![David S. Miller](/assets/img/avatar_default.png)
Currently allocations are very constrained for 32-bit processes. It grows down-up from 0x70000000 to 0xf0000000 which gives about 2GB of stack + dynamic mmap() space. So support the top-down method, and we need to override the generic helper function in order to deal with D-cache coloring. With these changes I was able to squeeze out a mmap() just over 3.6GB in size in a 32-bit process. Signed-off-by: David S. Miller <davem@davemloft.net>
418 lines
11 KiB
C
418 lines
11 KiB
C
/*
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* linux/fs/binfmt_aout.c
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*
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* Copyright (C) 1991, 1992, 1996 Linus Torvalds
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*
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* Hacked a bit by DaveM to make it work with 32-bit SunOS
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* binaries on the sparc64 port.
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*/
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/mman.h>
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#include <linux/a.out.h>
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#include <linux/errno.h>
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#include <linux/signal.h>
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#include <linux/string.h>
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#include <linux/fs.h>
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#include <linux/file.h>
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#include <linux/stat.h>
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#include <linux/fcntl.h>
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#include <linux/ptrace.h>
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#include <linux/user.h>
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#include <linux/slab.h>
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#include <linux/binfmts.h>
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#include <linux/personality.h>
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#include <linux/init.h>
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#include <asm/system.h>
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#include <asm/uaccess.h>
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#include <asm/pgalloc.h>
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#include <asm/mmu_context.h>
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static int load_aout32_binary(struct linux_binprm *, struct pt_regs * regs);
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static int load_aout32_library(struct file*);
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static int aout32_core_dump(long signr, struct pt_regs * regs, struct file *file);
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static struct linux_binfmt aout32_format = {
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NULL, THIS_MODULE, load_aout32_binary, load_aout32_library, aout32_core_dump,
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PAGE_SIZE
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};
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static void set_brk(unsigned long start, unsigned long end)
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{
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start = PAGE_ALIGN(start);
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end = PAGE_ALIGN(end);
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if (end <= start)
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return;
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down_write(¤t->mm->mmap_sem);
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do_brk(start, end - start);
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up_write(¤t->mm->mmap_sem);
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}
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/*
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* These are the only things you should do on a core-file: use only these
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* macros to write out all the necessary info.
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*/
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static int dump_write(struct file *file, const void *addr, int nr)
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{
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return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
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}
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#define DUMP_WRITE(addr, nr) \
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if (!dump_write(file, (void *)(addr), (nr))) \
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goto end_coredump;
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#define DUMP_SEEK(offset) \
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if (file->f_op->llseek) { \
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if (file->f_op->llseek(file,(offset),0) != (offset)) \
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goto end_coredump; \
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} else file->f_pos = (offset)
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/*
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* Routine writes a core dump image in the current directory.
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* Currently only a stub-function.
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*
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* Note that setuid/setgid files won't make a core-dump if the uid/gid
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* changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable"
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* field, which also makes sure the core-dumps won't be recursive if the
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* dumping of the process results in another error..
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*/
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static int aout32_core_dump(long signr, struct pt_regs *regs, struct file *file)
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{
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mm_segment_t fs;
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int has_dumped = 0;
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unsigned long dump_start, dump_size;
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struct user dump;
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# define START_DATA(u) (u.u_tsize)
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# define START_STACK(u) ((regs->u_regs[UREG_FP]) & ~(PAGE_SIZE - 1))
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fs = get_fs();
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set_fs(KERNEL_DS);
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has_dumped = 1;
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current->flags |= PF_DUMPCORE;
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strncpy(dump.u_comm, current->comm, sizeof(dump.u_comm));
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dump.signal = signr;
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dump_thread(regs, &dump);
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/* If the size of the dump file exceeds the rlimit, then see what would happen
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if we wrote the stack, but not the data area. */
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if ((dump.u_dsize+dump.u_ssize) >
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current->signal->rlim[RLIMIT_CORE].rlim_cur)
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dump.u_dsize = 0;
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/* Make sure we have enough room to write the stack and data areas. */
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if ((dump.u_ssize) >
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current->signal->rlim[RLIMIT_CORE].rlim_cur)
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dump.u_ssize = 0;
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/* make sure we actually have a data and stack area to dump */
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set_fs(USER_DS);
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if (!access_ok(VERIFY_READ, (void __user *) START_DATA(dump), dump.u_dsize))
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dump.u_dsize = 0;
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if (!access_ok(VERIFY_READ, (void __user *) START_STACK(dump), dump.u_ssize))
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dump.u_ssize = 0;
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set_fs(KERNEL_DS);
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/* struct user */
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DUMP_WRITE(&dump,sizeof(dump));
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/* now we start writing out the user space info */
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set_fs(USER_DS);
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/* Dump the data area */
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if (dump.u_dsize != 0) {
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dump_start = START_DATA(dump);
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dump_size = dump.u_dsize;
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DUMP_WRITE(dump_start,dump_size);
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}
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/* Now prepare to dump the stack area */
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if (dump.u_ssize != 0) {
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dump_start = START_STACK(dump);
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dump_size = dump.u_ssize;
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DUMP_WRITE(dump_start,dump_size);
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}
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/* Finally dump the task struct. Not be used by gdb, but could be useful */
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set_fs(KERNEL_DS);
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DUMP_WRITE(current,sizeof(*current));
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end_coredump:
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set_fs(fs);
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return has_dumped;
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}
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/*
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* create_aout32_tables() parses the env- and arg-strings in new user
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* memory and creates the pointer tables from them, and puts their
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* addresses on the "stack", returning the new stack pointer value.
