diff options
Diffstat (limited to 'fs/binfmt_elf.c')
| -rw-r--r-- | fs/binfmt_elf.c | 58 |
1 files changed, 40 insertions, 18 deletions
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index 08e4414b837..4482a0673b1 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -148,6 +148,7 @@ create_elf_tables(struct linux_binprm *bprm, struct elfhdr *exec, elf_addr_t *elf_info; int ei_index = 0; struct task_struct *tsk = current; + struct vm_area_struct *vma; /* * If this architecture has a platform capability string, copy it @@ -234,6 +235,15 @@ create_elf_tables(struct linux_binprm *bprm, struct elfhdr *exec, sp = (elf_addr_t __user *)bprm->p; #endif + + /* + * Grow the stack manually; some architectures have a limit on how + * far ahead a user-space access may be in order to grow the stack. + */ + vma = find_extend_vma(current->mm, bprm->p); + if (!vma) + return -EFAULT; + /* Now, let's put argc (and argv, envp if appropriate) on the stack */ if (__put_user(argc, sp++)) return -EFAULT; @@ -254,8 +264,8 @@ create_elf_tables(struct linux_binprm *bprm, struct elfhdr *exec, size_t len; if (__put_user((elf_addr_t)p, argv++)) return -EFAULT; - len = strnlen_user((void __user *)p, PAGE_SIZE*MAX_ARG_PAGES); - if (!len || len > PAGE_SIZE*MAX_ARG_PAGES) + len = strnlen_user((void __user *)p, MAX_ARG_STRLEN); + if (!len || len > MAX_ARG_STRLEN) return 0; p += len; } @@ -266,8 +276,8 @@ create_elf_tables(struct linux_binprm *bprm, struct elfhdr *exec, size_t len; if (__put_user((elf_addr_t)p, envp++)) return -EFAULT; - len = strnlen_user((void __user *)p, PAGE_SIZE*MAX_ARG_PAGES); - if (!len || len > PAGE_SIZE*MAX_ARG_PAGES) + len = strnlen_user((void __user *)p, MAX_ARG_STRLEN); + if (!len || len > MAX_ARG_STRLEN) return 0; p += len; } @@ -777,10 +787,6 @@ static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs) } /* OK, This is the point of no return */ - current->mm->start_data = 0; - current->mm->end_data = 0; - current->mm->end_code = 0; - current->mm->mmap = NULL; current->flags &= ~PF_FORKNOEXEC; current->mm->def_flags = def_flags; @@ -988,9 +994,13 @@ static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs) compute_creds(bprm); current->flags &= ~PF_FORKNOEXEC; - create_elf_tables(bprm, &loc->elf_ex, + retval = create_elf_tables(bprm, &loc->elf_ex, (interpreter_type == INTERPRETER_AOUT), load_addr, interp_load_addr); + if (retval < 0) { + send_sig(SIGKILL, current, 0); + goto out; + } /* N.B. passed_fileno might not be initialized? */ if (interpreter_type == INTERPRETER_AOUT) current->mm->arg_start += strlen(passed_fileno) + 1; @@ -1189,7 +1199,7 @@ static int dump_seek(struct file *file, loff_t off) * * I think we should skip something. But I am not sure how. H.J. */ -static int maydump(struct vm_area_struct *vma) +static int maydump(struct vm_area_struct *vma, unsigned long mm_flags) { /* The vma can be set up to tell us the answer directly. */ if (vma->vm_flags & VM_ALWAYSDUMP) @@ -1199,15 +1209,19 @@ static int maydump(struct vm_area_struct *vma) if (vma->vm_flags & (VM_IO | VM_RESERVED)) return 0; - /* Dump shared memory only if mapped from an anonymous file. */ - if (vma->vm_flags & VM_SHARED) - return vma->vm_file->f_path.dentry->d_inode->i_nlink == 0; + /* By default, dump shared memory if mapped from an anonymous file. */ + if (vma->vm_flags & VM_SHARED) { + if (vma->vm_file->f_path.dentry->d_inode->i_nlink == 0) + return test_bit(MMF_DUMP_ANON_SHARED, &mm_flags); + else + return test_bit(MMF_DUMP_MAPPED_SHARED, &mm_flags); + } - /* If it hasn't been written to, don't write it out */ + /* By default, if it hasn't been written to, don't write it out. */ if (!vma->anon_vma) - return 0; + return test_bit(MMF_DUMP_MAPPED_PRIVATE, &mm_flags); - return 1; + return test_bit(MMF_DUMP_ANON_PRIVATE, &mm_flags); } /* An ELF note in memory */ @@ -1499,6 +1513,7 @@ static int elf_core_dump(long signr, struct pt_regs *regs, struct file *file) #endif int thread_status_size = 0; elf_addr_t *auxv; + unsigned long mm_flags; #ifdef ELF_CORE_WRITE_EXTRA_NOTES int extra_notes_size; #endif @@ -1642,6 +1657,13 @@ static int elf_core_dump(long signr, struct pt_regs *regs, struct file *file) dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE); + /* + * We must use the same mm->flags while dumping core to avoid + * inconsistency between the program headers and bodies, otherwise an + * unusable core file can be generated. + */ + mm_flags = current->mm->flags; + /* Write program headers for segments dump */ for (vma = first_vma(current, gate_vma); vma != NULL; vma = next_vma(vma, gate_vma)) { @@ -1654,7 +1676,7 @@ static int elf_core_dump(long signr, struct pt_regs *regs, struct file *file) phdr.p_offset = offset; phdr.p_vaddr = vma->vm_start; phdr.p_paddr = 0; - phdr.p_filesz = maydump(vma) ? sz : 0; + phdr.p_filesz = maydump(vma, mm_flags) ? sz : 0; phdr.p_memsz = sz; offset += phdr.p_filesz; phdr.p_flags = vma->vm_flags & VM_READ ? PF_R : 0; @@ -1698,7 +1720,7 @@ static int elf_core_dump(long signr, struct pt_regs *regs, struct file *file) vma = next_vma(vma, gate_vma)) { unsigned long addr; - if (!maydump(vma)) + if (!maydump(vma, mm_flags)) continue; for (addr = vma->vm_start; |