From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 014A4C47082 for ; Tue, 8 Jun 2021 12:34:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D694E61287 for ; Tue, 8 Jun 2021 12:34:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232351AbhFHMgU (ORCPT ); Tue, 8 Jun 2021 08:36:20 -0400 Received: from mail-il1-f175.google.com ([209.85.166.175]:44794 "EHLO mail-il1-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232575AbhFHMgU (ORCPT ); Tue, 8 Jun 2021 08:36:20 -0400 Received: by mail-il1-f175.google.com with SMTP id i17so19313582ilj.11 for ; Tue, 08 Jun 2021 05:34:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=RFjaSjMQkwJHmF1f66mLNTaQ78R9sIE9PBhzCroLQMY=; b=o8/P5qBAwUYoUd4z6K+jAndy3R6WGes0iunS2TpqMLJXgkkdvOeBoD5oPzVNmGUJRe K163FAKL44Wxi6InbLRhSaAWFocm2stX6ROQwKFCVqWbQUSwGwXRVm5r71VidRZ2Qre7 5g8S1/+M2P4zz8KAtbksDmgtMjmGaOKJVmMtDML3L5+5qvDXF7q9GOBekEwCzcYzZPFK BMid53OotedNPznxo4WgaIxMZbvOJcv8Z0aHYqiex/fc0rQjTUQl3WKD3Cte2N4I5mnP 4IPRrGUHG7J4d4v94cvNsiggn9qT0iknTUryD+s5oxPGlHqJeLMQbu0nX/V8qOv7fZJY Qt/Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=RFjaSjMQkwJHmF1f66mLNTaQ78R9sIE9PBhzCroLQMY=; b=Bs1FpTsudtiOwjvSkeHIBlEyH0yWjNq2t1+KOhN7FZ+Xht9eSnf5uZj5FHiqiLDErK vQM3OsVHyYvEMIlEC1BieGea1N1TYHwID/K31wfixCEd8PuUnLjGmYnzUKkCpHCJm3vE Cezb1ecdIQv9SYdH7ybvD/vGm98k6dCW6C9HLOAa4yVVJpllUUlUbNRNHMA/ASlDv7n3 UWH9pu/TJhIN1PEFXGVh+Ni1NsRA9RJ1VzLRPcjo+7D7wpp/nBS0cOcev7djItgam0CP PS/pmsE+QdDzY00nmqnRZ34Vj0wt/Q5YifZAP/SqG6B+h1EhCt5kOcU14CCoM3SHMVp/ lY3w== X-Gm-Message-State: AOAM531cmedXWxSHJOFafVfeRuAXpPIsb7Vhd6VsubILXghO4UbXBDAq RPN/Bv+CXqksR0oaqMObC3TJEqNxk88j8IvBtJY= X-Google-Smtp-Source: ABdhPJyG0OKM4slE3EaJRjzmz3IxGPzXO2EFmYIzsZf9WEBqHgwUst+iBeZz1i7s/tdPbGWm5+ZNJiqIW2JKnuW2EdE= X-Received: by 2002:a05:6e02:14a:: with SMTP id j10mr20334078ilr.250.1623155607279; Tue, 08 Jun 2021 05:33:27 -0700 (PDT) MIME-Version: 1.0 References: <162315490411353@kroah.com> In-Reply-To: <162315490411353@kroah.com> From: Amir Goldstein Date: Tue, 8 Jun 2021 15:33:16 +0300 Message-ID: Subject: Re: FAILED: patch "[PATCH] fanotify: fix permission model of unprivileged group" failed to apply to 5.12-stable tree To: Greg KH Cc: stable , Christian Brauner , Jan Kara , Matthew Bobrowski Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Tue, Jun 8, 2021 at 3:21 PM wrote: > > > The patch below does not apply to the 5.12-stable tree. I wrongly tagged this # v5.12+ It fixed a commit merge in this cycle. Sorry for the noise. Thanks, Amir. > If someone wants it applied there, or to any other stable or longterm > tree, then please email the backport, including the original git commit > id to . > > thanks, > > greg k-h > > ------------------ original commit in Linus's tree ------------------ > > From a8b98c808eab3ec8f1b5a64be967b0f4af4cae43 Mon Sep 17 00:00:00 2001 > From: Amir Goldstein > Date: Mon, 24 May 2021 16:53:21 +0300 > Subject: [PATCH] fanotify: fix permission model of unprivileged group > > Reporting event->pid should depend on the privileges of the user that > initialized the group, not the privileges of the user reading the > events. > > Use an internal group flag FANOTIFY_UNPRIV to record the fact that the > group was initialized by an unprivileged user. > > To be on the safe side, the premissions to setup filesystem and mount > marks now require that both the user that initialized the group and > the user setting up the mark have CAP_SYS_ADMIN. > > Link: https://lore.kernel.org/linux-fsdevel/CAOQ4uxiA77_P5vtv7e83g0+9d7B5W9ZTE4GfQEYbWmfT1rA=VA@mail.gmail.com/ > Fixes: 7cea2a3c505e ("fanotify: support limited functionality for unprivileged users") > Cc: # v5.12+ > Link: https://lore.kernel.org/r/20210524135321.2190062-1-amir73il@gmail.com > Reviewed-by: Matthew Bobrowski > Acked-by: Christian Brauner > Signed-off-by: Amir Goldstein > Signed-off-by: Jan Kara > > diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c > index 71fefb30e015..be5b6d2c01e7 100644 > --- a/fs/notify/fanotify/fanotify_user.c > +++ b/fs/notify/fanotify/fanotify_user.c > @@ -424,11 +424,18 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group, > * events generated by the listener process itself, without disclosing > * the pids of other processes. > */ > - if (!capable(CAP_SYS_ADMIN) && > + if (FAN_GROUP_FLAG(group, FANOTIFY_UNPRIV) && > task_tgid(current) != event->pid) > metadata.pid = 0; > > - if (path && path->mnt && path->dentry) { > + /* > + * For now, fid mode is required for an unprivileged listener and > + * fid mode does not report fd in events. Keep this check anyway > + * for safety in case fid mode requirement is relaxed in the future > + * to allow unprivileged listener to get events with no fd and no fid. > + */ > + if (!FAN_GROUP_FLAG(group, FANOTIFY_UNPRIV) && > + path && path->mnt && path->dentry) { > fd = create_fd(group, path, &f); > if (fd < 0) > return fd; > @@ -1040,6 +1047,7 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags) > int f_flags, fd; > unsigned int fid_mode = flags & FANOTIFY_FID_BITS; > unsigned int class = flags & FANOTIFY_CLASS_BITS; > + unsigned int internal_flags = 0; > > pr_debug("%s: flags=%x event_f_flags=%x\n", > __func__, flags, event_f_flags); > @@ -1053,6 +1061,13 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags) > */ > if ((flags & FANOTIFY_ADMIN_INIT_FLAGS) || !fid_mode) > return -EPERM; > + > + /* > + * Setting the internal flag FANOTIFY_UNPRIV on the group > + * prevents setting mount/filesystem marks on this group and > + * prevents reporting pid and open fd in events. > + */ > + internal_flags |= FANOTIFY_UNPRIV; > } > > #ifdef CONFIG_AUDITSYSCALL > @@ -1105,7 +1120,7 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags) > goto out_destroy_group; > } > > - group->fanotify_data.flags = flags; > + group->fanotify_data.flags = flags | internal_flags; > group->memcg = get_mem_cgroup_from_mm(current->mm); > > group->fanotify_data.merge_hash = fanotify_alloc_merge_hash(); > @@ -1305,11 +1320,13 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask, > group = f.file->private_data; > > /* > - * An unprivileged user is not allowed to watch a mount point nor > - * a filesystem. > + * An unprivileged user is not allowed to setup mount nor filesystem > + * marks. This also includes setting up such marks by a group that > + * was initialized by an unprivileged user. > */ > ret = -EPERM; > - if (!capable(CAP_SYS_ADMIN) && > + if ((!capable(CAP_SYS_ADMIN) || > + FAN_GROUP_FLAG(group, FANOTIFY_UNPRIV)) && > mark_type != FAN_MARK_INODE) > goto fput_and_out; > > @@ -1460,6 +1477,7 @@ static int __init fanotify_user_setup(void) > max_marks = clamp(max_marks, FANOTIFY_OLD_DEFAULT_MAX_MARKS, > FANOTIFY_DEFAULT_MAX_USER_MARKS); > > + BUILD_BUG_ON(FANOTIFY_INIT_FLAGS & FANOTIFY_INTERNAL_GROUP_FLAGS); > BUILD_BUG_ON(HWEIGHT32(FANOTIFY_INIT_FLAGS) != 10); > BUILD_BUG_ON(HWEIGHT32(FANOTIFY_MARK_FLAGS) != 9); > > diff --git a/fs/notify/fdinfo.c b/fs/notify/fdinfo.c > index a712b2aaa9ac..57f0d5d9f934 100644 > --- a/fs/notify/fdinfo.c > +++ b/fs/notify/fdinfo.c > @@ -144,7 +144,7 @@ void fanotify_show_fdinfo(struct seq_file *m, struct file *f) > struct fsnotify_group *group = f->private_data; > > seq_printf(m, "fanotify flags:%x event-flags:%x\n", > - group->fanotify_data.flags, > + group->fanotify_data.flags & FANOTIFY_INIT_FLAGS, > group->fanotify_data.f_flags); > > show_fdinfo(m, f, fanotify_fdinfo); > diff --git a/include/linux/fanotify.h b/include/linux/fanotify.h > index bad41bcb25df..a16dbeced152 100644 > --- a/include/linux/fanotify.h > +++ b/include/linux/fanotify.h > @@ -51,6 +51,10 @@ extern struct ctl_table fanotify_table[]; /* for sysctl */ > #define FANOTIFY_INIT_FLAGS (FANOTIFY_ADMIN_INIT_FLAGS | \ > FANOTIFY_USER_INIT_FLAGS) > > +/* Internal group flags */ > +#define FANOTIFY_UNPRIV 0x80000000 > +#define FANOTIFY_INTERNAL_GROUP_FLAGS (FANOTIFY_UNPRIV) > + > #define FANOTIFY_MARK_TYPE_BITS (FAN_MARK_INODE | FAN_MARK_MOUNT | \ > FAN_MARK_FILESYSTEM) > >