|  | /* | 
|  | *  linux/fs/binfmt_aout.c | 
|  | * | 
|  | *  Copyright (C) 1991, 1992, 1996  Linus Torvalds | 
|  | */ | 
|  |  | 
|  | #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/coredump.h> | 
|  | #include <linux/slab.h> | 
|  |  | 
|  | #include <asm/uaccess.h> | 
|  | #include <asm/cacheflush.h> | 
|  | #include <asm/a.out-core.h> | 
|  |  | 
|  | static int load_aout_binary(struct linux_binprm *, struct pt_regs * regs); | 
|  | static int load_aout_library(struct file*); | 
|  | static int aout_core_dump(struct coredump_params *cprm); | 
|  |  | 
|  | static struct linux_binfmt aout_format = { | 
|  | .module		= THIS_MODULE, | 
|  | .load_binary	= load_aout_binary, | 
|  | .load_shlib	= load_aout_library, | 
|  | .core_dump	= aout_core_dump, | 
|  | .min_coredump	= PAGE_SIZE | 
|  | }; | 
|  |  | 
|  | #define BAD_ADDR(x)	((unsigned long)(x) >= TASK_SIZE) | 
|  |  | 
|  | static int set_brk(unsigned long start, unsigned long end) | 
|  | { | 
|  | start = PAGE_ALIGN(start); | 
|  | end = PAGE_ALIGN(end); | 
|  | if (end > start) { | 
|  | unsigned long addr; | 
|  | addr = vm_brk(start, end - start); | 
|  | if (BAD_ADDR(addr)) | 
|  | return addr; | 
|  | } | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | /* | 
|  | * Routine writes a core dump image in the current directory. | 
|  | * Currently only a stub-function. | 
|  | * | 
|  | * Note that setuid/setgid files won't make a core-dump if the uid/gid | 
|  | * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable" | 
|  | * field, which also makes sure the core-dumps won't be recursive if the | 
|  | * dumping of the process results in another error.. | 
|  | */ | 
|  |  | 
|  | static int aout_core_dump(struct coredump_params *cprm) | 
|  | { | 
|  | struct file *file = cprm->file; | 
|  | mm_segment_t fs; | 
|  | int has_dumped = 0; | 
|  | void __user *dump_start; | 
|  | int dump_size; | 
|  | struct user dump; | 
|  | #ifdef __alpha__ | 
|  | #       define START_DATA(u)	((void __user *)u.start_data) | 
|  | #else | 
|  | #	define START_DATA(u)	((void __user *)((u.u_tsize << PAGE_SHIFT) + \ | 
|  | u.start_code)) | 
|  | #endif | 
|  | #       define START_STACK(u)   ((void __user *)u.start_stack) | 
|  |  | 
|  | fs = get_fs(); | 
|  | set_fs(KERNEL_DS); | 
|  | has_dumped = 1; | 
|  | current->flags |= PF_DUMPCORE; | 
|  | strncpy(dump.u_comm, current->comm, sizeof(dump.u_comm)); | 
|  | dump.u_ar0 = offsetof(struct user, regs); | 
|  | dump.signal = cprm->signr; | 
|  | aout_dump_thread(cprm->regs, &dump); | 
|  |  | 
|  | /* If the size of the dump file exceeds the rlimit, then see what would happen | 
|  | if we wrote the stack, but not the data area.  */ | 
|  | if ((dump.u_dsize + dump.u_ssize+1) * PAGE_SIZE > cprm->limit) | 
|  | dump.u_dsize = 0; | 
|  |  | 
|  | /* Make sure we have enough room to write the stack and data areas. */ | 
|  | if ((dump.u_ssize + 1) * PAGE_SIZE > cprm->limit) | 
|  | dump.u_ssize = 0; | 
|  |  | 
|  | /* make sure we actually have a data and stack area to dump */ | 
|  | set_fs(USER_DS); | 
|  | if (!access_ok(VERIFY_READ, START_DATA(dump), dump.u_dsize << PAGE_SHIFT)) | 
|  | dump.u_dsize = 0; | 
|  | if (!access_ok(VERIFY_READ, START_STACK(dump), dump.u_ssize << PAGE_SHIFT)) | 
|  | dump.u_ssize = 0; | 
|  |  | 
|  | set_fs(KERNEL_DS); | 
|  | /* struct user */ | 
|  | if (!dump_write(file, &dump, sizeof(dump))) | 
|  | goto end_coredump; | 
|  | /* Now dump all of the user data.  Include malloced stuff as well */ | 
|  | if (!dump_seek(cprm->file, PAGE_SIZE - sizeof(dump))) | 
|  | goto end_coredump; | 
|  | /* now we start writing out the user space info */ | 
|  | set_fs(USER_DS); | 
|  | /* Dump the data area */ | 
|  | if (dump.u_dsize != 0) { | 
|  | dump_start = START_DATA(dump); | 
|  | dump_size = dump.u_dsize << PAGE_SHIFT; | 
|  | if (!dump_write(file, dump_start, dump_size)) | 
