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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: 王贇 <yun.wang@linux.alibaba.com>, Abaci <abaci@linux.alibaba.com>,
	"David S . Miller" <davem@davemloft.net>,
	"Sasha Levin" <sashal@kernel.org>,
	netdev@vger.kernel.org, linux-security-module@vger.kernel.org
Subject: [PATCH AUTOSEL 4.9 4/5] net: fix NULL pointer reference in cipso_v4_doi_free
Date: Mon, 30 Aug 2021 08:00:52 -0400	[thread overview]
Message-ID: <20210830120053.1018205-4-sashal@kernel.org> (raw)
In-Reply-To: <20210830120053.1018205-1-sashal@kernel.org>

From: 王贇 <yun.wang@linux.alibaba.com>

[ Upstream commit 733c99ee8be9a1410287cdbb943887365e83b2d6 ]

In netlbl_cipsov4_add_std() when 'doi_def->map.std' alloc
failed, we sometime observe panic:

  BUG: kernel NULL pointer dereference, address:
  ...
  RIP: 0010:cipso_v4_doi_free+0x3a/0x80
  ...
  Call Trace:
   netlbl_cipsov4_add_std+0xf4/0x8c0
   netlbl_cipsov4_add+0x13f/0x1b0
   genl_family_rcv_msg_doit.isra.15+0x132/0x170
   genl_rcv_msg+0x125/0x240

This is because in cipso_v4_doi_free() there is no check
on 'doi_def->map.std' when 'doi_def->type' equal 1, which
is possibe, since netlbl_cipsov4_add_std() haven't initialize
it before alloc 'doi_def->map.std'.

This patch just add the check to prevent panic happen for similar
cases.

Reported-by: Abaci <abaci@linux.alibaba.com>
Signed-off-by: Michael Wang <yun.wang@linux.alibaba.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/ipv4/cipso_ipv4.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c
index 553cda6f887a..160800d21f10 100644
--- a/net/ipv4/cipso_ipv4.c
+++ b/net/ipv4/cipso_ipv4.c
@@ -480,14 +480,16 @@ void cipso_v4_doi_free(struct cipso_v4_doi *doi_def)
 	if (!doi_def)
 		return;
 
-	switch (doi_def->type) {
-	case CIPSO_V4_MAP_TRANS:
-		kfree(doi_def->map.std->lvl.cipso);
-		kfree(doi_def->map.std->lvl.local);
-		kfree(doi_def->map.std->cat.cipso);
-		kfree(doi_def->map.std->cat.local);
-		kfree(doi_def->map.std);
-		break;
+	if (doi_def->map.std) {
+		switch (doi_def->type) {
+		case CIPSO_V4_MAP_TRANS:
+			kfree(doi_def->map.std->lvl.cipso);
+			kfree(doi_def->map.std->lvl.local);
+			kfree(doi_def->map.std->cat.cipso);
+			kfree(doi_def->map.std->cat.local);
+			kfree(doi_def->map.std);
+			break;
+		}
 	}
 	kfree(doi_def);
 }
-- 
2.30.2


  parent reply	other threads:[~2021-08-30 12:01 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-30 12:00 [PATCH AUTOSEL 4.9 1/5] qed: Fix the VF msix vectors flow Sasha Levin
2021-08-30 12:00 ` [PATCH AUTOSEL 4.9 2/5] qede: Fix memset corruption Sasha Levin
2021-08-30 12:00 ` [PATCH AUTOSEL 4.9 3/5] perf/x86/amd/ibs: Work around erratum #1197 Sasha Levin
2021-08-30 12:00 ` Sasha Levin [this message]
2021-08-30 12:00 ` [PATCH AUTOSEL 4.9 5/5] cryptoloop: add a deprecation warning Sasha Levin

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