The patch titled procfs: mem permission cleanup has been added to the -mm tree. Its filename is procfs-mem-permission-cleanup.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: procfs: mem permission cleanup From: Roland McGrath <roland@xxxxxxxxxx> This cleans up the permission checks done for /proc/PID/mem i/o calls. It puts all the logic in a new function, check_mem_permission(). The old code repeated the (!MAY_PTRACE(task) || !ptrace_may_attach(task)) magical expression multiple times. The new function does all that work in one place, with clear comments. The old code called security_ptrace() twice on successful checks, once in MAY_PTRACE() and once in __ptrace_may_attach(). Now it's only called once, and only if all other checks have succeeded. Signed-off-by: Roland McGrath <roland@xxxxxxxxxx> Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx> Cc: Oleg Nesterov <oleg@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/proc/base.c | 38 +++++++++++++++++++++++++++++--------- 1 file changed, 29 insertions(+), 9 deletions(-) diff -puN fs/proc/base.c~procfs-mem-permission-cleanup fs/proc/base.c --- a/fs/proc/base.c~procfs-mem-permission-cleanup +++ a/fs/proc/base.c @@ -195,12 +195,32 @@ static int proc_root_link(struct inode * return result; } -#define MAY_PTRACE(task) \ - (task == current || \ - (task->parent == current && \ - (task->ptrace & PT_PTRACED) && \ - (task_is_stopped_or_traced(task)) && \ - security_ptrace(current,task) == 0)) +/* + * Return zero if current may access user memory in @task, -error if not. + */ +static int check_mem_permission(struct task_struct *task) +{ + /* + * A task can always look at itself, in case it chooses + * to use system calls instead of load instructions. + */ + if (task == current) + return 0; + + /* + * If current is actively ptrace'ing, and would also be + * permitted to freshly attach with ptrace now, permit it. + */ + if (task->parent == current && (task->ptrace & PT_PTRACED) && + task_is_stopped_or_traced(task) && + ptrace_may_attach(task)) + return 0; + + /* + * Noone else is allowed. + */ + return -EPERM; +} struct mm_struct *mm_for_maps(struct task_struct *task) { @@ -722,7 +742,7 @@ static ssize_t mem_read(struct file * fi if (!task) goto out_no_task; - if (!MAY_PTRACE(task) || !ptrace_may_attach(task)) + if (check_mem_permission(task)) goto out; ret = -ENOMEM; @@ -748,7 +768,7 @@ static ssize_t mem_read(struct file * fi this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count; retval = access_process_vm(task, src, page, this_len, 0); - if (!retval || !MAY_PTRACE(task) || !ptrace_may_attach(task)) { + if (!retval || check_mem_permission(task)) { if (!ret) ret = -EIO; break; @@ -792,7 +812,7 @@ static ssize_t mem_write(struct file * f if (!task) goto out_no_task; - if (!MAY_PTRACE(task) || !ptrace_may_attach(task)) + if (check_mem_permission(task)) goto out; copied = -ENOMEM; _ Patches currently in -mm which might be from roland@xxxxxxxxxx are origin.patch git-x86.patch x86-handle_vm86_trap-cleanup.patch x86_64-ia32-ptrace-vs-enosys.patch x86_64-ptrace-vs-enosys.patch x86_64-ia32-ptrace-vs-enosys-sysenter-syscall.patch git-powerpc.patch git-selinux.patch add-rusage_thread.patch remove-unused-variable-from-send_signal.patch turn-legacy_queue-macro-into-static-inline-function.patch consolidate-checking-for-ignored-legacy-signals.patch consolidate-checking-for-ignored-legacy-signals-simplify.patch signals-do_signal_stop-use-signal_group_exit.patch signals-do_group_exit-use-signal_group_exit-more-consistently.patch lock_task_sighand-add-rcu-lock-unlock.patch k_getrusage-dont-take-rcu_read_lock.patch do_task_stat-dont-take-rcu_read_lock.patch signals-consolidate-checks-for-whether-or-not-to-ignore-a-signal.patch signals-clean-dequeue_signal-from-excess-checks-and-assignments.patch signals-consolidate-send_sigqueue-and-send_group_sigqueue.patch signals-cleanup-security_task_kill-usage-implementation.patch signals-re-assign-cld_continued-notification-from-the-sender-to-reciever.patch kill_pid_info-dont-take-now-unneeded-tasklist_lock.patch handle_stop_signal-unify-partial-full-stop-handling.patch handle_stop_signal-use-the-cached-p-signal-value.patch get_signal_to_deliver-use-the-cached-signal-sighand-values.patch signals-send_sigqueue-dont-take-rcu-lock.patch signals-send_sigqueue-dont-forget-about-handle_stop_signal.patch signals-__group_complete_signal-cache-the-value-of-p-signal.patch signals-send_group_sigqueue-dont-take-tasklist_lock.patch signals-move-handle_stop_signal-into-send_signal.patch signals-do_tkill-dont-use-tasklist_lock.patch signals-do_tkill-dont-use-tasklist_lock-comment.patch signals-send_sig_info-dont-take-tasklist_lock.patch signals-microoptimize-the-usage-of-curr_target.patch signals-move-the-definition-of-__group_complete_signal-up.patch signals-change-send_signal-do_send_sigqueue-to-take-boolean-group-parameter.patch signals-use-__group_complete_signal-for-the-specific-signals-too.patch signals-fold-complete_signal-into-send_signal-do_send_sigqueue.patch signals-unify-send_sigqueue-send_group_sigqueue-completely.patch signals-join-send_sigqueue-with-send_group_sigqueue.patch signals-handle_stop_signal-dont-worry-about-sigkill.patch signals-cleanup-the-usage-of-print_fatal_signal.patch signals-fold-sig_ignored-into-handle_stop_signal.patch signals-fold-sig_ignored-into-handle_stop_signal-comment.patch signals-document-cld_continued-notification-mechanics.patch signals-document-cld_continued-notification-mechanics-more.patch signals-send_signal-be-paranoid-about-signalfd_notify.patch signals-check_kill_permission-check-session-under-tasklist_lock.patch signals-check_kill_permission-remove-tasklist_lock.patch signals-fix-sbin-init-protection-from-unwanted-signals.patch signals-de_thread-simplify-the-child_reaper-switching.patch signals-allow-the-kernel-to-actually-kill-sbin-init.patch ptrace-introduce-task_detached-helper.patch reparent_thread-use-same_thread_group.patch document-de_thread-with-exit_notify-connection.patch ptrace-introduce-ptrace_reparented-helper.patch ptrace-__ptrace_unlink-use-the-ptrace_reparented-helper.patch ptrace-ptrace_attach-use-send_sig_info-instead-force_sig_specific.patch ptrace-allow-to-ptrace-sbin-init.patch procfs-mem-permission-cleanup.patch free_pidmap-turn-it-into-free_pidmapstruct-upid.patch pids-de_thread-dont-clear-session-pgrp-pids-for-the-old-leader.patch pids-introduce-change_pid-helper.patch pids-sys_setpgid-use-change_pid-helper.patch pids-__set_special_pids-use-change_pid-helper.patch pids-sys_getsid-fix-unsafe-pid-usage-fix-possible-0-instead-of-esrch.patch pids-sys_getpgid-fix-unsafe-pid-usage-s-tasklist-rcu.patch put_pid-make-sure-we-dont-free-the-live-pid.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html