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=1792678440; b=GHb5lFyRKEtlx/rUN9j1KPY16aO7GgtTWSsK/tBsZU49LlzlWOfD2B9N+ssejycm5B6z pvmaTeuumtjpl2bP0rYWrdXSGBD2lWTuAjaMZrLI5/d4ZbbhjNFUKFQxlkoSb14ZVZa4S /a4pJq9l2E8kcl9o5EIUR7xep1CQvRTAZX002ZiEYS8Xi2fs/oXbW3A1WBlPHE4ED5GOa 82yEPyvlhPGarZiOeNTsaiR4xRU74I1Cecmfk4dPmE7taL8sCDVih1arAEHyW4f/lZMz1 sgb8je8TgT+E3WVmlgNiA1geuJxcWlv75N/FNO3GoKgFIj2TODqqFDt+eZqFZheeIIg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792678440; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=clU2j4pqxdEjQb9dH3FUI5e5sN2lER/XbaJydlIq1xU=; b=skbmCl1663YLrgX0weK+G7PhvHTWAO+FQZHFG8w6CRMzt86PIOFFdyo0XXZ+D/spkxB2 cbe2yjpVKbTckJp17BxtjsLyWHubsSVGF6lT9q+ULObwCwY27I3iM4tAym7JQrxza2Vet ggYDg/SQJKcPNUNA/msQVg329NDJgBze0Oc4AYSLg9mDk9dNL1QGScoAss0qd4T7Mcm0w inir6vN2m1y7Qiw4Cn5p5pltXTxHulhfO+BLczpX6jz2adbIeXsXNk0Pwf2qYRmihoSg/ ukpzm1PYyq++28BEeKibUxeeIWQc6Ki9l5ha6gZhL1FSa5WdtIFCZMUmb6fPqPb7jsQ== 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=W09zTr40; 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 0AFEF606A319 for ; Thu, 22 Oct 2026 14:13:59 +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=W09zTr40 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 08DA01F000C1; Thu, 22 Oct 2026 14:13:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792678439; bh=clU2j4pqxdEjQb9dH3FUI5e5sN2lER/XbaJydlIq1xU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=W09zTr40wG+duwF4aj0HBY6OXNMIm+blEkqkGeFYNDxL01v8WxRCEdhTRI0CCn/PJ bOXs4eitPzU5Mq3imMoy25NjpPpRhcHzGSXe2c7HJUhW4IQaIrxyRkibZU7uA/zVt0 jfrTX56YigYruOWfVQMgznwp/fmb+UCUwES09hUbgtYBBw0A6b+A1FUlLBfjdCQZBZ XLLwi44DtDbg0A0hlLV7GTPwPYa/t7o7J4QmycszwfRSJVQiWVwTOepKryBtfNhxko fzfaFE8KiOns7BTgYxezDOFZltwLnBn52IwHJ24lXXEzzgCvNUETLZKjpRSIHU/bKR cpBNo8eAH+l5A== From: Sasha Levin To: stable@vger.kernel.org Cc: Dibin Moolakadan Subrahmanian , Mitul Golani , Ankit Nautiyal , Joonas Lahtinen , Sasha Levin Subject: [PATCH 6.1.y] drm/i915/dmc: Harden DMC firmware payload parsing Date: Thu, 22 Oct 2026 10:13:57 -0400 Message-ID: <20261022141334.1514530-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026102111-speller-abacus-9b11@gregkh> References: <2026102111-speller-abacus-9b11@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: Adapted 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 e52ecc0738a60..722fdffb09f93 100644 --- a/drivers/gpu/drm/i915/display/intel_dmc.c +++ b/drivers/gpu/drm/i915/display/intel_dmc.c @@ -645,7 +645,7 @@ 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; } @@ -660,13 +660,21 @@ 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; @@ -674,12 +682,15 @@ 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