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 95DB815E8B; Mon, 30 Dec 2024 15:49:45 +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=1735573785; cv=none; b=rY4nHKR9JUZpv+FgfeJ/eBFFzbfNqBuMhC4Mn6y6L8fk1+e7TImCW/21Tt3HxwSXAMVl3oAHNMFifp3KL5Mvjpnd2IruCxsKhvQFIkyqK+Ser4quUzUXg1N0tB73A+XrIrkBq6z7Ps8A81865Rm15fi1VmK++sZ5WfDyuamWxac= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1735573785; c=relaxed/simple; bh=QUETmkJkJh9/gyMWjwNK6k2HdH8ymU4B3Y8OaCP9JCM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=bwOe9UUmBAR84xruPiU3CzZOzf2wy2sNVkkJJlA1B0+gAcV/Wa0wVKLdZglXBu1GjyPLAYzOrMRNx9qY2X/50mz8PCdbxMoc+gC//D1kJL6Yc3NBqUKeISeNLIMCY2ME2Bs+nI1lhkfKHwO4R2Pc3/iVfbItl7xaMs3le7cSDT8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=UJKtKWOW; 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="UJKtKWOW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 169ECC4CED0; Mon, 30 Dec 2024 15:49:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1735573785; bh=QUETmkJkJh9/gyMWjwNK6k2HdH8ymU4B3Y8OaCP9JCM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UJKtKWOWpoXvvSgPrND2Tv92OliEWwPtgDRStngOpNamu2rY9M3ulrQ9fxUaOaY/O 9J0Y4zhO6swCV1wYpnQvHn/tpSicjbwEGfYjj6QL2MbquDmKQJQ5HJvzzz5bE/x5pq ATLDOOvy1OhEaF7YCDBck8/uMY93OQnOWh4oKmsw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Cong Wang , Daniel Borkmann , John Fastabend , Sasha Levin Subject: [PATCH 6.6 08/86] bpf: Check negative offsets in __bpf_skb_min_len() Date: Mon, 30 Dec 2024 16:42:16 +0100 Message-ID: <20241230154212.032708953@linuxfoundation.org> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20241230154211.711515682@linuxfoundation.org> References: <20241230154211.711515682@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Cong Wang [ Upstream commit 9ecc4d858b92c1bb0673ad9c327298e600c55659 ] skb_network_offset() and skb_transport_offset() can be negative when they are called after we pull the transport header, for example, when we use eBPF sockmap at the point of ->sk_data_ready(). __bpf_skb_min_len() uses an unsigned int to get these offsets, this leads to a very large number which then causes bpf_skb_change_tail() failed unexpectedly. Fix this by using a signed int to get these offsets and ensure the minimum is at least zero. Fixes: 5293efe62df8 ("bpf: add bpf_skb_change_tail helper") Signed-off-by: Cong Wang Signed-off-by: Daniel Borkmann Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20241213034057.246437-2-xiyou.wangcong@gmail.com Signed-off-by: Sasha Levin --- net/core/filter.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) diff --git a/net/core/filter.c b/net/core/filter.c index bc52ab3374f3..34320ce70096 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -3731,13 +3731,22 @@ static const struct bpf_func_proto bpf_skb_adjust_room_proto = { static u32 __bpf_skb_min_len(const struct sk_buff *skb) { - u32 min_len = skb_network_offset(skb); + int offset = skb_network_offset(skb); + u32 min_len = 0; - if (skb_transport_header_was_set(skb)) - min_len = skb_transport_offset(skb); - if (skb->ip_summed == CHECKSUM_PARTIAL) - min_len = skb_checksum_start_offset(skb) + - skb->csum_offset + sizeof(__sum16); + if (offset > 0) + min_len = offset; + if (skb_transport_header_was_set(skb)) { + offset = skb_transport_offset(skb); + if (offset > 0) + min_len = offset; + } + if (skb->ip_summed == CHECKSUM_PARTIAL) { + offset = skb_checksum_start_offset(skb) + + skb->csum_offset + sizeof(__sum16); + if (offset > 0) + min_len = offset; + } return min_len; } -- 2.39.5