid(), current_uid()) && gid_eq(current_egid(), current_gid())) |
| set_dumpable(current->mm, 1); |
| else |
| set_dumpable(current->mm, suid_dumpable); |
| |
| set_task_comm(current, bprm->tcomm); |
| |
| /* 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; |
| |
| /* install the new credentials */ |
| if (!uid_eq(bprm->cred->uid, current_euid()) || |
| !gid_eq(bprm->cred->gid, current_egid())) { |
| current->pdeath_signal = 0; |
| } else { |
| would_dump(bprm, bprm->file); |
| if (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP) |
| set_dumpable(current->mm, suid_dumpable); |
| } |
| |
| /* |
| * Flush performance counters when crossing a |
| * security domain: |
| */ |
| if (!get_dumpable(current->mm)) |
| perf_event_exit_task(current); |
| |
| /* An exec changes our domain. We are no longer part of the thread |
| group */ |
| |
| current->self_exec_id++; |
| |
| flush_signal_handlers(current, 0); |
| do_close_on_exec(current->files); |
| } |
| EXPORT_SYMBOL(setup_new_exec); |
| |
| /* |
| * Prepare credentials and lock ->cred_guard_mutex. |
| * install_exec_creds() commits the new creds and drops the lock. |
| * Or, if exec fails before, free_bprm() should release ->cred and |
| * and unlock. |
| */ |
| int prepare_bprm_creds(struct linux_binprm *bprm) |
| { |
| if (mutex_lock_interruptible(¤t->signal->cred_guard_mutex)) |
| return -ERESTARTNOINTR; |
| |
| bprm->cred = prepare_exec_creds(); |
| if (likely(bprm->cred)) |
| return 0; |
| |
| mutex_unlock(¤t->signal->cred_guard_mutex); |
| return -ENOMEM; |
| } |
| |
| void free_bprm(struct linux_binprm *bprm) |
| { |
| free_arg_pages(bprm); |
| if (bprm->cred) { |
| mutex_unlock(¤t->signal->cred_guard_mutex); |
| abort_creds(bprm->cred); |
| } |
| kfree(bprm); |
| } |
| |
| /* |
| * install the new credentials for this executable |
| */ |
| void install_exec_creds(struct linux_binprm *bprm) |
| { |
| security_bprm_committing_creds(bprm); |
| |
| commit_creds(bprm->cred); |
| bprm->cred = NULL; |
| /* |
| * cred_guard_mutex must be held at least to this point to prevent |
| * ptrace_attach() from altering our determination of the task's |
| * credentials; any time after this it may be unlocked. |
| */ |
| security_bprm_committed_creds(bprm); |
| mutex_unlock(¤t->signal->cred_guard_mutex); |
| } |
| EXPORT_SYMBOL(install_exec_creds); |
| |
| /* |
| * determine how safe it is to execute the proposed program |
| * - the caller must hold ->cred_guard_mutex to protect against |
| * PTRACE_ATTACH |
| */ |
| static int check_unsafe_exec(struct linux_binprm *bprm) |
| { |
| struct task_struct *p = current, *t; |
| unsigned n_fs; |
| int res = 0; |
| |
| if (p->ptrace) { |
| if (p->ptrace & PT_PTRACE_CAP) |
| bprm->unsafe |= LSM_UNSAFE_PTRACE_CAP; |
| else |
| bprm->unsafe |= LSM_UNSAFE_PTRACE; |
| } |
| |
| /* |
| * This isn't strictly necessary, but it makes it harder for LSMs to |
| * mess up. |
| */ |
| if (current->no_new_privs) |
| bprm->unsafe |= LSM_UNSAFE_NO_NEW_PRIVS; |
| |
| n_fs = 1; |
| spin_lock(&p->fs->lock); |
| rcu_read_lock(); |
| for (t = next_thread(p); t != p; t = next_thread(t)) { |
| if (t->fs == p->fs) |
| n_fs++; |
| } |
| rcu_read_unlock(); |
| |
| if (p->fs->users > n_fs) { |
| bprm->unsafe |= LSM_UNSAFE_SHARE; |
| } else { |
| res = -EAGAIN; |
| if (!p->fs->in_exec) { |
| p->fs->in_exec = 1; |
| res = 1; |
| } |
| } |
| spin_unlock(&p->fs->lock); |
| |
| return res; |
| } |
| |
| /* |
| * Fill the binprm structure from the inode. |
| * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes |
| * |
| * This may be called multiple times for binary chains (scripts for example). |
| */ |
| int prepare_binprm(struct linux_binprm *bprm) |
| { |
| umode_t mode; |
