| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * a.out loader for x86-64 |
| * |
| * Copyright (C) 1991, 1992, 1996 Linus Torvalds |
| * Hacked together by Andi Kleen |
| */ |
| |
| #include <linux/module.h> |
| |
| #include <linux/time.h> |
| #include <linux/kernel.h> |
| #include <linux/mm.h> |
| #include <linux/mman.h> |
| #include <linux/a.out.h> |
| #include <linux/errno.h> |
| #include <linux/signal.h> |
| #include <linux/string.h> |
| #include <linux/fs.h> |
| #include <linux/file.h> |
| #include <linux/stat.h> |
| #include <linux/fcntl.h> |
| #include <linux/ptrace.h> |
| #include <linux/user.h> |
| #include <linux/binfmts.h> |
| #include <linux/personality.h> |
| #include <linux/init.h> |
| #include <linux/jiffies.h> |
| #include <linux/perf_event.h> |
| #include <linux/sched/task_stack.h> |
| |
| #include <linux/uaccess.h> |
| #include <asm/pgalloc.h> |
| #include <asm/cacheflush.h> |
| #include <asm/user32.h> |
| #include <asm/ia32.h> |
| |
| #undef WARN_OLD |
| |
| static int load_aout_binary(struct linux_binprm *); |
| static int load_aout_library(struct file *); |
| |
| static struct linux_binfmt aout_format = { |
| .module = THIS_MODULE, |
| .load_binary = load_aout_binary, |
| .load_shlib = load_aout_library, |
| }; |
| |
| static int set_brk(unsigned long start, unsigned long end) |
| { |
| start = PAGE_ALIGN(start); |
| end = PAGE_ALIGN(end); |
| if (end <= start) |
| return 0; |
| return vm_brk(start, end - start); |
| } |
| |
| |
| /* |
| * create_aout_tables() parses the env- and arg-strings in new user |
| * memory and creates the pointer tables from them, and puts their |
| * addresses on the "stack", returning the new stack pointer value. |
| */ |
| static u32 __user *create_aout_tables(char __user *p, struct linux_binprm *bprm) |
| { |
| u32 __user *argv, *envp, *sp; |
| int argc = bprm->argc, envc = bprm->envc; |
| |
| sp = (u32 __user *) ((-(unsigned long)sizeof(u32)) & (unsigned long) p); |
| sp -= envc+1; |
| envp = sp; |
| sp -= argc+1; |
| argv = sp; |
| put_user((unsigned long) envp, --sp); |
| put_user((unsigned long) argv, --sp); |
| put_user(argc, --sp); |
| current->mm->arg_start = (unsigned long) p; |
| while (argc-- > 0) { |
| char c; |
| |
| put_user((u32)(unsigned long)p, argv++); |
| do { |
| get_user(c, p++); |
| } while (c); |
| } |
| put_user(0, argv); |
| current->mm->arg_end = current->mm->env_start = (unsigned long) p; |
| while (envc-- > 0) { |
| char c; |
| |
| put_user((u32)(unsigned long)p, envp++); |
| do { |
| get_user(c, p++); |
| } while (c); |
| } |
| put_user(0, envp); |
| current->mm->env_end = (unsigned long) p; |
| return sp; |
| } |
| |
| /* |
| * These are the functions used to load a.out style executables and shared |
| * libraries. There is no binary dependent code anywhere else. |
| */ |
| static int load_aout_binary(struct linux_binprm *bprm) |
| { |
| unsigned long error, fd_offset, rlim; |
| struct pt_regs *regs = current_pt_regs(); |
| struct exec ex; |
| int retval; |
| |
| ex = *((struct exec *) bprm->buf); /* exec-header */ |
| if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC && |
| N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) || |
| N_TRSIZE(ex) || N_DRSIZE(ex) || |
| i_size_read(file_inode(bprm->file)) < |
| ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) { |
| return -ENOEXEC; |
| } |
| |
| fd_offset = N_TXTOFF(ex); |
| |
| /* Check initial limits. This avoids letting people circumvent |
| * size limits imposed on them by creating programs with large |
| * arrays in the data or bss. |
| */ |
| rlim = rlimit(RLIMIT_DATA); |
| if (rlim >= RLIM_INFINITY) |
| rlim = ~0; |
| if (ex.a_data + ex.a_bss > rlim) |
| return -ENOMEM; |
| |
| /* Flush all traces of the currently running executable */ |
| retval = begin_new_exec(bprm); |
| if (retval) |
| return retval; |
| |
| /* OK, This is the point of no return */ |
| set_personality(PER_LINUX); |
| set_personality_ia32(false); |
| |
| setup_new_exec(bprm); |
| |
| regs->cs = __USER32_CS; |
| regs->r8 = regs->r9 = regs->r10 = regs->r11 = regs->r12 = |
| regs->r13 = regs->r14 = regs->r15 = 0; |
| |
| current->mm->end_code = ex.a_text + |
| (current->mm->start_code = N_TXTADDR(ex)); |
| current->mm->end_data = ex.a_data + |
| (current->mm->start_data = N_DATADDR(ex)); |
| current->mm->brk = ex.a_bss + |
| (current->mm->start_brk = N_BSSADDR(ex)); |
| |
| retval = setup_arg_pages(bprm, IA32_STACK_TOP, EXSTACK_DEFAULT); |
| if (retval < 0) |
| return retval; |
| |
| if (N_MAGIC(ex) == OMAGIC) { |
| unsigned long text_addr, map_size; |
| |
