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 7C2BC32E72F for ; Sat, 25 Jul 2026 15:22:38 +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=1784992963; cv=none; b=H0aNTswWhX00xVOZaC3q7e8W6O7YdvsAiD4uiiSq2wKJ2KL9PvEfw7j+jL/4GsbHDCuHKrlTO6KtTXSmb7MAz24RshPCTh8PN5t6dbTYtW0NT9OP9K6Xg225Q+7JlWD/MtYSn5i+VmAw9glnq6U0Itx9vR7TAWY5EFCyjpiM2bY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784992963; c=relaxed/simple; bh=rnIkIXShOOPtoTNnZWCwHm5mYVgvh1+zT22xFBgJoyY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=pAVtF7wwbF0uJfnVGEeR6UFKDo9hNvz++CVoS/N/DSe7JU8/cCIRVhmHc44/6wKYFXXfNz52KOJLjZc0Iyb7MeGBpCPwVrR5z7m4i86iWsNlfv2ttSiIWrHomRWhk3S6qNYeJHSqRndoAcZuniior0AlfemdHTpXA36LGZkRN/4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=HtuFvAJA; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="HtuFvAJA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 24CC11F000E9; Sat, 25 Jul 2026 15:22:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784992954; bh=tnCIGRidywhKVV2Vw/UCpeoIVO0Pj7ycRIfB9pNrrfs=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=HtuFvAJASBA7Ou6ifC2vydWixeHP1osB6PvvqGqGYQ5tRHJiHC3d7KSqR1lqieWpi HZyL8QYNhMCKf4YYp3NIbN+Ctr56DURIB1uELOCn8ctS5LCW6nCn/YygyPJJCFTZUq Isal9VTKuL3lSIe91gmsFlyiyXR7Et3gFJI96QjtETe5BkfCQ5TLhzvQAIqdSCnJbN 61zTqgQD8KH2nmNQOXxuVYmMDSB8O4zKetlTdt9j/jk5CQFn1vbwgHN/j7aC+bONnd byEqhFL7NyQf/i8jDp4FCjCrMratJnZatuJ4fcATpedZsGWSUbhBC2A56nTI76A121 do9M8QRyKuFDQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Maoyi Xie , Mika Westerberg , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.15.y] net: thunderbolt: Fix frags[] overflow by bounding frame_count Date: Sat, 25 Jul 2026 11:22:31 -0400 Message-ID: <20260725152231.3857257-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026072027-siding-engraving-011b@gregkh> References: <2026072027-siding-engraving-011b@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Maoyi Xie [ Upstream commit 55d9895f89970501fe126d1026b586b04a224c27 ] tbnet_poll() assembles a multi-frame ThunderboltIP packet into one skb. The first frame goes into the skb linear area and every further frame is added as a page fragment. skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags, page, hdr_size, frame_size, TBNET_RX_PAGE_SIZE - hdr_size); A packet of frame_count frames therefore ends up with frame_count - 1 fragments. tbnet_check_frame() only bounds the peer supplied frame_count to TBNET_RING_SIZE / 4 (64), which is far above MAX_SKB_FRAGS (17 by default). A peer that sends a packet of 19 or more small frames pushes nr_frags past MAX_SKB_FRAGS, so skb_add_rx_frag() writes past skb_shinfo()->frags[] and corrupts memory after the shared info. Tighten the start of packet bound to MAX_SKB_FRAGS + 1 so a packet can never produce more fragments than frags[] can hold. This matches the recent skb frags overflow fixes in other receive paths, for example f0813bcd2d9d ("net: wwan: t7xx: fix potential skb->frags overflow in RX path") and 600dc40554dc ("net: usb: cdc-phonet: fix skb frags[] overflow in rx_complete()"). Fixes: e69b6c02b4c3 ("net: Add support for networking over Thunderbolt cable") Cc: stable@vger.kernel.org Signed-off-by: Maoyi Xie Acked-by: Mika Westerberg Link: https://patch.msgid.link/178163152194.2486768.14724194232649760778@maoyixie.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/net/thunderbolt.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/net/thunderbolt.c b/drivers/net/thunderbolt.c index ba9f7062f5a7d4..649477b97b0584 100644 --- a/drivers/net/thunderbolt.c +++ b/drivers/net/thunderbolt.c @@ -746,8 +746,12 @@ static bool tbnet_check_frame(struct tbnet *net, const struct tbnet_frame *tf, return true; } - /* Start of packet, validate the frame header */ - if (frame_count == 0 || frame_count > TBNET_RING_SIZE / 4) { + /* Start of packet, validate the frame header. tbnet_poll() puts the + * first frame in the skb linear area and every further frame in a page + * fragment, so a packet may not span more than MAX_SKB_FRAGS + 1 frames + * without overflowing skb_shinfo()->frags[]. + */ + if (frame_count == 0 || frame_count > MAX_SKB_FRAGS + 1) { net->stats.rx_length_errors++; return false; } -- 2.53.0