[PATCH] x86: Remove a.out support

[PATCH] x86: Remove a.out support

[Borislav Petkov]

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.

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

Re: [PATCH] x86: Remove a.out support

[Kees Cook]

On Thu, Jan 13, 2022 at 05:01:15PM +0100, Borislav Petkov 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.
> 
> Signed-off-by: Borislav Petkov <bp@suse.de>

Yes please. :)

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook

Re: [PATCH] x86: Remove a.out support

[Theodore Ts'o]

On Thu, Jan 13, 2022 at 05:01:15PM +0100, Borislav Petkov 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.
> 
> Signed-off-by: Borislav Petkov <bp@suse.de>

Let's pour one out for being able to run Minix binaries on Linux.  :-)

Speaking of which, if we're doing this, are there some old system
calls that we could remove at the same time?

      	       	       	     	  - Ted

Re: [PATCH] x86: Remove a.out support

[Borislav Petkov]

On Thu, Jan 13, 2022 at 01:47:34PM -0500, Theodore Ts'o wrote:
> Let's pour one out for being able to run Minix binaries on Linux.  :-)

https://en.wikipedia.org/wiki/Minix_3:

"2013-02-21 ... Dropped support for a.out binaries"

They themselves killed that support a lot earlier. :-)

> Speaking of which, if we're doing this, are there some old system
> calls that we could remove at the same time?

Good question.

Unfortunately, I'm just the janitor removing this and a.out is waaay
before my time. :-)

But I'm open to suggestions on how to determine which are those obsolete
syscalls.

Btw, pls do note that this is removing only the x86 a.out support -
other arches (m68k and alpha) still select HAVE_AOUT and thus the
respective glue in fs/binfmt_aout.c

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

Re: [PATCH] x86: Remove a.out support

[Theodore Ts'o]

On Thu, Jan 13, 2022 at 11:56:53PM +0100, Borislav Petkov wrote:
> On Thu, Jan 13, 2022 at 01:47:34PM -0500, Theodore Ts'o wrote:
> > Let's pour one out for being able to run Minix binaries on Linux.  :-)
> 
> https://en.wikipedia.org/wiki/Minix_3:
> 
> "2013-02-21 ... Dropped support for a.out binaries"
> 
> They themselves killed that support a lot earlier. :-)

Well, Minix 3 is a very different beast than the Minix 1.x that Linus
used when he was boot-strapping Linux back in 1991.  :-)

Among other things Minux 1.x is system call compatible with the
original V7 Unix from AT&T, whereas Minux 2.x and higher switch to
having system calls that were Posix comaptible --- and Minix 2, being
at teaching OS, wouldn't have kept any backwards compatibility when
Prof. Tannenbaum released the 2nd edition of his Operating Systems
Design and Implementation book in 1997.

> > Speaking of which, if we're doing this, are there some old system
> > calls that we could remove at the same time?
> 
> Good question.
> 
> Unfortunately, I'm just the janitor removing this and a.out is waaay
> before my time. :-)
> 
> But I'm open to suggestions on how to determine which are those obsolete
> syscalls.

Historically there were a couple of different C libraries
which x86 binaries for Linux could use:

A) minix's libc -- used by binaries compiled using the Minix 1 toolchain
B) Libc 4 -- a fork of GNU Libc version 1, for a.out execuables
C) Libc 5 -- a fork of GNU Libc version 1, for ELF execuables
D) Libc 6 -- GNU Libc version 2, for ELF executables

So I think what this would boil down to is finding those system calls
that were used by (A) and (B), but not referenced in (C) and (D).  I
guess we'd also have to check to make sure that some of these ancient
system calls might still be used by some of the micro libc's, such as
dietlibc, musl, etc.

Is it worth doing?  Perhaps; perhaps not.  It probably wouldn't reduce
the size of the kernel by all *that* much, but getting rid of cruft is
kind of a good thing for its own sake.

Cheers.

						- Ted

RE: [PATCH] x86: Remove a.out support

[David Laight]

From: Borislav Petkov
> Sent: 13 January 2022 22:57
...
> 
> Btw, pls do note that this is removing only the x86 a.out support -
> other arches (m68k and alpha) still select HAVE_AOUT and thus the
> respective glue in fs/binfmt_aout.c

I didn't think alpha was that old :-)
m68k is another matter.
But I've probably dismembered the only old m68k system disk I've had
to extract the magnets.

