diff options
Diffstat (limited to 'fs/binfmt_aout.c')
| -rw-r--r-- | fs/binfmt_aout.c | 423 |
1 files changed, 423 insertions, 0 deletions
diff --git a/fs/binfmt_aout.c b/fs/binfmt_aout.c new file mode 100644 index 000000000..4c556680f --- /dev/null +++ b/fs/binfmt_aout.c @@ -0,0 +1,423 @@ +/* + * 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 *); +static int load_aout_library(struct file*); + +#ifdef CONFIG_COREDUMP +/* + * 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) +{ + 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; + strncpy(dump.u_comm, current->comm, sizeof(dump.u_comm)); + dump.u_ar0 = offsetof(struct user, regs); + dump.signal = cprm->siginfo->si_signo; + 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_emit(cprm, &dump, sizeof(dump))) + goto end_coredump; +/* Now dump all of the user data. Include malloced stuff as well */ + if (!dump_skip(cprm, 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_emit(cprm, 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_emit(cprm, dump_start, dump_size)) + goto end_coredump; + } +end_coredump: + set_fs(fs); + return has_dumped; +} +#else +#define aout_core_dump NULL +#endif + +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; +} + +/* + * 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 = current_pt_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(file_inode(bprm->file)) < 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->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)); + + retval = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT); + if (retval < 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)) + return error; + + error = read_code(bprm->file, text_addr, pos, + ex.a_text+ex.a_data); + if ((signed long)error < 0) + return error; + } 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: %pD\n", + bprm->file); + } + + if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) { + vm_brk(N_TXTADDR(ex), ex.a_text+ex.a_data); + 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, + 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, + fd_offset + ex.a_text); + if (error != N_DATADDR(ex)) + return error; + } +beyond_if: + set_binfmt(&aout_format); + + retval = set_brk(current->mm->start_brk, current->mm->brk); + if (retval < 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_inode(file); + + 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->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) { + if (printk_ratelimit()) + { + printk(KERN_WARNING + "N_TXTOFF is not page aligned. Please convert library: %pD\n", + file); + } + vm_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss); + + 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, + 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"); |