From 8b51304ed3184826fb262c1e9d3e58b0b00fd083 Mon Sep 17 00:00:00 2001 From: Bodo Stroesser Date: Sat, 3 Sep 2005 15:57:49 -0700 Subject: [PATCH] uml: increase granularity of host capability checking This change enables SKAS0/SKAS3 to work with all combinations of /proc/mm and PTRACE_FAULTINFO being available or not. Also it changes the initialization of proc_mm and ptrace_faultinfo slightly, to ease forcing SKAS0 on a patched host. Forcing UML to run without /proc/mm or PTRACE_FAULTINFO by cmdline parameter can be implemented with a setup resetting the related variable. Signed-off-by: Bodo Stroesser Signed-off-by: Jeff Dike Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/um/kernel/skas/mmu.c | 52 +++++++++++++++++++++++++---------------------- 1 file changed, 28 insertions(+), 24 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 d232daa42c31..d837223e22af 100644 --- a/arch/um/kernel/skas/mmu.c +++ b/arch/um/kernel/skas/mmu.c @@ -77,23 +77,14 @@ int init_new_context_skas(struct task_struct *task, struct mm_struct *mm) struct mm_struct *cur_mm = current->mm; struct mm_id *cur_mm_id = &cur_mm->context.skas.id; struct mm_id *mm_id = &mm->context.skas.id; - unsigned long stack; - int from, ret; + unsigned long stack = 0; + int from, ret = -ENOMEM; - if(proc_mm){ - if((cur_mm != NULL) && (cur_mm != &init_mm)) - from = cur_mm->context.skas.id.u.mm_fd; - else from = -1; + if(!proc_mm || !ptrace_faultinfo){ + stack = get_zeroed_page(GFP_KERNEL); + if(stack == 0) + goto out; - ret = new_mm(from); - if(ret < 0){ - printk("init_new_context_skas - new_mm failed, " - "errno = %d\n", ret); - return ret; - } - mm_id->u.mm_fd = ret; - } - else { /* This zeros the entry that pgd_alloc didn't, needed since * we are about to reinitialize it, and want mm.nr_ptes to * be accurate. @@ -103,20 +94,30 @@ int init_new_context_skas(struct task_struct *task, struct mm_struct *mm) ret = init_stub_pte(mm, CONFIG_STUB_CODE, (unsigned long) &__syscall_stub_start); if(ret) - goto out; - - ret = -ENOMEM; - stack = get_zeroed_page(GFP_KERNEL); - if(stack == 0) - goto out; - mm_id->stack = stack; + goto out_free; ret = init_stub_pte(mm, CONFIG_STUB_DATA, stack); if(ret) goto out_free; mm->nr_ptes--; + } + mm_id->stack = stack; + if(proc_mm){ + if((cur_mm != NULL) && (cur_mm != &init_mm)) + from = cur_mm_id->u.mm_fd; + else from = -1; + + ret = new_mm(from, stack); + if(ret < 0){ + printk("init_new_context_skas - new_mm failed, " + "errno = %d\n", ret); + goto out_free; + } + mm_id->u.mm_fd = ret; + } + else { if((cur_mm != NULL) && (cur_mm != &init_mm)) mm_id->u.pid = copy_context_skas0(stack, cur_mm_id->u.pid); @@ -126,7 +127,8 @@ int init_new_context_skas(struct task_struct *task, struct mm_struct *mm) return 0; out_free: - free_page(mm_id->stack); + if(mm_id->stack != 0) + free_page(mm_id->stack); out: return ret; } @@ -137,8 +139,10 @@ void destroy_context_skas(struct mm_struct *mm) if(proc_mm) os_close_file(mmu->id.u.mm_fd); - else { + else os_kill_ptraced_process(mmu->id.u.pid, 1); + + if(!proc_mm || !ptrace_faultinfo){ free_page(mmu->id.stack); free_page(mmu->last_page_table); } -- cgit v1.2.3