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)

Re: [PATCH] x86: Remove a.out support

[Arnd Bergmann]

On Fri, Jan 14, 2022 at 5:06 AM Theodore Ts'o <tytso@mit.edu> wrote:
> On Thu, Jan 13, 2022 at 11:56:53PM +0100, Borislav Petkov wrote:
> >
> > But I'm open to suggestions on how to determine which are those obsolete
> > syscalls.
>
> Historically there were a couple of different C libraries
> which x86 binaries for Linux could use:
>
> A) minix's libc -- used by binaries compiled using the Minix 1 toolchain
> B) Libc 4 -- a fork of GNU Libc version 1, for a.out execuables
> C) Libc 5 -- a fork of GNU Libc version 1, for ELF execuables
> D) Libc 6 -- GNU Libc version 2, for ELF executables
>
> So I think what this would boil down to is finding those system calls
> that were used by (A) and (B), but not referenced in (C) and (D).  I
> guess we'd also have to check to make sure that some of these ancient
> system calls might still be used by some of the micro libc's, such as
> dietlibc, musl, etc.
>
> Is it worth doing?  Perhaps; perhaps not.  It probably wouldn't reduce
> the size of the kernel by all *that* much, but getting rid of cruft is
> kind of a good thing for its own sake.

For reference, these are the system calls that are implemented on i386
as of 5.16 but have been replaced on modern architectures, from
ooking only in the linux sources:

2 i386 fork sys_fork
5 i386 open sys_open compat_sys_open
7 i386 waitpid sys_waitpid
8 i386 creat sys_creat
9 i386 link sys_link
10 i386 unlink sys_unlink
13 i386 time sys_time32
14 i386 mknod sys_mknod
15 i386 chmod sys_chmod
16 i386 lchown sys_lchown16
16 i386 lchown sys_lchown16
18 i386 oldstat sys_stat
22 i386 umount sys_oldumount
23 i386 setuid sys_setuid16
24 i386 getuid sys_getuid16
25 i386 stime sys_stime32
27 i386 alarm sys_alarm
28 i386 oldfstat sys_fstat
29 i386 pause sys_pause
30 i386 utime sys_utime32
33 i386 access sys_access
34 i386 nice sys_nice
38 i386 rename sys_rename
39 i386 mkdir sys_mkdir
40 i386 rmdir sys_rmdir
42 i386 pipe sys_pipe
46 i386 setgid sys_setgid16
47 i386 getgid sys_getgid16
48 i386 signal sys_signal
49 i386 geteuid sys_geteuid16
50 i386 getegid sys_getegid16
59 i386 oldolduname sys_olduname
62 i386 ustat sys_ustat compat_sys_ustat
63 i386 dup2 sys_dup2
65 i386 getpgrp sys_getpgrp
67 i386 sigaction sys_sigaction compat_sys_sigaction
68 i386 sgetmask sys_sgetmask
69 i386 ssetmask sys_ssetmask
70 i386 setreuid sys_setreuid16
71 i386 setregid sys_setregid16
72 i386 sigsuspend sys_sigsuspend
73 i386 sigpending sys_sigpending compat_sys_sigpending
80 i386 getgroups sys_getgroups16
81 i386 setgroups sys_setgroups16
82 i386 select sys_old_select compat_sys_old_select
83 i386 symlink sys_symlink
84 i386 oldlstat sys_lstat
85 i386 readlink sys_readlink
86 i386 uselib sys_uselib
89 i386 readdir sys_old_readdir compat_sys_old_readdir
95 i386 fchown sys_fchown16
101 i386 ioperm sys_ioperm
102 i386 socketcall sys_socketcall compat_sys_socketcall
109 i386 olduname sys_uname
110 i386 iopl sys_iopl
117 i386 ipc sys_ipc compat_sys_ipc
119 i386 sigreturn sys_sigreturn compat_sys_sigreturn
123 i386 modify_ldt sys_modify_ldt
126 i386 sigprocmask sys_sigprocmask compat_sys_sigprocmask
135 i386 sysfs sys_sysfs
138 i386 setfsuid sys_setfsuid16
139 i386 setfsgid sys_setfsgid16
141 i386 getdents sys_getdents compat_sys_getdents
142 i386 _newselect sys_select compat_sys_select
164 i386 setresuid sys_setresuid16
165 i386 getresuid sys_getresuid16
168 i386 poll sys_poll
170 i386 setresgid sys_setresgid16
171 i386 getresgid sys_getresgid
182 i386 chown sys_chown16
190 i386 vfork sys_vfork
243 i386 set_thread_area sys_set_thread_area
244 i386 get_thread_area sys_get_thread_area
254 i386 epoll_create sys_epoll_create
256 i386 epoll_wait sys_epoll_wait
271 i386 utimes sys_utimes_time32
291 i386 inotify_init sys_inotify_init
299 i386 futimesat sys_futimesat_time32
321 i386 signalfd sys_signalfd compat_sys_signalfd
323 i386 eventfd sys_eventfd
384 i386 arch_prctl sys_arch_prctl compat_sys_arch_prctl

Looking at libc-4.7.2 from Slackware-3.0, the highest syscall number
used there is 182 (chown16), anything later is presumably added
after the ELF transition was done. All of the syscalls referenced in
libc-4.7 are still referenced in libc-5.0, so nothing is obviously changed
between those.

