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

tip-bot2 for Borislav Petkov
2022-03-11T14:43:36Z

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");