| struct inode * inode = bprm->file->f_path.dentry->d_inode; |
| int retval; |
| |
| mode = inode->i_mode; |
| if (bprm->file->f_op == NULL) |
| return -EACCES; |
| |
| /* clear any previous set[ug]id data from a previous binary */ |
| bprm->cred->euid = current_euid(); |
| bprm->cred->egid = current_egid(); |
| |
| if (!(bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID) && |
| !current->no_new_privs) { |
| /* Set-uid? */ |
| if (mode & S_ISUID) { |
| if (!kuid_has_mapping(bprm->cred->user_ns, inode->i_uid)) |
| return -EPERM; |
| bprm->per_clear |= PER_CLEAR_ON_SETID; |
| bprm->cred->euid = inode->i_uid; |
| |
| } |
| |
| /* Set-gid? */ |
| /* |
| * If setgid is set but no group execute bit then this |
| * is a candidate for mandatory locking, not a setgid |
| * executable. |
| */ |
| if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) { |
| if (!kgid_has_mapping(bprm->cred->user_ns, inode->i_gid)) |
| return -EPERM; |
| bprm->per_clear |= PER_CLEAR_ON_SETID; |
| bprm->cred->egid = inode->i_gid; |
| } |
| } |
| |
| /* fill in binprm security blob */ |
| retval = security_bprm_set_creds(bprm); |
| if (retval) |
| return retval; |
| bprm->cred_prepared = 1; |
| |
| memset(bprm->buf, 0, BINPRM_BUF_SIZE); |
| return kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE); |
| } |
| |
| EXPORT_SYMBOL(prepare_binprm); |
| |
| /* |
| * Arguments are '\0' separated strings found at the location bprm->p |
| * points to; chop off the first by relocating brpm->p to right after |
| * the first '\0' encountered. |
| */ |
| int remove_arg_zero(struct linux_binprm *bprm) |
| { |
| int ret = 0; |
| unsigned long offset; |
| char *kaddr; |
| struct page *page; |
| |
| if (!bprm->argc) |
| return 0; |
| |
| do { |
| offset = bprm->p & ~PAGE_MASK; |
| page = get_arg_page(bprm, bprm->p, 0); |
| if (!page) { |
| ret = -EFAULT; |
| goto out; |
| } |
| kaddr = kmap_atomic(page); |
| |
| for (; offset < PAGE_SIZE && kaddr[offset]; |
| offset++, bprm->p++) |
| ; |
| |
| kunmap_atomic(kaddr); |
| put_arg_page(page); |
| |
| if (offset == PAGE_SIZE) |
| free_arg_page(bprm, (bprm->p >> PAGE_SHIFT) - 1); |
| } while (offset == PAGE_SIZE); |
| |
| bprm->p++; |
| bprm->argc--; |
| ret = 0; |
| |
| out: |
| return ret; |
| } |
| EXPORT_SYMBOL(remove_arg_zero); |
| |
| /* |
| * cycle the list of binary formats handler, until one recognizes the image |
| */ |
| int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs) |
| { |
| unsigned int depth = bprm->recursion_depth; |
| int try,retval; |
| struct linux_binfmt *fmt; |
| pid_t old_pid, old_vpid; |
| |
| retval = security_bprm_check(bprm); |
| if (retval) |
| return retval; |
| |
| retval = audit_bprm(bprm); |
| if (retval) |
| return retval; |
| |
| /* Need to fetch pid before load_binary changes it */ |
| old_pid = current->pid; |
| rcu_read_lock(); |
| old_vpid = task_pid_nr_ns(current, task_active_pid_ns(current->parent)); |
| rcu_read_unlock(); |
| |
| retval = -ENOENT; |
| for (try=0; try<2; try++) { |
| read_lock(&binfmt_lock); |
| list_for_each_entry(fmt, &formats, lh) { |
| int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary; |
| if (!fn) |
| continue; |
| if (!try_module_get(fmt->module)) |
| continue; |
| read_unlock(&binfmt_lock); |
| retval = fn(bprm, regs); |
| /* |
| * Restore the depth counter to its starting value |
| * in this call, so we don't have to rely on every |
| * load_binary function to restore it on return. |
| */ |
| bprm->recursion_depth = depth; |
| if (retval >= 0) { |
| if (depth == 0) { |
| trace_sched_process_exec(current, old_pid, bprm); |
| ptrace_event(PTRACE_EVENT_EXEC, old_vpid); |
| } |
| put_binfmt(fmt); |
| allow_write_access(bprm->file); |
| if (bprm->file) |
| fput(bprm->file); |
