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=1792774235; b=ds5IcZ0r9Dw8UBrBSYY/t+lvNullI5btmskCVrBqetoWDoei+vVbhXkJTGoELq7UMwaw /Yp7cK0K/ifPdGkc+gUeurfJTqCMaGsmySgI5X7ZiYA4/ejJKj2O18A+SHPNyzL881Yds WPq481mJ/x0i2FD8IR2QptCdpyi/MdQB2SWnNZStEAvsbfecUZ2OjPgAdf73/FngS4L6d 3ueOD5POHhozIYOT/0OimtRxNbqWqmjAUbVOghe0KYGXEHcMYVzLMmXaxIKZeF7R80Xty gkwDhKRbEWTGUR9uCHK8XYO70tTJsU0V5VkYHi/j8EsHwCFXpSXR7UNzJ/t/ssj6zKA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792774235; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=9tn2rXB/H9ox0J+/C64OdYdxD89mYnoy4np60qM+QlI=; b=f+qMoA88ekZt2FTXQOt41GNFXJImFTiyRCMH1c+EeKN23TU/z6Yq4NDzLKj2n6In0H4G kXan4O2/7Aja/hi/3xf+8pJsrA6VlvjILSdnezqd07dlZXc21TBi1QBaqhWrK4ENxXyYV +HAF9MhOoIJcSai78J0P96QFR0DMOAAquejY7hnF2X/+aNhh5oDhr7qWgyft+CR7QWZHC D+3QR9Ib7Y0vwFsP3vb0G9uVK9yBQsk8McAV+J0rG800o0lLHKc1GvbTt///aM7ysRiVS 93kMZuJ50QXd7PTH+U4gZTDTix57oElCpltbUUc8j1DL0FhVvHFT1A+PHXImfkf+eiA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=SABNuzSm; 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 196A9606A31B; Fri, 23 Oct 2026 16:50:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=SABNuzSm Received: by smtp.kernel.org (Postfix) with ESMTPSA id 616221F01828; Fri, 23 Oct 2026 16:50:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792774234; bh=9tn2rXB/H9ox0J+/C64OdYdxD89mYnoy4np60qM+QlI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=SABNuzSmaJSKfjWXqRzTCkW5xdNcLQSX4wMzKDpFRaML0EW3rJE89+w88dE5Rnmbi 9ciMP6zdrb3vGvToVe/mMgKRnxIuIbwDsn6ChsBlHLWZav5zgTLexk+Ijds8dScBTc GXpYRoVMG0unV4xqXT/S3yttxkfzWPyCujXtTWow= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Dibin Moolakadan Subrahmanian , Mitul Golani , Ankit Nautiyal , Joonas Lahtinen , Sasha Levin Subject: [PATCH 6.18 165/193] drm/i915/dmc: Harden DMC firmware payload parsing Date: Fri, 23 Oct 2026 18:37:22 +0200 Message-ID: <20261023163718.116287421@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261023163714.201276352@linuxfoundation.org> References: <20261023163714.201276352@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ 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 Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/i915/display/intel_dmc.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) --- a/drivers/gpu/drm/i915/display/intel_dmc.c +++ b/drivers/gpu/drm/i915/display/intel_dmc.c @@ -1132,7 +1132,7 @@ static u32 parse_dmc_fw_header(struct in } /* 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; } @@ -1178,13 +1178,21 @@ static u32 parse_dmc_fw_header(struct in 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; @@ -1192,7 +1200,6 @@ static u32 parse_dmc_fw_header(struct in 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)) { @@ -1204,6 +1211,10 @@ static u32 parse_dmc_fw_header(struct in 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);