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=1792673707; b=MYp8/KZbPD5jAgwrId38qUVcqLVbX+pL8o4nYEBRBxv754h18EIeY/cUCdy7cwAZ7Zk9 z7gzjvwZojPnO20wTZhbArol4ZYes4rit+rkXFeRJSuSA67fpGJLisYCpP+kSsIGBkflw 80xGJl/Np2Cgp+dPadUAeK3QQMDeFjKSIU2iA6egVlzQ92p4s/EkkD4jl/kLSr1OTTAV3 h0X1WJXT269FiUm8wFX+E+w5uM7647yA0uZUTs1x5kjwHKz7cDOcJGxs/UOWyFq8PPFuR /KGxzZh/XZ0hn+TCOmz7dSQtboJrQcFQ9OljfK8kVfIbYzb/yET1IOkBM2M2TgcN4/w== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792673707; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=H8DFoxt5zy8uCsvpWqodTyMFJID0sWP0UTMoV2TVPto=; b=C6GL6doxMXOecDWHnnIDKwb5xQVRn89JUR5eYdISjLU3qn2fRIKHyDybYDx7GteGRwKl o5ZgkFLGAyuWLjNzZgz9ZNln2GrTJHp78UCaPjKH15U6AmUjFS9eSCB5mO1IjETL4N6aI A4hFTHuLxqifCApA6w6C18IBk+4GtJN58y2ZwC8P81uJOdUhxXwQj2el+47+7C4a+M84V gxiJPgdze30I0G2F7OZHcbMQTP0Ys0FsrgJVJ6mGvsjW+VlJNLE+aHlJkQgBd6lBa2GOi qpKytIv7JBPVx/I+y1p7IqpROsWCVqNSLR8b4vTlzCHY2Isiw0xw2YAy47/D6VE0ZnA== 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=eXepuRjC; 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 46695606A319 for ; Thu, 22 Oct 2026 12:55:07 +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=eXepuRjC Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6F9631F000C1; Thu, 22 Oct 2026 12:55:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792673707; bh=H8DFoxt5zy8uCsvpWqodTyMFJID0sWP0UTMoV2TVPto=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=eXepuRjCPJvK97ahUuZYelFUD0PgBO2KGKj6wip4tcABzDQWZO4JlIjajQb8JdpmT elMZqD0VUvJnEvwVhZ++P7RACZ4tEkQbBKkgTiGfgeZNFLBsGtikkXoGNL/E6zJfWM kHCCRwHqGiJE4kgcF8yh+D1t7VsaBnLmZh0UO0ixOzc3xXpJykQXIcQG/6eIzbMxaj mVKPUpvLSqDV9OAedaEQar9XooqUa5kPwcsADkp+dGFJQY4UqhY26LtQM/AC/Klybg VTsT/vrH24q9myglDp1k21OuNcg4FfkG7G+m8OHpl0aehFWJ4+7d/DnmRvxbr4F1t7 La7U692wBgIkA== From: Sasha Levin To: stable@vger.kernel.org Cc: Dibin Moolakadan Subrahmanian , Mitul Golani , Ankit Nautiyal , Joonas Lahtinen , Sasha Levin Subject: [PATCH 6.12.y] drm/i915/dmc: Harden DMC firmware payload parsing Date: Thu, 22 Oct 2026 08:55:05 -0400 Message-ID: <20261022125422.1187451-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026102110-spry-excursion-fbc9@gregkh> References: <2026102110-spry-excursion-fbc9@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 logging arguments from `display->drm` to `&i915->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 7c756d5ba2a22..641dabf275e73 100644 --- a/drivers/gpu/drm/i915/display/intel_dmc.c +++ b/drivers/gpu/drm/i915/display/intel_dmc.c @@ -796,7 +796,7 @@ 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; } @@ -819,13 +819,21 @@ static u32 parse_dmc_fw_header(struct intel_dmc *dmc, disable_dmc_evt(i915, 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(&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; @@ -833,12 +841,15 @@ 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