Excluding the syscalls that are referenced in libc5 brings the
candidates down to

7       i386    waitpid                 sys_waitpid
16      i386    lchown                  sys_lchown16
18      i386    oldstat                 sys_stat
28      i386    oldfstat                sys_fstat
48      i386    signal                  sys_signal
59      i386    oldolduname             sys_olduname
68      i386    sgetmask                sys_sgetmask
69      i386    ssetmask                sys_ssetmask
84      i386    oldlstat                sys_lstat
109     i386    olduname                sys_uname
119     i386    sigreturn               sys_sigreturn
123     i386    modify_ldt              sys_modify_ldt
135     i386    sysfs                   sys_sysfs
141     i386    getdents                sys_getdents
142     i386    _newselect              sys_select
164     i386    setresuid               sys_setresuid16
165     i386    getresuid               sys_getresuid16
168     i386    poll                    sys_poll
170     i386    setresgid               sys_setresgid16
171     i386    getresgid               sys_getresgid16

This is probably a mix of some things that are too old
for libc5, some that are too new, and some that were never
part of libc but are called from other places.

Some may be misrepresented here because the macros got
renamed: libc5 calls 'uname' but expects it to be what the
kernel now calls '__NR_olduname'. I could not find out
which of the 'stat' family it expects because the headers
are incomplete in the slackware source package.

       Arnd

Re: [PATCH] x86: Remove a.out support

[Geert Uytterhoeven]

Hi Boris,

On Fri, Jan 14, 2022 at 3:36 PM Borislav Petkov <bp@alien8.de> wrote:
> Btw, pls do note that this is removing only the x86 a.out support -
> other arches (m68k and alpha) still select HAVE_AOUT and thus the
> respective glue in fs/binfmt_aout.c

Quoting myself (do I need a canned response for this? ;-):
   "I think it's safe to assume no one still runs a.out binaries on m68k."

https://lore.kernel.org/r/CAMuHMdVGT1QN8WUqNcU8ihPLncUGfrjV49wb-8nHUgHhOzLeNw@mail.gmail.com/
https://lore.kernel.org/r/CAMuHMdW+m0Q+j3rsQdMXnrEPm+XB5Y2AQrxW5sD1mZAKgmEqoA@mail.gmail.com

Of course, m68k is not encumbered by a.out Netscape binaries, unlike
ia32 and alpha ;-)

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH] x86: Remove a.out support

[Theodore Ts'o]

On Fri, Jan 14, 2022 at 03:52:29PM +0100, Geert Uytterhoeven wrote:
> Hi Boris,
> 
> On Fri, Jan 14, 2022 at 3:36 PM Borislav Petkov <bp@alien8.de> wrote:
> > Btw, pls do note that this is removing only the x86 a.out support -
> > other arches (m68k and alpha) still select HAVE_AOUT and thus the
> > respective glue in fs/binfmt_aout.c
> 
> Quoting myself (do I need a canned response for this? ;-):
>    "I think it's safe to assume no one still runs a.out binaries on m68k."
> 
> https://lore.kernel.org/r/CAMuHMdVGT1QN8WUqNcU8ihPLncUGfrjV49wb-8nHUgHhOzLeNw@mail.gmail.com/
> https://lore.kernel.org/r/CAMuHMdW+m0Q+j3rsQdMXnrEPm+XB5Y2AQrxW5sD1mZAKgmEqoA@mail.gmail.com
> 
> Of course, m68k is not encumbered by a.out Netscape binaries, unlike
> ia32 and alpha ;-)

And Alpha's a.out Netscape binary is what required OSF/1 compatible
system calls, so if and when we ever can nuke a.out Alpha support, so
perhaps there might also be an opporunity to remove OSF/1
compatibility support...

