From fcbb27b0ec6dcbc5a5108cb8fb19eae64593d204 Mon Sep 17 00:00:00 2001 From: Timothy Pearson Date: Wed, 23 Aug 2017 14:45:25 -0500 Subject: Initial import of modified Linux 2.6.28 tree Original upstream URL: git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git | branch linux-2.6.28.y --- fs/binfmt_aout.c | 546 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 546 insertions(+) create mode 100644 fs/binfmt_aout.c (limited to 'fs/binfmt_aout.c') diff --git a/fs/binfmt_aout.c b/fs/binfmt_aout.c new file mode 100644 index 0000000..204cfd1 --- /dev/null +++ b/fs/binfmt_aout.c @@ -0,0 +1,546 @@ +/* + * linux/fs/binfmt_aout.c + * + * Copyright (C) 1991, 1992, 1996 Linus Torvalds + */ + +#include + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include + +static int load_aout_binary(struct linux_binprm *, struct pt_regs * regs); +static int load_aout_library(struct file*); +static int aout_core_dump(long signr, struct pt_regs *regs, struct file *file, unsigned long limit); + +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; + down_write(¤t->mm->mmap_sem); + addr = do_brk(start, end - start); + up_write(¤t->mm->mmap_sem); + if (BAD_ADDR(addr)) + return addr; + } + return 0; +} + +/* + * These are the only things you should do on a core-file: use only these + * macros to write out all the necessary info. + */ + +static int dump_write(struct file *file, const void *addr, int nr) +{ + return file->f_op->write(file, addr, nr, &file->f_pos) == nr; +} + +#define DUMP_WRITE(addr, nr) \ + if (!dump_write(file, (void *)(addr), (nr))) \ + goto end_coredump; + +#define DUMP_SEEK(offset) \ +if (file->f_op->llseek) { \ + if (file->f_op->llseek(file,(offset),0) != (offset)) \ + goto end_coredump; \ +} else file->f_pos = (offset) + +/* + * 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(long signr, struct pt_regs *regs, struct file *file, unsigned long limit) +{ + mm_segment_t fs; + int has_dumped = 0; + unsigned long dump_start, dump_size; + struct user dump; +#if defined(__alpha__) +# define START_DATA(u) (u.start_data) +#elif defined(__arm__) +# define START_DATA(u) ((u.u_tsize << PAGE_SHIFT) + u.start_code) +#elif defined(__sparc__) +# define START_DATA(u) (u.u_tsize) +#elif defined(__i386__) || defined(__mc68000__) || defined(__arch_um__) +# define START_DATA(u) (u.u_tsize << PAGE_SHIFT) +#endif +#ifdef __sparc__ +# define START_STACK(u) ((regs->u_regs[UREG_FP]) & ~(PAGE_SIZE - 1)) +#else +# define START_STACK(u) (u.start_stack) +#endif + + fs = get_fs(); + set_fs(KERNEL_DS); + has_dumped = 1; + current->flags |= PF_DUMPCORE; + strncpy(dump.u_comm, current->comm, sizeof(dump.u_comm)); +#ifndef __sparc__ + dump.u_ar0 = offsetof(struct user, regs); +#endif + dump.signal = signr; + aout_dump_thread(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. */ +#ifdef __sparc__ + if ((dump.u_dsize + dump.u_ssize) > limit) + dump.u_dsize = 0; +#else + if ((dump.u_dsize + dump.u_ssize+1) * PAGE_SIZE > limit) + dump.u_dsize = 0; +#endif + +/* Make sure we have enough room to write the stack and data areas. */ +#ifdef __sparc__ + if (dump.u_ssize > limit) + dump.u_ssize = 0; +#else + if ((dump.u_ssize + 1) * PAGE_SIZE > limit) + dump.u_ssize = 0; +#endif + +/* make sure we actually have a data and stack area to dump */ + set_fs(USER_DS); +#ifdef __sparc__ + if (!access_ok(VERIFY_READ, (void __user *)START_DATA(dump), dump.u_dsize)) + dump.u_dsize = 0; + if (!access_ok(VERIFY_READ, (void __user *)START_STACK(dump), dump.u_ssize)) + dump.u_ssize = 0; +#else + if (!access_ok(VERIFY_READ, (void __user *)START_DATA(dump), dump.u_dsize << PAGE_SHIFT)) + dump.u_dsize = 0; + if (!access_ok(VERIFY_READ, (void __user *)START_STACK(dump), dump.u_ssize << PAGE_SHIFT)) + dump.u_ssize = 0; +#endif + + set_fs(KERNEL_DS); +/* struct user */ + DUMP_WRITE(&dump,sizeof(dump)); +/* Now dump all of the user data. Include malloced stuff as well */ +#ifndef __sparc__ + DUMP_SEEK(PAGE_SIZE); +#endif +/* 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); +#ifdef __sparc__ + dump_size = dump.u_dsize; +#else + dump_size = dump.u_dsize << PAGE_SHIFT; +#endif + DUMP_WRITE(dump_start,dump_size); + } +/* Now