| bprm->file = NULL; |
| current->did_exec = 1; |
| proc_exec_connector(current); |
| return retval; |
| } |
| read_lock(&binfmt_lock); |
| put_binfmt(fmt); |
| if (retval != -ENOEXEC || bprm->mm == NULL) |
| break; |
| if (!bprm->file) { |
| read_unlock(&binfmt_lock); |
| return retval; |
| } |
| } |
| read_unlock(&binfmt_lock); |
| #ifdef CONFIG_MODULES |
| if (retval != -ENOEXEC || bprm->mm == NULL) { |
| break; |
| } else { |
| #define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e)) |
| if (printable(bprm->buf[0]) && |
| printable(bprm->buf[1]) && |
| printable(bprm->buf[2]) && |
| printable(bprm->buf[3])) |
| break; /* -ENOEXEC */ |
| if (try) |
| break; /* -ENOEXEC */ |
| request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2])); |
| } |
| #else |
| break; |
| #endif |
| } |
| return retval; |
| } |
| |
| EXPORT_SYMBOL(search_binary_handler); |
| |
| /* |
| * sys_execve() executes a new program. |
| */ |
| static int do_execve_common(const char *filename, |
| struct user_arg_ptr argv, |
| struct user_arg_ptr envp, |
| struct pt_regs *regs) |
| { |
| struct linux_binprm *bprm; |
| struct file *file; |
| struct files_struct *displaced; |
| bool clear_in_exec; |
| int retval; |
| const struct cred *cred = current_cred(); |
| |
| /* |
| * We move the actual failure in case of RLIMIT_NPROC excess from |
| * set*uid() to execve() because too many poorly written programs |
| * don't check setuid() return code. Here we additionally recheck |
| * whether NPROC limit is still exceeded. |
| */ |
| if ((current->flags & PF_NPROC_EXCEEDED) && |
| atomic_read(&cred->user->processes) > rlimit(RLIMIT_NPROC)) { |
| retval = -EAGAIN; |
| goto out_ret; |
| } |
| |
| /* We're below the limit (still or again), so we don't want to make |
| * further execve() calls fail. */ |
| current->flags &= ~PF_NPROC_EXCEEDED; |
| |
| retval = unshare_files(&displaced); |
| if (retval) |
| goto out_ret; |
| |
| retval = -ENOMEM; |
| bprm = kzalloc(sizeof(*bprm), GFP_KERNEL); |
| if (!bprm) |
| goto out_files; |
| |
| retval = prepare_bprm_creds(bprm); |
| if (retval) |
| goto out_free; |
| |
| retval = check_unsafe_exec(bprm); |
| if (retval < 0) |
| goto out_free; |
| clear_in_exec = retval; |
| current->in_execve = 1; |
| |
| file = open_exec(filename); |
| retval = PTR_ERR(file); |
| if (IS_ERR(file)) |
| goto out_unmark; |
| |
| sched_exec(); |
| |
| bprm->file = file; |
| bprm->filename = filename; |
| bprm->interp = filename; |
| |
| retval = bprm_mm_init(bprm); |
| if (retval) |
| goto out_file; |
| |
| bprm->argc = count(argv, MAX_ARG_STRINGS); |
| if ((retval = bprm->argc) < 0) |
| goto out; |
| |
| bprm->envc = count(envp, MAX_ARG_STRINGS); |
| if ((retval = bprm->envc) < 0) |
| goto out; |
| |
| retval = prepare_binprm(bprm); |
| if (retval < 0) |
| goto out; |
| |
| retval = copy_strings_kernel(1, &bprm->filename, bprm); |
| if (retval < 0) |
| goto out; |
| |
| bprm->exec = bprm->p; |
| retval = copy_strings(bprm->envc, envp, bprm); |
| if (retval < 0) |
| goto out; |
| |
| retval = copy_strings(bprm->argc, argv, bprm); |
| if (retval < 0) |
| goto out; |
| |
| retval = search_binary_handler(bprm,regs); |
| if (retval < 0) |
| goto out; |
| |
| /* execve succeeded */ |
| current->fs->in_exec = 0; |
| current->in_execve = 0; |
| acct_update_integrals(current); |
| free_bprm(bprm); |
| if (displaced) |
| put_files_struct(displaced); |
| return retval; |
| |
| out: |
| if (bprm->mm) { |
| acct_arg_size(bprm, 0); |
| mmput(bprm->mm); |
| } |
| |
| out_file: |
| if (bprm->file) { |
| allow_write_access(bprm->file); |
| fput(bprm->file); |
| } |
| |
| out_unmark: |
| if (clear_in_exec) |
| current->fs->in_exec = 0; |
| current->in_execve = 0; |
| |
