From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f180.google.com (mail-pg1-f180.google.com [209.85.215.180]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 53B0D1F4634 for ; Sat, 5 Sep 2026 14:16:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.180 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788617804; cv=none; b=kMUUqlVbRC2aGsJALKO8l2CSpS4D+v1SvqH0hzVGxV1NiugA6XN9Q5TXR3jNiVViZEu9TLkRdS9fCQvfQiQV3Y5MzkwXWCx0Mmz4RRgLgaugAf0wVHf6/wm9c8cmf3IptLp8217Ns3dCWRKJG49iCoeAsiP/s0Mrun3rDpM630A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788617804; c=relaxed/simple; bh=Uq2QKVVyZAJ3iw6CumjZWhFioqu61MDeX2nc5nXbbvk=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=eKM2KUI1V00TfTAvrnArqHXwKZY334QDL9fOnWliIykrNZBIohFcU3Jwrd+lT6Zsq/pAH2ARTrEfpNC9C8M8IYFitSnt+jVuFjUv9w+QWMLR1qIVPqnBrCcZFu0OkizOo19zJ05c4IXkRlpH6OjTTSMZjSoUGewU40X1NPBWuD0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=C/IY6p2r; arc=none smtp.client-ip=209.85.215.180 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="C/IY6p2r" Received: by mail-pg1-f180.google.com with SMTP id 41be03b00d2f7-cc1b838f9b6so2325018a12.3 for ; Sat, 05 Sep 2026 07:16:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1788617803; x=1789222603; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to:content-type; bh=abSqaXjYNWpx1velmfbb4Gcwy1xXArcmn2otfVZnNGs=; b=C/IY6p2rFxMtFFafnTecKroKFG5z3EIZcVIZvgQedzwwUBKuJ+E6q5jk140+itu5wA gMV7J/3VCdyZSo4/xyGfga87wLDf18zTj+7O5j9f4BT2IgtxnQ0lxKEPB/6Qqn+1XAaT EUTYszbA3uGn3Zq/+c1pqg5laAEl6xFr9OvPQXMm31QeIURHr9yccn8nuiTAdzWTcaHp IZn+UXWSExOKf4qBNvZvE4iMNKkdTfHZkmGYAhtn6s+qUWvD/JRrRnTwDxruXgGNSvYQ 0j8N41FX069DKZ+btgYAxOf7ZEEM27ITbAWez1+dRvlsJTppCVcMxERhS3OFzKbH9qse B0Hg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1788617803; x=1789222603; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=abSqaXjYNWpx1velmfbb4Gcwy1xXArcmn2otfVZnNGs=; b=BvEW5KmW8O4qCLu8g+TFKgSIRszRV/7tart97l4qd49plHzYxcuUqv090mqisscg+a ZV0AMAFLcW6g9LUjawAJs8R6b8PONoyLK01FSD8LT0j7b2TaC1wO32kOqbOn1vq6P7D+ ujHlHqU9QBlxO3l9y2Y1/v0QRlxLBpaWqq6nGqal+jtUxyFJhrSTGybZVeR5f/ASc3oY 1oE7jDDrNtM+wAaicJzNBhs98Nam3tUttJSkYepi/YfDaOISyriXDErn12mVrxM7DlK2 5v7G+DgA7HWKyZYZgrzGLEwfpX69czl17X7dU5TqpKhOeIEZsIWuoECBSkZ/QVwWVqo/ nkAw== X-Forwarded-Encrypted: i=1; AKwUvBxyo1z4KxYsIKQ4nuQUt0canJmzCEqwTs7t8OOoziVQHVX5PQqRRBx785/2XFcVIpJ0X6qhEjMx6xrwYKoE7PmDU2qVPrc=@vger.kernel.org X-Gm-Message-State: AFuF++mIKXb9Eq0YwV9RzVrOM4rzMbbR1justti6t6zDoZfxfGavtszZ 6tNLYnIaRP7Dr764pLxLWLRTwLYW4FkEhEsI8atvwDcBYriXzQZjdN2D X-Gm-Gg: AYBFou143BzTNXyv1UN2ok0ox8G6L0jtk1BPtA+dNAwL6ihOFydp595MkRljgoA7ykd o7rwfoBM9b71BKjmCGGvlbrP+/cPseLeQDoctg1hGZuMX4lYjLFduG3vnP3Bo/8o4Yp+xQeuFB8 ODFzuQ22UYs0R35SK0LhNK+goFK60tr9WWcX05rGbX88tRqV4hWpjVmD06wAgMkvUptHydH1VSo LZSrKOnCgaSkKnjBp1vnCh6lWOVuE8z4c+vfHKHbx03xZg4I8TLVyxnQEiswOLxCY8hQC0weu3p AwGvryPVXfRArEjAMQ/FdzVGa2U3a16dv0fu7ev+qV8Ong7rpaao/tCXEza+5VsqYC5W/LlEe7C 2TwkjERzAGV/jBb3DjYwyYWIqhNqMflZ5X9YtXzvY3k4Au9t9Vp+PFALclZ3W1aFLN9AQ60agNN R+duURiMf5wrnyUQIpjb14STD0lGVhrD9QUWkr2G59q14es2X/hzUASn96R3L5JpiO3xtJk16Ww IB7yzAFooJGhxFCQedizB7NH0oRNLAQ X-Received: by 2002:a17:90b:2ecd:b0:396:40e6:f631 with SMTP id 98e67ed59e1d1-39b2609f306mr22399265a91.3.1788617802530; Sat, 05 Sep 2026 07:16:42 -0700 (PDT) Received: from Biostar-A520MT.. ([187.94.13.245]) by smtp.gmail.com with ESMTPSA id a92af1059eb24-143243bfbe3sm13596787c88.11.2026.09.05.07.16.