From nobody Thu Nov 28 19:53:25 2024 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5CD59183098 for ; Sun, 29 Sep 2024 14:43:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727621002; cv=none; b=o7u913SI74dM0CK9AHAqS6pdbiONIsn62gn9Bop0MYwEQfb1/veNarNivFBG3fHWFnnVKf6D3QkbrWXdQFKxJkTZxp2dB8QHBcJRIlj3qRy2QDr2DPvOHJHjbLzmTiiKOOjFg12fiIq0dWNQeBSVTSgQ7U+sRzo39FA5qNnGNQ8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727621002; c=relaxed/simple; bh=FfaZhrQq34BZlheLdSwojN4sapArypT72+Y+nLTOLDA=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; b=HfBnbHLGkdmbH4HZ9zr6ATiqY5e158mmKy8m0m7hCYUuNM1XpeELRbMX2oARkYbDV97uLyMr+gwfuuZjjSlEmJu+OPB3TioiRk+SMDTIVdMrqD9Y3EDWc92L9QuQWe638r7/+fq6FZTS6rbOtWpQyTFj/Y0/7yt7Y6LUmXDf1CA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=fcOlL1X9; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="fcOlL1X9" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1727621000; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to; bh=PFEiL3F5MSjU++Jxe01AvOazddBzZZRjIDhG9rgyzoQ=; b=fcOlL1X9TFa4n8u/GCm8dWpVUOpDmdhiRws/8o/KJTDva0nQyHtKi7KGxGe6lE7ac6hsli 2V3CV4FlleOhUfOy9o/0TLn1BX6sm5N0o6J39/T81V+DJgBi9hH+oQCLEKT0unIZei5kLy NzbyHbJfnuoqjHyCTBZrKuAAnbGMU/k= Received: from mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-530-2aiClEGVNq6dSkKRgCxqKg-1; Sun, 29 Sep 2024 10:43:16 -0400 X-MC-Unique: 2aiClEGVNq6dSkKRgCxqKg-1 Received: from mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (unknown [10.30.177.15]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 42BB0195FE21; Sun, 29 Sep 2024 14:43:15 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.45.224.44]) by mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with SMTP id 90E271979060; Sun, 29 Sep 2024 14:43:12 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Sun, 29 Sep 2024 16:43:01 +0200 (CEST) Date: Sun, 29 Sep 2024 16:42:58 +0200 From: Oleg Nesterov To: Andrii Nakryiko , Jiri Olsa , Masami Hiramatsu , Peter Zijlstra Cc: Liao Chang , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: [PATCH 7/7] uprobes: deny mremap(xol_vma) Message-ID: <20240929144258.GA9492@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20240929144201.GA9429@redhat.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 3.0 on 10.30.177.15 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" kernel/events/uprobes.c assumes that xol_area->vaddr is always correct but a malicious application can remap its "[uprobes]" vma to another adress to confuse the kernel. Introduce xol_mremap() to make this impossible. With this change utask->xol_vaddr in xol_free_insn_slot() can't be invalid, we can turn the offset check into WARN_ON_ONCE(offset >=3D PAGE_SIZE). Signed-off-by: Oleg Nesterov --- kernel/events/uprobes.c | 30 +++++++++++++++++------------- 1 file changed, 17 insertions(+), 13 deletions(-) diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index da45d0e5bcf4..20c58b6ee1ad 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -1475,9 +1475,15 @@ static vm_fault_t xol_fault(const struct vm_special_= mapping *sm, return 0; } =20 +static int xol_mremap(const struct vm_special_mapping *sm, struct vm_area_= struct *new_vma) +{ + return -EPERM; +} + static const struct vm_special_mapping xol_mapping =3D { .name =3D "[uprobes]", .fault =3D xol_fault, + .mremap =3D xol_mremap, }; =20 /* Slot allocation for XOL */ @@ -1670,21 +1676,19 @@ static void xol_free_insn_slot(struct uprobe_task *= utask) { struct xol_area *area =3D current->mm->uprobes_state.xol_area; unsigned long offset =3D utask->xol_vaddr - area->vaddr; + unsigned int slot_nr; =20 utask->xol_vaddr =3D 0; - /* - * xol_vaddr must fit into [area->vaddr, area->vaddr + PAGE_SIZE). - * This check can only fail if the "[uprobes]" vma was mremap'ed. - */ - if (offset < PAGE_SIZE) { - int slot_nr =3D offset / UPROBE_XOL_SLOT_BYTES; - - clear_bit(slot_nr, area->bitmap); - atomic_dec(&area->slot_count); - smp_mb__after_atomic(); /* pairs with prepare_to_wait() */ - if (waitqueue_active(&area->wq)) - wake_up(&area->wq); - } + /* xol_vaddr must fit into [area->vaddr, area->vaddr + PAGE_SIZE) */ + if (WARN_ON_ONCE(offset >=3D PAGE_SIZE)) + return; + + slot_nr =3D offset / UPROBE_XOL_SLOT_BYTES; + clear_bit(slot_nr, area->bitmap); + atomic_dec(&area->slot_count); + smp_mb__after_atomic(); /* pairs with prepare_to_wait() */ + if (waitqueue_active(&area->wq)) + wake_up(&area->wq); } =20 void __weak arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr, --=20 2.25.1.362.g51ebf55