| out_free: |
| free_bprm(bprm); |
| |
| out_files: |
| if (displaced) |
| reset_files_struct(displaced); |
| out_ret: |
| return retval; |
| } |
| |
| int do_execve(const char *filename, |
| const char __user *const __user *__argv, |
| const char __user *const __user *__envp, |
| struct pt_regs *regs) |
| { |
| struct user_arg_ptr argv = { .ptr.native = __argv }; |
| struct user_arg_ptr envp = { .ptr.native = __envp }; |
| return do_execve_common(filename, argv, envp, regs); |
| } |
| |
| #ifdef CONFIG_COMPAT |
| int compat_do_execve(char *filename, |
| compat_uptr_t __user *__argv, |
| compat_uptr_t __user *__envp, |
| struct pt_regs *regs) |
| { |
| struct user_arg_ptr argv = { |
| .is_compat = true, |
| .ptr.compat = __argv, |
| }; |
| struct user_arg_ptr envp = { |
| .is_compat = true, |
| .ptr.compat = __envp, |
| }; |
| return do_execve_common(filename, argv, envp, regs); |
| } |
| #endif |
| |
| void set_binfmt(struct linux_binfmt *new) |
| { |
| struct mm_struct *mm = current->mm; |
| |
| if (mm->binfmt) |
| module_put(mm->binfmt->module); |
| |
| mm->binfmt = new; |
| if (new) |
| __module_get(new->module); |
| } |
| |
| EXPORT_SYMBOL(set_binfmt); |
| |
| static int expand_corename(struct core_name *cn) |
| { |
| char *old_corename = cn->corename; |
| |
| cn->size = CORENAME_MAX_SIZE * atomic_inc_return(&call_count); |
| cn->corename = krealloc(old_corename, cn->size, GFP_KERNEL); |
| |
| if (!cn->corename) { |
| kfree(old_corename); |
| return -ENOMEM; |
| } |
| |
| return 0; |
| } |
| |
| static int cn_printf(struct core_name *cn, const char *fmt, ...) |
| { |
| char *cur; |
| int need; |
| int ret; |
| va_list arg; |
| |
| va_start(arg, fmt); |
| need = vsnprintf(NULL, 0, fmt, arg); |
| va_end(arg); |
| |
| if (likely(need < cn->size - cn->used - 1)) |
| goto out_printf; |
| |
| ret = expand_corename(cn); |
| if (ret) |
| goto expand_fail; |
| |
| out_printf: |
| cur = cn->corename + cn->used; |
| va_start(arg, fmt); |
| vsnprintf(cur, need + 1, fmt, arg); |
| va_end(arg); |
| cn->used += need; |
| return 0; |
| |
| expand_fail: |
| return ret; |
| } |
| |
| static void cn_escape(char *str) |
| { |
| for (; *str; str++) |
| if (*str == '/') |
| *str = '!'; |
| } |
| |
| static int cn_print_exe_file(struct core_name *cn) |
| { |
| struct file *exe_file; |
| char *pathbuf, *path; |
| int ret; |
| |
| exe_file = get_mm_exe_file(current->mm); |
| if (!exe_file) { |
| char *commstart = cn->corename + cn->used; |
| ret = cn_printf(cn, "%s (path unknown)", current->comm); |
| cn_escape(commstart); |
| return ret; |
| } |
| |
| pathbuf = kmalloc(PATH_MAX, GFP_TEMPORARY); |
| if (!pathbuf) { |
| ret = -ENOMEM; |
| goto put_exe_file; |
| } |
| |
| path = d_path(&exe_file->f_path, pathbuf, PATH_MAX); |
| if (IS_ERR(path)) { |
| ret = PTR_ERR(path); |
| goto free_buf; |
| } |
| |
| cn_escape(path); |
| |
| ret = cn_printf(cn, "%s", path); |
| |
| free_buf: |
| kfree(pathbuf); |
| put_exe_file: |
| fput(exe_file); |
| return ret; |
| } |
| |
| /* format_corename will inspect the pattern parameter, and output a |
| * name into corename, which must have space for at least |
| * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator. |
| */ |
| static int format_corename(struct core_name *cn, long signr) |
| { |
| const struct cred *cred = current_cred(); |
| const char *pat_ptr = core_pattern; |
| int ispipe = (*pat_ptr == '|'); |
| int pid_in_pattern = 0; |
| int err = 0; |
| |
| cn->size = CORENAME_MAX_SIZE * atomic_read(&call_count); |
| cn->corename = kmalloc(cn->size, GFP_KERNEL); |
| cn->used = 0; |
| |
| if (!cn->corename) |
| return -ENOMEM; |
| |
| /* Repeat as long as we have more pattern to process and more output |
| space */ |
| while (*pat_ptr) { |
