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 0597C36A36C; Tue, 16 Jun 2026 18:20:32 +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=1781634034; cv=none; b=higbjd3bruHccBfq4IKHLjX7xVMTNJawlXmS+O+Q3oCq9juPt9oSD5fLZy3LUf4KBini2TICu53hImb83f0Pha6Z3umSJOwcmDpSZCxEDC7rLsfyeYFILPwGZhE0cHT5YCRL926QAk7LR7MFARRQppOpckpHPQHQRpZneblvveM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781634034; c=relaxed/simple; bh=agwTz32qFb4co7yDp+OoVXwNqfRzkzIq4EsmkicwZQg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=MLD2im+0aLD3aGDHnLRJAeOmTRMC9Hz6ENZuPUcmKHxMnOAbEqAlvIdHQOVwr4K25rBRjjIvEFVV/kFWR/+mx5sfXp452lZWAC+yrPTENyiGu+j+uKxdeaXW8RHNxWCkGDeYV2zv2IY2gZ5uMqRuX2nKtj9xD6ADfK04OSulKpI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=1s3jo7HY; 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="1s3jo7HY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CDA371F000E9; Tue, 16 Jun 2026 18:20:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1781634032; bh=rdFodYKGAY9MzP9rh1GnhS8sFqNi8FpQudbpXRWpzp0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=1s3jo7HYeh44TnuxPmwvC0xqRAkPT0zVsETr+ajnm0FauDpgBPIYyA52E7ZOyvm7A LGzidnpklVjDDBM8YSRycBdXvrHArLTnQz+sgu/MGECa/J25HDBnMUJayAxdUvciDa bHQp+xwON7Sp3DUnREGLwklC34lQY5NNnwxzL1jU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Kyle Zeng , Kuniyuki Iwashima , Willem de Bruijn , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.15 188/411] net: guard timestamp cmsgs to real error queue skbs Date: Tue, 16 Jun 2026 20:27:06 +0530 Message-ID: <20260616145110.689573451@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260616145100.376842714@linuxfoundation.org> References: <20260616145100.376842714@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 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kyle Zeng [ Upstream commit 1ee90b77b727df903033db873c75caac5c27ec98 ] skb_is_err_queue() treats PACKET_OUTGOING as the sole marker for an skb from sk_error_queue. That assumption is not true for AF_PACKET sockets: outgoing packet taps are also delivered to packet sockets with skb->pkt_type == PACKET_OUTGOING, but their skb->cb is owned by AF_PACKET instead of struct sock_exterr_skb. If such an skb is received with timestamping enabled, the generic timestamp cmsg path can read AF_PACKET control-buffer state as sock_exterr_skb::opt_stats. With SO_RXQ_OVFL enabled, the packet drop counter overlaps opt_stats. An odd drop count makes the path emit SCM_TIMESTAMPING_OPT_STATS with skb->len and skb->data. For non-linear skbs this copies past the linear head and can trigger hardened usercopy or disclose adjacent heap contents. Keep skb_is_err_queue() local to net/socket.c, but make it verify that the PACKET_OUTGOING marker is paired with the sock_rmem_free destructor installed by sock_queue_err_skb(). AF_PACKET receive skbs use normal receive ownership and no longer pass as error-queue skbs, while legitimate sk_error_queue entries keep the PACKET_OUTGOING marker and sock_rmem_free ownership. Fixes: 8605330aac5a ("tcp: fix SCM_TIMESTAMPING_OPT_STATS for normal skbs") Signed-off-by: Kyle Zeng Reviewed-by: Kuniyuki Iwashima Reviewed-by: Willem de Bruijn Link: https://patch.msgid.link/20260607021819.49698-1-kylebot@openai.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- include/net/sock.h | 1 + net/core/skbuff.c | 6 +++--- net/socket.c | 11 ++++++----- 3 files changed, 10 insertions(+), 8 deletions(-) diff --git a/include/net/sock.h b/include/net/sock.h index ee9c398dd8f25e..962acf4a644da9 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -1868,6 +1868,7 @@ struct sk_buff *sock_omalloc(struct sock *sk, unsigned long size, gfp_t priority); void skb_orphan_partial(struct sk_buff *skb); void sock_rfree(struct sk_buff *skb); +void sock_rmem_free(struct sk_buff *skb); void sock_efree(struct sk_buff *skb); #ifdef CONFIG_INET void sock_edemux(struct sk_buff *skb); diff --git a/net/core/skbuff.c b/net/core/skbuff.c index a8d09eff26f11c..1d3784480834bb 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -4814,7 +4814,7 @@ int skb_cow_data(struct sk_buff *skb, int tailbits, struct sk_buff **trailer) } EXPORT_SYMBOL_GPL(skb_cow_data); -static void sock_rmem_free(struct sk_buff *skb) +void sock_rmem_free(struct sk_buff *skb) { struct sock *sk = skb->sk; @@ -4823,8 +4823,8 @@ static void sock_rmem_free(struct sk_buff *skb) static void skb_set_err_queue(struct sk_buff *skb) { - /* pkt_type of skbs received on local sockets is never PACKET_OUTGOING. - * So, it is safe to (mis)use it to mark skbs on the error queue. + /* The error-queue test in skb_is_err_queue() matches this marker + * with the sock_rmem_free destructor installed by sock_queue_err_skb(). */ skb->pkt_type = PACKET_OUTGOING; BUILD_BUG_ON(PACKET_OUTGOING == 0); diff --git a/net/socket.c b/net/socket.c index f3d0a8d66cceee..cc7ba4702d1380 100644 --- a/net/socket.c +++ b/net/socket.c @@ -795,12 +795,13 @@ EXPORT_SYMBOL(kernel_sendmsg_locked); static bool skb_is_err_queue(const struct sk_buff *skb) { - /* pkt_type of skbs enqueued on the error queue are set to - * PACKET_OUTGOING in skb_set_err_queue(). This is only safe to do - * in recvmsg, since skbs received on a local socket will never - * have a pkt_type of PACKET_OUTGOING. + /* Error-queue skbs are marked as PACKET_OUTGOING in + * skb_set_err_queue() and use the destructor installed by + * sock_queue_err_skb(). PACKET_OUTGOING alone is not unique: + * AF_PACKET outgoing taps use the same pkt_type. */ - return skb->pkt_type == PACKET_OUTGOING; + return skb->pkt_type == PACKET_OUTGOING && + skb->destructor == sock_rmem_free; } /* On transmit, software and hardware timestamps are returned independently. -- 2.53.0