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*/
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static u32 __user *create_aout32_tables(char __user *p, struct linux_binprm *bprm)
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{
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u32 __user *argv;
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u32 __user *envp;
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u32 __user *sp;
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int argc = bprm->argc;
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int envc = bprm->envc;
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sp = (u32 __user *)((-(unsigned long)sizeof(char *))&(unsigned long)p);
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/* This imposes the proper stack alignment for a new process. */
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sp = (u32 __user *) (((unsigned long) sp) & ~7);
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if ((envc+argc+3)&1)
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--sp;
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sp -= envc+1;
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envp = sp;
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sp -= argc+1;
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argv = sp;
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put_user(argc,--sp);
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current->mm->arg_start = (unsigned long) p;
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while (argc-->0) {
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char c;
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put_user(((u32)(unsigned long)(p)),argv++);
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do {
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get_user(c,p++);
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} while (c);
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}
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put_user(NULL,argv);
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current->mm->arg_end = current->mm->env_start = (unsigned long) p;
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while (envc-->0) {
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char c;
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put_user(((u32)(unsigned long)(p)),envp++);
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do {
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get_user(c,p++);
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} while (c);
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}
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put_user(NULL,envp);
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current->mm->env_end = (unsigned long) p;
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return sp;
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}
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/*
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* These are the functions used to load a.out style executables and shared
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* libraries. There is no binary dependent code anywhere else.
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*/
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static int load_aout32_binary(struct linux_binprm * bprm, struct pt_regs * regs)
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{
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struct exec ex;
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unsigned long error;
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unsigned long fd_offset;
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unsigned long rlim;
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unsigned long orig_thr_flags;
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int retval;
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ex = *((struct exec *) bprm->buf); /* exec-header */
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if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
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N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
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N_TRSIZE(ex) || N_DRSIZE(ex) ||
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bprm->file->f_dentry->d_inode->i_size < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
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return -ENOEXEC;
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}
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fd_offset = N_TXTOFF(ex);
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/* Check initial limits. This avoids letting people circumvent
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* size limits imposed on them by creating programs with large
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* arrays in the data or bss.
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*/
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rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur;
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if (rlim >= RLIM_INFINITY)
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rlim = ~0;
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if (ex.a_data + ex.a_bss > rlim)
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return -ENOMEM;
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/* Flush all traces of the currently running executable */
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retval = flush_old_exec(bprm);
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if (retval)
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return retval;
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/* OK, This is the point of no return */
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set_personality(PER_SUNOS);
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current->mm->end_code = ex.a_text +
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(current->mm->start_code = N_TXTADDR(ex));
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current->mm->end_data = ex.a_data +
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(current->mm->start_data = N_DATADDR(ex));
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current->mm->brk = ex.a_bss +
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(current->mm->start_brk = N_BSSADDR(ex));
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current->mm->free_area_cache = current->mm->mmap_base;
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current->mm->cached_hole_size = 0;
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current->mm->mmap = NULL;
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compute_creds(bprm);
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current->flags &= ~PF_FORKNOEXEC;
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if (N_MAGIC(ex) == NMAGIC) {
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loff_t pos = fd_offset;
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/* Fuck me plenty... */
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down_write(¤t->mm->mmap_sem);
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error = do_brk(N_TXTADDR(ex), ex.a_text);
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up_write(¤t->mm->mmap_sem);
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bprm->file->f_op->read(bprm->file, (char __user *)N_TXTADDR(ex),
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ex.a_text, &pos);
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down_write(¤t->mm->mmap_sem);
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error = do_brk(N_DATADDR(ex), ex.a_data);
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up_write(¤t->mm->mmap_sem);
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bprm->file->f_op->read(bprm->file, (char __user *)N_DATADDR(ex),
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ex.a_data, &pos);
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goto beyond_if;
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}
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if (N_MAGIC(ex) == OMAGIC) {
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loff_t pos = fd_offset;
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down_write(¤t->mm->mmap_sem);
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do_brk(N_TXTADDR(ex) & PAGE_MASK,
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ex.a_text+ex.a_data + PAGE_SIZE - 1);
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up_write(¤t->mm->mmap_sem);
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bprm->file->f_op->read(bprm->file, (char __user *)N_TXTADDR(ex),
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ex.a_text+ex.a_data, &pos);
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} else {
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static unsigned long error_time;
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if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
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(N_MAGIC(ex) != NMAGIC) && (jiffies-error_time) > 5*HZ)
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{
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printk(KERN_NOTICE "executable not page aligned\n");
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error_time = jiffies;
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}