| if (*pat_ptr != '%') { |
| if (*pat_ptr == 0) |
| goto out; |
| err = cn_printf(cn, "%c", *pat_ptr++); |
| } else { |
| switch (*++pat_ptr) { |
| /* single % at the end, drop that */ |
| case 0: |
| goto out; |
| /* Double percent, output one percent */ |
| case '%': |
| err = cn_printf(cn, "%c", '%'); |
| break; |
| /* pid */ |
| case 'p': |
| pid_in_pattern = 1; |
| err = cn_printf(cn, "%d", |
| task_tgid_vnr(current)); |
| break; |
| /* uid */ |
| case 'u': |
| err = cn_printf(cn, "%d", cred->uid); |
| break; |
| /* gid */ |
| case 'g': |
| err = cn_printf(cn, "%d", cred->gid); |
| break; |
| /* signal that caused the coredump */ |
| case 's': |
| err = cn_printf(cn, "%ld", signr); |
| break; |
| /* UNIX time of coredump */ |
| case 't': { |
| struct timeval tv; |
| do_gettimeofday(&tv); |
| err = cn_printf(cn, "%lu", tv.tv_sec); |
| break; |
| } |
| /* hostname */ |
| case 'h': { |
| char *namestart = cn->corename + cn->used; |
| down_read(&uts_sem); |
| err = cn_printf(cn, "%s", |
| utsname()->nodename); |
| up_read(&uts_sem); |
| cn_escape(namestart); |
| break; |
| } |
| /* executable */ |
| case 'e': { |
| char *commstart = cn->corename + cn->used; |
| err = cn_printf(cn, "%s", current->comm); |
| cn_escape(commstart); |
| break; |
| } |
| case 'E': |
| err = cn_print_exe_file(cn); |
| break; |
| /* core limit size */ |
| case 'c': |
| err = cn_printf(cn, "%lu", |
| rlimit(RLIMIT_CORE)); |
| break; |
| default: |
| break; |
| } |
| ++pat_ptr; |
| } |
| |
| if (err) |
| return err; |
| } |
| |
| /* Backward compatibility with core_uses_pid: |
| * |
| * If core_pattern does not include a %p (as is the default) |
| * and core_uses_pid is set, then .%pid will be appended to |
| * the filename. Do not do this for piped commands. */ |
| if (!ispipe && !pid_in_pattern && core_uses_pid) { |
| err = cn_printf(cn, ".%d", task_tgid_vnr(current)); |
| if (err) |
| return err; |
| } |
| out: |
| return ispipe; |
| } |
| |
| 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; |
| do { |
| task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK); |
| if (t != current && t->mm) { |
| sigaddset(&t->pending.signal, SIGKILL); |
| signal_wake_up(t, 1); |
| nr++; |
| } |
| } while_each_thread(start, t); |
| |
| return nr; |
| } |
| |
| static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm, |
| struct core_state *core_state, int exit_code) |
| { |
| struct task_struct *g, *p; |
| unsigned long flags; |
| int nr = -EAGAIN; |
| |
| spin_lock_irq(&tsk->sighand->siglock); |
| if (!signal_group_exit(tsk->signal)) { |
| mm->core_state = core_state; |
| nr = zap_process(tsk, exit_code); |
| } |
| spin_unlock_irq(&tsk->sighand->siglock); |
| if (unlikely(nr < 0)) |
| return nr; |
| |
| if (atomic_read(&mm->mm_users) == nr + 1) |
| goto done; |
| /* |
| * We should find and kill all tasks which use this mm, and we should |
| * count them correctly into ->nr_threads. We don't take tasklist |
| * lock, but this is safe wrt: |
| * |
| * fork: |
| * None of sub-threads can fork after zap_process(leader). All |
| * processes which were created before this point should be |
| * visible to zap_threads() because copy_process() adds the new |
| * process to the tail of init_task.tasks list, and lock/unlock |
| * of ->siglock provides a memory barrier. |
| * |
| * do_exit: |
| * The caller holds mm->mmap_sem. This means that the task which |
| * uses this mm can't pass exit_mm(), so it can't exit or clear |
| * its ->mm. |
| * |
| * de_thread: |
| * It does list_replace_rcu(&leader->tasks, ¤t->tasks), |
| * we must see either old or new leader, this does not matter. |
| * However, it can change p->sighand, so lock_task_sighand(p) |