						- Ted

Re: [PATCH] x86: Remove a.out support

[Geert Uytterhoeven]

Hi Ted,

On Fri, Jan 14, 2022 at 7:58 PM Theodore Ts'o <tytso@mit.edu> wrote:
> On Fri, Jan 14, 2022 at 03:52:29PM +0100, Geert Uytterhoeven wrote:
> > On Fri, Jan 14, 2022 at 3:36 PM Borislav Petkov <bp@alien8.de> wrote:
> > > Btw, pls do note that this is removing only the x86 a.out support -
> > > other arches (m68k and alpha) still select HAVE_AOUT and thus the
> > > respective glue in fs/binfmt_aout.c
> >
> > Quoting myself (do I need a canned response for this? ;-):
> >    "I think it's safe to assume no one still runs a.out binaries on m68k."
> >
> > https://lore.kernel.org/r/CAMuHMdVGT1QN8WUqNcU8ihPLncUGfrjV49wb-8nHUgHhOzLeNw@mail.gmail.com/
> > https://lore.kernel.org/r/CAMuHMdW+m0Q+j3rsQdMXnrEPm+XB5Y2AQrxW5sD1mZAKgmEqoA@mail.gmail.com
> >
> > Of course, m68k is not encumbered by a.out Netscape binaries, unlike
> > ia32 and alpha ;-)
>
> And Alpha's a.out Netscape binary is what required OSF/1 compatible
> system calls, so if and when we ever can nuke a.out Alpha support, so
> perhaps there might also be an opporunity to remove OSF/1
> compatibility support...

As we seem to be reiterating a discussion from 2019, let's read last
time's summary first:
https://www.linuxjournal.com/content/deprecating-aout-binaries

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH] x86: Remove a.out support

[Borislav Petkov]

Just to answer the "do we still wanna support running original a.out
binaries" aspect...

On Thu, Jan 13, 2022 at 11:06:03PM -0500, Theodore Ts'o wrote:
> > > Let's pour one out for being able to run Minix binaries on Linux.  :-)
> > 
> > https://en.wikipedia.org/wiki/Minix_3:
> > 
> > "2013-02-21 ... Dropped support for a.out binaries"
> > 
> > They themselves killed that support a lot earlier. :-)
> 
> Well, Minix 3 is a very different beast than the Minix 1.x

Right, but if the Minix 1.x successor has deemed a.out support obsolete
and has removed in 2013 I figure we can too. :-)

And, btw, Alan had a good, practical idea at the time we talked about
deprecating a.out support:

https://lore.kernel.org/all/20190305134347.4be2449c@alans-desktop/

And that is probably the best thing to do: if people wanna run old a.out
binaries, they can either write an a.out loader as an ELF program or
slap an old linux distro in a VM and do that there just fine.

If you look at the original thread which started this:

https://lore.kernel.org/all/CAG48ez1RVd5mQ_Pb6eygQESaZhpQz765OAZYSoPE0kPqfZEXQg@mail.gmail.com/

it looked even back then like a.out support is so rusty, bitrotten and
broken that we're probably even doing ourselves a favor to remove it.

Especially if not even the toolchains would even create an a.out
executable and no one even noticed.

So...

> that Linus used when he was boot-strapping Linux back in 1991. :-)
>
> Among other things Minux 1.x is system call compatible with the
> original V7 Unix from AT&T, whereas Minux 2.x and higher switch to
> having system calls that were Posix comaptible --- and Minix 2, being
> at teaching OS, wouldn't have kept any backwards compatibility when
> Prof. Tannenbaum released the 2nd edition of his Operating Systems
> Design and Implementation book in 1997.

I had a lot of fun reading that book. :-)

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

Re: [PATCH] x86: Remove a.out support

[Borislav Petkov]

On Fri, Jan 14, 2022 at 03:52:29PM +0100, Geert Uytterhoeven wrote:
> Quoting myself (do I need a canned response for this? ;-):
>    "I think it's safe to assume no one still runs a.out binaries on m68k."

I remember now that I've looked at the thread from back then but what
are you trying to say with your quote?

Do you wanna see another patch which rips out a.out support from m68k?

I could do one ontop but besides build-testing I can't test any other
way on m68k...

:-)

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

Re: [PATCH] x86: Remove a.out support

[Geert Uytterhoeven]

Hi Boris,

On Fri, Jan 14, 2022 at 8:12 PM Borislav Petkov <bp@alien8.de> wrote:
> On Fri, Jan 14, 2022 at 03:52:29PM +0100, Geert Uytterhoeven wrote:
> > Quoting myself (do I need a canned response for this? ;-):
> >    "I think it's safe to assume no one still runs a.out binaries on m68k."
>
> I remember now that I've looked at the thread from back then but what
> are you trying to say with your quote?
>
> Do you wanna see another patch which rips out a.out support from m68k?
>
> I could do one ontop but besides build-testing I can't test any other
> way on m68k...
>
> :-)

I mean that I can rip it out on m68k.

Who's gonna take care of alpha?

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH] x86: Remove a.out support

[Borislav Petkov]

On Fri, Jan 14, 2022 at 08:21:36PM +0100, Geert Uytterhoeven wrote:
> I mean that I can rip it out on m68k.
> 
> Who's gonna take care of alpha?

