From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 BD2D617DFE7; Thu, 2 Apr 2026 13:41:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775137307; cv=none; b=Cb5OnS/rmBhb9gRQCSwCIXP5rJLe5icT5z4slOwwlVHOijgGF9aSZ3K1OetLMLt3MpOdyROauAQ4hBceo5SdjtYie3zWk+PRX0+OdUvc25BFL6WwC/ga+iMC6Gwt5umbxT9WNmFkexMjqM3rbvMfU3S5eRReOtA5LkDhZeTosc8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775137307; c=relaxed/simple; bh=y+4Ba2RbjgWbWGBtG4CNWeYwQ3D0Ktt09+OLEN8nWsI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=oe2BNs5FnHdbVTXaXnXWc+ukB/t6mPst91vpvhrgtSax+a5/GM2f4Tuw0bUhAH6+jpHOP9bP21kwRqry8ocV+Fqd5Sg2GWR+3chTwZn6I1yJm+N2jox9PjAG7QxgRWuoDrhXlWs7ghFRSbM+4Uzv9dRtwE5O59U49vzjV0T6dXM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=biCGoDrc; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="biCGoDrc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 99C49C116C6; Thu, 2 Apr 2026 13:41:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1775137307; bh=y+4Ba2RbjgWbWGBtG4CNWeYwQ3D0Ktt09+OLEN8nWsI=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=biCGoDrcZXF3+ybM9OAjlA/o9t+w0yen5GjrrEJbqbWptnQH7ycACGdcOOL5YIqt7 Z9LsDPnCvrenIyLWZP93/iwrJHUiN/4Q6C+PuoEpCFv3RaPuOsxO90bzXqOAqtOn/j 2FmCr7vKwi7IHI+e5wGUyQtRML0yZ0MC21tD+aFDII0LPbNcXQpd/xpQm7LmVzDcm6 Ysal31cUE6R5gQ6xeO5yeBxWedm24q/ziSEzcHomvBD8mfnROBiVFrLy8tHsjGTu+I f+N3p8p/d+DNHzr8b7Edp1fByw+wUzG+WkgO0eKfbIg1Wg6Gf9xheG59mW02GwsnFY SAySoiKsnuIiw== Message-ID: <001dd80c-adfd-4f28-8c2b-68f0ef9ce8ff@kernel.org> Date: Thu, 2 Apr 2026 15:41:42 +0200 Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] prctl: require checkpoint_restore_ns_capable for PR_SET_MM_MAP To: Oleg Nesterov , Qi Tang Cc: Andrew Morton , Cyrill Gorcunov , Lorenzo Stoakes , linux-kernel@vger.kernel.org, stable@vger.kernel.org References: <20260402111332.55957-1-tpluszz77@gmail.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 4/2/26 15:13, Oleg Nesterov wrote: > Note also the comment above validate_prctl_map_addr() called by > prctl_set_mm_map(), "we don't require any capability here ...". > > Oleg. > > On 04/02, Oleg Nesterov wrote: >> >> On 04/02, Qi Tang wrote: >>> >>> The original commit f606b77f1a9e ("prctl: PR_SET_MM -- introduce >>> PR_SET_MM_MAP operation") states "we require the caller to be at least >>> user-namespace root user", but this was never enforced in the code. >>> >>> Add a checkpoint_restore_ns_capable() check at the top of >>> prctl_set_mm_map(), after the PR_SET_MM_MAP_SIZE early return. This >>> requires CAP_CHECKPOINT_RESTORE or CAP_SYS_ADMIN in the caller's >>> user namespace, matching the stated design intent and the existing >>> check for exe_fd changes. >> >> Can't really comment... but if you add this check at the start, then you >> should also remove the same checkpoint_restore_ns_capable() check below? >> In the "if (prctl_map.exe_fd != (u32)-1)" block. >> > I'll note that the man page is wrong as well. PR_SET_MM lists PR_SET_MM_MAP, but states "The calling process must have the CAP_SYS_RESOURCE capability." -- Cheers, David