From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792682072; b=tUN1rs3YIUn68S+LdR70y9hHyWBRtFKKru0H8EJEo0b/fHCf6w8KyVeHC4Xo4TDarRqs GyaNWRWba0WsEHwu8UG+00saqOAtngZ1F27eNqSNz0FqfpDSnH3gZZNZYJjjE7ncaWX+M tNN9dl8BH0JOAzxNfSJ5qSkTf1q37ULD5XQNqkWjWQbscQNajx8tRJgUJQJVrlpynmK8N 8lxgDKQW+dGCL398CxWepU4U8TsTUCtD8xDHZd2HZeaBl1GmPSOZI5sBBkOqtSGQHfSEe fSiLkMapEVID2reWKUvfdCDgoFiExaBxjeqSaxW6qGvm9VLk+u8CsKdDPqam/ooMt0g== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792682072; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=+54fDur+D7mK8N1hyKo2kfkibhnJ75lsD6CQJTGplec=; b=dFeCbh6lOgjCE5eUNjFx9dVbAQBtbDrxs5cT86bmVEPXOmOZJBPgh1gin58uuBA8lE+p CFgsHFmVpGpGjSmPxp1FxRJjtpgXGE/yjlDGGvgvYyqog7F8tHnlu9UygmVxhY79oLEeO xALuonUxG3P0jBFQWnpDpv8sldDNqVU+Muh5wbKvqJuweSoOHpQf+plFibHdUQZWG1q3p O48Ax825pVNbLZMC9MDYU7Kir6vr1JKQedKzCPwJMnoqgCkNFTMkCjLXCTBqPf9y9yD2B o4s0IsyaM4F0KhiP6KUfWtLsqIefcRNFreiIzj0k+W9HCc/4TQA6PvGdB42dTac51JA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=QYp8yi4L; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3269F606ACD9 for ; Thu, 22 Oct 2026 15:14:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=QYp8yi4L Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5BA041F01825; Thu, 22 Oct 2026 15:14:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792682072; bh=+54fDur+D7mK8N1hyKo2kfkibhnJ75lsD6CQJTGplec=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=QYp8yi4LeOkwrGwAQoOMqnau5Tmv5PnWghwzkfWqC1bFJ4F4ZNKnDM8yyo49jWOgu VuR2iFnL+7tzYc9Wi7Yf+rwVdQXU+NL2fRaTnrijbnxrgMj51eB8G6MJTFxENzobqO VlFlktx7RXDAUT1wbv+r+OI2GIg5PMbpWHGqWhzmWJv9X6Qs05XO/DMV4PR5ojwcgn FWOBf1Umw+cKqpv+a8DgLS6b+X8WnlLKyD/FheAIVOCMkzbWS06PRx4Rev4Z4ffrlW PmN40hpfzzz3rb4zD92FGfgMNMJRM3a8qiHhX2e0k3+ecKwczpqT8l3+H1yvZKm7fK wBnP8XP7z9beA== From: Sasha Levin To: stable@vger.kernel.org Cc: Dibin Moolakadan Subrahmanian , Mitul Golani , Ankit Nautiyal , Joonas Lahtinen , Sasha Levin Subject: [PATCH 5.15.y] drm/i915/dmc: Harden DMC firmware payload parsing Date: Thu, 22 Oct 2026 11:14:30 -0400 Message-ID: <20261022150729.1593802-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026102111-chief-uneven-0c72@gregkh> References: <2026102111-chief-uneven-0c72@gregkh> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Dibin Moolakadan Subrahmanian [ Upstream commit 8bb1858db453cd4250e3b633f5d2d09206024ca6 ] Validate the conversion of the DMC firmware size from dwords to bytes using check_mul_overflow() before calculating the firmware payload size. Reject zero-length payloads and zero MMIO counts in the DMC firmware header so malformed firmware is caught early. Also set dmc_fw_size only after the payload allocation succeeds. Fixes: eb805623d8b1 ("drm/i915/skl: Add support to load SKL CSR firmware.") Cc: stable@vger.kernel.org Assisted-by: Claude-Code:Sonnet-5 Signed-off-by: Dibin Moolakadan Subrahmanian Reviewed-by: Mitul Golani Signed-off-by: Ankit Nautiyal Link: https://patch.msgid.link/20260922133535.3180973-5-dibin.moolakadan.subrahmanian@intel.com (cherry picked from commit efde6601a1f1daedfe3dcc2816c934ddb44e3eef) Signed-off-by: Joonas Lahtinen [ sashal: changed drm_err() calls to use &i915->drm instead of display->drm ] Signed-off-by: Sasha Levin --- drivers/gpu/drm/i915/display/intel_dmc.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/i915/display/intel_dmc.c b/drivers/gpu/drm/i915/display/intel_dmc.c index 0e04d4dd1c132..a0d6eb90d55a3 100644 --- a/drivers/gpu/drm/i915/display/intel_dmc.c +++ b/drivers/gpu/drm/i915/display/intel_dmc.c @@ -477,7 +477,7 @@ static u32 parse_dmc_fw_header(struct intel_dmc *dmc, } /* Cache the dmc header info. */ - if (mmio_count > mmio_count_max) { + if (!mmio_count || mmio_count > mmio_count_max) { drm_err(&i915->drm, "DMC firmware has wrong mmio count %u\n", mmio_count); return 0; } @@ -492,13 +492,21 @@ static u32 parse_dmc_fw_header(struct intel_dmc *dmc, dmc_info->mmioaddr[i] = _MMIO(mmioaddr[i]); dmc_info->mmiodata[i] = mmiodata[i]; } - dmc_info->mmio_count = mmio_count; - dmc_info->start_mmioaddr = start_mmioaddr; rem_size -= header_len_bytes; /* fw_size is in dwords, so multiplied by 4 to convert into bytes. */ - payload_size = dmc_header->fw_size * 4; + if (check_mul_overflow(dmc_header->fw_size, 4u, &payload_size)) { + drm_err(&i915->drm, "DMC fw_size too large (%u dwords)\n", + dmc_header->fw_size); + return 0; + } + + if (!payload_size) { + drm_err(&i915->drm, "DMC firmware has empty payload\n"); + return 0; + } + if (rem_size < payload_size) goto error_truncated; @@ -506,12 +514,15 @@ static u32 parse_dmc_fw_header(struct intel_dmc *dmc, drm_err(&i915->drm, "DMC FW too big (%u bytes)\n", payload_size); return 0; } - dmc_info->dmc_fw_size = dmc_header->fw_size; dmc_info->payload = kmalloc(payload_size, GFP_KERNEL); if (!dmc_info->payload) return 0; + dmc_info->mmio_count = mmio_count; + dmc_info->start_mmioaddr = start_mmioaddr; + dmc_info->dmc_fw_size = dmc_header->fw_size; + payload = (u8 *)(dmc_header) + header_len_bytes; memcpy(dmc_info->payload, payload, payload_size); -- 2.53.0