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 03F4E2E7BBF; Thu, 3 Jul 2025 15:02:46 +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=1751554967; cv=none; b=p0Mmh2MLILmhEQkWmPfLENpbQ7p7FcQYadYTrkG36HdqksZXK6YH6mEHmZkcvutgF+EitfYZR8SFrJONNsFGK1qecrerot48GCt5WRIlwcRj7i1Wiwc8saTjH7pZ/LOUFRllClMvDE8jZVwhFDZbGOprUZ1uG6isMIeGfcrk/vQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751554967; c=relaxed/simple; bh=/HfwqvIv9C/chl6CVP/ZqOWK4l6BjKW4OdSRhu0vXmE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=QZ6SIYDYnhHwBDw72wKnqUlZlb2mYInqFS3vkEgn0VlZqADudoxoohDXYJKMo9yX1UXAkZwLenj7Nyo/SKXIsnPA9GEdYH1yZLlQr88NAo4ZSBaI25tMe5ZHCihNY5R/NZBdF+M7RAsO1SiggJZGCgD/LIwPZoOyJbn8spFTDT4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=f/Xzbncy; 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="f/Xzbncy" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1B5C0C4CEE3; Thu, 3 Jul 2025 15:02:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1751554966; bh=/HfwqvIv9C/chl6CVP/ZqOWK4l6BjKW4OdSRhu0vXmE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=f/XzbncyGXQNkU3X7DovUOZcm8H2ujFoR23SWg1fZIzV9AucJhPfCrXBz55zzYL97 kT6z+DDPceerT4fRIBdfkiFi4gjCkYl0plOW1u4ezABHRli8ZWa4e+EruMz/RLgJao H4oabRNkbgL++EiTkGvPQ17/QYO6Zo0WQYpnLe6w= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+1316233c4c6803382a8b@syzkaller.appspotmail.com, Eric Dumazet , Cong Wang , Gengming Liu , Simon Horman , "David S. Miller" , Sasha Levin Subject: [PATCH 6.15 135/263] atm: clip: prevent NULL deref in clip_push() Date: Thu, 3 Jul 2025 16:40:55 +0200 Message-ID: <20250703144009.774238337@linuxfoundation.org> X-Mailer: git-send-email 2.50.0 In-Reply-To: <20250703144004.276210867@linuxfoundation.org> References: <20250703144004.276210867@linuxfoundation.org> User-Agent: quilt/0.68 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 6.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit b993ea46b3b601915ceaaf3c802adf11e7d6bac6 ] Blamed commit missed that vcc_destroy_socket() calls clip_push() with a NULL skb. If clip_devs is NULL, clip_push() then crashes when reading skb->truesize. Fixes: 93a2014afbac ("atm: fix a UAF in lec_arp_clear_vccs()") Reported-by: syzbot+1316233c4c6803382a8b@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/68556f59.a00a0220.137b3.004e.GAE@google.com/T/#u Signed-off-by: Eric Dumazet Cc: Cong Wang Cc: Gengming Liu Reviewed-by: Simon Horman Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/atm/clip.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/net/atm/clip.c b/net/atm/clip.c index 61b5b700817de..b234dc3bcb0d4 100644 --- a/net/atm/clip.c +++ b/net/atm/clip.c @@ -193,12 +193,6 @@ static void clip_push(struct atm_vcc *vcc, struct sk_buff *skb) pr_debug("\n"); - if (!clip_devs) { - atm_return(vcc, skb->truesize); - kfree_skb(skb); - return; - } - if (!skb) { pr_debug("removing VCC %p\n", clip_vcc); if (clip_vcc->entry) @@ -208,6 +202,11 @@ static void clip_push(struct atm_vcc *vcc, struct sk_buff *skb) return; } atm_return(vcc, skb->truesize); + if (!clip_devs) { + kfree_skb(skb); + return; + } + skb->dev = clip_vcc->entry ? clip_vcc->entry->neigh->dev : clip_devs; /* clip_vcc->entry == NULL if we don't have an IP address yet */ if (!skb->dev) { -- 2.39.5