/* * 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/config.h>#include <linux/slab.h>#include <linux/file.h>#include <linux/mman.h>#include <linux/a.out.h>#include <linux/stat.h>#include <linux/fcntl.h>#include <linux/smp_lock.h>#include <linux/init.h>#include <linux/pagemap.h>#include <linux/highmem.h>#include <linux/spinlock.h>#include <linux/key.h>#include <linux/personality.h>#include <linux/binfmts.h>#include <linux/swap.h>#include <linux/utsname.h>#include <linux/module.h>#include <linux/namei.h>#include <linux/proc_fs.h>#include <linux/ptrace.h>#include <linux/mount.h>#include <linux/security.h>#include <linux/syscalls.h>#include <linux/rmap.h>#include <linux/acct.h> #include <asm/uaccess.h>#include <asm/mmu_context.h> #ifdef CONFIG_KMOD#include <linux/kmod.h>#endif int core_uses_pid;char core_pattern[65] = "core";/* The maximal length of core_pattern is also specified in sysctl.c */ static struct linux_binfmt *formats;static DEFINE_RWLOCK(binfmt_lock); int register_binfmt(struct linux_binfmt * fmt){ struct linux_binfmt ** tmp = &formats; if (!fmt) return -EINVAL; if (fmt->next) return -EBUSY; write_lock(&binfmt_lock); while (*tmp) { if (fmt == *tmp) { write_unlock(&binfmt_lock); return -EBUSY; } tmp = &(*tmp)->next; } fmt->next = formats; formats = fmt; write_unlock(&binfmt_lock); return 0; } EXPORT_SYMBOL(register_binfmt); int unregister_binfmt(struct linux_binfmt * fmt){ struct linux_binfmt ** tmp = &formats; write_lock(&binfmt_lock); while (*tmp) { if (fmt == *tmp) { *tmp = fmt->next; write_unlock(&binfmt_lock); return 0; } tmp = &(*tmp)->next; } write_unlock(&binfmt_lock); return -EINVAL;} 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. */asmlinkage long sys_uselib(const char __user * library){ struct file * file; struct nameidata nd; int error; nd.intent.open.flags = FMODE_READ; error = __user_walk(library, LOOKUP_FOLLOW|LOOKUP_OPEN, &nd); if (error) goto out; error = -EINVAL; if (!S_ISREG(nd.dentry->d_inode->i_mode)) goto exit; error = permission(nd.dentry->d_inode, MAY_READ | MAY_EXEC, &nd); if (error) goto exit; file = dentry_open(nd.dentry, nd.mnt, O_RDONLY); error = PTR_ERR(file); if (IS_ERR(file)) goto out; error = -ENOEXEC; if(file->f_op) { struct linux_binfmt * fmt; read_lock(&binfmt_lock); for (fmt = formats ; fmt ; fmt = fmt->next) { 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); } fput(file);out: return error;exit: path_release(&nd); goto out;} /* * count() counts the number of strings in array ARGV. */static int count(char __user * __user * argv, int max){ int i = 0; if (argv != NULL) { for (;;) { char __user * p; if (get_user(p, argv)) return -EFAULT; if (!p) break; argv++; if(++i > max) return -E2BIG; cond_resched(); } } return i;} /* * 'copy_strings()' copies argument/environment strings from user * memory to free pages in kernel mem. These are in a format ready * to be put directly into the top of new user memory. */int copy_strings(int argc,char __user * __user * argv, struct linux_binprm *bprm){ struct page *kmapped_page = NULL; char *kaddr = NULL; int ret; while (argc-- > 0) { char __user *str; int len; unsigned long pos; if (get_user(str, argv+argc) || !