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=1792633806; b=sv4uDtfZ6Ac031lkUu6bcV4LgpnAeaMHm99RTEobtajg/8JPrmrXBGZ7WBdTGgHykK5p PMBFhYAHxyDFQbuZZxUjy8aLdM4swh0SjD+ULlm7ms0wjDtExSYXo6SUOfCIrFaa/3Bcc lJCX2Hn9QhTUdEWBKa0/0qKdUwtGOjAG3IGY8Yx9xC7rwiT7IBQ4sxxU0FhPUsxTs1e/l RbThkQ1Fbzago4kByTxZHdGXusm6ZqQ61QbczkbugxcJe3OjsS9W1eg20lYi0P+MADzil hOE3KmexshtAGFHYHs412n6uwqNnjDAndGromIGh/9Aq6mEQ4E75stTTqSaZzcCfdEg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792633806; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=qr/Rm+ILrxVANLtARrqeGvnJWRvrGPZ1Z8mpGvPnjeA=; b=1C2Rm76cnBWX8SkJXLCjbq2qlBVFCVizsR1cNNmHqPA1c2TZWz6ipfVPwjVFjms4Kp+o BhIpYQiTjCxfY7Ytvg1hX49O9ML/hSUGw0A7yBLBs/Po8PvsOE+WkmFAahMd0+t3rVbTH YIFo9EnuB5dVnbKIIRkFxiKeAjcYQIrl69j0DSXRfhZrhYiRs8yo9tWGqmIgIhilwLnyq zN98Rbr/6liYYkmi35dY+TeSwlG0RTb/J5/XA9RnpfaqT/S62Ou3Oxz8MySUgoLzEbzQb yPB+KeeuRIwOYodCK27DHDzRHeWar41UBCzZY4loNRjTj993k3RYH61jzPJtwdC2eug== 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=gzmzUXR3; 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 EA5DF606A31A for ; Thu, 22 Oct 2026 01:50:05 +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=gzmzUXR3 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 041BA1F000C1; Thu, 22 Oct 2026 01:50:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792633805; bh=qr/Rm+ILrxVANLtARrqeGvnJWRvrGPZ1Z8mpGvPnjeA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=gzmzUXR3jh07sosfNQ1rVSPBMKsDFQpzCFwe36jfojs89MlZOQ8o5ip1eiyryJSoO +chpsJ4LL7PNehy3+d76oEBfsXZEZg7SRpN8RqQv//YPa0Y7R6QXeMyMHY9ET5DY7t hhY3FcbdwB+iCfHcLmvMbQDoRgxZ6qnNqA50uAbBTX6JwjErkui3MOtndF8xMYJ5CQ LfxHmmAsRdcK5uN/qJrpjSEaWznpjuNuUpvo7Cq8wZV74nSl0TTkiI3fKNB5yi7q5t /FBS9x2A2dWtQk3B7/YDDcwJ95oevWQjx1oavwNO5nw+GAoy9NMeQu6wk/+HJufTb7 9X31JOFhzj90Q== From: Sasha Levin To: stable@vger.kernel.org Cc: Dibin Moolakadan Subrahmanian , Mitul Golani , Ankit Nautiyal , Joonas Lahtinen , Sasha Levin Subject: [PATCH 7.2.y] drm/i915/dmc: Harden DMC firmware payload parsing Date: Wed, 21 Oct 2026 21:50:02 -0400 Message-ID: <20261022014926.920567-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026102110-duct-scaling-e1b3@gregkh> References: <2026102110-duct-scaling-e1b3@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 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 36a28da65fcf0..630a5cd68bbd7 100644 --- a/drivers/gpu/drm/i915/display/intel_dmc.c +++ b/drivers/gpu/drm/i915/display/intel_dmc.c @@ -1165,7 +1165,7 @@ 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(display->drm, "DMC firmware has wrong mmio count %u\n", mmio_count); return 0; } @@ -1211,13 +1211,21 @@ static u32 parse_dmc_fw_header(struct intel_dmc *dmc, disable_dmc_evt(display, dmc_id, dmc_info->mmioaddr[i], dmc_info->mmiodata[i]) ? " (disabling)" : ""); } - 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(display->drm, "DMC fw_size too large (%u dwords)\n", + dmc_header->fw_size); + return 0; + } + + if (!payload_size) { + drm_err(display->drm, "DMC firmware has empty payload\n"); + return 0; + } + if (rem_size < payload_size) goto error_truncated; @@ -1225,7 +1233,6 @@ static u32 parse_dmc_fw_header(struct intel_dmc *dmc, drm_err(display->drm, "DMC FW too big (%u bytes)\n", payload_size); return 0; } - dmc_info->dmc_fw_size = dmc_header->fw_size; if (!dmc_load_addr_sanity_check(dmc, start_mmioaddr, payload_size, dmc_header->header_ver, dmc_id)) { @@ -1237,6 +1244,10 @@ static u32 parse_dmc_fw_header(struct intel_dmc *dmc, 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