From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 D3D982AEEB; Wed, 30 Sep 2026 15:57:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790783851; cv=none; b=GVIFTT26PxtrAJqClN7b+i51Mk1QTze9hLhct+qKxPwNdJTblVkP5iDyHtTBni7f+V64N6C25JSC1DOYhaYJMHu+EXNQR+TQE0UWdsmJhLCRyvfVgmFz0tGNxnTZhMWt92bmOs9EDaB+Eo9njHrZmGPd+xAD391/MU2cjATaSfw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790783851; c=relaxed/simple; bh=4r38ndvo9nmftH4x9vPhOxVVwfmTCXzSHo7SroiZTEI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=XPp5M6Z2PwhWF0B1KHxr3XkQl/rUPiZpQ2i1V3bBzYvdq3zO88YfZ0y/95JUDSEaOaHYKIvuVRGB8/1GyIvdF223GYr9R/PqQeos0LFkW6Z4xn9Y/UVYpwPPw0pmpg2BfjMrRA5NdYm+LEMuvU1uG5i8LkLTHM7XgrLBRrPFjNY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=dJT0urDx; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="dJT0urDx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 57FD01F00898; Wed, 30 Sep 2026 15:57:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790783846; bh=zJbbHeT4X0qnsvi2LICZLziSJyW2j4/eH7Gtg3kGFik=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=dJT0urDxWjtk0VwVMweiiIhrWxevPR8AC2kcjhC5GxTBmDcRHJjsafukDqp++aggP miXFTW7MHeem2QvmfLis5qE6sdSQZHQppGHI3BmQhljfkzsWF+5XagiX6z+g3gNDDu kdkkaJPlFm7cqSRdU99CaMWV0jpcXAS01v9qFXbk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.10 541/595] llc: fix skb UAF and leaks on llc_mac_hdr_init() failure Date: Wed, 30 Sep 2026 17:27:14 +0200 Message-ID: <20260930152359.346854516@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152347.700140858@linuxfoundation.org> References: <20260930152347.700140858@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 72f9dd522f8d6c5a00be9695c7bb74631eb5069e ] In llc_conn_ac_resend_i_xxx_x_set_0_or_send_rr(), if llc_mac_hdr_init() fails, kfree_skb(skb) is called instead of kfree_skb(nskb). This leaks the newly allocated nskb, reads from the freed skb via LLC_I_GET_NR(pdu), and double-frees skb when llc_conn_state_process() drops its reference. In llc_sap_action_send_xid_r() and llc_sap_action_send_test_r(), nskb is leaked if llc_mac_hdr_init() returns an error. Free nskb in all three error paths. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Closes: https://lore.kernel.org/netdev/179022851638.2160803.1808206741379444999@kernel.org/ Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20260924082951.1599377-2-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/llc/llc_c_ac.c | 2 +- net/llc/llc_s_ac.c | 4 ++++ 2 files changed, 5 insertions(+), 1 deletion(-) diff --git a/net/llc/llc_c_ac.c b/net/llc/llc_c_ac.c index 647c0554d04cd..8e18b264408ad 100644 --- a/net/llc/llc_c_ac.c +++ b/net/llc/llc_c_ac.c @@ -443,7 +443,7 @@ int llc_conn_ac_resend_i_xxx_x_set_0_or_send_rr(struct sock *sk, if (likely(!rc)) llc_conn_send_pdu(sk, nskb); else - kfree_skb(skb); + kfree_skb(nskb); } if (rc) { nr = LLC_I_GET_NR(pdu); diff --git a/net/llc/llc_s_ac.c b/net/llc/llc_s_ac.c index 942ace4af18d8..188d8f92b0243 100644 --- a/net/llc/llc_s_ac.c +++ b/net/llc/llc_s_ac.c @@ -127,6 +127,8 @@ int llc_sap_action_send_xid_r(struct llc_sap *sap, struct sk_buff *skb) rc = llc_mac_hdr_init(nskb, mac_sa, mac_da); if (likely(!rc)) rc = dev_queue_xmit(nskb); + else + kfree_skb(nskb); out: return rc; } @@ -176,6 +178,8 @@ int llc_sap_action_send_test_r(struct llc_sap *sap, struct sk_buff *skb) rc = llc_mac_hdr_init(nskb, mac_sa, mac_da); if (likely(!rc)) rc = dev_queue_xmit(nskb); + else + kfree_skb(nskb); out: return rc; } -- 2.53.0