From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yujuan Qi Subject: [PATCH] Cipso: cipso_v4_optptr enter infinite loop Date: Mon, 31 Jul 2017 11:23:01 +0800 Message-ID: <1501471381-12808-1-git-send-email-yujuan.qi@mediatek.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Ryder Lee , "yujuan.qi" , netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mediatek-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Casey Schaufler To: Paul Moore , "David S. Miller" Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+glpam-linux-mediatek=m.gmane.org-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: netdev.vger.kernel.org From: "yujuan.qi" in for(),if((optlen > 0) && (optptr[1] == 0)), enter infinite loop. Test: receive a packet which the ip length > 20 and the first byte of ip option is 0, produce this issue Signed-off-by: yujuan.qi --- net/ipv4/cipso_ipv4.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c index ae20616..0d1e07d 100644 --- a/net/ipv4/cipso_ipv4.c +++ b/net/ipv4/cipso_ipv4.c @@ -1523,9 +1523,17 @@ unsigned char *cipso_v4_optptr(const struct sk_buff *skb) int taglen; for (optlen = iph->ihl*4 - sizeof(struct iphdr); optlen > 0; ) { - if (optptr[0] == IPOPT_CIPSO) + switch (optptr[0]) { + case IPOPT_CIPSO: return optptr; - taglen = optptr[1]; + case IPOPT_END: + return NULL; + case IPOPT_NOOP: + taglen = 1; + break; + default: + taglen = optptr[1]; + } optlen -= taglen; optptr += taglen; } -- 1.9.1