| * must be used. Since p->mm != NULL and we hold ->mmap_sem |
| * it can't fail. |
| * |
| * Note also that "g" can be the old leader with ->mm == NULL |
| * and already unhashed and thus removed from ->thread_group. |
| * This is OK, __unhash_process()->list_del_rcu() does not |
| * clear the ->next pointer, we will find the new leader via |
| * next_thread(). |
| */ |
| rcu_read_lock(); |
| for_each_process(g) { |
| if (g == tsk->group_leader) |
| continue; |
| if (g->flags & PF_KTHREAD) |
| continue; |
| p = g; |
| do { |
| if (p->mm) { |
| if (unlikely(p->mm == mm)) { |
| lock_task_sighand(p, &flags); |
| nr += zap_process(p, exit_code); |
| unlock_task_sighand(p, &flags); |
| } |
| break; |
| } |
| } while_each_thread(g, p); |
| } |
| rcu_read_unlock(); |
| done: |
| atomic_set(&core_state->nr_threads, nr); |
| return nr; |
| } |
| |
| static int coredump_wait(int exit_code, struct core_state *core_state) |
| { |
| struct task_struct *tsk = current; |
| struct mm_struct *mm = tsk->mm; |
| int core_waiters = -EBUSY; |
| |
| init_completion(&core_state->startup); |
| core_state->dumper.task = tsk; |
| core_state->dumper.next = NULL; |
| |
| down_write(&mm->mmap_sem); |
| if (!mm->core_state) |
| core_waiters = zap_threads(tsk, mm, core_state, exit_code); |
| up_write(&mm->mmap_sem); |
| |
| if (core_waiters > 0) { |
| struct core_thread *ptr; |
| |
| wait_for_completion(&core_state->startup); |
| /* |
| * Wait for all the threads to become inactive, so that |
| * all the thread context (extended register state, like |
| * fpu etc) gets copied to the memory. |
| */ |
| ptr = core_state->dumper.next; |
| while (ptr != NULL) { |
| wait_task_inactive(ptr->task, 0); |
| ptr = ptr->next; |
| } |
| } |
| |
| return core_waiters; |
| } |
| |
| static void coredump_finish(struct mm_struct *mm) |
| { |
| struct core_thread *curr, *next; |
| struct task_struct *task; |
| |
| next = mm->core_state->dumper.next; |
| while ((curr = next) != NULL) { |
| next = curr->next; |
| task = curr->task; |
| /* |
| * see exit_mm(), curr->task must not see |
| * ->task == NULL before we read ->next. |
| */ |
| smp_mb(); |
| curr->task = NULL; |
| wake_up_process(task); |
| } |
| |
| mm->core_state = NULL; |
| } |
| |
| /* |
| * set_dumpable converts traditional three-value dumpable to two flags and |
| * stores them into mm->flags. It modifies lower two bits of mm->flags, but |
| * these bits are not changed atomically. So get_dumpable can observe the |
| * intermediate state. To avoid doing unexpected behavior, get get_dumpable |
| * return either old dumpable or new one by paying attention to the order of |
| * modifying the bits. |
| * |
| * dumpable | mm->flags (binary) |
| * old new | initial interim final |
| * ---------+----------------------- |
| * 0 1 | 00 01 01 |
| * 0 2 | 00 10(*) 11 |
| * 1 0 | 01 00 00 |
| * 1 2 | 01 11 11 |
| * 2 0 | 11 10(*) 00 |
| * 2 1 | 11 11 01 |
| * |
| * (*) get_dumpable regards interim value of 10 as 11. |
| */ |
| void set_dumpable(struct mm_struct *mm, int value) |
| { |
| switch (value) { |
| case SUID_DUMPABLE_DISABLED: |
| clear_bit(MMF_DUMPABLE, &mm->flags); |
| smp_wmb(); |
| clear_bit(MMF_DUMP_SECURELY, &mm->flags); |
| break; |
| case SUID_DUMPABLE_ENABLED: |
| set_bit(MMF_DUMPABLE, &mm->flags); |
| smp_wmb(); |
| clear_bit(MMF_DUMP_SECURELY, &mm->flags); |
| break; |
| case SUID_DUMPABLE_SAFE: |
| set_bit(MMF_DUMP_SECURELY, &mm->flags); |
| smp_wmb(); |
| set_bit(MMF_DUMPABLE, &mm->flags); |
| break; |
| } |
| } |
| |
| static int __get_dumpable(unsigned long mm_flags) |
| { |
| int ret; |
| |
| ret = mm_flags & MMF_DUMPABLE_MASK; |
| return (ret > SUID_DUMPABLE_ENABLED) ? SUID_DUMPABLE_SAFE : 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; |
