From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f69.google.com (mail-wm1-f69.google.com [209.85.128.69]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 84EBC47277C for ; Wed, 2 Sep 2026 12:50:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.69 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788353425; cv=none; b=Y3mJvepO6NhNWdtIpu4wvVB5Yb9hiV3sktu0QW7O49wgzCzjz5/9gyDjNfwIKOF5p+pqrbCjOdrBpvGgliwU5pZId6cC8BWxxIFFJXP6mgC8SRWQ3Wg8FjhuwNQ/9Cw/c1WHwEfABluDJpwOAGSOsxRg3UKG4OeS+6Nann3qzb8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788353425; c=relaxed/simple; bh=Q6o+psk043H7QaDBOb2T9aD1u8V/v8iD/Wiko61zjSk=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=nq4vPwmYFLxswSn89IvBBV4BD3D0BuRZOTreUAdFNdeVkKESmX90KiG2wuypebNePzZx6Vv5HTqjBToiwDO6ASgIMH9X6LEaN/PSVACpMFGZiYo3u7V5E+W3qVpFmGsuBEbQ9WetdHGpo1GiAJ0WOPD+/dcGk5MNgKz/vWvnorM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--aliceryhl.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=qZAs3zsh; arc=none smtp.client-ip=209.85.128.69 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--aliceryhl.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="qZAs3zsh" Received: by mail-wm1-f69.google.com with SMTP id 5b1f17b1804b1-49cd55ee2f7so9144865e9.0 for ; Wed, 02 Sep 2026 05:50:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1788353421; x=1788958221; darn=vger.kernel.org; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:from:to:cc:subject:date:message-id:reply-to :content-type; bh=24c84bwyDgqYl1alrwdlSmQQcTBYQp/BbzXBbK2dqKk=; b=qZAs3zshERZ8aK+3OuPOmyGilAJv8I7QrWrPr/zkG/7T7+DUBnNg3quob9ua3BtrAY bEkgVTyZMulI7Lb6EI0uiSWGm5Xo26P8M3iqtEa6c6sTXbIW/Z6DoEwrmDOHlqmij+Jy loqBkSHx0NGoIoBBgIa9qh9/yxMU7hdLA5bJbWET/Mqsoi4IW9DCVdabKNzfYVe2atJg /svje9aS3j7JN1OIjTEoG8DxxumdaGE2+1MkHSlcFOUyi8u9dcq/Zc7wYHEIEYOtsunT X3ZDhmKHziza3DebG8b0C9SQU3OsXLihYdwrPzMGwG5uTic0gwJtPy+xR02HK4Q1UqVA 7/Hg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1788353421; x=1788958221; h=content-type:cc:to:from:subject:message-id:references:mime-version :in-reply-to:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=24c84bwyDgqYl1alrwdlSmQQcTBYQp/BbzXBbK2dqKk=; b=OthUFtV5HDDlF/5xXEwziQ+W4kRMPA5sz4Eh+GpC2nevOhsZ8piZCjs0oBCmYdvUM6 fkLELvvW7wf7RRxKXCanUKpCKkR/DDYyn4b19GmxTwGcKxrfshkKFwVpGB8DindPqJY3 DjsnXMgtc83iW+3zFgMWp+eGUSPnQlLxihvGks0AHXx+Nz8piTfchFKxvfYU+wrpKAnX iGF6aDeGj16b82GB/QsGs6ffWglUkwE+GI/P+NUbOeN/KackxbgZ/UtjWC1PCdQk9sI/ LWFiUwxA3Di8RvDbhifK2ESoM0K9ufigwxB0+U9AQjS9a/Grxg9Tk9y05uUbuE08bheG y9wQ== X-Forwarded-Encrypted: i=1; AHgh+RqxidHUtEvQqJyPD+/US7gqnscOlTrHgoQ2dAHcJOpe2bV/QK1g85Nqr71O2thkH074CBuCq9k=@vger.kernel.org X-Gm-Message-State: AFuF++nYmGu2PTYY6gul/QuRzAJOOsi8PiAlaW9RsAgdCnWQfzdcov2a 4lhYJZNDIJX2qKhCDl+LATjwxmY0DaFD9IMOimNsLKvjIbpy/xmQh8T1+1f0BdA8lz5PxnrNxiw B120ZMWJmI67uPjP3HQ== X-Received: from wmjx6.prod.google.com ([2002:a05:600c:21c6:b0:499:b2b5:78e8]) (user=aliceryhl job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:530e:b0:49c:d618:e341 with SMTP id 5b1f17b1804b1-49ce584bb4amr93341175e9.14.1788353421254; Wed, 02 Sep 2026 05:50:21 -0700 (PDT) Date: Wed, 2 Sep 2026 12:50:20 +0000 In-Reply-To: <20260901205250.1638304-6-cmllamas@google.com> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260901205250.1638304-1-cmllamas@google.com> <20260901205250.1638304-6-cmllamas@google.com> Message-ID: Subject: Re: [PATCH v4 5/7] binder: check vma->vm_start in binder_vma_close() From: Alice Ryhl To: Carlos Llamas Cc: Greg Kroah-Hartman , "Arve =?utf-8?B?SGrDuG5uZXbDpWc=?=" , Todd Kjos , Christian Brauner , kernel-team@android.com, linux-kernel@vger.kernel.org, Suren Baghdasaryan , stable@vger.kernel.org, Sashiko Content-Type: text/plain; charset="utf-8" On Tue, Sep 01, 2026 at 08:52:45PM +0000, Carlos Llamas wrote: > Certain operations like a failed mremap() might trigger vm_ops->close() > on temporary mappings. To avoid tearing-down the main binder mapping on > these, let's verify that the VMA matches the expected starting address. > > Cc: stable@vger.kernel.org > Fixes: 457b9a6f09f0 ("Staging: android: add binder driver") > Reported-by: Sashiko > Closes: https://sashiko.dev/#/patchset/20260831224145.169403-1-cmllamas@google.com?part=1 > Signed-off-by: Carlos Llamas > --- > drivers/android/binder.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/android/binder.c b/drivers/android/binder.c > index 185128577829..3d359490436e 100644 > --- a/drivers/android/binder.c > +++ b/drivers/android/binder.c > @@ -6018,6 +6018,9 @@ static void binder_vma_close(struct vm_area_struct *vma) > { > struct binder_proc *proc = vma->vm_private_data; > > + if (vma->vm_start != proc->alloc.vm_start) > + return; So .. this does work in the case of mremap, but how about instead doing this? static int binder_mremap(struct vm_area_struct *vma) { vma->vm_private_data = NULL; return -EINVAL; } and then check for NULL in binder_vma_close() instead? I think that logic would be a bit easier to understand. Alice