(len = strnlen_user(str, bprm->p))) { ret = -EFAULT; goto out; } if (bprm->p < len) { ret = -E2BIG; goto out; } bprm->p -= len; /* XXX: add architecture specific overflow check here. */ pos = bprm->p; while (len > 0) { int i, new, err; int offset, bytes_to_copy; struct page *page; offset = pos % PAGE_SIZE; i = pos/PAGE_SIZE; page = bprm->page[i]; new = 0; if (!page) { page = alloc_page(GFP_HIGHUSER); bprm->page[i] = page; if (!page) { ret = -ENOMEM; goto out; } new = 1; } if (page != kmapped_page) { if (kmapped_page) kunmap(kmapped_page); kmapped_page = page; kaddr = kmap(kmapped_page); } if (new && offset) memset(kaddr, 0, offset); bytes_to_copy = PAGE_SIZE - offset; if (bytes_to_copy > len) { bytes_to_copy = len; if (new) memset(kaddr+offset+len, 0, PAGE_SIZE-offset-len); } err = copy_from_user(kaddr+offset, str, bytes_to_copy); if (err) { ret = -EFAULT; goto out; } pos += bytes_to_copy; str += bytes_to_copy; len -= bytes_to_copy; } } ret = 0;out: if (kmapped_page) kunmap(kmapped_page); return ret;} /* * Like copy_strings, but get argv and its values from kernel memory. */int copy_strings_kernel(int argc,char ** argv, struct linux_binprm *bprm){ int r; mm_segment_t oldfs = get_fs(); set_fs(KERNEL_DS); r = copy_strings(argc, (char __user * __user *)argv, bprm); set_fs(oldfs); return r;} EXPORT_SYMBOL(copy_strings_kernel); #ifdef CONFIG_MMU/* * This routine is used to map in a page into an address space: needed by * execve() for the initial stack and environment pages. * * vma->vm_mm->mmap_sem is held for writing. */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; if (unlikely(anon_vma_prepare(vma))) goto out_sig; 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); if (!pte) goto out; if (!pte_none(*pte)) { pte_unmap(pte); goto out; } mm->rss++; lru_cache_add_active(page); set_pte(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); /* no need for flush_tlb */ return;out: spin_unlock(&mm->page_table_lock);out_sig: __free_page(page); force_sig(SIGKILL, current);} #define EXTRA_STACK_VM_PAGES 20 /* random */ int setup_arg_pages(struct linux_binprm *bprm, unsigned long stack_top, int executable_stack){ unsigned long stack_base; struct vm_area_struct *mpnt; struct mm_struct *mm = current->mm; int i, ret; long arg_size; #ifdef CONFIG_STACK_GROWSUP /* Move the argument and environment strings to the bottom of the * stack space. */ int offset, j; char *to, *from; /* Start by shifting all the pages down */ i = 0; for (j = 0; j < MAX_ARG_PAGES; j++) { struct page *page = bprm->page[j]; if (!page) continue; bprm->page[i++] = page; } /* Now move them within their pages */ offset = bprm->p % PAGE_SIZE; to = kmap(bprm->page[0]); for (j = 1; j < i; j++) { memmove(to, to + offset, PAGE_SIZE - offset); from = kmap(bprm->page[j]); memcpy(to + PAGE_SIZE - offset, from, offset); kunmap(bprm->page[j - 1]); to = from; } memmove(to, to + offset, PAGE_SIZE - offset); kunmap(bprm->page[j - 1]); /* Limit stack size to 1GB */ stack_base = current->signal->rlim[RLIMIT_STACK].rlim_max; if (stack_base > (1 << 30)) stack_base = 1 << 30; stack_base = PAGE_ALIGN(stack_top - stack_base); /* Adjust bprm->p to point to the end of the strings. */ bprm->p = stack_base + PAGE_SIZE * i - offset; mm->arg_start = stack_base; arg_size = i << PAGE_SHIFT; /* zero pages that were copied above */ while (i < MAX_ARG_PAGES) bprm->page[i++] = NULL;#else stack_base = stack_top - MAX_ARG_PAGES * PAGE_SIZE; bprm->p += stack_base; mm->arg_start = bprm->p; arg_size = stack_top - (PAGE_MASK & (unsigned long) mm->arg_start);#endif arg_size += EXTRA_STACK_VM_PAGES * PAGE_SIZE; if (bprm->loader) bprm->loader += stack_base; bprm->exec += stack_base; mpnt = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL); if (!mpnt) return -ENOMEM; if (security_vm_enough_memory(arg_size >> PAGE_SHIFT)) { kmem_cache_free(vm_area_cachep, mpnt); return -ENOMEM; } memset(mpnt, 0, sizeof(*mpnt)); down_write(&mm->mmap_sem); { mpnt->vm_mm = mm;#ifdef CONFIG_STACK_GROWSUP mpnt->vm_start = stack_base; mpnt->vm_end = stack_base + arg_size;#else mpnt->vm_end = stack_top; mpnt->vm_start = mpnt->vm_end - arg_size;#endif /* 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)) mpnt->vm_flags = VM_STACK_FLAGS | VM_EXEC; else if (executable_stack == EXSTACK_DISABLE_X) mpnt->vm_flags = VM_STACK_FLAGS & ~VM_EXEC; else mpnt->vm_flags = VM_STACK_FLAGS; mpnt->vm_flags |= mm->def_flags; mpnt->vm_page_prot = protection_map[mpnt->vm_flags & 0x7]; if ((ret = insert_vm_struct(mm, mpnt))) { up_write(&mm->mmap_sem); kmem_cache_free(vm_area_cachep, mpnt); return ret; } mm->stack_vm = mm->total_vm = vma_pages(mpnt); } for (i = 0 ; i < MAX_ARG_PAGES ; i++) { struct page *page = bprm->page[i]; if (page) { bprm->page[i] = NULL; install_arg_page(mpnt, page, stack_base); } stack_base += PAGE_SIZE; } up_write(&mm->mmap_sem); return 0;} EXPORT_SYMBOL(setup_arg_pages); #define free_arg_pages(bprm) do { } while (0) #else static inline void free_arg_pages(struct linux_binprm *bprm){ int i; for (i = 0; i < MAX_ARG_PAGES; i++) { if (bprm->page[i]) __free_page(bprm->page[i]); bprm->page[i] = NULL; }} #endif /* CONFIG_MMU */ struct file *open_exec(const char *name){ struct nameidata nd; int err; struct file *file; nd.intent.open.flags = FMODE_READ; err = path_lookup(name, LOOKUP_FOLLOW|LOOKUP_OPEN, &nd); file = ERR_PTR(err); if (!err) { struct inode *inode = nd.dentry->d_inode; file = ERR_PTR(-EACCES); if (!(nd.mnt->mnt_flags & MNT_NOEXEC) &&Lines 1–500 of 1496. 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/* * 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/config.h> #include <linux/slab.h> #include <linux/file.h> #include <linux/mman.h> #include <linux/a.out.h> #include <linux/stat.h> #include <linux/fcntl.h> #include <linux/smp_lock.h> #include <linux/init.h> #include <linux/pagemap.h> #include <linux/highmem.h> #include <linux/spinlock.h> #include <linux/key.h> #include <linux/personality.h> #include <linux/binfmts.h> #include <linux/swap.h> #include <linux/utsname.h> #include <linux/module.h> #include <linux/namei.h> #include <linux/proc_fs.h> #include <linux/ptrace.h> #include <linux/mount.h> #include <linux/security.h> #include <linux/syscalls.h> #include <linux/rmap.h> #include <linux/acct.h> #include <asm/uaccess.h> #include <asm/mmu_context.h> #ifdef CONFIG_KMOD #include <linux/kmod.h> #endif int core_uses_pid; char core_pattern[65] = "core"; /* The maximal length of core_pattern is also specified in sysctl.c */ static struct linux_binfmt *formats; static DEFINE_RWLOCK(binfmt_lock); int register_binfmt(struct linux_binfmt * fmt) { struct linux_binfmt ** tmp = &formats; if (!fmt) return -EINVAL; if (fmt->next) return -EBUSY; write_lock(&binfmt_lock); while (*tmp) { if (fmt == *tmp) { write_unlock(&binfmt_lock); return -EBUSY; } tmp = &(*tmp)->next; } fmt->next = formats; formats = fmt; write_unlock(&binfmt_lock); return 0; } EXPORT_SYMBOL(register_binfmt); int unregister_binfmt(struct linux_binfmt * fmt) { struct linux_binfmt ** tmp = &formats; write_lock(&binfmt_lock); while (*tmp) { if (fmt == *tmp) { *tmp = fmt->next; write_unlock(&binfmt_lock); return 0; } tmp = &(*tmp)->next; } write_unlock(&binfmt_lock); return -EINVAL; } 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. */ asmlinkage long sys_uselib(const char __user * library) { struct file * file; struct nameidata nd; int error; nd.intent.open.flags = FMODE_READ; error = __user_walk(library, LOOKUP_FOLLOW|LOOKUP_OPEN, &nd); if (error) goto out; error = -EINVAL; if (!S_ISREG(nd.dentry->d_inode->i_mode)) goto exit; error = permission(nd.dentry->d_inode, MAY_READ | MAY_EXEC, &nd); if (error) goto exit; file = dentry_open(nd.dentry, nd.mnt, O_RDONLY); error = PTR_ERR(file); if (IS_ERR(file)) goto out; error = -ENOEXEC; if(file->f_op) { struct linux_binfmt * fmt; read_lock(&binfmt_lock); for (fmt = formats ; fmt ; fmt = fmt->next) { 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); } fput(file); out: return error; exit: path_release(&nd); goto out; } /* * count() counts the number of strings in array ARGV. */ static int count(char __user * __user * argv, int max) { int i = 0; if (argv != NULL) { for (;;) { char __user * p; if (get_user(p, argv)) return -EFAULT; if (!p) break; argv++; if(++i > max) return -E2BIG; cond_resched(); } } return i; } /* * 'copy_strings()' copies argument/environment strings from user * memory to free pages in kernel mem. These are in a format ready * to be put directly into the top of new user memory. */ int copy_strings(int argc,char __user * __user * argv, struct linux_binprm *bprm) { struct page *kmapped_page = NULL; char *kaddr = NULL; int ret; while (argc-- > 0) { char __user *str; int len; unsigned long pos; if (get_user(str, argv+argc) || !(len = strnlen_user(str, bprm->p))) { ret = -EFAULT; goto out; } if (bprm->p < len) { ret = -E2BIG; goto out; } bprm->p -= len; /* XXX: add architecture specific overflow check here. */ pos = bprm->p; while (len > 0) { int i, new, err; int offset, bytes_to_copy; struct page *page; offset = pos % PAGE_SIZE; i = pos/PAGE_SIZE; page = bprm->page[i]; new = 0; if (!page) { page = alloc_page(GFP_HIGHUSER); bprm->page[i] = page; if (!page) { ret = -ENOMEM; goto out; } new = 1; } if (page != kmapped_page) { if (kmapped_page) kunmap(kmapped_page); kmapped_page = page; kaddr = kmap(kmapped_page); } if (new && offset) memset(kaddr, 0, offset); bytes_to_copy = PAGE_SIZE - offset; if (bytes_to_copy > len) { bytes_to_copy = len; if (new) memset(kaddr+offset+len, 0, PAGE_SIZE-offset-len); } err = copy_from_user(kaddr+offset, str, bytes_to_copy); if (err) { ret = -EFAULT; goto out; } pos += bytes_to_copy; str += bytes_to_copy; len -= bytes_to_copy; } } ret = 0; out: if (kmapped_page) kunmap(kmapped_page); return ret; } /* * Like copy_strings, but get argv and its values from kernel memory. */ int copy_strings_kernel(int argc,char ** argv, struct linux_binprm *bprm) { int r; mm_segment_t oldfs = get_fs(); set_fs(KERNEL_DS); r = copy_strings(argc, (char __user * __user *)argv, bprm); set_fs(oldfs); return r; } EXPORT_SYMBOL(copy_strings_kernel); #ifdef CONFIG_MMU /* * This routine is used to map in a page into an address space: needed by * execve() for the initial stack and environment pages. * * vma->vm_mm->mmap_sem is held for writing. */ 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; if (unlikely(anon_vma_prepare(vma))) goto out_sig; 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); if (!pte) goto out; if (!pte_none(*pte)) { pte_unmap(pte); goto out; } mm->rss++; lru_cache_add_active(page); set_pte(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); /* no need for flush_tlb */ return; out: spin_unlock(&mm->page_table_lock); out_sig: __free_page(page); force_sig(SIGKILL, current); } #define EXTRA_STACK_VM_PAGES 20 /* random */ int setup_arg_pages(struct linux_binprm *bprm, unsigned long stack_top, int executable_stack) { unsigned long stack_base; struct vm_area_struct *mpnt; struct mm_struct *mm = current->mm; int i, ret; long arg_size; #ifdef CONFIG_STACK_GROWSUP /* Move the argument and environment strings to the bottom of the * stack space. */ int offset, j; char *to, *from; /* Start by shifting all the pages down */ i = 0; for (j = 0; j < MAX_ARG_PAGES; j++) { struct page *page = bprm->page[j]; if (!page) continue; bprm->page[i++] = page; } /* Now move them within their pages */ offset = bprm->p % PAGE_SIZE; to = kmap(bprm->page[0]); for (j = 1; j < i; j++) { memmove(to, to + offset, PAGE_SIZE - offset); from = kmap(bprm->page[j]); memcpy(to + PAGE_SIZE - offset, from, offset); kunmap(bprm->page[j - 1]); to = from; } memmove(to, to + offset, PAGE_SIZE - offset); kunmap(bprm->page[j - 1]); /* Limit stack size to 1GB */ stack_base = current->signal->rlim[RLIMIT_STACK].rlim_max; if (stack_base > (1 << 30)) stack_base = 1 << 30; stack_base = PAGE_ALIGN(stack_top - stack_base); /* Adjust bprm->p to point to the end of the strings. */ bprm->p = stack_base + PAGE_SIZE * i - offset; mm->arg_start = stack_base; arg_size = i << PAGE_SHIFT; /* zero pages that were copied above */ while (i < MAX_ARG_PAGES) bprm->page[i++] = NULL; #else stack_base = stack_top - MAX_ARG_PAGES * PAGE_SIZE; bprm->p += stack_base; mm->arg_start = bprm->p; arg_size = stack_top - (PAGE_MASK & (unsigned long) mm->arg_start); #endif arg_size += EXTRA_STACK_VM_PAGES * PAGE_SIZE; if (bprm->loader) bprm->loader += stack_base; bprm->exec += stack_base; mpnt = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL); if (!mpnt) return -ENOMEM; if (security_vm_enough_memory(arg_size >> PAGE_SHIFT)) { kmem_cache_free(vm_area_cachep, mpnt); return -ENOMEM; } memset(mpnt, 0, sizeof(*mpnt)); down_write(&mm->mmap_sem); { mpnt->vm_mm = mm; #ifdef CONFIG_STACK_GROWSUP mpnt->vm_start = stack_base; mpnt->vm_end = stack_base + arg_size; #else mpnt->vm_end = stack_top; mpnt->vm_start = mpnt->vm_end - arg_size; #endif /* 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)) mpnt->vm_flags = VM_STACK_FLAGS | VM_EXEC; else if (executable_stack == EXSTACK_DISABLE_X) mpnt->vm_flags = VM_STACK_FLAGS & ~VM_EXEC; else mpnt->vm_flags = VM_STACK_FLAGS; mpnt->vm_flags |= mm->def_flags; mpnt->vm_page_prot = protection_map[mpnt->vm_flags & 0x7]; if ((ret = insert_vm_struct(mm, mpnt))) { up_write(&mm->mmap_sem); kmem_cache_free(vm_area_cachep, mpnt); return ret; } mm->stack_vm = mm->total_vm = vma_pages(mpnt); } for (i = 0 ; i < MAX_ARG_PAGES ; i++) { struct page *page = bprm->page[i]; if (page) { bprm->page[i] = NULL; install_arg_page(mpnt, page, stack_base); } stack_base += PAGE_SIZE; } up_write(&mm->mmap_sem); return 0; } EXPORT_SYMBOL(setup_arg_pages); #define free_arg_pages(bprm) do { } while (0) #else static inline void free_arg_pages(struct linux_binprm *bprm) { int i; for (i = 0; i < MAX_ARG_PAGES; i++) { if (bprm->page[i]) __free_page(bprm->page[i]); bprm->page[i] = NULL; } } #endif /* CONFIG_MMU */ struct file *open_exec(const char *name) { struct nameidata nd; int err; struct file *file; nd.intent.open.flags = FMODE_READ; err = path_lookup(name, LOOKUP_FOLLOW|LOOKUP_OPEN, &nd); file = ERR_PTR(err); if (!err) { struct inode *inode = nd.dentry->d_inode; file = ERR_PTR(-EACCES); if (!(nd.mnt->mnt_flags & MNT_NOEXEC) &&