| text_addr = N_TXTADDR(ex); |
| map_size = ex.a_text+ex.a_data; |
| |
| error = vm_brk(text_addr & PAGE_MASK, map_size); |
| |
| if (error) |
| return error; |
| |
| error = read_code(bprm->file, text_addr, 32, |
| ex.a_text + ex.a_data); |
| if ((signed long)error < 0) |
| return error; |
| } else { |
| #ifdef WARN_OLD |
| static unsigned long error_time, error_time2; |
| if ((ex.a_text & 0xfff || ex.a_data & 0xfff) && |
| (N_MAGIC(ex) != NMAGIC) && |
| time_after(jiffies, error_time2 + 5*HZ)) { |
| printk(KERN_NOTICE "executable not page aligned\n"); |
| error_time2 = jiffies; |
| } |
| |
| if ((fd_offset & ~PAGE_MASK) != 0 && |
| time_after(jiffies, error_time + 5*HZ)) { |
| printk(KERN_WARNING |
| "fd_offset is not page aligned. Please convert " |
| "program: %pD\n", |
| bprm->file); |
| error_time = jiffies; |
| } |
| #endif |
| |
| if (!bprm->file->f_op->mmap || (fd_offset & ~PAGE_MASK) != 0) { |
| error = vm_brk(N_TXTADDR(ex), ex.a_text+ex.a_data); |
| if (error) |
| return error; |
| |
| read_code(bprm->file, N_TXTADDR(ex), fd_offset, |
| ex.a_text+ex.a_data); |
| goto beyond_if; |
| } |
| |
| error = vm_mmap(bprm->file, N_TXTADDR(ex), ex.a_text, |
| PROT_READ | PROT_EXEC, |
| MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | |
| MAP_EXECUTABLE | MAP_32BIT, |
| fd_offset); |
| |
| if (error != N_TXTADDR(ex)) |
| return error; |
| |
| error = vm_mmap(bprm->file, N_DATADDR(ex), ex.a_data, |
| PROT_READ | PROT_WRITE | PROT_EXEC, |
| MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | |
| MAP_EXECUTABLE | MAP_32BIT, |
| fd_offset + ex.a_text); |
| if (error != N_DATADDR(ex)) |
| return error; |
| } |
| |
| beyond_if: |
| error = set_brk(current->mm->start_brk, current->mm->brk); |
| if (error) |
| return error; |
| |
| set_binfmt(&aout_format); |
| |
| current->mm->start_stack = |
| (unsigned long)create_aout_tables((char __user *)bprm->p, bprm); |
| /* start thread */ |
| loadsegment(fs, 0); |
| loadsegment(ds, __USER32_DS); |
| loadsegment(es, __USER32_DS); |
| load_gs_index(0); |
| (regs)->ip = ex.a_entry; |
| (regs)->sp = current->mm->start_stack; |
| (regs)->flags = 0x200; |
| (regs)->cs = __USER32_CS; |
| (regs)->ss = __USER32_DS; |
| regs->r8 = regs->r9 = regs->r10 = regs->r11 = |
| regs->r12 = regs->r13 = regs->r14 = regs->r15 = 0; |
| set_fs(USER_DS); |
| return 0; |
| } |
| |
| static int load_aout_library(struct file *file) |
| { |
| unsigned long bss, start_addr, len, error; |
| int retval; |
| struct exec ex; |
| loff_t pos = 0; |
| |
| retval = -ENOEXEC; |
| error = kernel_read(file, &ex, sizeof(ex), &pos); |
| if (error != sizeof(ex)) |
| goto out; |
| |
| /* We come in here for the regular a.out style of shared libraries */ |
| if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) || |
| N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) || |
| i_size_read(file_inode(file)) < |
| ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) { |
| goto out; |
| } |
| |
| if (N_FLAGS(ex)) |
| goto out; |
| |
| /* For QMAGIC, the starting address is 0x20 into the page. We mask |
| this off to get the starting address for the page */ |
| |
| start_addr = ex.a_entry & 0xfffff000; |
| |
| if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) { |
| #ifdef WARN_OLD |
| static unsigned long error_time; |
| if (time_after(jiffies, error_time + 5*HZ)) { |
| printk(KERN_WARNING |
| "N_TXTOFF is not page aligned. Please convert " |
| "library: %pD\n", |
| file); |
| error_time = jiffies; |
| } |
| #endif |
| retval = vm_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss); |
| if (retval) |
| goto out; |
| |
| read_code(file, start_addr, N_TXTOFF(ex), |
| ex.a_text + ex.a_data); |
| retval = 0; |
| goto out; |
| } |
| /* Now use mmap to map the library into memory. */ |
| error = vm_mmap(file, start_addr, ex.a_text + ex.a_data, |
| PROT_READ | PROT_WRITE | PROT_EXEC, |
| MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_32BIT, |
| N_TXTOFF(ex)); |
| retval = error; |
| if (error != start_addr) |
| goto out; |
| |
| len = PAGE_ALIGN(ex.a_text + ex.a_data); |
| bss = ex.a_text + ex.a_data + ex.a_bss; |
| if (bss > len) { |
| retval = vm_brk(start_addr + len, bss - len); |
| if (retval) |
| goto out; |
| } |
| retval = 0; |
| out: |
| return retval; |
| } |
| |
| static int __init init_aout_binfmt(void) |
| { |
| register_binfmt(&aout_format); |
| return 0; |
| } |
| |
| static void __exit exit_aout_binfmt(void) |
| { |
| unregister_binfmt(&aout_format); |
| } |
| |
| module_init(init_aout_binfmt); |
| module_exit(exit_aout_binfmt); |
| MODULE_LICENSE("GPL"); |