From: Seungjin Bae <eeodqql09@gmail.com> mainline inclusion from mainline-v6.19-rc1 commit b647d2574e4583c2e3b0ab35568f60c88e910840 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/12718 CVE: CVE-2025-68362 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- 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 <eeodqql09@gmail.com> Signed-off-by: Ping-Ke Shih <pkshih@realtek.com> Link: https://patch.msgid.link/20251118013258.1789949-2-eeodqql09@gmail.com Signed-off-by: Fanhua Li <lifanhua5@huawei.com> --- .../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 eb68b2d3caa12..79905cc8ec25c 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) -- 2.43.0