netfilter: nfnetlink_queue: fix maximum packet length to userspace

The packets that we send via NFQUEUE are encapsulated in the NFQA_PAYLOAD
attribute. The length of the packet in userspace is obtained via
attr->nla_len field. This field contains the size of the Netlink
attribute header plus the packet length.

If the maximum packet length is specified, ie. 65535 bytes, and
packets in the range of (65531,65535] are sent to userspace, the
attr->nla_len overflows and it reports bogus lengths to the
application.

To fix this, this patch limits the maximum packet length to 65531
bytes. If larger packet length is specified, the packet that we
send to user-space is truncated to 65531 bytes.

To support 65535 bytes packets, we have to revisit the idea of
the 32-bits Netlink attribute length.
Reported-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>
上级 7be54ca4
master alk-4.19.24 alk-4.19.30 alk-4.19.34 alk-4.19.36 alk-4.19.43 alk-4.19.48 alk-4.19.57 ck-4.19.67 ck-4.19.81 ck-4.19.91 github/fork/deepanshu1422/fix-typo-in-comment github/fork/haosdent/fix-typo linux-next v4.19.91 v4.19.90 v4.19.89 v4.19.88 v4.19.87 v4.19.86 v4.19.85 v4.19.84 v4.19.83 v4.19.82 v4.19.81 v4.19.80 v4.19.79 v4.19.78 v4.19.77 v4.19.76 v4.19.75 v4.19.74 v4.19.73 v4.19.72 v4.19.71 v4.19.70 v4.19.69 v4.19.68 v4.19.67 v4.19.66 v4.19.65 v4.19.64 v4.19.63 v4.19.62 v4.19.61 v4.19.60 v4.19.59 v4.19.58 v4.19.57 v4.19.56 v4.19.55 v4.19.54 v4.19.53 v4.19.52 v4.19.51 v4.19.50 v4.19.49 v4.19.48 v4.19.47 v4.19.46 v4.19.45 v4.19.44 v4.19.43 v4.19.42 v4.19.41 v4.19.40 v4.19.39 v4.19.38 v4.19.37 v4.19.36 v4.19.35 v4.19.34 v4.19.33 v4.19.32 v4.19.31 v4.19.30 v4.19.29 v4.19.28 v4.19.27 v4.19.26 v4.19.25 v4.19.24 v4.19.23 v4.19.22 v4.19.21 v4.19.20 v4.19.19 v4.19.18 v4.19.17 v4.19.16 v4.19.15 v4.19.14 v4.19.13 v4.19.12 v4.19.11 v4.19.10 v4.19.9 v4.19.8 v4.19.7 v4.19.6 v4.19.5 v4.19.4 v4.19.3 v4.19.2 v4.19.1 v4.19 v4.19-rc8 v4.19-rc7 v4.19-rc6 v4.19-rc5 v4.19-rc4 v4.19-rc3 v4.19-rc2 v4.19-rc1 ck-release-21 ck-release-20 ck-release-19.2 ck-release-19.1 ck-release-19 ck-release-18 ck-release-17.2 ck-release-17.1 ck-release-17 ck-release-16 ck-release-15.1 ck-release-15 ck-release-14 ck-release-13.2 ck-release-13 ck-release-12 ck-release-11 ck-release-10 ck-release-9 ck-release-7 alk-release-15 alk-release-14 alk-release-13.2 alk-release-13 alk-release-12 alk-release-11 alk-release-10 alk-release-9 alk-release-7
无相关合并请求
......@@ -526,9 +526,13 @@ nfqnl_set_mode(struct nfqnl_instance *queue,
case NFQNL_COPY_PACKET:
queue->copy_mode = mode;
/* we're using struct nlattr which has 16bit nla_len */
if (range > 0xffff)
queue->copy_range = 0xffff;
/* We're using struct nlattr which has 16bit nla_len. Note that
* nla_len includes the header length. Thus, the maximum packet
* length that we support is 65531 bytes. We send truncated
* packets if the specified length is larger than that.
*/
if (range > 0xffff - NLA_HDRLEN)
queue->copy_range = 0xffff - NLA_HDRLEN;
else
queue->copy_range = range;
break;
......
Markdown is supported
0% .
You are about to add 0 people to the discussion. Proceed with caution.
先完成此消息的编辑!
想要评论请 注册