diff options
Diffstat (limited to 'fs/binfmt_elf_fdpic.c')
| -rw-r--r-- | fs/binfmt_elf_fdpic.c | 53 |
1 files changed, 39 insertions, 14 deletions
diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c index 863250157aa7..b1adb92e69de 100644 --- a/fs/binfmt_elf_fdpic.c +++ b/fs/binfmt_elf_fdpic.c @@ -104,19 +104,36 @@ static void __exit exit_elf_fdpic_binfmt(void) core_initcall(init_elf_fdpic_binfmt); module_exit(exit_elf_fdpic_binfmt); -static int is_elf_fdpic(struct elfhdr *hdr, struct file *file) +static int is_elf(struct elfhdr *hdr, struct file *file) { if (memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0) return 0; if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) return 0; - if (!elf_check_arch(hdr) || !elf_check_fdpic(hdr)) + if (!elf_check_arch(hdr)) return 0; if (!file->f_op->mmap) return 0; return 1; } +#ifndef elf_check_fdpic +#define elf_check_fdpic(x) 0 +#endif + +#ifndef elf_check_const_displacement +#define elf_check_const_displacement(x) 0 +#endif + +static int is_constdisp(struct elfhdr *hdr) +{ + if (!elf_check_fdpic(hdr)) + return 1; + if (elf_check_const_displacement(hdr)) + return 1; + return 0; +} + /*****************************************************************************/ /* * read the program headers table into memory @@ -192,8 +209,18 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm) /* check that this is a binary we know how to deal with */ retval = -ENOEXEC; - if (!is_elf_fdpic(&exec_params.hdr, bprm->file)) + if (!is_elf(&exec_params.hdr, bprm->file)) goto error; + if (!elf_check_fdpic(&exec_params.hdr)) { +#ifdef CONFIG_MMU + /* binfmt_elf handles non-fdpic elf except on nommu */ + goto error; +#else + /* nommu can only load ET_DYN (PIE) ELF */ + if (exec_params.hdr.e_type != ET_DYN) + goto error; +#endif + } /* read the program header table */ retval = elf_fdpic_fetch_phdrs(&exec_params, bprm->file); @@ -270,13 +297,13 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm) } - if (elf_check_const_displacement(&exec_params.hdr)) + if (is_constdisp(&exec_params.hdr)) exec_params.flags |= ELF_FDPIC_FLAG_CONSTDISP; /* perform insanity checks on the interpreter */ if (interpreter_name) { retval = -ELIBBAD; - if (!is_elf_fdpic(&interp_params.hdr, interpreter)) + if (!is_elf(&interp_params.hdr, interpreter)) goto error; interp_params.flags = ELF_FDPIC_FLAG_PRESENT; @@ -307,9 +334,9 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm) retval = -ENOEXEC; if (stack_size == 0) - goto error; + stack_size = 131072UL; /* same as exec.c's default commit */ - if (elf_check_const_displacement(&interp_params.hdr)) + if (is_constdisp(&interp_params.hdr)) interp_params.flags |= ELF_FDPIC_FLAG_CONSTDISP; /* flush all traces of the currently running executable */ @@ -320,7 +347,10 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm) /* there's now no turning back... the old userspace image is dead, * defunct, deceased, etc. */ - set_personality(PER_LINUX_FDPIC); + if (elf_check_fdpic(&exec_params.hdr)) + set_personality(PER_LINUX_FDPIC); + else + set_personality(PER_LINUX); if (elf_read_implies_exec(&exec_params.hdr, executable_stack)) current->personality |= READ_IMPLIES_EXEC; @@ -375,10 +405,7 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm) PAGE_ALIGN(current->mm->start_brk); #else - /* create a stack and brk area big enough for everyone - * - the brk heap starts at the bottom and works up - * - the stack starts at the top and works down - */ + /* create a stack area and zero-size brk area */ stack_size = (stack_size + PAGE_SIZE - 1) & PAGE_MASK; if (stack_size < PAGE_SIZE * 2) stack_size = PAGE_SIZE * 2; @@ -401,8 +428,6 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm) current->mm->brk = current->mm->start_brk; current->mm->context.end_brk = current->mm->start_brk; - current->mm->context.end_brk += - (stack_size > PAGE_SIZE) ? (stack_size - PAGE_SIZE) : 0; current->mm->start_stack = current->mm->start_brk + stack_size; #endif |