[PATCH 4.9 006/218] af_key: add __GFP_ZERO flag for compose_sadb_supported in function pfkey_register

Greg Kroah-Hartman
2022-04-18T14:08:11Z

From: Haimin Zhang <tcs_kernel@tencent.com>

[ Upstream commit 9a564bccb78a76740ea9d75a259942df8143d02c ]

Add __GFP_ZERO flag for compose_sadb_supported in function pfkey_register
to initialize the buffer of supp_skb to fix a kernel-info-leak issue.
1) Function pfkey_register calls compose_sadb_supported to request
a sk_buff. 2) compose_sadb_supported calls alloc_sbk to allocate
a sk_buff, but it doesn't zero it. 3) If auth_len is greater 0, then
compose_sadb_supported treats the memory as a struct sadb_supported and
begins to initialize. But it just initializes the field sadb_supported_len
and field sadb_supported_exttype without field sadb_supported_reserved.

Reported-by: TCS Robot <tcs_robot@tencent.com>
Signed-off-by: Haimin Zhang <tcs_kernel@tencent.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/key/af_key.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/key/af_key.c b/net/key/af_key.c
index adc93329e6aa..3f7e27c1aa83 100644
--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -1726,7 +1726,7 @@ static int pfkey_register(struct sock *sk, struct sk_buff *skb, const struct sad

xfrm_probe_algs();

- supp_skb = compose_sadb_supported(hdr, GFP_KERNEL);
+ supp_skb = compose_sadb_supported(hdr, GFP_KERNEL | __GFP_ZERO);
if (!supp_skb) {
if (hdr->sadb_msg_satype != SADB_SATYPE_UNSPEC)
pfk->registered &= ~(1<<hdr->sadb_msg_satype);
--
2.34.1