I'm sceptical anyone would:

$ ./scripts/get_maintainer.pl -f arch/alpha/
Richard Henderson <rth@twiddle.net> (odd fixer:ALPHA PORT)
Ivan Kokshaysky <ink@jurassic.park.msu.ru> (odd fixer:ALPHA PORT)

which leaves me. I could give it a try.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

RE: [PATCH] x86: Remove a.out support

[David Laight]

From: Geert Uytterhoeven
> Sent: 14 January 2022 19:22
...
> Who's gonna take care of alpha?

Would anyone notice if the knife slipped?

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)

Re: [PATCH] x86: Remove a.out support

[Borislav Petkov]

On Fri, Jan 14, 2022 at 08:35:53PM +0100, Borislav Petkov wrote:
> On Fri, Jan 14, 2022 at 08:21:36PM +0100, Geert Uytterhoeven wrote:
> > I mean that I can rip it out on m68k.
> > 
> > Who's gonna take care of alpha?
> 
> I'm sceptical anyone would:
> 
> $ ./scripts/get_maintainer.pl -f arch/alpha/
> Richard Henderson <rth@twiddle.net> (odd fixer:ALPHA PORT)
> Ivan Kokshaysky <ink@jurassic.park.msu.ru> (odd fixer:ALPHA PORT)
> 
> which leaves me. I could give it a try.

Well, on that old thread from 2019 people expressed the wish to be able
to run a.out binaries on Alpha. Let's see whether that has changed in
the meantime.

/me CCs them.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

Re: [PATCH] x86: Remove a.out support

[John Paul Adrian Glaubitz]

Hi Borislav!

On 1/15/22 12:37, Borislav Petkov wrote:
> On Fri, Jan 14, 2022 at 08:35:53PM +0100, Borislav Petkov wrote:
>> On Fri, Jan 14, 2022 at 08:21:36PM +0100, Geert Uytterhoeven wrote:
>>> I mean that I can rip it out on m68k.
>>>
>>> Who's gonna take care of alpha?
>>
>> I'm sceptical anyone would:
>>
>> $ ./scripts/get_maintainer.pl -f arch/alpha/
>> Richard Henderson <rth@twiddle.net> (odd fixer:ALPHA PORT)
>> Ivan Kokshaysky <ink@jurassic.park.msu.ru> (odd fixer:ALPHA PORT)
>>
>> which leaves me. I could give it a try.
> 
> Well, on that old thread from 2019 people expressed the wish to be able
> to run a.out binaries on Alpha. Let's see whether that has changed in
> the meantime.

Checking on the message I sent three years ago, it didn't seem that I was opposed
to removing a.out support, but that I would be happy to help test the patches.

I don't have any particular use case for a.out support either.

Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer - glaubitz@debian.org
`. `'   Freie Universitaet Berlin - glaubitz@physik.fu-berlin.de
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913

[PATCH] a.out: Stop building a.out/osf1 support on alpha and m68k

[Eric W. Biederman]

There has been repeated discussion on removing a.out support, the most
recent was[1].  Having read through a bunch of the discussion it looks
like no one has see any reason why we need to keep a.out support.

The m68k maintainer has even come out in favor of removing a.out
support[2].

At a practical level with only two rarely used architectures building
a.out support, it gets increasingly hard to test and to care about.
Which means the code will almost certainly bit-rot.

Let's see if anyone cares about a.out support on the last two
architectures that build it, by disabling the build of the support in
Kconfig.  If anyone cares, this can be easily reverted, and we can then
have a discussion about what it is going to take to support a.out
binaries in the long term.

Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: linux-alpha@vger.kernel.org
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: linux-m68k@lists.linux-m68k.org
[1] https://lkml.kernel.org/r/20220113160115.5375-1-bp@alien8.de
[2] https://lkml.kernel.org/r/CAMuHMdUbTNNr16YY1TFe=-uRLjg6yGzgw_RqtAFpyhnOMM5Pvw@mail.gmail.com
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---

Kees do you think you could add this to your execve branch?