| |
| pipe = file->f_path.dentry->d_inode->i_pipe; |
| |
| pipe_lock(pipe); |
| pipe->readers++; |
| pipe->writers--; |
| |
| while ((pipe->readers > 1) && (!signal_pending(current))) { |
| wake_up_interruptible_sync(&pipe->wait); |
| kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
| pipe_wait(pipe); |
| } |
| |
| pipe->readers--; |
| pipe->writers++; |
| pipe_unlock(pipe); |
| |
| } |
| |
| |
| /* |
| * umh_pipe_setup |
| * helper function to customize the process used |
| * to collect the core in userspace. Specifically |
| * it sets up a pipe and installs it as fd 0 (stdin) |
| * for the process. Returns 0 on success, or |
| * PTR_ERR on failure. |
| * Note that it also sets the core limit to 1. This |
| * is a special value that we use to trap recursive |
| * core dumps |
| */ |
| static int umh_pipe_setup(struct subprocess_info *info, struct cred *new) |
| { |
| struct file *files[2]; |
| struct fdtable *fdt; |
| struct coredump_params *cp = (struct coredump_params *)info->data; |
| struct files_struct *cf = current->files; |
| int err = create_pipe_files(files, 0); |
| if (err) |
| return err; |
| |
| cp->file = files[1]; |
| |
| sys_close(0); |
| fd_install(0, files[0]); |
| spin_lock(&cf->file_lock); |
| fdt = files_fdtable(cf); |
| __set_open_fd(0, fdt); |
| __clear_close_on_exec(0, fdt); |
| spin_unlock(&cf->file_lock); |
| |
| /* and disallow core files too */ |
| current->signal->rlim[RLIMIT_CORE] = (struct rlimit){1, 1}; |
| |
| return 0; |
| } |
| |
| void do_coredump(long signr, int exit_code, struct pt_regs *regs) |
| { |
| struct core_state core_state; |
| struct core_name cn; |
| struct mm_struct *mm = current->mm; |
| struct linux_binfmt * binfmt; |
| const struct cred *old_cred; |
| struct cred *cred; |
| int retval = 0; |
| int flag = 0; |
| int ispipe; |
| bool need_nonrelative = false; |
| 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 = mm->binfmt; |
| if (!binfmt || !binfmt->core_dump) |
| goto fail; |
| if (!__get_dumpable(cprm.mm_flags)) |
| goto fail; |
| |
| cred = prepare_creds(); |
| if (!cred) |
| 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, and only into a controlled |
| * environment (pipe handler or fully qualified path). |
| */ |
| if (__get_dumpable(cprm.mm_flags) == SUID_DUMPABLE_SAFE) { |
| /* Setuid core dump mode */ |
| flag = O_EXCL; /* Stop rewrite attacks */ |
| cred->fsuid = GLOBAL_ROOT_UID; /* Dump root private */ |
| need_nonrelative = true; |
| } |
| |
| retval = coredump_wait(exit_code, &core_state); |
| if (retval < 0) |
| goto fail_creds; |
| |
| old_cred = override_creds(cred); |
| |
| /* |
| * Clear any false indication of pending signals that might |
| * be seen by the filesystem code called to write the core file. |
| */ |
| clear_thread_flag(TIF_SIGPENDING); |
| |
| ispipe = format_corename(&cn, signr); |
| |
| if (ispipe) { |
| int dump_count; |
| char **helper_argv; |
| |
| if (ispipe < 0) { |
| printk(KERN_WARNING "format_corename failed\n"); |
| printk(KERN_WARNING "Aborting core\n"); |
| goto fail_corename; |
| } |
| |
| if (cprm.limit == 1) { |
| /* See umh_pipe_setup() which sets RLIMIT_CORE = 1. |
| * |
| * Normally core limits are irrelevant to pipes, since |
| * we're not writing to the file system, but we use |
| * cprm.limit of 1 here as a speacial value, this is a |
| * consistent way to catch recursive crashes. |
| * We can still crash if the core_pattern binary sets |
| * RLIM_CORE = !1, but it runs as root, and can do |
| * lots of stupid things. |
| * |
| * Note that we use task_tgid_vnr here to grab the pid |
| * of the process group leader. That way we get the |
| * right pid if a thread in a multi-threaded |
| * core_pattern process dies. |
| */ |