|  | goto end_coredump; | 
|  | } | 
|  | /* Now prepare to dump the stack area */ | 
|  | if (dump.u_ssize != 0) { | 
|  | dump_start = START_STACK(dump); | 
|  | dump_size = dump.u_ssize << PAGE_SHIFT; | 
|  | if (!dump_write(file, dump_start, dump_size)) | 
|  | goto end_coredump; | 
|  | } | 
|  | end_coredump: | 
|  | set_fs(fs); | 
|  | return has_dumped; | 
|  | } | 
|  |  | 
|  | /* | 
|  | * 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 unsigned long __user *create_aout_tables(char __user *p, struct linux_binprm * bprm) | 
|  | { | 
|  | char __user * __user *argv; | 
|  | char __user * __user *envp; | 
|  | unsigned long __user *sp; | 
|  | int argc = bprm->argc; | 
|  | int envc = bprm->envc; | 
|  |  | 
|  | sp = (void __user *)((-(unsigned long)sizeof(char *)) & (unsigned long) p); | 
|  | #ifdef __alpha__ | 
|  | /* whee.. test-programs are so much fun. */ | 
|  | put_user(0, --sp); | 
|  | put_user(0, --sp); | 
|  | if (bprm->loader) { | 
|  | put_user(0, --sp); | 
|  | put_user(1003, --sp); | 
|  | put_user(bprm->loader, --sp); | 
|  | put_user(1002, --sp); | 
|  | } | 
|  | put_user(bprm->exec, --sp); | 
|  | put_user(1001, --sp); | 
|  | #endif | 
|  | sp -= envc+1; | 
|  | envp = (char __user * __user *) sp; | 
|  | sp -= argc+1; | 
|  | argv = (char __user * __user *) sp; | 
|  | #ifndef __alpha__ | 
|  | put_user((unsigned long) envp,--sp); | 
|  | put_user((unsigned long) argv,--sp); | 
|  | #endif | 
|  | put_user(argc,--sp); | 
|  | current->mm->arg_start = (unsigned long) p; | 
|  | while (argc-->0) { | 
|  | char c; | 
|  | put_user(p,argv++); | 
|  | do { | 
|  | get_user(c,p++); | 
|  | } while (c); | 
|  | } | 
|  | put_user(NULL,argv); | 
|  | current->mm->arg_end = current->mm->env_start = (unsigned long) p; | 
|  | while (envc-->0) { | 
|  | char c; | 
|  | put_user(p,envp++); | 
|  | do { | 
|  | get_user(c,p++); | 
|  | } while (c); | 
|  | } | 
|  | put_user(NULL,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, struct pt_regs * regs) | 
|  | { | 
|  | struct exec ex; | 
|  | unsigned long error; | 
|  | unsigned long fd_offset; | 
|  | unsigned long rlim; | 
|  | 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(bprm->file->f_path.dentry->d_inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) { | 
|  | return -ENOEXEC; | 
|  | } | 
|  |  | 
|  | /* | 
|  | * Requires a mmap handler. This prevents people from using a.out | 
|  | * as part of an exploit attack against /proc-related vulnerabilities. | 
|  | */ | 
|  | if (!bprm->file->f_op || !bprm->file->f_op->mmap) | 
|  | 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 = flush_old_exec(bprm); | 
|  | if (retval) | 
|  | return retval; | 
|  |  | 
|  | /* OK, This is the point of no return */ | 
|  | #ifdef __alpha__ | 
|  | SET_AOUT_PERSONALITY(bprm, ex); | 
|  | #else | 
|  | set_personality(PER_LINUX); | 
|  | #endif | 
|  | setup_new_exec(bprm); | 
|  |  | 
|  | 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)); | 
|  | current->mm->free_area_cache = current->mm->mmap_base; | 
|  | current->mm->cached_hole_size = 0; | 
|  |  | 
|  | retval = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT); | 
|  | if (retval < 0) { | 
|  | /* Someone check-me: is this error path enough? */ | 
|  | send_sig(SIGKILL, current, 0); | 
|  | return retval; | 
|  | } | 
|  |  | 
|  | install_exec_creds(bprm); | 
|  |  | 
|  | if (N_MAGIC(ex) == OMAGIC) { | 
|  | unsigned long text_addr, map_size; | 
|  | loff_t pos; | 
|  |  | 
|  | text_addr = N_TXTADDR(ex); | 
|  |  | 
|  | #ifdef __alpha__ | 
|  | pos = fd_offset; | 
|  | map_size = ex.a_text+ex.a_data + PAGE_SIZE - 1; | 
|  | #else | 
|  | pos = 32; | 
|  | map_size = ex.a_text+ex.a_data; | 
|  | #endif | 
|  | error = vm_brk(text_addr & PAGE_MASK, map_size); | 
|  | if (error != (text_addr & PAGE_MASK)) { | 