I think this should be a complimentary patch to Borislav Petkov's patch
at the top of this tread to remove a.out support on x86.

 arch/alpha/Kconfig | 1 -
 arch/m68k/Kconfig  | 1 -
 2 files changed, 2 deletions(-)

diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig
index 4e87783c90ad..14c97acea351 100644
--- a/arch/alpha/Kconfig
+++ b/arch/alpha/Kconfig
@@ -12,7 +12,6 @@ config ALPHA
 	select FORCE_PCI if !ALPHA_JENSEN
 	select PCI_DOMAINS if PCI
 	select PCI_SYSCALL if PCI
-	select HAVE_AOUT
 	select HAVE_ASM_MODVERSIONS
 	select HAVE_PCSPKR_PLATFORM
 	select HAVE_PERF_EVENTS
diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig
index 936e1803c7c7..268b3860d40d 100644
--- a/arch/m68k/Kconfig
+++ b/arch/m68k/Kconfig
@@ -17,7 +17,6 @@ config M68K
 	select GENERIC_CPU_DEVICES
 	select GENERIC_IOMAP
 	select GENERIC_IRQ_SHOW
-	select HAVE_AOUT if MMU
 	select HAVE_ASM_MODVERSIONS
 	select HAVE_DEBUG_BUGVERBOSE
 	select HAVE_EFFICIENT_UNALIGNED_ACCESS if !CPU_HAS_NO_UNALIGNED
-- 
2.29.2

Re: [PATCH] a.out: Stop building a.out/osf1 support on alpha and m68k

[Linus Torvalds]

On Wed, Mar 9, 2022 at 12:04 PM Eric W. Biederman <ebiederm@xmission.com> wrote:
>
> Let's see if anyone cares about a.out support on the last two
> architectures that build it, by disabling the build of the support in
> Kconfig.

Oh, I'm pretty sure we can't do this.

a.out on alpha is afaik still very much alive - well, as alive as
anything alpha is - although it's called "ECOFF".

It's the native Tru64 (aka "DEC OSF/1", aka "Digital UNIX") format, so
it's more than some old legacy Linux thing.

We still call it "a.out", but the history is that a.out with some
extensions became COFF, which then became ECOFF, so our a.out code
really covers the whole gamut.

Yeah, we don't actually parse any of the extensions that make COFF
what it is, or ECOFF what _it_ is, but the a.out loader ends up
working "well enough" for simple binaries by using ugly code like

  #define N_TXTOFF(x) \
    ((long) N_MAGIC(x) == ZMAGIC ? 0 : \
     (sizeof(struct exec) + (x).fh.f_nscns*SCNHSZ + SCNROUND - 1) &
~(SCNROUND - 1))

which jumps over all the section headers.

But sure, it would be interesting to know if any alpha people care - I
just have this suspicion that we can't drop it that easily because of
the non-Linux legacy.

                   Linus

Re: [PATCH] a.out: Stop building a.out/osf1 support on alpha and m68k

[Kees Cook]

On Wed, Mar 09, 2022 at 12:37:54PM -0800, Linus Torvalds wrote:
> On Wed, Mar 9, 2022 at 12:04 PM Eric W. Biederman <ebiederm@xmission.com> wrote:
> >
> > Let's see if anyone cares about a.out support on the last two
> > architectures that build it, by disabling the build of the support in
> > Kconfig.
> [...]
> But sure, it would be interesting to know if any alpha people care - I
> just have this suspicion that we can't drop it that easily because of
> the non-Linux legacy.

It looks like the only distro supporting Alpha is Gentoo. I pulled
down the installation media, and everything is ELF except for firmware
COFF files:

$ find . -type f | xargs file | grep -Ei ':.*(out|coff)'
./lib/firmware/meson/vdec/g12a_hevc_mmu.bin: MIPSEB MIPS-III ECOFF executable not stripped - version 0.0
./lib/firmware/meson/vdec/g12a_vp9.bin: MIPSEB MIPS-III ECOFF executable not stripped - version 0.0
./lib/firmware/meson/vdec/gxl_hevc_mmu.bin: MIPSEB MIPS-III ECOFF executable not stripped - version 0.0
./lib/firmware/meson/vdec/gxl_vp9.bin: MIPSEB MIPS-III ECOFF executable not stripped - version 0.0
./lib/firmware/meson/vdec/sm1_hevc_mmu.bin: MIPSEB MIPS-III ECOFF executable not stripped - version 0.0
./lib/firmware/meson/vdec/sm1_vp9_mmu.bin: MIPSEB MIPS-III ECOFF executable not stripped - version 0.0
./lib/firmware/qca/crbtfw32.tlv: mc68k COFF object not stripped

So, since it's an easy revert, sure. Let's do it.

-- 
Kees Cook

Re: [PATCH] a.out: Stop building a.out/osf1 support on alpha and m68k

[Kees Cook]

On Wed, 09 Mar 2022 14:03:42 -0600, Eric W. Biederman wrote:
> There has been repeated discussion on removing a.out support, the most
> recent was[1].  Having read through a bunch of the discussion it looks
> like no one has see any reason why we need to keep a.out support.
> 
> The m68k maintainer has even come out in favor of removing a.out
> support[2].
> 
> [...]