| printk(KERN_WARNING |
| "Process %d(%s) has RLIMIT_CORE set to 1\n", |
| task_tgid_vnr(current), current->comm); |
| printk(KERN_WARNING "Aborting core\n"); |
| goto fail_unlock; |
| } |
| cprm.limit = RLIM_INFINITY; |
| |
| dump_count = atomic_inc_return(&core_dump_count); |
| if (core_pipe_limit && (core_pipe_limit < dump_count)) { |
| printk(KERN_WARNING "Pid %d(%s) over core_pipe_limit\n", |
| task_tgid_vnr(current), current->comm); |
| printk(KERN_WARNING "Skipping core dump\n"); |
| goto fail_dropcount; |
| } |
| |
| helper_argv = argv_split(GFP_KERNEL, cn.corename+1, NULL); |
| if (!helper_argv) { |
| printk(KERN_WARNING "%s failed to allocate memory\n", |
| __func__); |
| goto fail_dropcount; |
| } |
| |
| retval = call_usermodehelper_fns(helper_argv[0], helper_argv, |
| NULL, UMH_WAIT_EXEC, umh_pipe_setup, |
| NULL, &cprm); |
| argv_free(helper_argv); |
| if (retval) { |
| printk(KERN_INFO "Core dump to %s pipe failed\n", |
| cn.corename); |
| goto close_fail; |
| } |
| } else { |
| struct inode *inode; |
| |
| if (cprm.limit < binfmt->min_coredump) |
| goto fail_unlock; |
| |
| if (need_nonrelative && cn.corename[0] != '/') { |
| printk(KERN_WARNING "Pid %d(%s) can only dump core "\ |
| "to fully qualified path!\n", |
| task_tgid_vnr(current), current->comm); |
| printk(KERN_WARNING "Skipping core dump\n"); |
| goto fail_unlock; |
| } |
| |
| cprm.file = filp_open(cn.corename, |
| O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag, |
| 0600); |
| if (IS_ERR(cprm.file)) |
| goto fail_unlock; |
| |
| inode = cprm.file->f_path.dentry->d_inode; |
| if (inode->i_nlink > 1) |
| goto close_fail; |
| if (d_unhashed(cprm.file->f_path.dentry)) |
| goto close_fail; |
| /* |
| * AK: actually i see no reason to not allow this for named |
| * pipes etc, but keep the previous behaviour for now. |
| */ |
| if (!S_ISREG(inode->i_mode)) |
| goto close_fail; |
| /* |
| * Dont allow local users get cute and trick others to coredump |
| * into their pre-created files. |
| */ |
| if (!uid_eq(inode->i_uid, current_fsuid())) |
| goto close_fail; |
| if (!cprm.file->f_op || !cprm.file->f_op->write) |
| goto close_fail; |
| if (do_truncate(cprm.file->f_path.dentry, 0, 0, cprm.file)) |
| goto close_fail; |
| } |
| |
| retval = binfmt->core_dump(&cprm); |
| if (retval) |
| current->signal->group_exit_code |= 0x80; |
| |
| if (ispipe && core_pipe_limit) |
| wait_for_dump_helpers(cprm.file); |
| close_fail: |
| if (cprm.file) |
| filp_close(cprm.file, NULL); |
| fail_dropcount: |
| if (ispipe) |
| atomic_dec(&core_dump_count); |
| fail_unlock: |
| kfree(cn.corename); |
| fail_corename: |
| coredump_finish(mm); |
| revert_creds(old_cred); |
| fail_creds: |
| put_cred(cred); |
| fail: |
| return; |
| } |
| |
| /* |
| * Core dumping helper functions. These are the only things you should |
| * do on a core-file: use only these functions to write out all the |
| * necessary info. |
| */ |
| int dump_write(struct file *file, const void *addr, int nr) |
| { |
| return access_ok(VERIFY_READ, addr, nr) && file->f_op->write(file, addr, nr, &file->f_pos) == nr; |
| } |
| EXPORT_SYMBOL(dump_write); |
| |
| int dump_seek(struct file *file, loff_t off) |
| { |
| int ret = 1; |
| |
| if (file->f_op->llseek && file->f_op->llseek != no_llseek) { |
| if (file->f_op->llseek(file, off, SEEK_CUR) < 0) |
| return 0; |
| } else { |
| char *buf = (char *)get_zeroed_page(GFP_KERNEL); |
| |
| if (!buf) |
| return 0; |
| while (off > 0) { |
| unsigned long n = off; |
| |
| if (n > PAGE_SIZE) |
| n = PAGE_SIZE; |
| if (!dump_write(file, buf, n)) { |
| ret = 0; |
| break; |
| } |
| off -= n; |
| } |
| free_page((unsigned long)buf); |
| } |
| return ret; |
| } |
| EXPORT_SYMBOL(dump_seek); |