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 E37A226F2AD for ; Mon, 24 Nov 2025 14:50:48 +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=1763995849; cv=none; b=QIpx9KAm5LjIw/1VVeffDXU9TPOBE2PBDE0JA0jvr66kOX7PewW+27PoZEBZaVQbpOmtVjWozPVBBlW9Y7BpXKTyFyLB30kEk1rlpJTdysH0ZT2Cr9KGa/AkaGlbNd0NqwfPmKC9lHviLtQtlJGlJFX4FReMPBpwSfuhm3wCYsg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763995849; c=relaxed/simple; bh=U1DlVLfZ2HhDp+QUcAihuyMgg/P2ejCMNTUv2cC900M=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=nCrnS6r1PGYcXRQ46RuMshdqOI67+QLnrFBcyh1vhnEEF10Kwlm34S1oGCayhovap29a3H4ebpIjwJwIJ7s1hUoNVWgthjE6bTh5JPOyCKKogN1g1B/5ZsxgXU35Ym4qtHyS0wexIi2AMfUyd+Ny7aX4VPHw3cmOKiL5jxrUTVo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=zukuhWj0; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="zukuhWj0" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0AD5EC4CEF1; Mon, 24 Nov 2025 14:50:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1763995848; bh=U1DlVLfZ2HhDp+QUcAihuyMgg/P2ejCMNTUv2cC900M=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=zukuhWj0PmF4SV8R8jeLxkhcH2kPpxyEI0Fit22+foawTYLhT7OlwxI2Wc5FIff97 +XBkxLZVEHWVyC/fkVN5MuOUZYZc37VvYO/nn/IBdxbR2Ad6p9tobqG5cp54SvG3oF DHVxL39L24UC/uvn7Ue74yxzP+Om7aFlvsI4LnHU= Date: Mon, 24 Nov 2025 15:50:45 +0100 From: Greg KH To: Sasha Levin Cc: stable@vger.kernel.org, Sebastian Ene , Will Deacon , Marc Zyngier Subject: Re: [PATCH 6.6.y] KVM: arm64: Check the untrusted offset in FF-A memory share Message-ID: <2025112405-campus-flatworm-25a5@gregkh> References: <2025112429-pasture-geometry-591b@gregkh> <20251124141134.4098048-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251124141134.4098048-1-sashal@kernel.org> On Mon, Nov 24, 2025 at 09:11:34AM -0500, Sasha Levin wrote: > From: Sebastian Ene > > [ Upstream commit 103e17aac09cdd358133f9e00998b75d6c1f1518 ] > > Verify the offset to prevent OOB access in the hypervisor > FF-A buffer in case an untrusted large enough value > [U32_MAX - sizeof(struct ffa_composite_mem_region) + 1, U32_MAX] > is set from the host kernel. > > Signed-off-by: Sebastian Ene > Acked-by: Will Deacon > Link: https://patch.msgid.link/20251017075710.2605118-1-sebastianene@google.com > Signed-off-by: Marc Zyngier > Signed-off-by: Sasha Levin > --- > arch/arm64/kvm/hyp/nvhe/ffa.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/arch/arm64/kvm/hyp/nvhe/ffa.c b/arch/arm64/kvm/hyp/nvhe/ffa.c > index 8d21ab904f1a9..eacf4ba1d88e9 100644 > --- a/arch/arm64/kvm/hyp/nvhe/ffa.c > +++ b/arch/arm64/kvm/hyp/nvhe/ffa.c > @@ -425,7 +425,7 @@ static void __do_ffa_mem_xfer(const u64 func_id, > DECLARE_REG(u32, npages_mbz, ctxt, 4); > struct ffa_composite_mem_region *reg; > struct ffa_mem_region *buf; > - u32 offset, nr_ranges; > + u32 offset, nr_ranges, checked_offset; > int ret = 0; > > if (addr_mbz || npages_mbz || fraglen > len || > @@ -460,7 +460,12 @@ static void __do_ffa_mem_xfer(const u64 func_id, > goto out_unlock; > } > > - if (fraglen < offset + sizeof(struct ffa_composite_mem_region)) { > + if (check_add_overflow(offset, sizeof(struct ffa_composite_mem_region), &checked_offset)) { > + ret = FFA_RET_INVALID_PARAMETERS; > + goto out_unlock; > + } I was told that a "straight" backport like this was not correct, so we need a "better" one :( Sebastian, can you provide the correct backport for 6.6.y please? thanks, greg k-h