Applied to for-next/execve, thanks!

[1/1] a.out: Stop building a.out/osf1 support on alpha and m68k
      https://git.kernel.org/kees/c/f451569b9da8

-- 
Kees Cook

Re: [PATCH] a.out: Stop building a.out/osf1 support on alpha and m68k

[Geert Uytterhoeven]

On Wed, Mar 9, 2022 at 9:04 PM Eric W. Biederman <ebiederm@xmission.com> wrote:
> There has been repeated discussion on removing a.out support, the most
> recent was[1].  Having read through a bunch of the discussion it looks
> like no one has see any reason why we need to keep a.out support.
>
> The m68k maintainer has even come out in favor of removing a.out
> support[2].
>
> At a practical level with only two rarely used architectures building
> a.out support, it gets increasingly hard to test and to care about.
> Which means the code will almost certainly bit-rot.
>
> Let's see if anyone cares about a.out support on the last two
> architectures that build it, by disabling the build of the support in
> Kconfig.  If anyone cares, this can be easily reverted, and we can then
> have a discussion about what it is going to take to support a.out
> binaries in the long term.
>
> Cc: Richard Henderson <rth@twiddle.net>
> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
> Cc: Matt Turner <mattst88@gmail.com>
> Cc: linux-alpha@vger.kernel.org
> Cc: Geert Uytterhoeven <geert@linux-m68k.org>
> Cc: linux-m68k@lists.linux-m68k.org
> [1] https://lkml.kernel.org/r/20220113160115.5375-1-bp@alien8.de
> [2] https://lkml.kernel.org/r/CAMuHMdUbTNNr16YY1TFe=-uRLjg6yGzgw_RqtAFpyhnOMM5Pvw@mail.gmail.com
> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

>  arch/m68k/Kconfig  | 1 -

Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

[PATCH] x86: Remove a.out support

[Eric W. Biederman]

From: Borislav Petkov <bp@suse.de>
Date: Thu, 13 Jan 2022 17:01:15 +0100
Subject: [PATCH] x86: Remove a.out support

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.

Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20220113160115.5375-1-bp@alien8.de
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
---

Kees can you pick this one up in for-next/execve as well?

It still applies cleanly and the actual patch seems to have gotten lost
in the conversation about what more we could do.

Thanks,
Eric


 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 9f5bd41bf660..b6563d6681c1 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2827,13 +2827,6 @@ 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

Re: [PATCH] x86: Remove a.out support

[Linus Torvalds]

On Thu, Mar 10, 2022 at 3:29 PM Eric W. Biederman <ebiederm@xmission.com> wrote:
>
> Kees can you pick this one up in for-next/execve as well?
>
> It still applies cleanly and the actual patch seems to have gotten lost
> in the conversation about what more we could do.

Side note: there are similar other turds if a.out goes away, ie on
alpha it's OSF4_COMPAT, and it enables support for a couple of legacy
OSF/1 system calls.

I think that was also discussed in the (old) a.out deprecation thread
back in 2019..

               Linus

Re: [PATCH] x86: Remove a.out support

[Arnd Bergmann]

On Fri, Mar 11, 2022 at 12:35 AM Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> On Thu, Mar 10, 2022 at 3:29 PM Eric W. Biederman <ebiederm@xmission.com> wrote:
> >
> > Kees can you pick this one up in for-next/execve as well?
> >
> > It still applies cleanly and the actual patch seems to have gotten lost
> > in the conversation about what more we could do.
>
> Side note: there are similar other turds if a.out goes away, ie on
> alpha it's OSF4_COMPAT, and it enables support for a couple of legacy
> OSF/1 system calls.
>
> I think that was also discussed in the (old) a.out deprecation thread
> back in 2019..

The only thing that actually depends on CONFIG_OSF4_COMPAT seems to be
the custom logic in readv() and writev(). Those are the two that you removed
in your patch back then[1].

For the other system calls, I fear we can only try to guess which of them
are used in Linux applications and which ones are not. These were always
available to normal Linux user space, so the ones that are similar to our
syscalls could have been used in glibc, e.g. mmap, wait4, stat.