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 05 Sep 2026 07:16:41 -0700 (PDT) From: Breno Rodrigues Alves To: gregkh@linuxfoundation.org Cc: torvalds@linux-foundation.org, linux-media@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, Breno Rodrigues Alves Subject: [PATCH] media: dvb-core: purge unsafe ULE debug and fix pre-existing vulnerabilities Date: Sat, 5 Sep 2026 11:16:37 -0300 Message-ID: <20260905141637.22501-1-breno3011alves@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit This commit completely removes the unmaintained DVB_ULE_DEBUG code block from dvb_net.c and its Kconfig definition to eliminate lockless race conditions and cleans up the unused function signature parameter in dvb_net_ule_check_crc() to resolve compilation failures. Additionally, this patch addresses two pre-existing critical security issues: 1. Fixes a Use-After-Free (UAF) vulnerability in dvb_net_remove_if() by invoking unregister_netdev() before flushing the workqueues, ensuring no new callbacks can queue tasks after flushes. 2. Fixes an Out-of-Bounds (OOB) memory read vulnerability in the ULE extension header parsing loop by introducing a strict bounds check against the skb tail pointer. Assisted-by: OpenCode AI Signed-off-by: Breno Rodrigues Alves --- drivers/media/dvb-core/Kconfig | 11 -------- drivers/media/dvb-core/dvb_net.c | 57 ++++++++++++++------------------ 2 files changed, 25 insertions(+), 43 deletions(-) diff --git a/drivers/media/dvb-core/Kconfig b/drivers/media/dvb-core/Kconfig index 8b3f2d53c..c6a97add8 100644 --- a/drivers/media/dvb-core/Kconfig +++ b/drivers/media/dvb-core/Kconfig @@ -67,14 +67,3 @@ config DVB_DEMUX_SECTION_LOSS_LOG If you are unsure about this, say N here. -config DVB_ULE_DEBUG - bool "Enable DVB net ULE packet debug messages" - depends on DVB_CORE - help - Enable extra log messages meant to detect problems while - handling DVB network ULE packet loss inside the Kernel. - - Should not be enabled on normal cases, as logs can - be very verbose. - - If you are unsure about this, say N here. diff --git a/drivers/media/dvb-core/dvb_net.c b/drivers/media/dvb-core/dvb_net.c index a2159b2bc..5060b8866 100644 --- a/drivers/media/dvb-core/dvb_net.c +++ b/drivers/media/dvb-core/dvb_net.c @@ -68,19 +68,6 @@ static inline __u32 iov_crc32( __u32 c, struct kvec *iov, unsigned int cnt ) #define DVB_NET_MULTICAST_MAX 10 -#ifdef DVB_ULE_DEBUG -/* - * The code inside DVB_ULE_DEBUG keeps a history of the - * last 100 TS cells processed. - */ -static