|  | send_sig(SIGKILL, current, 0); | 
|  | return error; | 
|  | } | 
|  |  | 
|  | error = bprm->file->f_op->read(bprm->file, | 
|  | (char __user *)text_addr, | 
|  | ex.a_text+ex.a_data, &pos); | 
|  | if ((signed long)error < 0) { | 
|  | send_sig(SIGKILL, current, 0); | 
|  | return error; | 
|  | } | 
|  |  | 
|  | flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data); | 
|  | } else { | 
|  | if ((ex.a_text & 0xfff || ex.a_data & 0xfff) && | 
|  | (N_MAGIC(ex) != NMAGIC) && printk_ratelimit()) | 
|  | { | 
|  | printk(KERN_NOTICE "executable not page aligned\n"); | 
|  | } | 
|  |  | 
|  | if ((fd_offset & ~PAGE_MASK) != 0 && printk_ratelimit()) | 
|  | { | 
|  | printk(KERN_WARNING | 
|  | "fd_offset is not page aligned. Please convert program: %s\n", | 
|  | bprm->file->f_path.dentry->d_name.name); | 
|  | } | 
|  |  | 
|  | if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) { | 
|  | loff_t pos = fd_offset; | 
|  | vm_brk(N_TXTADDR(ex), ex.a_text+ex.a_data); | 
|  | bprm->file->f_op->read(bprm->file, | 
|  | (char __user *)N_TXTADDR(ex), | 
|  | ex.a_text+ex.a_data, &pos); | 
|  | flush_icache_range((unsigned long) N_TXTADDR(ex), | 
|  | (unsigned long) N_TXTADDR(ex) + | 
|  | 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, | 
|  | fd_offset); | 
|  |  | 
|  | if (error != N_TXTADDR(ex)) { | 
|  | send_sig(SIGKILL, current, 0); | 
|  | 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, | 
|  | fd_offset + ex.a_text); | 
|  | if (error != N_DATADDR(ex)) { | 
|  | send_sig(SIGKILL, current, 0); | 
|  | return error; | 
|  | } | 
|  | } | 
|  | beyond_if: | 
|  | set_binfmt(&aout_format); | 
|  |  | 
|  | retval = set_brk(current->mm->start_brk, current->mm->brk); | 
|  | if (retval < 0) { | 
|  | send_sig(SIGKILL, current, 0); | 
|  | return retval; | 
|  | } | 
|  |  | 
|  | current->mm->start_stack = | 
|  | (unsigned long) create_aout_tables((char __user *) bprm->p, bprm); | 
|  | #ifdef __alpha__ | 
|  | regs->gp = ex.a_gpvalue; | 
|  | #endif | 
|  | start_thread(regs, ex.a_entry, current->mm->start_stack); | 
|  | return 0; | 
|  | } | 
|  |  | 
|  | static int load_aout_library(struct file *file) | 
|  | { | 
|  | struct inode * inode; | 
|  | unsigned long bss, start_addr, len; | 
|  | unsigned long error; | 
|  | int retval; | 
|  | struct exec ex; | 
|  |  | 
|  | inode = file->f_path.dentry->d_inode; | 
|  |  | 
|  | retval = -ENOEXEC; | 
|  | error = kernel_read(file, 0, (char *) &ex, sizeof(ex)); | 
|  | 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(inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) { | 
|  | goto out; | 
|  | } | 
|  |  | 
|  | /* | 
|  | * Requires a mmap handler. This prevents people from using a.out | 
|  | * as part of an exploit attack against /proc-related vulnerabilities. | 
|  | */ | 
|  | if (!file->f_op || !file->f_op->mmap) | 
|  | 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) { | 
|  | loff_t pos = N_TXTOFF(ex); | 
|  |  | 
|  | if (printk_ratelimit()) | 
|  | { | 
|  | printk(KERN_WARNING | 
|  | "N_TXTOFF is not page aligned. Please convert library: %s\n", | 
|  | file->f_path.dentry->d_name.name); | 
|  | } | 
|  | vm_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss); | 
|  |  | 
|  | file->f_op->read(file, (char __user *)start_addr, | 
|  | ex.a_text + ex.a_data, &pos); | 
|  | flush_icache_range((unsigned long) start_addr, | 
|  | (unsigned long) start_addr + 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, | 
|  | 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) { | 
|  | error = vm_brk(start_addr + len, bss - len); | 
|  | retval = error; | 
|  | if (error != start_addr + len) | 
|  | 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); | 
|  | } | 
|  |  | 
|  | core_initcall(init_aout_binfmt); | 
|  | module_exit(exit_aout_binfmt); | 
|  | MODULE_LICENSE("GPL"); |