Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030513AbVIAWzt (ORCPT ); Thu, 1 Sep 2005 18:55:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030502AbVIAWxZ (ORCPT ); Thu, 1 Sep 2005 18:53:25 -0400 Received: from lakshmi.addtoit.com ([198.99.130.6]:38160 "EHLO lakshmi.solana.com") by vger.kernel.org with ESMTP id S1030501AbVIAWxX (ORCPT ); Thu, 1 Sep 2005 18:53:23 -0400 Message-Id: <200509012217.j81MHEgb011557@ccure.user-mode-linux.org> X-Mailer: exmh version 2.7.2 01/07/2005 with nmh-1.0.4 To: akpm@osdl.org cc: linux-kernel@vger.kernel.org, user-mode-linux-devel@lists.sourceforge.net, Bodo Stroesser Subject: [PATCH 8/12] UML - Increase granularity of host capability checking Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Thu, 01 Sep 2005 18:17:14 -0400 From: Jeff Dike Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8082 Lines: 271 From: Bodo Stroesser 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 Index: test/arch/um/kernel/skas/include/skas.h =================================================================== --- test.orig/arch/um/kernel/skas/include/skas.h 2005-09-01 16:03:16.000000000 -0400 +++ test/arch/um/kernel/skas/include/skas.h 2005-09-01 16:21:00.000000000 -0400 @@ -33,7 +33,7 @@ unsigned long len, int r, int w, int x, int done, void *data); extern void user_signal(int sig, union uml_pt_regs *regs, int pid); -extern int new_mm(int from); +extern int new_mm(int from, unsigned long stack); extern int start_userspace(unsigned long stub_stack); extern int copy_context_skas0(unsigned long stack, int pid); extern void get_skas_faultinfo(int pid, struct faultinfo * fi); Index: test/arch/um/kernel/skas/mmu.c =================================================================== --- test.orig/arch/um/kernel/skas/mmu.c 2005-09-01 16:03:16.000000000 -0400 +++ test/arch/um/kernel/skas/mmu.c 2005-09-01 16:21:00.000000000 -0400 @@ -77,23 +77,14 @@ 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; - - 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 { + if(!proc_mm || !ptrace_faultinfo){ + stack = get_zeroed_page(GFP_KERNEL); + if(stack == 0) + goto out; + /* 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 @@ 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; dec_mm_counter(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 @@ 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 @@ 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); } Index: test/arch/um/kernel/skas/process.c =================================================================== --- test.orig/arch/um/kernel/skas/process.c 2005-09-01 16:02:46.000000000 -0400 +++ test/arch/um/kernel/skas/process.c 2005-09-01 16:21:00.000000000 -0400 @@ -138,6 +138,8 @@ } extern int __syscall_stub_start; +int stub_code_fd = -1; +__u64 stub_code_offset; static int userspace_tramp(void *stack) { @@ -152,31 +154,31 @@ /* This has a pte, but it can't be mapped in with the usual * tlb_flush mechanism because this is part of that mechanism */ - int fd; - __u64 offset; - - fd = phys_mapping(to_phys(&__syscall_stub_start), &offset); addr = mmap64((void *) UML_CONFIG_STUB_CODE, page_size(), - PROT_EXEC, MAP_FIXED | MAP_PRIVATE, fd, offset); + PROT_EXEC, MAP_FIXED | MAP_PRIVATE, + stub_code_fd, stub_code_offset); if(addr == MAP_FAILED){ - printk("mapping mmap stub failed, errno = %d\n", + printk("mapping stub code failed, errno = %d\n", errno); exit(1); } if(stack != NULL){ + int fd; + __u64 offset; + fd = phys_mapping(to_phys(stack), &offset); addr = mmap((void *) UML_CONFIG_STUB_DATA, page_size(), PROT_READ | PROT_WRITE, MAP_FIXED | MAP_SHARED, fd, offset); if(addr == MAP_FAILED){ - printk("mapping segfault stack failed, " + printk("mapping stub stack failed, " "errno = %d\n", errno); exit(1); } } } - if(!ptrace_faultinfo && (stack != NULL)){ + if(!ptrace_faultinfo){ unsigned long v = UML_CONFIG_STUB_CODE + (unsigned long) stub_segv_handler - (unsigned long) &__syscall_stub_start; @@ -202,6 +204,10 @@ unsigned long sp; int pid, status, n, flags; + if ( stub_code_fd == -1 ) + stub_code_fd = phys_mapping(to_phys(&__syscall_stub_start), + &stub_code_offset); + stack = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE | PROT_EXEC, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); if(stack == MAP_FAILED) @@ -363,6 +369,53 @@ return pid; } +/* + * This is used only, if proc_mm is available, while PTRACE_FAULTINFO + * isn't. Opening /proc/mm creates a new mm_context, which lacks the stub-pages + * Thus, we map them using /proc/mm-fd + */ +void map_stub_pages(int fd, unsigned long code, + unsigned long data, unsigned long stack) +{ + struct proc_mm_op mmop; + int n; + + mmop = ((struct proc_mm_op) { .op = MM_MMAP, + .u = + { .mmap = + { .addr = code, + .len = PAGE_SIZE, + .prot = PROT_EXEC, + .flags = MAP_FIXED | MAP_PRIVATE, + .fd = stub_code_fd, + .offset = stub_code_offset + } } }); + n = os_write_file(fd, &mmop, sizeof(mmop)); + if(n != sizeof(mmop)) + panic("map_stub_pages : /proc/mm map for code failed, " + "err = %d\n", -n); + + if ( stack ) { + __u64 map_offset; + int map_fd = phys_mapping(to_phys((void *)stack), &map_offset); + mmop = ((struct proc_mm_op) + { .op = MM_MMAP, + .u = + { .mmap = + { .addr = data, + .len = PAGE_SIZE, + .prot = PROT_READ | PROT_WRITE, + .flags = MAP_FIXED | MAP_SHARED, + .fd = map_fd, + .offset = map_offset + } } }); + n = os_write_file(fd, &mmop, sizeof(mmop)); + if(n != sizeof(mmop)) + panic("map_stub_pages : /proc/mm map for data failed, " + "err = %d\n", -n); + } +} + void new_thread(void *stack, void **switch_buf_ptr, void **fork_buf_ptr, void (*handler)(int)) { Index: test/arch/um/kernel/skas/process_kern.c =================================================================== --- test.orig/arch/um/kernel/skas/process_kern.c 2005-09-01 16:02:46.000000000 -0400 +++ test/arch/um/kernel/skas/process_kern.c 2005-09-01 16:21:00.000000000 -0400 @@ -129,7 +129,9 @@ return(0); } -int new_mm(int from) +extern void map_stub_pages(int fd, unsigned long code, + unsigned long data, unsigned long stack); +int new_mm(int from, unsigned long stack) { struct proc_mm_op copy; int n, fd; @@ -148,6 +150,9 @@ "err = %d\n", -n); } + if(!ptrace_faultinfo) + map_stub_pages(fd, CONFIG_STUB_CODE, CONFIG_STUB_DATA, stack); + return(fd); } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/