Non-trivial changes: Invert 'if's to simplify logic. Use 'goto' in conjunction with the above, when appropriate.
Signed-off-by: Alejandro Colomar <[email protected]> --- fs/binfmt_elf.c | 115 +++++++++++++++++++++++++----------------------- 1 file changed, 59 insertions(+), 56 deletions(-) diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c index b5e1e0a0917a..dbd50b5bf238 100644 --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -1079,65 +1079,68 @@ static int load_elf_binary(struct linux_binprm *bprm) */ if (elf_ex->e_type == ET_EXEC || load_addr_set) { elf_flags |= MAP_FIXED; - } else if (elf_ex->e_type == ET_DYN) { - /* - * This logic is run once for the first LOAD Program - * Header for ET_DYN binaries to calculate the - * randomization (load_bias) for all the LOAD - * Program Headers, and to calculate the entire - * size of the ELF mapping (total_size). (Note that - * load_addr_set is set to true later once the - * initial mapping is performed.) - * - * There are effectively two types of ET_DYN - * binaries: programs (i.e. PIE: ET_DYN with INTERP) - * and loaders (ET_DYN without INTERP, since they - * _are_ the ELF interpreter). The loaders must - * be loaded away from programs since the program - * may otherwise collide with the loader (especially - * for ET_EXEC which does not have a randomized - * position). For example to handle invocations of - * "./ld.so someprog" to test out a new version of - * the loader, the subsequent program that the - * loader loads must avoid the loader itself, so - * they cannot share the same load range. Sufficient - * room for the brk must be allocated with the - * loader as well, since brk must be available with - * the loader. - * - * Therefore, programs are loaded offset from - * ELF_ET_DYN_BASE and loaders are loaded into the - * independently randomized mmap region (0 load_bias - * without MAP_FIXED). - */ - if (interpreter) { - load_bias = ELF_ET_DYN_BASE; - if (current->flags & PF_RANDOMIZE) - load_bias += arch_mmap_rnd(); - alignment = maximum_alignment(elf_phdata, elf_ex->e_phnum); - if (alignment) - load_bias &= ~(alignment - 1); - elf_flags |= MAP_FIXED; - } else - load_bias = 0; + goto proceed_normally; + } + if (elf_ex->e_type != ET_DYN) + goto proceed_normally; + /* + * This logic is run once for the first LOAD Program + * Header for ET_DYN binaries to calculate the + * randomization (load_bias) for all the LOAD + * Program Headers, and to calculate the entire + * size of the ELF mapping (total_size). (Note that + * load_addr_set is set to true later once the + * initial mapping is performed.) + * + * There are effectively two types of ET_DYN + * binaries: programs (i.e. PIE: ET_DYN with INTERP) + * and loaders (ET_DYN without INTERP, since they + * _are_ the ELF interpreter). The loaders must + * be loaded away from programs since the program + * may otherwise collide with the loader (especially + * for ET_EXEC which does not have a randomized + * position). For example to handle invocations of + * "./ld.so someprog" to test out a new version of + * the loader, the subsequent program that the + * loader loads must avoid the loader itself, so + * they cannot share the same load range. Sufficient + * room for the brk must be allocated with the + * loader as well, since brk must be available with + * the loader. + * + * Therefore, programs are loaded offset from + * ELF_ET_DYN_BASE and loaders are loaded into the + * independently randomized mmap region (0 load_bias + * without MAP_FIXED). + */ + if (interpreter) { + load_bias = ELF_ET_DYN_BASE; + if (current->flags & PF_RANDOMIZE) + load_bias += arch_mmap_rnd(); + alignment = maximum_alignment(elf_phdata, elf_ex->e_phnum); + if (alignment) + load_bias &= ~(alignment - 1); + elf_flags |= MAP_FIXED; + } else { + load_bias = 0; + } - /* - * Since load_bias is used for all subsequent loading - * calculations, we must lower it by the first vaddr - * so that the remaining calculations based on the - * ELF vaddrs will be correctly offset. The result - * is then page aligned. - */ - load_bias = ELF_PAGESTART(load_bias - vaddr); + /* + * Since load_bias is used for all subsequent loading + * calculations, we must lower it by the first vaddr + * so that the remaining calculations based on the + * ELF vaddrs will be correctly offset. The result + * is then page aligned. + */ + load_bias = ELF_PAGESTART(load_bias - vaddr); - total_size = total_mapping_size(elf_phdata, - elf_ex->e_phnum); - if (!total_size) { - retval = -EINVAL; - goto out_free_dentry; - } + total_size = total_mapping_size(elf_phdata, + elf_ex->e_phnum); + if (!total_size) { + retval = -EINVAL; + goto out_free_dentry; } - +proceed_normally: /* FIXME: a better label name? */ error = elf_map(bprm->file, load_bias + vaddr, elf_ppnt, elf_prot, elf_flags, total_size); if (BAD_ADDR(error)) { -- 2.28.0
