From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B4A3430FF1D; Fri, 9 Jan 2026 12:29:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767961782; cv=none; b=Vcb3FFUxVawYcWdF2FE2TKN3gUfzqCoAZOTxuAasGO/zDquk7Jjdv47wMNloY2uxJ43QRP5yjKnh2ago/QCqwFH3Uxjld9Ajf+b+viknp1P0LLAnCzipCS5VtZYoLgIGZI3IHkFb2BsXN4YJXZ9+U2UWJ4SqGPbl0j8DfRb8bd0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767961782; c=relaxed/simple; bh=ONE6s//qI3BcEXwp6FoeJlEHt8WMv3UqDOqZGE76Rrk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=niXnQXJY65leJGoMG1dKd7njGDYBGLYD4G2A55kXPx45YN4XnzID4OP0VbdyfLq0qQxuzkNb4ShcVHHYDXEys7H5fXhOKhPoGbpJ7YVcSz2ROUqhF7cCv2uJfMy2XqeyYxhIwrMSgmfoC0oAdlgQXfQ/3bje2iYAmxZC4IAaeEk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=RtluQO0m; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="RtluQO0m" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3EEADC4CEF1; Fri, 9 Jan 2026 12:29:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1767961782; bh=ONE6s//qI3BcEXwp6FoeJlEHt8WMv3UqDOqZGE76Rrk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RtluQO0mI9MN7PBUI4j89K0SGI/DK3k5pmrH09JKXI0Zbuz6YvxLs4+BVM8b1MjmO +keQx64Audl15KK9qnHZXNQOXBelwxhN4LiBg9n82eVOKymMQM3OZM7WXZxJOyO3bs X0WS/QKpd4H7eXZ9+zYwpuaiAy/TqsOr61a9gA34= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Seungjin Bae , Ping-Ke Shih , Sasha Levin Subject: [PATCH 6.1 133/634] wifi: rtl818x: rtl8187: Fix potential buffer underflow in rtl8187_rx_cb() Date: Fri, 9 Jan 2026 12:36:51 +0100 Message-ID: <20260109112122.457129866@linuxfoundation.org> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260109112117.407257400@linuxfoundation.org> References: <20260109112117.407257400@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Seungjin Bae [ Upstream commit b647d2574e4583c2e3b0ab35568f60c88e910840 ] The rtl8187_rx_cb() calculates the rx descriptor header address by subtracting its size from the skb tail pointer. However, it does not validate if the received packet (skb->len from urb->actual_length) is large enough to contain this header. If a truncated packet is received, this will lead to a buffer underflow, reading memory before the start of the skb data area, and causing a kernel panic. Add length checks for both rtl8187 and rtl8187b descriptor headers before attempting to access them, dropping the packet cleanly if the check fails. Fixes: 6f7853f3cbe4 ("rtl8187: change rtl8187_dev.c to support RTL8187B (part 2)") Signed-off-by: Seungjin Bae Signed-off-by: Ping-Ke Shih Link: https://patch.msgid.link/20251118013258.1789949-2-eeodqql09@gmail.com Signed-off-by: Sasha Levin --- .../wireless/realtek/rtl818x/rtl8187/dev.c | 27 +++++++++++++------ 1 file changed, 19 insertions(+), 8 deletions(-) diff --git a/drivers/net/wireless/realtek/rtl818x/rtl8187/dev.c b/drivers/net/wireless/realtek/rtl818x/rtl8187/dev.c index fa3fb93f4485d..fd67c11bbf618 100644 --- a/drivers/net/wireless/realtek/rtl818x/rtl8187/dev.c +++ b/drivers/net/wireless/realtek/rtl818x/rtl8187/dev.c @@ -338,14 +338,16 @@ static void rtl8187_rx_cb(struct urb *urb) spin_unlock_irqrestore(&priv->rx_queue.lock, f); skb_put(skb, urb->actual_length); - if (unlikely(urb->status)) { - dev_kfree_skb_irq(skb); - return; - } + if (unlikely(urb->status)) + goto free_skb; if (!priv->is_rtl8187b) { - struct rtl8187_rx_hdr *hdr = - (typeof(hdr))(skb_tail_pointer(skb) - sizeof(*hdr)); + struct rtl8187_rx_hdr *hdr; + + if (skb->len < sizeof(struct rtl8187_rx_hdr)) + goto free_skb; + + hdr = (typeof(hdr))(skb_tail_pointer(skb) - sizeof(*hdr)); flags = le32_to_cpu(hdr->flags); /* As with the RTL8187B below, the AGC is used to calculate * signal strength. In this case, the scaling @@ -355,8 +357,12 @@ static void rtl8187_rx_cb(struct urb *urb) rx_status.antenna = (hdr->signal >> 7) & 1; rx_status.mactime = le64_to_cpu(hdr->mac_time); } else { - struct rtl8187b_rx_hdr *hdr = - (typeof(hdr))(skb_tail_pointer(skb) - sizeof(*hdr)); + struct rtl8187b_rx_hdr *hdr; + + if (skb->len < sizeof(struct rtl8187b_rx_hdr)) + goto free_skb; + + hdr = (typeof(hdr))(skb_tail_pointer(skb) - sizeof(*hdr)); /* The Realtek datasheet for the RTL8187B shows that the RX * header contains the following quantities: signal quality, * RSSI, AGC, the received power in dB, and the measured SNR. @@ -409,6 +415,11 @@ static void rtl8187_rx_cb(struct urb *urb) skb_unlink(skb, &priv->rx_queue); dev_kfree_skb_irq(skb); } + return; + +free_skb: + dev_kfree_skb_irq(skb); + return; } static int rtl8187_init_urbs(struct ieee80211_hw *dev) -- 2.51.0