From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 DDE3E26F2BF for ; Tue, 23 Jun 2026 12:19:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782217155; cv=none; b=X/qWZ7oGaeTgRCxmBZo4vnTRAGx4DMZnYocwaWCXkR8wOBuELaUPf6Y5d3OsgN57+ElueDsu/evsbh+GUmvas4gHBZutFGmf9rixT7ekmOyMSPivarv2WTtzId6+zP2vYrSRHmefMX+s5imrFbXSguM3Sw0CEqMAvJ++OPB1Uyk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782217155; c=relaxed/simple; bh=/c4USNILwJ+Grilg6KhpEjIIKxyAqEhS8O3f0ma0K+s=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=ikCehzzI1NukPhjExp4FRV3lPWn/ANUrO3FfcpNWNrltjTD/OnBgAcLQiAro5UQpa/G7s3LLQKT3rDuuDISJ6tl9iYJCodvd3/VqJmfvdB4kS18FzDt7hMSLkIU/mewXAs3UbPeyFSp6IJEQgFvno879CoavjOgsCSsGGiPhpvU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=m2knUe1M; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="m2knUe1M" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 145E61F000E9; Tue, 23 Jun 2026 12:19:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782217154; bh=okApS8kA1BHmpX9NtGOiC0KXJACuDAVb6ZoT6zw+Ygs=; h=From:To:Cc:Subject:In-Reply-To:References:Date; b=m2knUe1M/njq7jjIqMM0aYd0IQ1XadhqQ4jHEZXlizp3dwr2PJ2e3+wjZ0In7VD6r +/Pkf7DTaEef2gEGsEyTvnu1KWETnlSwseXzQ0BP6nB7fOkEZ0SwRdHibAG9V3aLz2 xFqh4wBNAyd/83J23xxCJTz6i06Xw7goDbYaJT8QMTkdJ5XPeVBWESgp3K0viBLkPs V30JcTeKkiT7nLtPEaHhjNVQGN/g9YjHKPZxpfJ4VxEiWx7GcEQQ8rtaegWUBuNW7l N+9jFDja10LrcQIoov0l7Vbv4xErtjZ11aJ7GMV9bJefR1ifZ3PmI3k7E5MWLp5cge wzrxfxhdONdbw== From: Pratyush Yadav To: Tarun Sahu Cc: Mike Rapoport , Pasha Tatashin , Pratyush Yadav , Andrew Morton , Alexander Graf , kexec@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v5 1/3] mm/memfd_luo: validate serialized_data before conversion In-Reply-To: <20260623105201.3724592-2-tarunsahu@google.com> (Tarun Sahu's message of "Tue, 23 Jun 2026 10:51:59 +0000") References: <20260623105201.3724592-1-tarunsahu@google.com> <20260623105201.3724592-2-tarunsahu@google.com> Date: Tue, 23 Jun 2026 14:19:11 +0200 Message-ID: <2vxz5x39o3eo.fsf@kernel.org> User-Agent: Gnus/5.13 (Gnus v5.13) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain On Tue, Jun 23 2026, Tarun Sahu wrote: > In memfd_luo_finish() and memfd_luo_retrieve(), phys_to_virt() was called > on args->serialized_data before checking if the physical address is valid. > Since physical address 0 does not map to virtual NULL (due to direct > mapping offsets), the subsequent check 'if (!ser)' was ineffective at > catching a missing serialized_data, leading to unsafe dereferences later. > > Validate that args->serialized_data is non-zero before calling > phys_to_virt(). > > Fixes: b3749f174d68 ("mm: memfd_luo: allow preserving memfd") > Signed-off-by: Tarun Sahu Reviewed-by: Pratyush Yadav (Google) [...] -- Regards, Pratyush Yadav