         Arnd

[1] https://lore.kernel.org/all/CAHk-=wgt7M6yA5BJCJo0nF22WgPJnN8CvViL9CAJmd+S+Civ6w@mail.gmail.com/

[2] $ git grep sys_osf arch/alpha/kernel/syscalls/syscall.tbl
7 common osf_wait4 sys_osf_wait4
17 common brk sys_osf_brk
21 common osf_mount sys_osf_mount
43 common osf_set_program_attributes sys_osf_set_program_attributes
48 common osf_sigprocmask sys_osf_sigprocmask
71 common mmap sys_osf_mmap
93 common osf_select sys_osf_select
100 common getpriority sys_osf_getpriority
112 common osf_sigstack sys_osf_sigstack
116 common osf_gettimeofday sys_osf_gettimeofday
117 common osf_getrusage sys_osf_getrusage
120 common readv sys_osf_readv
121 common writev sys_osf_writev
122 common osf_settimeofday sys_osf_settimeofday
138 common osf_utimes sys_osf_utimes
156 common sigaction sys_osf_sigaction
159 common osf_getdirentries sys_osf_getdirentries
160 common osf_statfs sys_osf_statfs
161 common osf_fstatfs sys_osf_fstatfs
165 common osf_getdomainname sys_osf_getdomainname
207 common osf_utsname sys_osf_utsname
224 common osf_stat sys_osf_stat
225 common osf_lstat sys_osf_lstat
226 common osf_fstat sys_osf_fstat
227 common osf_statfs64 sys_osf_statfs64
228 common osf_fstatfs64 sys_osf_fstatfs64
241 common osf_sysinfo sys_osf_sysinfo
244 common osf_proplist_syscall sys_osf_proplist_syscall
251 common osf_usleep_thread sys_osf_usleep_thread
256 common osf_getsysinfo sys_osf_getsysinfo
257 common osf_setsysinfo sys_osf_setsysinfo

Re: [PATCH] x86: Remove a.out support

[Borislav Petkov]

On Thu, Mar 10, 2022 at 05:29:13PM -0600, Eric W. Biederman wrote:
> Kees can you pick this one up in for-next/execve as well?

I can carry it through tip, no probs.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

[tip: x86/cleanups] x86: Remove a.out support

[tip-bot2 for Borislav Petkov]

The following commit has been merged into the x86/cleanups branch of tip:

Commit-ID:     f9444ea5e20847d1dd4a98d4dff4cc97655834bb
Gitweb:        https://git.kernel.org/tip/f9444ea5e20847d1dd4a98d4dff4cc97655834bb
Author:        Borislav Petkov <bp@suse.de>
AuthorDate:    Thu, 13 Jan 2022 14:26:10 +01:00
Committer:     Borislav Petkov <bp@suse.de>
CommitterDate: Fri, 11 Mar 2022 11:06:32 +01:00

x86: Remove a.out support

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.

Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220113160115.5375-1-bp@alien8.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 9f5bd41..b6563d6 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2827,13 +2827,6 @@ 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 8e4d039..e481056 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 9bd1524..0000000
--- 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");

[tip: x86/cleanups] x86: Remove a.out support

[tip-bot2 for Borislav Petkov]

The following commit has been merged into the x86/cleanups branch of tip:

Commit-ID:     c7bda0dca98cca351a9bc852b3df8b9b99ffd400
Gitweb:        https://git.kernel.org/tip/c7bda0dca98cca351a9bc852b3df8b9b99ffd400
Author:        Borislav Petkov <bp@suse.de>
AuthorDate:    Thu, 13 Jan 2022 14:26:10 +01:00
Committer:     Borislav Petkov <bp@suse.de>
CommitterDate: Mon, 11 Apr 2022 18:04:27 +02:00

x86: Remove a.out support

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.

Fold in a hunk removing the reference to arch/x86/ia32/ia32_aout.c in
MAINTAINERS:

  https://lore.kernel.org/r/20220316050828.17255-1-lukas.bulwahn@gmail.com

Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220113160115.5375-1-bp@alien8.de
---
 MAINTAINERS               |   1 +-
 arch/x86/Kconfig          |   7 +-
 arch/x86/ia32/Makefile    |   2 +-
 arch/x86/ia32/ia32_aout.c | 325 +-------------------------------------
 4 files changed, 335 deletions(-)
 delete mode 100644 arch/x86/ia32/ia32_aout.c

diff --git a/MAINTAINERS b/MAINTAINERS
index fd768d4..795e4c7 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7378,7 +7378,6 @@ L:	linux-mm@kvack.org
 S:	Supported
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git for-next/execve
 F:	arch/alpha/kernel/binfmt_loader.c
-F:	arch/x86/ia32/ia32_aout.c
 F:	fs/*binfmt_*.c
 F:	fs/exec.c
 F:	include/linux/binfmts.h
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index b0142e0..69231f6 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -2838,13 +2838,6 @@ 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_ABI
 	bool "x32 ABI for 64-bit mode"
 	depends on X86_64
diff --git a/arch/x86/ia32/Makefile b/arch/x86/ia32/Makefile
index 8e4d039..e481056 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 9bd1524..0000000
--- 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");