From 4f47e6df9d16e20800ca69824c68b3cab663e44f Mon Sep 17 00:00:00 2001
From: Haimin Zhang <tcs_kernel@tencent.com>
Date: Tue, 8 Mar 2022 11:20:28 +0800
Subject: [PATCH] af_key: add __GFP_ZERO flag for compose_sadb_supported in
 function pfkey_register
Git-commit: 9a564bccb78a76740ea9d75a259942df8143d02c
Patch-mainline: v5.17
References: CVE-2022-1353 bsc#1198516

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: Denis Kirjanov <denis.kirjanov@suse.com>
---
 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 72f8e44838d9..06376c06169d 100644
--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -1709,7 +1709,7 @@ 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);
-- 
2.16.4