From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from cstnet.cn (smtp21.cstnet.cn [159.226.251.21]) (using TLSv1.2 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C0CA836C0CF; Mon, 6 Jul 2026 09:30:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=159.226.251.21 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783330251; cv=none; b=KMWb0lsPupohy0Z2LoNnuVGjIHSvu8uni1xj+hUlKuxX8SYoqPupjRYEtVhUQuapLtZkoBmgjLbzC9BTq4C0JtZushjmAoEQG0UceWVchJtBPeOe5C4v2wA+h0q8dV/i/Fjxusezl5iZS57S4ZvF5tCxH3jNsv5xClxFUy01F7U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783330251; c=relaxed/simple; bh=UKJaYzXQgBA6GYJ11kuKjmpr1u2CLrWsEtlsja4jrVc=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=igMes17rnO7c/jvzhgutONXgtyQkbHsSF57LDKTcO5S4ifLktmSbxEsJ7+7IY/jgAQhHfkxm0ypU0YKMUr3XpZVPf+YLbqB9gOMMN/QhtqPB1F7BDwZ2hlipntso7f7Oj+ogEz/3l/KNdJe+jN2hZoyCs6ggi9uB1bff6eTcoE8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=iscas.ac.cn; spf=pass smtp.mailfrom=iscas.ac.cn; arc=none smtp.client-ip=159.226.251.21 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=iscas.ac.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=iscas.ac.cn Received: from localhost.localdomain (unknown [111.196.245.140]) by APP-01 (Coremail) with SMTP id qwCowAAHp8_AdUtqOnbxBA--.1276S2; Mon, 06 Jul 2026 17:30:40 +0800 (CST) From: Pengpeng Hou To: Bernie Thompson Cc: Pengpeng Hou , Helge Deller , linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: [PATCH] fbdev: udlfb: validate vendor descriptor items Date: Mon, 6 Jul 2026 17:30:38 +0800 Message-ID: <20260706093038.80131-1-pengpeng@iscas.ac.cn> X-Mailer: git-send-email 2.50.1 Precedence: bulk X-Mailing-List: linux-fbdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID:qwCowAAHp8_AdUtqOnbxBA--.1276S2 X-Coremail-Antispam: 1UD129KBjvJXoW7Wry3Cw1rAF47ZF48JrWDurg_yoW8Xr1Dpa 13Ja4YqrW7Aw47trW3Kw4UZF1rAayxGF9IyFyxt34Ygw4ak34ag345CFy8W3ySqF4kAr40 gr1Yk3y7G3Z8KFJanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUkE14x267AKxVWUJVW8JwAFc2x0x2IEx4CE42xK8VAvwI8IcIk0 rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02 1l84ACjcxK6xIIjxv20xvE14v26ryj6F1UM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r4U JVWxJr1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2z4x0Y4vEx4A2jsIEc7CjxVAFwI0_Gc CE3s1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG64xvF2IEw4CE5I8CrVC2j2WlYx0E 2Ix0cI8IcVAFwI0_Jw0_WrylYx0Ex4A2jsIE14v26r4j6F4UMcvjeVCFs4IE7xkEbVWUJV W8JwACjcxG0xvY0x0EwIxGrwACjI8F5VA0II8E6IAqYI8I648v4I1lc7CjxVAaw2AFwI0_ JF0_Jw1l42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG67 AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r126r1DMIIY rxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Gr0_Xr1lIxAIcVC0I7IYx2IY6xkF7I0E14 v26F4j6r4UJwCI42IY6xAIw20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Gr0_ Cr1lIxAIcVC2z280aVCY1x0267AKxVW8Jr0_Cr1UYxBIdaVFxhVjvjDU0xZFpf9x0JU2Q6 JUUUUU= X-CM-SenderInfo: pshqw1xhqjqxpvfd2hldfou0/ dlfb_parse_vendor_descriptor() walks key-length-value items inside the DisplayLink vendor descriptor. Require each item to contain its key, length and declared value bytes before reading item-specific fields such as max_area. Signed-off-by: Pengpeng Hou --- drivers/video/fbdev/udlfb.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) diff --git a/drivers/video/fbdev/udlfb.c b/drivers/video/fbdev/udlfb.c index fdbb8671a810..e78d6f95c9c5 100644 --- a/drivers/video/fbdev/udlfb.c +++ b/drivers/video/fbdev/udlfb.c @@ -1586,19 +1586,29 @@ static int dlfb_parse_vendor_descriptor(struct dlfb_data *dlfb, desc += 5; /* the fixed header we've already parsed */ while (desc < desc_end) { + char *value; u8 length; u16 key; - key = *desc++; - key |= (u16)*desc++ << 8; + if (desc_end - desc < sizeof(key) + sizeof(length)) + goto unrecognized; + + key = get_unaligned_le16(desc); + desc += sizeof(key); length = *desc++; + if (length > desc_end - desc) + goto unrecognized; + + value = desc; switch (key) { case 0x0200: { /* max_area */ - u32 max_area = *desc++; - max_area |= (u32)*desc++ << 8; - max_area |= (u32)*desc++ << 16; - max_area |= (u32)*desc++ << 24; + u32 max_area; + + if (length < sizeof(max_area)) + goto unrecognized; + + max_area = get_unaligned_le32(value); dev_warn(&intf->dev, "DL chip limited to %d pixel modes\n", max_area); -- 2.43.0