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if (!bprm->file->f_op->mmap) {
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loff_t pos = fd_offset;
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down_write(¤t->mm->mmap_sem);
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do_brk(0, ex.a_text+ex.a_data);
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up_write(¤t->mm->mmap_sem);
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bprm->file->f_op->read(bprm->file,
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(char __user *)N_TXTADDR(ex),
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ex.a_text+ex.a_data, &pos);
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goto beyond_if;
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}
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down_write(¤t->mm->mmap_sem);
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error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
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PROT_READ | PROT_EXEC,
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MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
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fd_offset);
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up_write(¤t->mm->mmap_sem);
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if (error != N_TXTADDR(ex)) {
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send_sig(SIGKILL, current, 0);
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return error;
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}
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down_write(¤t->mm->mmap_sem);
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error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
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PROT_READ | PROT_WRITE | PROT_EXEC,
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MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
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fd_offset + ex.a_text);
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up_write(¤t->mm->mmap_sem);
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if (error != N_DATADDR(ex)) {
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send_sig(SIGKILL, current, 0);
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return error;
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}
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}
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beyond_if:
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set_binfmt(&aout32_format);
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set_brk(current->mm->start_brk, current->mm->brk);
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/* Make sure STACK_TOP returns the right thing. */
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orig_thr_flags = current_thread_info()->flags;
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current_thread_info()->flags |= _TIF_32BIT;
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retval = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);
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if (retval < 0) {
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current_thread_info()->flags = orig_thr_flags;
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/* Someone check-me: is this error path enough? */
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send_sig(SIGKILL, current, 0);
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return retval;
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}
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current->mm->start_stack =
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(unsigned long) create_aout32_tables((char __user *)bprm->p, bprm);
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tsb_context_switch(current->mm);
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start_thread32(regs, ex.a_entry, current->mm->start_stack);
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if (current->ptrace & PT_PTRACED)
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send_sig(SIGTRAP, current, 0);
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return 0;
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}
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/* N.B. Move to .h file and use code in fs/binfmt_aout.c? */
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static int load_aout32_library(struct file *file)
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{
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struct inode * inode;
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unsigned long bss, start_addr, len;
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unsigned long error;
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int retval;
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struct exec ex;
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inode = file->f_dentry->d_inode;
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retval = -ENOEXEC;
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error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
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if (error != sizeof(ex))
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goto out;
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/* We come in here for the regular a.out style of shared libraries */
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if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
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N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
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inode->i_size < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
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goto out;
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}
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if (N_MAGIC(ex) == ZMAGIC && N_TXTOFF(ex) &&
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(N_TXTOFF(ex) < inode->i_sb->s_blocksize)) {
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printk("N_TXTOFF < BLOCK_SIZE. Please convert library\n");
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goto out;
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}
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if (N_FLAGS(ex))
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goto out;
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/* For QMAGIC, the starting address is 0x20 into the page. We mask
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this off to get the starting address for the page */
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start_addr = ex.a_entry & 0xfffff000;
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/* Now use mmap to map the library into memory. */
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down_write(¤t->mm->mmap_sem);
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error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
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PROT_READ | PROT_WRITE | PROT_EXEC,
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MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
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N_TXTOFF(ex));
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up_write(¤t->mm->mmap_sem);
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retval = error;
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if (error != start_addr)
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goto out;
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len = PAGE_ALIGN(ex.a_text + ex.a_data);
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bss = ex.a_text + ex.a_data + ex.a_bss;
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if (bss > len) {
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down_write(¤t->mm->mmap_sem);
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error = do_brk(start_addr + len, bss - len);
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up_write(¤t->mm->mmap_sem);
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retval = error;
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if (error != start_addr + len)
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goto out;
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}
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retval = 0;
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out:
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return retval;
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}
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static int __init init_aout32_binfmt(void)
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{
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return register_binfmt(&aout32_format);
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}
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static void __exit exit_aout32_binfmt(void)
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{
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unregister_binfmt(&aout32_format);
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}
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module_init(init_aout32_binfmt);
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module_exit(exit_aout32_binfmt);
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