[PATCH AUTOSEL 5.13 216/219] net: fix NULL pointer reference in cipso_v4_doi_free

Sasha Levin sashal at kernel.org
Thu Sep 9 11:46:32 UTC 2021

From: 王贇 <yun.wang at 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:

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

Reported-by: Abaci <abaci at linux.alibaba.com>
Signed-off-by: Michael Wang <yun.wang at linux.alibaba.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Sasha Levin <sashal at kernel.org>
 net/netlabel/netlabel_cipso_v4.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/netlabel/netlabel_cipso_v4.c b/net/netlabel/netlabel_cipso_v4.c
index 4f50a64315cf..e34ab5b227f3 100644
--- a/net/netlabel/netlabel_cipso_v4.c
+++ b/net/netlabel/netlabel_cipso_v4.c
@@ -144,8 +144,8 @@ static int netlbl_cipsov4_add_std(struct genl_info *info,
 		return -ENOMEM;
 	doi_def->map.std = kzalloc(sizeof(*doi_def->map.std), GFP_KERNEL);
 	if (doi_def->map.std == NULL) {
-		ret_val = -ENOMEM;
-		goto add_std_failure;
+		kfree(doi_def);
+		return -ENOMEM;
 	doi_def->type = CIPSO_V4_MAP_TRANS;

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