Messages in this thread |  | | Date | Sat, 12 Mar 2022 18:06:26 +0000 | From | James Jones <> | Subject | Re: [PATCH] x86: Remove a.out support |
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On 3/12/22 9:54 AM, James Jones wrote: >> From: Borislav Petkov <bp@suse.de> >> >> Commit >> >> eac616557050 ("x86: Deprecate a.out support") >> >> deprecated a.out support with the promise to remove it a couple of >> releases later. That commit landed in v5.1. >> >> Now it is more than a couple of releases later, no one has complained so >> remove it. > > Sorry for taking so long to complain, but I have been meaning to note > that I and a few others are still using a.out. I saw it go by in my > morning Google news skim that this went in, and figured it was now or > never. The use case is running an old set of tools to build programs for > the Atari Jaguar. Namely, Atari's assembler (mac) and linker (aln). The > alternative is running windows versions in dosbox, or using some > replacements that have been developed based on an even older, > less-featureful version of the source code for mac and aln, but which > still haven't managed to add back in all the features needed to build > some programs or use the Atari debugging tools (Also available in a.out > only). > > I've been running with a few local patches to fix the a.out build and > add the Kconfig options back for the last year or so to enable this on a > few of my machines, and it's been working fine. I know of at least one > other person doing this. If the code itself and supporting > syscalls/other code go away though, it'll probably become impractical. > If others are open to it, I can share my small local patches along with > a revert of this change. I'd also like to ask whether much is gained by > deleting this code as far as reducing maintenance burden. It has > survived nearly untouched since the deprecation notice and still works > modulo a broken preprocessor macro in fs/exec.c. > > For the curious, or if anyone wants proof I'm not making this up and > really do spend time on these things, my amalgamation of Jaguar tools & > docs, including copies of the old mac and aln a.out binaries, is > available here: > > https://github.com/cubanismo/jaguar-sdk
Apologies, fixing x86 maintainer alias address.
> Thanks, > -James > >> Signed-off-by: Borislav Petkov <bp@suse.de> >> --- >> arch/x86/Kconfig | 7 - >> arch/x86/ia32/Makefile | 2 - >> arch/x86/ia32/ia32_aout.c | 325 -------------------------------------- >> 3 files changed, 334 deletions(-) >> delete mode 100644 arch/x86/ia32/ia32_aout.c >> >> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig >> index 976dd6b532bf..6f3d63dbbddf 100644 >> --- a/arch/x86/Kconfig >> +++ b/arch/x86/Kconfig >> @@ -2835,13 +2835,6 @@ config IA32_EMULATION >> 64-bit kernel. You should likely turn this on, unless you're >> 100% sure that you don't have any 32-bit programs left. >> >> -config IA32_AOUT >> - tristate "IA32 a.out support" >> - depends on IA32_EMULATION >> - depends on BROKEN >> - help >> - Support old a.out binaries in the 32bit emulation. >> - >> config X86_X32 >> bool "x32 ABI for 64-bit mode" >> depends on X86_64 >> diff --git a/arch/x86/ia32/Makefile b/arch/x86/ia32/Makefile >> index 8e4d0391ff6c..e481056698de 100644 >> --- a/arch/x86/ia32/Makefile >> +++ b/arch/x86/ia32/Makefile >> @@ -5,7 +5,5 @@ >> >> obj-$(CONFIG_IA32_EMULATION) := ia32_signal.o >> >> -obj-$(CONFIG_IA32_AOUT) += ia32_aout.o >> - >> audit-class-$(CONFIG_AUDIT) := audit.o >> obj-$(CONFIG_IA32_EMULATION) += $(audit-class-y) >> diff --git a/arch/x86/ia32/ia32_aout.c b/arch/x86/ia32/ia32_aout.c >> deleted file mode 100644 >> index 9bd15241fadb..000000000000 >> --- a/arch/x86/ia32/ia32_aout.c >> +++ /dev/null >> @@ -1,325 +0,0 @@ >> -// SPDX-License-Identifier: GPL-2.0-only >> -/* >> - * a.out loader for x86-64 >> - * >> - * Copyright (C) 1991, 1992, 1996 Linus Torvalds >> - * Hacked together by Andi Kleen >> - */ >> - >> -#include <linux/module.h> >> - >> -#include <linux/time.h> >> -#include <linux/kernel.h> >> -#include <linux/mm.h> >> -#include <linux/mman.h> >> -#include <linux/a.out.h> >> -#include <linux/errno.h> >> -#include <linux/signal.h> >> -#include <linux/string.h> >> -#include <linux/fs.h> >> -#include <linux/file.h> >> -#include <linux/stat.h> >> -#include <linux/fcntl.h> >> -#include <linux/ptrace.h> >> -#include <linux/user.h> >> -#include <linux/binfmts.h> >> -#include <linux/personality.h> >> -#include <linux/init.h> >> -#include <linux/jiffies.h> >> -#include <linux/perf_event.h> >> -#include <linux/sched/task_stack.h> >> - >> -#include <linux/uaccess.h> >> -#include <asm/cacheflush.h> >> -#include <asm/user32.h> >> -#include <asm/ia32.h> >> - >> -#undef WARN_OLD >> - >> -static int load_aout_binary(struct linux_binprm *); >> -static int load_aout_library(struct file *); >> - >> -static struct linux_binfmt aout_format = { >> - .module = THIS_MODULE, >> - .load_binary = load_aout_binary, >> - .load_shlib = load_aout_library, >> -}; >> - >> -static int set_brk(unsigned long start, unsigned long end) >> -{ >> - start = PAGE_ALIGN(start); >> - end = PAGE_ALIGN(end); >> - if (end <= start) >> - return 0; >> - return vm_brk(start, end - start); >> -} >> - >> - >> -/* >> - * 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 u32 __user *create_aout_tables(char __user *p, struct linux_binprm *bprm) >> -{ >> - u32 __user *argv, *envp, *sp; >> - int argc = bprm->argc, envc = bprm->envc; >> - >> - sp = (u32 __user *) ((-(unsigned long)sizeof(u32)) & (unsigned long) p); >> - sp -= envc+1; >> - envp = sp; >> - sp -= argc+1; >> - argv = sp; >> - put_user((unsigned long) envp, --sp); >> - put_user((unsigned long) argv, --sp); >> - put_user(argc, --sp); >> - current->mm->arg_start = (unsigned long) p; >> - while (argc-- > 0) { >> - char c; >> - >> - put_user((u32)(unsigned long)p, argv++); >> - do { >> - get_user(c, p++); >> - } while (c); >> - } >> - put_user(0, argv); >> - current->mm->arg_end = current->mm->env_start = (unsigned long) p; >> - while (envc-- > 0) { >> - char c; >> - >> - put_user((u32)(unsigned long)p, envp++); >> - do { >> - get_user(c, p++); >> - } while (c); >> - } >> - put_user(0, 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) >> -{ >> - unsigned long error, fd_offset, rlim; >> - struct pt_regs *regs = current_pt_regs(); >> - struct exec ex; >> - 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(file_inode(bprm->file)) < >> - ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) { >> - 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 = rlimit(RLIMIT_DATA); >> - 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 = begin_new_exec(bprm); >> - if (retval) >> - return retval; >> - >> - /* OK, This is the point of no return */ >> - set_personality(PER_LINUX); >> - set_personality_ia32(false); >> - >> - setup_new_exec(bprm); >> - >> - regs->cs = __USER32_CS; >> - regs->r8 = regs->r9 = regs->r10 = regs->r11 = regs->r12 = >> - regs->r13 = regs->r14 = regs->r15 = 0; >> - >> - 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)); >> - >> - retval = setup_arg_pages(bprm, IA32_STACK_TOP, EXSTACK_DEFAULT); >> - if (retval < 0) >> - return retval; >> - >> - if (N_MAGIC(ex) == OMAGIC) { >> - unsigned long text_addr, map_size; >> - >> - text_addr = N_TXTADDR(ex); >> - map_size = ex.a_text+ex.a_data; >> - >> - error = vm_brk(text_addr & PAGE_MASK, map_size); >> - >> - if (error) >> - return error; >> - >> - error = read_code(bprm->file, text_addr, 32, >> - ex.a_text + ex.a_data); >> - if ((signed long)error < 0) >> - return error; >> - } else { >> -#ifdef WARN_OLD >> - static unsigned long error_time, error_time2; >> - if ((ex.a_text & 0xfff || ex.a_data & 0xfff) && >> - (N_MAGIC(ex) != NMAGIC) && >> - time_after(jiffies, error_time2 + 5*HZ)) { >> - printk(KERN_NOTICE "executable not page aligned\n"); >> - error_time2 = jiffies; >> - } >> - >> - if ((fd_offset & ~PAGE_MASK) != 0 && >> - time_after(jiffies, error_time + 5*HZ)) { >> - printk(KERN_WARNING >> - "fd_offset is not page aligned. Please convert " >> - "program: %pD\n", >> - bprm->file); >> - error_time = jiffies; >> - } >> -#endif >> - >> - if (!bprm->file->f_op->mmap || (fd_offset & ~PAGE_MASK) != 0) { >> - error = vm_brk(N_TXTADDR(ex), ex.a_text+ex.a_data); >> - if (error) >> - return error; >> - >> - read_code(bprm->file, N_TXTADDR(ex), fd_offset, >> - ex.a_text+ex.a_data); >> - goto beyond_if; >> - } >> - >> - error = vm_mmap(bprm->file, N_TXTADDR(ex), ex.a_text, >> - PROT_READ | PROT_EXEC, >> - MAP_FIXED | MAP_PRIVATE | MAP_32BIT, >> - fd_offset); >> - >> - if (error != N_TXTADDR(ex)) >> - return error; >> - >> - error = vm_mmap(bprm->file, N_DATADDR(ex), ex.a_data, >> - PROT_READ | PROT_WRITE | PROT_EXEC, >> - MAP_FIXED | MAP_PRIVATE | MAP_32BIT, >> - fd_offset + ex.a_text); >> - if (error != N_DATADDR(ex)) >> - return error; >> - } >> - >> -beyond_if: >> - error = set_brk(current->mm->start_brk, current->mm->brk); >> - if (error) >> - return error; >> - >> - set_binfmt(&aout_format); >> - >> - current->mm->start_stack = >> - (unsigned long)create_aout_tables((char __user *)bprm->p, bprm); >> - /* start thread */ >> - loadsegment(fs, 0); >> - loadsegment(ds, __USER32_DS); >> - loadsegment(es, __USER32_DS); >> - load_gs_index(0); >> - (regs)->ip = ex.a_entry; >> - (regs)->sp = current->mm->start_stack; >> - (regs)->flags = 0x200; >> - (regs)->cs = __USER32_CS; >> - (regs)->ss = __USER32_DS; >> - regs->r8 = regs->r9 = regs->r10 = regs->r11 = >> - regs->r12 = regs->r13 = regs->r14 = regs->r15 = 0; >> - return 0; >> -} >> - >> -static int load_aout_library(struct file *file) >> -{ >> - unsigned long bss, start_addr, len, error; >> - int retval; >> - struct exec ex; >> - loff_t pos = 0; >> - >> - retval = -ENOEXEC; >> - error = kernel_read(file, &ex, sizeof(ex), &pos); >> - 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(file_inode(file)) < >> - ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) { >> - 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) { >> -#ifdef WARN_OLD >> - static unsigned long error_time; >> - if (time_after(jiffies, error_time + 5*HZ)) { >> - printk(KERN_WARNING >> - "N_TXTOFF is not page aligned. Please convert " >> - "library: %pD\n", >> - file); >> - error_time = jiffies; >> - } >> -#endif >> - retval = vm_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss); >> - if (retval) >> - goto out; >> - >> - read_code(file, start_addr, N_TXTOFF(ex), >> - ex.a_text + ex.a_data); >> - retval = 0; >> - goto out; >> - } >> - /* Now use mmap to map the library into memory. */ >> - error = vm_mmap(file, start_addr, ex.a_text + ex.a_data, >> - PROT_READ | PROT_WRITE | PROT_EXEC, >> - MAP_FIXED | MAP_PRIVATE | MAP_32BIT, >> - N_TXTOFF(ex)); >> - 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) { >> - retval = vm_brk(start_addr + len, bss - len); >> - if (retval) >> - goto out; >> - } >> - retval = 0; >> -out: >> - return retval; >> -} >> - >> -static int __init init_aout_binfmt(void) >> -{ >> - register_binfmt(&aout_format); >> - return 0; >> -} >> - >> -static void __exit exit_aout_binfmt(void) >> -{ >> - unregister_binfmt(&aout_format); >> -} >> - >> -module_init(init_aout_binfmt); >> -module_exit(exit_aout_binfmt); >> -MODULE_LICENSE("GPL"); >> -- >> 2.29.2 >
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