prepare to dump the stack area */ + if (dump.u_ssize != 0) { + dump_start = START_STACK(dump); +#ifdef __sparc__ + dump_size = dump.u_ssize; +#else + dump_size = dump.u_ssize << PAGE_SHIFT; +#endif + DUMP_WRITE(dump_start,dump_size); + } +/* Finally dump the task struct. Not be used by gdb, but could be useful */ + set_fs(KERNEL_DS); + DUMP_WRITE(current,sizeof(*current)); +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 __sparc__ + /* This imposes the proper stack alignment for a new process. */ + sp = (void __user *) (((unsigned long) sp) & ~7); + if ((envc+argc+3)&1) --sp; +#endif +#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(0x3eb, --sp); + put_user(bprm->loader, --sp); + put_user(0x3ea, --sp); + } + put_user(bprm->exec, --sp); + put_user(0x3e9, --sp); +#endif + sp -= envc+1; + envp = (char __user * __user *) sp; + sp -= argc+1; + argv = (char __user * __user *) sp; +#if defined(__i386__) || defined(__mc68000__) || defined(__arm__) || defined(__arch_um__) + 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 = current->signal->rlim[RLIMIT_DATA].rlim_cur; + 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 */ +#if defined(__alpha__) + SET_AOUT_PERSONALITY(bprm, ex); +#elif defined(__sparc__) + set_personality(PER_SUNOS); +#if !defined(__sparc_v9__) + memcpy(¤t->thread.core_exec, &ex, sizeof(struct exec)); +#endif +#else + set_personality(PER_LINUX); +#endif + + 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; + + compute_creds(bprm); + current->flags &= ~PF_FORKNOEXEC; +#ifdef __sparc__ + if (N_MAGIC(ex) == NMAGIC) { + loff_t pos = fd_offset; + /* Fuck me plenty... */ + /* */ + down_write(¤t->mm->mmap_sem); + error = do_brk(N_TXTADDR(ex), ex.a_text); + up_write(¤t->mm->mmap_sem); + bprm->file->f_op->read(bprm->file, (char *) N_TXTADDR(ex), + ex.a_text, &pos); + down_write(¤t->mm->mmap_sem); + error = do_brk(N_DATADDR(ex), ex.a_data); + up_write(¤t->mm->mmap_sem); + bprm->file->f_op->read(bprm->file, (char *) N_DATADDR(ex), + ex.a_data, &pos); + goto beyond_if; + } +#endif + + if (N_MAGIC(ex) == OMAGIC) { + unsigned long text_addr, map_size; + loff_t pos; + + text_addr = N_TXTADDR(ex); + +#if defined(__alpha__) || defined(__sparc__) + 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 + down_write(¤t->mm->mmap_sem); + error = do_brk(text_addr & PAGE_MASK, map_size); + up_write(¤t->mm->mmap_sem); + 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; + down_write(¤t->mm->mmap_sem); + do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data); + up_write(¤t->mm->mmap_sem); + 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; + } + + down_write(¤t->mm->mmap_sem); + error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text, + PROT_READ | PROT_EXEC, + MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE, + fd_offset); + up_write(¤t->mm->mmap_sem); + + if (error != N_TXTADDR(ex)) { + send_sig(SIGKILL, current, 0); + return error; + } + + down_write(¤t->mm->mmap_sem); + error = do_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); + up_write(¤t->mm->mmap_sem); + 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; + } + + 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; + } + + 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); + } + down_write(¤t->mm->mmap_sem); + do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss); + up_write(¤t->mm->mmap_sem); + + 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. */ + down_write(¤t->mm->mmap_sem); + error = do_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)); + up_write(¤t->mm->mmap_sem); + 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) { + down_write(¤t->mm->mmap_sem); + error = do_brk(start_addr + len, bss - len); + up_write(¤t->mm->mmap_sem); + retval = error; + if (error != start_addr + len) + goto out; + } + retval = 0; +out: + return retval; +} + +static int __init init_aout_binfmt(void) +{ + return register_binfmt(&aout_format); +} + +static void __exit exit_aout_binfmt(void) +{ + unregister_binfmt(&aout_format); +} + +core_initcall(init_aout_binfmt); +module_exit(exit_aout_binfmt); +MODULE_LICENSE("GPL"); -- cgit v1.1