From d0b5e15f0c0fdd759dd3dd48dc2dc2e7199e0da0 Mon Sep 17 00:00:00 2001 From: Richard Weinberger Date: Wed, 18 Mar 2015 21:31:27 +0100 Subject: um: Remove SKAS3/4 support Before we had SKAS0 UML had two modes of operation TT (tracing thread) and SKAS3/4 (separated kernel address space). TT was known to be insecure and got removed a long time ago. SKAS3/4 required a few (3 or 4) patches on the host side which never went mainline. The last host patch is 10 years old. With SKAS0 mode (separated kernel address space using 0 host patches), default since 2005, SKAS3/4 is obsolete and can be removed. Signed-off-by: Richard Weinberger --- arch/um/kernel/skas/mmu.c | 68 ++++++++++++++++------------------------------- 1 file changed, 23 insertions(+), 45 deletions(-) (limited to 'arch/um/kernel/skas/mmu.c') diff --git a/arch/um/kernel/skas/mmu.c b/arch/um/kernel/skas/mmu.c index 007d5503f49b..94abdcc1d6ad 100644 --- a/arch/um/kernel/skas/mmu.c +++ b/arch/um/kernel/skas/mmu.c @@ -54,35 +54,22 @@ int init_new_context(struct task_struct *task, struct mm_struct *mm) unsigned long stack = 0; int ret = -ENOMEM; - if (skas_needs_stub) { - stack = get_zeroed_page(GFP_KERNEL); - if (stack == 0) - goto out; - } + stack = get_zeroed_page(GFP_KERNEL); + if (stack == 0) + goto out; to_mm->id.stack = stack; if (current->mm != NULL && current->mm != &init_mm) from_mm = ¤t->mm->context; - if (proc_mm) { - ret = new_mm(stack); - if (ret < 0) { - printk(KERN_ERR "init_new_context_skas - " - "new_mm failed, errno = %d\n", ret); - goto out_free; - } - to_mm->id.u.mm_fd = ret; - } - else { - if (from_mm) - to_mm->id.u.pid = copy_context_skas0(stack, - from_mm->id.u.pid); - else to_mm->id.u.pid = start_userspace(stack); - - if (to_mm->id.u.pid < 0) { - ret = to_mm->id.u.pid; - goto out_free; - } + if (from_mm) + to_mm->id.u.pid = copy_context_skas0(stack, + from_mm->id.u.pid); + else to_mm->id.u.pid = start_userspace(stack); + + if (to_mm->id.u.pid < 0) { + ret = to_mm->id.u.pid; + goto out_free; } ret = init_new_ldt(to_mm, from_mm); @@ -105,9 +92,6 @@ void uml_setup_stubs(struct mm_struct *mm) { int err, ret; - if (!skas_needs_stub) - return; - ret = init_stub_pte(mm, STUB_CODE, (unsigned long) &__syscall_stub_start); if (ret) @@ -154,25 +138,19 @@ void destroy_context(struct mm_struct *mm) { struct mm_context *mmu = &mm->context; - if (proc_mm) - os_close_file(mmu->id.u.mm_fd); - else { - /* - * If init_new_context wasn't called, this will be - * zero, resulting in a kill(0), which will result in the - * whole UML suddenly dying. Also, cover negative and - * 1 cases, since they shouldn't happen either. - */ - if (mmu->id.u.pid < 2) { - printk(KERN_ERR "corrupt mm_context - pid = %d\n", - mmu->id.u.pid); - return; - } - os_kill_ptraced_process(mmu->id.u.pid, 1); + /* + * If init_new_context wasn't called, this will be + * zero, resulting in a kill(0), which will result in the + * whole UML suddenly dying. Also, cover negative and + * 1 cases, since they shouldn't happen either. + */ + if (mmu->id.u.pid < 2) { + printk(KERN_ERR "corrupt mm_context - pid = %d\n", + mmu->id.u.pid); + return; } + os_kill_ptraced_process(mmu->id.u.pid, 1); - if (skas_needs_stub) - free_page(mmu->id.stack); - + free_page(mmu->id.stack); free_ldt(mmu); } -- cgit v1.2.3