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From: Nazarov Sergey <s-nazarov@yandex.ru>
To: Paul Moore <paul@paul-moore.com>
Cc: "linux-security-module@vger.kernel.org" 
	<linux-security-module@vger.kernel.org>,
	"selinux@vger.kernel.org" <selinux@vger.kernel.org>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	Casey Schaufler <casey@schaufler-ca.com>
Subject: Re: Kernel memory corruption in CIPSO labeled TCP packets processing.
Date: Thu, 24 Jan 2019 17:46:03 +0300	[thread overview]
Message-ID: <11471341548341163@sas2-7b909973f402.qloud-c.yandex.net> (raw)
In-Reply-To: <CAHC9VhRhEvcU804qMfZik7qwohuCDfcbvJMHRT+DxMPvvMDEGQ@mail.gmail.com>

22.01.2019, 20:48, "Paul Moore" <paul@paul-moore.com>:
>
> Yes, exactly. If you don't pass the skb it shouldn't attempt to call
> icmp_send() in case of error.
>
> --
> paul moore
> www.paul-moore.com

You are right, sorry. We can do that without ip_options_compile modification.
Simplified patch 2:
---
 net/ipv4/cipso_ipv4.c |   18 ++++++++++++++++--
 1 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c
index 777fa3b..a4ed0a4 100644
--- a/net/ipv4/cipso_ipv4.c
+++ b/net/ipv4/cipso_ipv4.c
@@ -1735,13 +1735,27 @@ int cipso_v4_validate(const struct sk_buff *skb, unsigned char **option)
  */
 void cipso_v4_error(struct sk_buff *skb, int error, u32 gateway)
 {
+       unsigned char optbuf[sizeof(struct ip_options) + 40];
+       struct ip_options *opt = (struct ip_options *)optbuf;
+
        if (ip_hdr(skb)->protocol == IPPROTO_ICMP || error != -EACCES)
                return;
 
+       /* 
+        * We might be called above the IP layer,
+        * so we can not use icmp_send and IPCB here.
+        */
+
+       memset(opt, 0, sizeof(struct ip_options));
+       opt->optlen = ip_hdr(skb)->ihl*4 - sizeof(struct iphdr);
+       memcpy(opt->__data, (unsigned char *)&(ip_hdr(skb)[1]), opt->optlen);
+       if (ip_options_compile(dev_net(skb->dev), opt, NULL))
+               return;
+
        if (gateway)
-               icmp_send(skb, ICMP_DEST_UNREACH, ICMP_NET_ANO, 0);
+               __icmp_send(skb, ICMP_DEST_UNREACH, ICMP_NET_ANO, 0, opt);
        else
-               icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_ANO, 0);
+               __icmp_send(skb, ICMP_DEST_UNREACH, ICMP_HOST_ANO, 0, opt);
 }
 
 /**


  reply	other threads:[~2019-01-24 14:46 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-15 17:06 Kernel memory corruption in CIPSO labeled TCP packets processing Nazarov Sergey
2019-01-15 17:55 ` Casey Schaufler
2019-01-15 19:52   ` Paul Moore
2019-01-18 14:53     ` Paul Moore
2019-01-18 16:34       ` Nazarov Sergey
2019-01-18 17:17         ` Paul Moore
2019-01-21 17:11           ` Nazarov Sergey
2019-01-22 16:49             ` Paul Moore
2019-01-22 17:35               ` Nazarov Sergey
2019-01-22 17:48                 ` Paul Moore
2019-01-24 14:46                   ` Nazarov Sergey [this message]
2019-01-25 16:45                     ` Paul Moore
2019-01-28 13:10                       ` Nazarov Sergey
2019-01-28 22:18                         ` Paul Moore
2019-01-29  7:23                           ` Nazarov Sergey
2019-01-29 22:42                             ` Paul Moore
2019-01-30 13:11                               ` Nazarov Sergey
2019-01-31  2:10                                 ` Paul Moore
2019-01-31 13:20                                   ` Nazarov Sergey
2019-02-11 20:37                                     ` Paul Moore
2019-02-11 21:21                                       ` Nazarov Sergey
2019-02-11 23:43                                         ` Paul Moore
2019-02-12 15:10                                           ` [PATCH] NETWORKING: avoid use IPCB in cipso_v4_error Nazarov Sergey
2019-02-13 21:41                                             ` Paul Moore
2019-02-14 18:00                                               ` Nazarov Sergey
2019-02-14 18:59                                                 ` Stephen Smalley
2019-02-14 16:43                                             ` David Miller
2019-02-14 18:14                                               ` Nazarov Sergey
2019-02-15 19:02                                               ` Paul Moore
2019-02-15 20:00                                                 ` David Miller
2019-02-15 20:04                                                   ` Paul Moore
2019-02-18 13:39                                                     ` Nazarov Sergey
2019-02-19  1:25                                                       ` David Miller
2019-02-22 16:35                                                         ` Nazarov Sergey
2019-02-22 17:39                                                           ` [PATCH v2 0/2] " Nazarov Sergey
2019-02-25  1:33                                                             ` David Miller
2019-02-25 16:24                                                               ` [PATCH v2 1/2] " Nazarov Sergey
2019-02-25 22:07                                                                 ` Paul Moore
2019-02-25 22:33                                                                 ` David Miller
2019-02-25 23:30                                                                   ` Paul Moore
2019-02-25 16:27                                                               ` [PATCH v2 2/2] " Nazarov Sergey
2019-02-25 22:06                                                                 ` Paul Moore
2019-02-25 22:34                                                                 ` David Miller
2019-02-22 17:43                                                           ` [PATCH v2 1/2] " Nazarov Sergey
2019-02-22 17:50                                                           ` [PATCH v2 2/2] " Nazarov Sergey
2019-02-25  1:33                                                           ` [PATCH] " David Miller

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