unsigned char ule_hist[100*TS_SZ] = { 0 }; -static unsigned char *ule_where = ule_hist, ule_dump; - -static void hexdump(const unsigned char *buf, unsigned short len) -{ - print_hex_dump_debug("", DUMP_PREFIX_OFFSET, 16, 1, buf, len, true); -} -#endif struct dvb_net_priv { int in_use; @@ -320,16 +307,6 @@ static int dvb_net_ule_new_ts_cell(struct dvb_net_ule_handle *h) { /* We are about to process a new TS cell. */ -#ifdef DVB_ULE_DEBUG - if (ule_where >= &ule_hist[100*TS_SZ]) - ule_where = ule_hist; - memcpy(ule_where, h->ts, TS_SZ); - if (ule_dump) { - hexdump(ule_where, TS_SZ); - ule_dump = 0; - } - ule_where += TS_SZ; -#endif /* * Check TS h->error conditions: sync_byte, transport_error_indicator, @@ -382,6 +359,10 @@ static int handle_one_ule_extension(struct dvb_net_ule_handle *h, int ext_len) static int handle_ule_extensions(struct dvb_net_ule_handle *h) { int ext_len; + struct sk_buff *skb = h->priv->rx_skb; + unsigned char *tail = skb_tail_pointer(skb); + + h->ule_next_hdr = h->from_where; do { ext_len = h->ule_sndu_type; @@ -391,6 +372,11 @@ static int handle_ule_extensions(struct dvb_net_ule_handle *h) ext_len = handle_one_ule_extension(h, ext_len); if (ext_len < 0) return ext_len; + + /* Prevent Out-of-Bounds read from malformed long extension headers */ + if (h->ule_next_hdr + ext_len > tail) + return -EINVAL; + h->ule_next_hdr += ext_len; if (h->ule_next_hdr == tail) return -EINVAL; @@ -632,7 +618,6 @@ static void dvb_net_ule_check_crc(struct dvb_net_ule_handle *h, - struct kvec *iov, __u32 ule_crc, __u32 expected_crc) { pr_warn("%s: CRC32 check FAILED: %08x <> %08x\n", @@ -659,23 +644,6 @@ static void dvb_net_ule_check_crc(struct dvb_net_ule_handle *h, h->ts_remain > 2 ? *(unsigned short *)h->from_where : 0); - #ifdef DVB_ULE_DEBUG - hexdump(iov[0].iov_base, iov[0].iov_len); - hexdump(iov[1].iov_base, iov[1].iov_len); - hexdump(iov[2].iov_base, iov[2].iov_len); - - if (ule_where == ule_hist) { - hexdump(&ule_hist[98*TS_SZ], TS_SZ); - hexdump(&ule_hist[99*TS_SZ], TS_SZ); - } else if (ule_where == &ule_hist[TS_SZ]) { - hexdump(&ule_hist[99*TS_SZ], TS_SZ); - hexdump(ule_hist, TS_SZ); - } else { - hexdump(ule_where - TS_SZ - TS_SZ, TS_SZ); - hexdump(ule_where - TS_SZ, TS_SZ); - } - ule_dump = 1; - #endif h->dev->stats.rx_errors++; h->dev->stats.rx_crc_errors++; @@ -843,7 +811,7 @@ static void dvb_net_ule(struct net_device *dev, const u8 *buf, size_t buf_len) *(tail - 2) << 8 | *(tail - 1); - dvb_net_ule_check_crc(&h, iov, ule_crc, expected_crc); + dvb_net_ule_check_crc(&h, ule_crc, expected_crc); /* Prepare for next SNDU. */ reset_ule(h.priv); @@ -1214,9 +1182,9 @@ static void dvb_net_remove_if(struct dvb_net *dvbnet, unsigned int num) priv->in_use = 0; net = priv->net; + unregister_netdev(net); flush_work(&priv->set_multicast_list_wq); flush_work(&priv->restart_net_feed_wq); pr_info("removed network interface %s\n", net->name); - unregister_netdev(net); free_netdev(net); } -- 2.43.0